You are a senior clinical medicine educator. Your task is to produce dense, high-yield clinical notes covering FOUR systems: Respiratory, GI/Hepatobiliary, Endocrinology, and Neurology. For EACH system and its major topics, provide: 1. Most common etiology/cause (what appears most in exams) 2. Most common cause of MISDIAGNOSIS (what gets missed or confused) 3. Most common EXAM MISTAKES (what students write wrongly in MCQs/SAQs) 4. Most common WARD ERRORS (management mistakes made in clinical practice) 5. Most common EXAM EYE-CATCHERS (the classic "trap" presentations or buzzwords) 6. Clinical pearls for TREATMENT, DIFFERENTIAL DIAGNOSIS, and EXAM-RELATED traps Use knowledge from Harrison's Principles of Internal Medicine, Davidson's Principles and Practice, Kumar and Clark's Clinical Medicine, Oxford Handbook of Clinical Medicine, UpToDate, and Master the Wards by Conrad Fischer. Be EXTREMELY specific - give actual drug names, doses where critical, specific conditions, specific lab values, specific findings. Do NOT give generic advice. This is for a medical student/resident who needs to avoid classic mistakes. RESPIRATORY SYSTEM - cover these topics: - Asthma vs COPD (misdiagnosis traps) - Pneumonia (CAP, HAP, atypical) - common exam mistakes - Pulmonary embolism - ward errors and misdiagnosis - Pleural effusion - Light's criteria traps - Lung cancer - most missed presentations - Tuberculosis - treatment traps - Interstitial lung disease / pulmonary fibrosis - Pneumothorax - management errors - ARDS vs cardiogenic pulmonary edema - Obstructive sleep apnea - Sarcoidosis GI/HEPATOBILIARY SYSTEM - cover these topics: - Peptic ulcer disease - H. pylori traps, NSAID traps - GI bleeding (upper vs lower) - management errors - IBD (Crohn's vs UC) - classic exam distinctions, treatment traps - Cirrhosis complications (SBP, hepatic encephalopathy, hepatorenal syndrome, varices) - Acute liver failure vs chronic - Jaundice differential - pre-hepatic, hepatic, post-hepatic traps - Hepatitis B vs C - treatment and monitoring traps - Pancreatitis (acute vs chronic) - Ranson's criteria mistakes - Colorectal cancer screening exam traps - Celiac disease vs IBD vs IBS - misdiagnosis - Ascites management errors - Gallstone disease - cholecystitis vs cholangitis vs choledocholithiasis ENDOCRINOLOGY - cover these topics: - Diabetes mellitus (Type 1 vs 2) - DKA vs HHS management errors - Thyroid disorders (hypo vs hyper) - most missed presentations, treatment traps - Thyroid storm vs myxedema coma - Adrenal insufficiency (primary vs secondary) - Addison's crisis traps - Cushing's syndrome - diagnosis sequence errors - Conn's syndrome / primary hyperaldosteronism - misdiagnosis - Pheochromocytoma - dangerous treatment trap - Hypercalcemia - most common cause exam trap - Hypo/hypernatremia - SIADH vs DI management errors - Hypothyroidism causing hyperlipidemia/hyponatremia traps - MEN syndromes - exam associations - Hypoglycemia differential NEUROLOGY - cover these topics: - Stroke (ischemic vs hemorrhagic) - tPA contraindications, time window errors - TIA - most common misdiagnosis, ABCD2 score traps - Meningitis vs encephalitis - empiric treatment errors, LP timing - Epilepsy/seizures - first seizure management, status epilepticus errors - Multiple sclerosis - relapse treatment vs disease modification errors - Parkinson's disease - drug-induced Parkinsonism trap, treatment - Myasthenia gravis - cholinergic crisis vs myasthenic crisis - Guillain-Barré syndrome - spirometry trap, treatment errors (steroids CONTRAINDICATED) - Headache (migraine vs cluster vs tension vs SAH) - worst headache of life trap - Subdural vs epidural hematoma - classic presentation traps - Peripheral neuropathy - most common causes - Bell's palsy vs central facial palsy - exam distinction trap - Wernicke's encephalopathy - classic triad and treatment - Normal pressure hydrocephalus vs dementia - Horner's syndrome associations Format your response as structured notes with clear system headers, topic subheadings, and bullet points. Be dense and specific. Aim for maximum information density. Return the FULL notes for all four systems.

You are a senior clinical medicine educator compiling high-yield exam and ward notes. Produce dense, specific clinical notes for FOUR systems: Respiratory, GI/Hepatobiliary, Endocrinology, and Neurology. For EACH major topic within each system, structure your notes around these exact headings: - MOST COMMON CAUSE/ETIOLOGY (exam-relevant) - MOST COMMON MISDIAGNOSIS CAUSE - CLASSIC EXAM MISTAKES/TRAPS - WARD ERRORS (management mistakes in clinical practice) - EYE-CATCHERS (buzzword presentations, classic scenarios that appear in exams) - CLINICAL PEARLS (treatment, DDx, exam-specific) Use Harrison's Principles of Internal Medicine, Davidson's Principles and Practice, Kumar and Clark's Clinical Medicine, Oxford Handbook of Clinical Medicine, UpToDate, and Master the Wards by Conrad Fischer as reference frameworks. Be EXTREMELY specific: give drug names, doses where critical, lab values, criteria names, specific conditions. Maximum information density. This is for a medical student/resident. --- RESPIRATORY SYSTEM 1. ASTHMA vs COPD - MISDIAGNOSIS TRAP: COPD in a young non-smoker = think alpha-1 antitrypsin deficiency. Asthma in >40yo with smoking history often labeled COPD - check reversibility on spirometry (>12% AND >200mL = asthma). - EXAM MISTAKE: Students forget that in asthma FEV1/FVC <0.7 AND reversibility; in COPD FEV1/FVC <0.7 post-bronchodilator (fixed obstruction). - EXAM MISTAKE: Asthma severity - PEFR is used in acute attacks, NOT spirometry. - WARD ERROR: Giving beta-blockers (even topical eye drops - timolol) to asthmatics - can precipitate fatal bronchospasm. - WARD ERROR: Not checking inhaler technique before stepping up therapy. - EYE-CATCHER: Aspirin-exacerbated respiratory disease (Samter's triad) = asthma + nasal polyps + aspirin sensitivity. Classic exam scenario. - EYE-CATCHER: Vocal cord dysfunction mimics asthma - inspiratory stridor, normal PEFR, normal spirometry between attacks. - PEARL: LABA must NEVER be given as monotherapy in asthma (increases mortality) - always combine with ICS. - PEARL: Acute severe asthma - silent chest is WORSE than wheeze (no airflow = no sound = impending respiratory arrest). - PEARL: COPD exacerbation - target SpO2 88-92% (NOT 100%) - high flow O2 blunts hypoxic drive. 2. PNEUMONIA - MOST COMMON CAUSE CAP: Streptococcus pneumoniae (most common overall). Atypical = Mycoplasma (young adults, bilateral patchy), Legionella (AC systems, hyponatremia, diarrhea, relative bradycardia), Chlamydophila. - MISDIAGNOSIS: Legionella missed because it looks like typical pneumonia but has hyponatremia + diarrhea + liver function abnormalities + relative bradycardia. Urinary antigen is the KEY test. - EXAM MISTAKE: Legionella is NOT treated with beta-lactams - use fluoroquinolone or macrolide (intracellular organism). - EXAM MISTAKE: Aspiration pneumonia (right lower lobe most common upright, right upper lobe posterior segment if supine) vs aspiration pneumonitis (chemical, no antibiotics needed initially). - WARD ERROR: Not getting blood cultures BEFORE starting antibiotics in severe/hospitalized pneumonia. - WARD ERROR: Giving amoxicillin alone for atypical coverage - need macrolide or fluoroquinolone combination. - EYE-CATCHER: Pneumococcal pneumonia = rust-colored sputum, lobar consolidation, elderly/asplenic patients. - EYE-CATCHER: Klebsiella pneumonia = alcoholic or diabetic, upper lobe, "currant jelly" sputum, cavitation. - PEARL: CURB-65 score (Confusion, Urea >7, RR >30, BP <90/60, age >65) - score 0-1 outpatient, 2 hospital, 3+ ICU consideration. - PEARL: PCP (Pneumocystis jirovecii) in HIV - bilateral interstitial infiltrates, CD4 <200, raised LDH, treat with co-trimoxazole, add steroids if PaO2 <70mmHg. 3. PULMONARY EMBOLISM - MOST COMMON CAUSE: DVT (85-90%), deep vein thrombosis from lower limbs. - MISDIAGNOSIS: PE mimics many conditions - pleuritis, pneumonia, MI, panic attack, musculoskeletal pain. Most common misdiagnosis = pneumonia or anxiety/panic attack. - EXAM MISTAKE: "Classic triad" of PE (dyspnea + pleuritic pain + hemoptysis) occurs in only <20% - do NOT wait for it. - EXAM MISTAKE: ECG in PE - S1Q3T3 (deep S in I, Q wave and inverted T in III) and sinus tachycardia are common, but ECG is NONSPECIFIC. Most common ECG = sinus tachycardia alone. - EXAM MISTAKE: Normal D-dimer RULES OUT PE only in LOW pre-test probability (Wells score). High probability patient needs CT-PA regardless. - WARD ERROR: Giving heparin before CT-PA in hemodynamically STABLE patients (delay diagnosis). In UNSTABLE = thrombolyse empirically. - WARD ERROR: Not checking for contraindications to anticoagulation before starting treatment. - WARD ERROR: Stopping anticoagulation after 3 months in unprovoked PE - guidelines now suggest indefinite anticoagulation in unprovoked PE. - EYE-CATCHER: Saddle PE = hemodynamic instability, right heart strain on echo, thrombolysis indication. - EYE-CATCHER: Paradoxical embolism through PFO = stroke + DVT simultaneously. - PEARL: Massive PE = systolic BP <90mmHg = thrombolysis (tPA) unless absolute contraindication. Submassive = RV dysfunction, consider thrombolysis. - PEARL: Wells score: clinical signs DVT (+3), alternative diagnosis less likely (+3), HR >100 (+1.5), immobilization >3d (+1.5), prior DVT/PE (+1.5), hemoptysis (+1), malignancy (+1). 4. PLEURAL EFFUSION - EXAM MISTAKE: Light's criteria - exudate if ANY ONE of: pleural protein/serum protein >0.5, pleural LDH/serum LDH >0.6, pleural LDH > 2/3 upper limit normal serum LDH. Students often reverse the ratio. - EXAM MISTAKE: Transudates = heart failure (most common cause), cirrhosis, nephrotic syndrome, hypothyroidism, Meigs syndrome. Exudates = infection, malignancy, PE, TB, RA, SLE. - WARD ERROR: Performing thoracocentesis without checking coagulation/platelets. Contraindicated if INR >1.5 or platelets <50,000. - WARD ERROR: Removing >1.5L at once = risk of re-expansion pulmonary edema. - EYE-CATCHER: Meigs syndrome = ovarian fibroma + ascites + pleural effusion (transudate, right-sided more common) - removes with tumor excision. - EYE-CATCHER: Yellow nail syndrome = yellow nails + lymphedema + pleural effusion (exudate). - PEARL: Chylothorax (milky fluid, high triglycerides >110) = thoracic duct damage, most common cause = trauma or lymphoma. - PEARL: Empyema criteria (Frank's criteria) = pH <7.2, glucose <60, LDH >1000 = needs chest tube drainage. 5. LUNG CANCER - MOST COMMON: Adenocarcinoma (most common overall, peripheral, associated with non-smokers/women/East Asians, EGFR mutations). Small cell (central, paraneoplastic syndromes, "oat cells"). - MISDIAGNOSIS: Pancoast tumor missed - shoulder pain attributed to musculoskeletal, Horner's syndrome (ptosis, miosis, anhidrosis) at apex of lung. - EXAM MISTAKE: Squamous cell carcinoma = hypercalcemia via PTHrP (NOT PTH). Central location, cavitates. - EXAM MISTAKE: Small cell carcinoma = SIADH (hyponatremia), Cushing's (ACTH - ectopic), Lambert-Eaton syndrome (proximal weakness improves with repeated use - OPPOSITE of myasthenia gravis). - WARD ERROR: Ordering PET scan before tissue diagnosis - tissue biopsy first, staging after. - EYE-CATCHER: Superior vena cava syndrome = facial swelling, arm swelling, dilated neck veins, headache worse on bending forward = often small cell or lymphoma. - EYE-CATCHER: Hypertrophic osteoarthropathy = periosteal new bone formation, clubbing, arthropathy = adenocarcinoma most common. - PEARL: EGFR mutation = gefitinib/erlotinib (first line). ALK rearrangement = crizotinib. PD-L1 >50% = pembrolizumab. 6. TUBERCULOSIS - MOST COMMON CAUSE OF DEATH IN TB: Respiratory failure from extensive cavitary disease. - MISDIAGNOSIS: Primary TB in children = fever, hilar lymphadenopathy on CXR; often called "pneumonia." - EXAM MISTAKE: RIPE therapy = Rifampicin, Isoniazid, Pyrazinamide, Ethambutol for 2 months, then RI for 4 months (total 6 months). Meningeal/bone TB = 9-12 months. - EXAM MISTAKE: Rifampicin = orange urine/tears/secretions, liver enzyme inducer (reduces OCP efficacy, warfarin, etc.), causes red-orange discoloration. - WARD ERROR: Not giving pyridoxine (vitamin B6) with Isoniazid = peripheral neuropathy risk. - WARD ERROR: Not checking LFTs before starting TB therapy - isoniazid hepatitis risk. - WARD ERROR: Treating latent TB with INH monotherapy for 6-9 months (not full RIPE). - EYE-CATCHER: Miliary TB = hematogenous spread, "millet seeds" on CXR, can present with hepatosplenomegaly, pancytopenia, choroidal tubercles on fundoscopy. - EYE-CATCHER: Pott's disease = TB spine, cold abscess, kyphosis ("gibbus deformity"). - PEARL: Steroid adjuvant indicated in TB meningitis and pericarditis (reduces mortality). NOT routinely in pulmonary TB. 7. INTERSTITIAL LUNG DISEASE / IPF - MOST COMMON: IPF (Idiopathic Pulmonary Fibrosis) = most common ILD in elderly males, smoking history, bilateral basal crackles ("Velcro crackles"), clubbing. - MISDIAGNOSIS: IPF vs NSIP (non-specific interstitial pneumonia) - NSIP more common in connective tissue disease (RA, SLE, scleroderma), better prognosis. - EXAM MISTAKE: IPF on HRCT = UIP pattern (honeycombing + traction bronchiectasis + bilateral basal subpleural distribution). NOT ground glass (that's NSIP/organizing pneumonia). - EXAM MISTAKE: IPF treatment = pirfenidone or nintedanib (antifibrotic) - NOT steroids. Steroids worsen IPF but help hypersensitivity pneumonitis and sarcoidosis. - WARD ERROR: Giving steroids for IPF = accelerates fibrosis. - EYE-CATCHER: Bird fancier's lung (pigeon proteins) = hypersensitivity pneumonitis; farmer's lung (moldy hay, Thermophilic actinomyces). Remove from exposure = treatment. - EYE-CATCHER: Sarcoidosis = bilateral hilar lymphadenopathy + erythema nodosum + uveitis + hypercalcemia (due to 1-alpha hydroxylase in macrophages). Non-caseating granulomas. ACE level raised. - PEARL: Sarcoidosis Stage I = bilateral hilar LN only (no treatment needed). Stage II = parenchymal + hilar. Stage III = parenchymal only. Stage IV = fibrosis. 8. PNEUMOTHORAX - MOST COMMON CAUSE SPONTANEOUS: Tall thin young male, subpleural blebs rupture. - EXAM MISTAKE: Tension pneumothorax = tracheal deviation AWAY from the affected side, hypotension, absent breath sounds, distended neck veins = CLINICAL DIAGNOSIS - do NOT wait for CXR - immediate needle decompression at 2nd intercostal space, midclavicular line. - WARD ERROR: Chest X-ray before needle decompression in suspected tension pneumothorax = fatal delay. - WARD ERROR: Inserting chest drain in wrong space - 5th intercostal space, midaxillary line (safe triangle). - EYE-CATCHER: Iatrogenic pneumothorax post-subclavian line insertion or post-lung biopsy. - PEARL: Small (<2cm rim) primary spontaneous pneumothorax = high-flow O2 + observation. Large = aspiration or chest drain. 9. ARDS vs CARDIOGENIC PULMONARY EDEMA - EXAM MISTAKE: ARDS = non-cardiogenic, bilateral infiltrates, PaO2/FiO2 <300, PCWP <18 (normal). Cardiogenic = PCWP >18, responds to diuretics. - EXAM MISTAKE: Berlin criteria for ARDS severity: mild PaO2/FiO2 201-300, moderate 101-200, severe <100. - WARD ERROR: Using high tidal volumes in ARDS = volutrauma/barotrauma. Use 6mL/kg predicted body weight (ARDSNet protocol), plateau pressure <30 cmH2O. - WARD ERROR: Aggressive fluid resuscitation in ARDS = worsens oxygenation. - PEARL: Prone positioning for 16 hours/day in severe ARDS (PaO2/FiO2 <150) reduces mortality (PROSEVA trial). --- GI/HEPATOBILIARY SYSTEM 1. PEPTIC ULCER DISEASE - MOST COMMON CAUSE: H. pylori (80% of duodenal ulcers, 60-70% gastric ulcers). Second = NSAIDs. - MISDIAGNOSIS: Gastric ulcer vs gastric cancer - ALWAYS biopsy gastric ulcers (duodenal ulcers less likely malignant). Repeat endoscopy 6-8 weeks after treatment to confirm healing. - EXAM MISTAKE: Duodenal ulcers = pain relieved by eating (food buffers acid). Gastric ulcers = pain worse with eating. But this is NOT reliable in practice. - EXAM MISTAKE: H. pylori testing after antibiotics - urea breath test or stool antigen unreliable within 4 weeks of antibiotics or PPIs. Wait at least 4 weeks off antibiotics, 2 weeks off PPI. - WARD ERROR: Not using combination therapy for H. pylori - triple therapy = PPI + clarithromycin + amoxicillin (or metronidazole) x 7-14 days. Check local clarithromycin resistance. - WARD ERROR: Using NSAIDs + aspirin WITHOUT PPI gastroprotection in high-risk patients (elderly, history of peptic ulcer). - EYE-CATCHER: Zollinger-Ellison syndrome = gastrinoma (usually in pancreas/duodenum), multiple ulcers, refractory to PPI, diarrhea, elevated fasting serum gastrin >1000 pg/mL. Part of MEN-1. - PEARL: Perforation = surgical emergency. Anterior ulcers perforate; posterior ulcers bleed into pancreas (cause acute pancreatitis or pain radiating to back). 2. GI BLEEDING - UPPER GI BLEED: Coffee-ground vomiting, hematemesis, melena (digested blood = dark, tarry stool). BUN:Cr ratio >20 suggests upper GI source (digested blood absorbed). - MOST COMMON CAUSE UPPER GI: Peptic ulcer disease (most common), then esophageal varices, Mallory-Weiss tear. - MOST COMMON CAUSE LOWER GI: Diverticulosis (painless, massive, elderly), angiodysplasia, colorectal cancer. - MISDIAGNOSIS: Mesenteric ischemia missed in AF patient with post-prandial pain and weight loss - "fear to eat." Elevated lactate, out-of-proportion pain to exam findings. - EXAM MISTAKE: Rockford/Rockall score risk stratification in upper GI bleeding. Glasgow-Blatchford score for pre-endoscopy risk. - EXAM MISTAKE: Fresh blood per rectum (hematochezia) is USUALLY lower GI, but massive upper GI bleed can cause hematochezia too (rapid transit). - WARD ERROR: Not correcting coagulopathy (INR, platelets) before emergency endoscopy. - WARD ERROR: Not giving IV PPI (omeprazole 80mg bolus then infusion) before endoscopy in suspected peptic ulcer bleed. - WARD ERROR: Not giving octreotide/terlipressin empirically if variceal bleed suspected (lowers portal pressure). - EYE-CATCHER: Dieulafoy lesion = large tortuous artery in gastric submucosa, can cause massive bleed without ulcer, difficult to identify. - PEARL: Variceal bleed management: resuscitate, IV terlipressin/octreotide, IV ceftriaxone (prevents SBP), urgent endoscopy + banding. TIPS if refractory. 3. IBD (CROHN'S vs ULCERATIVE COLITIS) - EXAM DISTINCTION: - UC: Rectal bleeding, urgency, continuous from rectum upward, mucosal only, NEVER skip lesions, crypt abscesses, lead pipe colon. - Crohn's: Any part mouth to anus, skip lesions, transmural (cobblestone mucosa, fistulas, abscesses, strictures), non-caseating granulomas, NO rectal bleeding always. - MISDIAGNOSIS: Crohn's ileitis mistaken for appendicitis (terminal ileum involvement, RLQ pain). Infectious colitis (Campylobacter, C. diff) mistaken for IBD flare. - EXAM MISTAKE: UC has higher risk of colorectal cancer than Crohn's (colitis extent and duration). Surveillance colonoscopy after 8-10 years of disease. - EXAM MISTAKE: Toxic megacolon = colonic diameter >6cm, systemic toxicity = STOP laxatives/antidiarrheals, NG suction, IV steroids, surgical consult. If no improvement in 72h = colectomy. - WARD ERROR: Giving antidiarrheals in severe IBD flare = risk of toxic megacolon. - WARD ERROR: Not checking C. difficile before treating presumed IBD flare (can both occur together, but C. diff needs targeted treatment). - EYE-CATCHER: Extraintestinal manifestations: peripheral arthritis, ankylosing spondylitis (Crohn's more), primary sclerosing cholangitis (UC strongly associated - 70% of PSC patients have UC), erythema nodosum, pyoderma gangrenosum, uveitis/iritis, episcleritis. - PEARL: PSC = ulcerocolitis + cholestatic LFTs + "beaded" appearance on MRCP. High cancer risk (cholangiocarcinoma). Ursodeoxycholic acid does NOT prevent cancer in PSC. - PEARL: Crohn's treatment: 5-ASA (mild), steroids (moderate flare), azathioprine/6-MP (maintenance), biologics (anti-TNF: infliximab, adalimumab) for severe/fistulizing. 4. CIRRHOSIS AND COMPLICATIONS - MOST COMMON CAUSES: Alcohol (most common in Western countries), NAFLD/NASH (rising), Hepatitis C. - SBP (SPONTANEOUS BACTERIAL PERITONITIS): - DIAGNOSIS: Ascitic PMN >250 cells/mm3 (NOT >500). Treat empirically with ceftriaxone 2g IV daily. Do NOT wait for culture. - MISDIAGNOSIS: SBP symptoms can be minimal - ANY deterioration in cirrhotic patient with ascites = do diagnostic paracentesis. - WARD ERROR: Not giving IV albumin 1.5g/kg on Day 1 and 1g/kg on Day 3 = reduces hepatorenal syndrome risk. - PREVENTION: Norfloxacin 400mg BD or ciprofloxacin prophylaxis in high-risk patients (ascitic protein <10g/L or prior SBP). - HEPATIC ENCEPHALOPATHY: - PRECIPITANTS: GI bleed, infection, constipation, electrolyte disturbance, dehydration, medications (sedatives/opioids), excess dietary protein. - WARD ERROR: Using morphine/benzodiazepines in encephalopathic patient = worsens encephalopathy. - TREATMENT: Lactulose (reduces ammonia absorption), rifaximin (add-on for prevention of recurrence), treat precipitant. - EXAM MISTAKE: Not identifying and treating underlying precipitant. - HEPATORENAL SYNDROME (HRS): - DIAGNOSIS: Rising creatinine in cirrhotic without other cause, not responding to albumin challenge (1.5g/kg IV over 2 days while stopping diuretics). - WARD ERROR: Giving NSAIDs or nephrotoxic contrast in cirrhotic = precipitates HRS. - TREATMENT: Terlipressin + albumin (Type 1 HRS). TIPS or liver transplant definitive. - VARICES: - PRIMARY PREVENTION: Non-selective beta-blocker (propranolol or carvedilol) if medium/large varices. - WARD ERROR: Using selective beta-blockers (atenolol) instead of non-selective = does NOT reduce portal pressure adequately. - SECONDARY PREVENTION: Band ligation + NSBB. 5. JAUNDICE DIFFERENTIAL - PRE-HEPATIC (hemolysis): Unconjugated hyperbilirubinemia, raised LDH, reduced haptoglobin, normal LFTs, dark urine (urobilinogen) but NOT bilirubin in urine. - HEPATIC: Both conjugated + unconjugated raised, raised AST/ALT predominant (hepatocellular). - POST-HEPATIC (obstructive): Conjugated bilirubin raised, pale stools, dark urine (bilirubin in urine), raised ALP/GGT predominant, pruritus. - EXAM MISTAKE: In obstructive jaundice, ALP rises MORE than AST/ALT. In hepatitis, AST/ALT rise MORE than ALP. - EXAM MISTAKE: Courvoisier's law = palpable gallbladder in jaundiced patient = NOT gallstones (gallstone disease causes fibrosed, non-distensible GB) = think pancreatic/cholangiocarcinoma. - MISDIAGNOSIS: Hepatitis A (self-limiting, young person, travel history, fecal-oral) vs hepatitis E (pregnant women, developing countries, HIGH mortality in pregnancy). - PEARL: Gilbert's syndrome = benign unconjugated hyperbilirubinemia, fasting or illness precipitates. Normal LFTs, normal blood film. No treatment needed. 6. HEPATITIS B vs C - HEPATITIS B: - EXAM MISTAKE: HBsAg = active infection (acute or chronic). Anti-HBs = immunity (vaccination or resolved). Anti-HBc IgM = acute infection. Anti-HBc IgG = past infection or chronic. - WINDOW PERIOD: HBsAg cleared but Anti-HBs not yet appeared = only anti-HBc IgM positive. - TREATMENT: Tenofovir or entecavir (preferred). Do NOT use lamivudine alone (high resistance). - WARD ERROR: Not checking HBsAg before starting immunosuppression/chemotherapy = HBV reactivation risk = give prophylactic antiviral. - HEPATITIS C: - MISDIAGNOSIS: Many patients asymptomatic for decades. Anti-HCV positive = exposure, NOT active infection. Confirm with HCV RNA. - TREATMENT: Direct-acting antivirals (DAAs) - sofosbuvir-based regimens, >95% cure rate. Treatment now genotype-independent for most regimens. - WARD ERROR: Using pegylated interferon + ribavirin (old regimen) when DAAs available = inferior, more side effects. 7. PANCREATITIS - MOST COMMON CAUSES: Gallstones (most common, 40%) and alcohol (35%). "GET SMASHED" mnemonic (Gallstones, Ethanol, Trauma, Steroids, Mumps, Autoimmune, Scorpion sting, Hypercalcemia/Hypertriglycerides, ERCP/Emboli, Drugs). - EXAM MISTAKE: Ranson's criteria at admission vs 48h. AT ADMISSION: age >55, WBC >16,000, glucose >200, LDH >350, AST >250. AT 48H: Ca <8, PaO2 <60, base deficit >4, BUN rise >5, fluid sequestration >6L, Hct fall >10%. Score ≥3 = severe. - EXAM MISTAKE: Amylase/lipase - LIPASE is more specific and stays elevated longer than amylase. Amylase can be normal in chronic pancreatitis (burned-out gland). - WARD ERROR: Feeding restriction unnecessarily prolonged - early enteral feeding (NG tube) preferred in severe pancreatitis (maintains gut barrier, reduces infection). - WARD ERROR: Routine antibiotics in acute pancreatitis without evidence of infection = NOT indicated (despite necrosis). - EYE-CATCHER: Cullen's sign (periumbilical bruising) and Grey Turner's sign (flank bruising) = hemorrhagic pancreatitis = severe disease. - PEARL: Chronic pancreatitis = malabsorption + steatorrhea + diabetes + calcifications on AXR/CT. Treat with pancreatic enzyme replacement. 8. CELIAC vs IBD vs IBS - CELIAC: Anti-tTG IgA antibodies (most sensitive/specific), anti-endomysial antibodies. Confirm with duodenal biopsy (villous atrophy + crypt hyperplasia + increased intraepithelial lymphocytes). MUST be eating gluten at time of test. - MISDIAGNOSIS: IBS is a DIAGNOSIS OF EXCLUSION - must rule out celiac (bloating, diarrhea), IBD, thyroid disease, colorectal cancer. - EXAM MISTAKE: IgA deficiency = false-negative anti-tTG IgA in celiac = check total IgA first. If deficient, use anti-tTG IgG or anti-DGP antibodies. - EYE-CATCHER: Dermatitis herpetiformis = IgA deposits at dermal-epidermal junction, extremely itchy vesicular rash on extensor surfaces = celiac skin manifestation. - PEARL: IBS = Rome IV criteria: abdominal pain ≥1 day/week for 3 months, associated with defecation or change in stool frequency/form. 9. ASCITES MANAGEMENT - WARD ERROR: Large volume paracentesis (>5L) WITHOUT albumin replacement = circulatory dysfunction. Give albumin 8g/L of ascites removed. - WARD ERROR: Using spironolactone + furosemide in wrong ratio - START with spironolactone 100mg: furosemide 40mg (5:2 ratio) to maintain normokalemia. - EXAM MISTAKE: SAAG (Serum-Ascites Albumin Gradient) ≥1.1 = portal hypertension (transudate-like). <1.1 = non-portal (malignancy, peritoneal TB, pancreatitis). - PEARL: Refractory ascites = TIPS procedure or liver transplant. 10. GALLSTONE DISEASE - EXAM DISTINCTION: - Biliary colic: RUQ pain, no fever, no jaundice, triggered by fatty food. - Cholecystitis: RUQ pain + fever + Murphy's sign, no jaundice. US = thickened GB wall, pericholecystic fluid. - Cholangitis (Charcot's triad): RUQ pain + fever + JAUNDICE. Reynold's pentad adds confusion + shock. Medical emergency = IV antibiotics + ERCP. - Choledocholithiasis: Jaundice + raised ALP/GGT, bile duct stone on MRCP/EUS. - EXAM MISTAKE: Choledocholithiasis is treated with ERCP (stone extraction), NOT cholecystectomy alone. - WARD ERROR: Not covering with antibiotics before ERCP in cholangitis. - PEARL: Acalculous cholecystitis = in critically ill, ICU, septic patients. No stones. High mortality. --- ENDOCRINOLOGY 1. DIABETES MELLITUS - DKA vs HHS - DKA: - MOST COMMON PRECIPITANT: Infection (most common), then missed insulin, new diagnosis T1DM. - DIAGNOSIS: Glucose >200, pH <7.3, HCO3 <15, raised ketones. Anion gap metabolic acidosis. - WARD ERROR: Stopping insulin infusion when glucose reaches normal = DKA NOT resolved until anion gap closes and HCO3 normalizes. Continue insulin, start dextrose. - WARD ERROR: Not monitoring potassium - insulin drives K+ into cells = hypokalemia. Do NOT give insulin if K+ <3.5 - replace K+ first. - WARD ERROR: Giving sodium bicarbonate routinely in DKA = not indicated unless pH <6.9. - EXAM MISTAKE: Pseudohyponatremia in DKA - high glucose dilutes Na+. Correct: add 2.4 mmol/L Na+ for every 10 mmol/L glucose above 5. - HHS (Hyperosmolar Hyperglycemic State): - GLUCOSE usually >33 mmol/L, osmolality >320 mOsm/kg, NO significant ketoacidosis. - Typically elderly T2DM. High DVT risk = low molecular weight heparin prophylaxis. - WARD ERROR: Rehydrating too rapidly = cerebral edema (especially in HHS). - WARD ERROR: Insulin not needed initially in HHS - fluids alone often reduce glucose. Introduce insulin carefully. 2. THYROID DISORDERS - HYPOTHYROIDISM: - MOST COMMON CAUSE: Hashimoto's thyroiditis (autoimmune, anti-TPO antibodies, goiter). - MISDIAGNOSIS: Hypothyroidism presents as depression, weight gain, fatigue, constipation, cold intolerance, bradycardia, myxedema. Often misdiagnosed as depression alone. - EXAM MISTAKE: TSH raised, free T4 low = primary hypothyroidism. TSH low, free T4 low = secondary (pituitary) hypothyroidism. - WARD ERROR: Starting levothyroxine at full dose in elderly or cardiac patients = precipitates angina or AF. Start LOW, titrate slowly. - EYE-CATCHER: Subclinical hypothyroidism = raised TSH, normal T4. Treat if TSH >10 or symptomatic. - HYPERTHYROIDISM: - MOST COMMON CAUSE: Graves' disease (diffuse goiter, exophthalmos, pretibial myxedema = classic triad). Anti-TSH receptor antibodies. - EXAM MISTAKE: Toxic multinodular goiter (Plummer's disease) in elderly = AF, weight loss, no exophthalmos. - WARD ERROR: Not giving beta-blocker (propranolol) FIRST in hyperthyroidism to control symptoms while antithyroid drugs take effect. - WARD ERROR: Giving radioiodine in pregnancy = absolute contraindication. - PEARL: Antithyroid drugs = carbimazole (UK) or propylthiouracil (PTU, preferred in pregnancy 1st trimester - carbimazole teratogenic). PTU also blocks peripheral T4→T3 conversion. 3. THYROID STORM vs MYXEDEMA COMA - THYROID STORM: Precipitated by surgery, infection, trauma, radioiodine. Features: hyperpyrexia, tachycardia, AF, confusion, heart failure. Burch-Wartofsky score. - TREATMENT order: (1) PTU (blocks synthesis AND conversion), (2) Lugol's iodine 1 hour AFTER PTU (blocks release), (3) propranolol (controls HR), (4) hydrocortisone (blocks conversion, treats relative adrenal insufficiency), (5) treat precipitant. - EXAM MISTAKE: Giving iodine BEFORE PTU = iodine used as substrate to make more thyroid hormone (Jod-Basedow effect). - MYXEDEMA COMA: Hypothermia, bradycardia, hypotension, hypoventilation, decreased consciousness. Precipitated by cold, infection, drugs. - TREATMENT: IV levothyroxine + IV hydrocortisone (cortisol deficiency may coexist). Passive rewarming. - WARD ERROR: Active rewarming in myxedema coma = causes vasodilation and cardiovascular collapse. 4. ADRENAL INSUFFICIENCY - PRIMARY (ADDISON'S): Autoimmune (most common in developed world), TB (most common worldwide). - Features: HYPERPIGMENTATION (ACTH drives MSH receptor), hyponatremia, hyperkalemia, hypotension, hypoglycemia, eosinophilia. - MISDIAGNOSIS: Addison's presents gradually - fatigue, weight loss, anorexia, diarrhea, skin pigmentation. Often misdiagnosed as depression, IBD, or anorexia. - EXAM MISTAKE: Primary = low cortisol + HIGH ACTH. Secondary (pituitary) = low cortisol + LOW ACTH, NO hyperpigmentation, NO hyperkalemia. - ADDISONIAN CRISIS (ACUTE): - WARD ERROR: Giving IV saline ALONE without hydrocortisone = ineffective and dangerous. - TREATMENT: IV hydrocortisone 100mg stat, then 50mg every 6-8h, IV saline, glucose. - EXAM MISTAKE: Synacthen test diagnoses Addison's - primary = no rise in cortisol after ACTH. Secondary = delayed but eventual rise. 5. CUSHING'S SYNDROME - MOST COMMON CAUSE OVERALL: Exogenous corticosteroids (iatrogenic). - MOST COMMON ENDOGENOUS CAUSE: Pituitary adenoma (Cushing's DISEASE, 70%) secreting ACTH. - DIAGNOSIS SEQUENCE: 1. Confirm hypercortisolism (24h urinary free cortisol OR low-dose dexamethasone suppression test - 1mg overnight). 2. Determine if ACTH-dependent (raised ACTH) or independent (suppressed ACTH = adrenal cause). 3. If ACTH-dependent: High-dose dexamethasone suppression test - Cushing's DISEASE (pituitary) = cortisol suppresses >50%. Ectopic ACTH (SCLC) = does NOT suppress. - EXAM MISTAKE: Students start with imaging (MRI pituitary) before biochemical confirmation = wrong sequence. - WARD ERROR: Stopping corticosteroids abruptly in patient on long-term steroids = adrenal crisis. 6. CONN'S SYNDROME (PRIMARY HYPERALDOSTERONISM) - MISDIAGNOSIS: Most common curable cause of hypertension missed - should be screened in any hypertensive patient with hypokalemia (even without medication), refractory hypertension (≥3 drugs), adrenal incidentaloma + hypertension. - DIAGNOSIS: Aldosterone:renin ratio (ARR) >30-50 (with aldosterone >15 ng/dL) = screen positive. Confirm with salt loading or fludrocortisone suppression test. - EXAM MISTAKE: Renin is LOW in primary hyperaldosteronism (autonomous aldosterone = suppresses renin). Opposite of renovascular hypertension (raised renin). - TREATMENT: Adrenal adenoma = laparoscopic adrenalectomy. Bilateral hyperplasia = spironolactone/eplerenone. 7. PHEOCHROMOCYTOMA - DANGEROUS EXAM TRAP: NEVER biopsy or manipulate before alpha-blockade = hypertensive crisis. - TREATMENT SEQUENCE: (1) Alpha-blocker FIRST (phenoxybenzamine or doxazosin) x 10-14 days minimum, (2) THEN beta-blocker (to control reflex tachycardia from alpha-blockade), (3) THEN surgical resection. - WARD ERROR: Giving beta-blocker FIRST without alpha-blockade = unopposed alpha stimulation = severe hypertensive crisis. - DIAGNOSIS: 24h urinary catecholamines/metanephrines OR plasma free metanephrines (most sensitive). - EYE-CATCHER: Rule of 10s - 10% malignant, 10% bilateral, 10% extraadrenal (paraganglioma), 10% in children, 10% familial (VHL, NF1, MEN2, SDH mutations). 8. HYPERCALCEMIA - MOST COMMON CAUSE OVERALL: Primary hyperparathyroidism (outpatient/asymptomatic). Malignancy = most common cause in HOSPITALIZED patients. - EXAM DISTINCTION: PTH raised = primary hyperparathyroidism (adenoma 80%). PTH low = malignancy (PTHrP from squamous cell carcinoma lung, renal cell, breast). - SYMPTOMS: Bones, Stones, Groans, Psychic Moans (osteitis fibrosa cystica, nephrolithiasis, constipation/nausea, depression/confusion). - WARD ERROR: Not hydrating first in hypercalcemia before giving bisphosphonate. IV saline hydration is STEP 1. - TREATMENT: IV fluids → loop diuretics (if fluid overloaded) → bisphosphonates (zoledronic acid, takes 2-4 days to work) → calcitonin (fastest acting, tachyphylaxis develops). - EXAM MISTAKE: Thiazide diuretics RAISE calcium (reduce renal excretion). Loop diuretics LOWER calcium. 9. HYPO/HYPERNATREMIA - SIADH vs DI - SIADH: - CAUSES: CNS disease (meningitis, SAH), malignancy (SCLC most common), drugs (carbamazepine, SSRIs, thiazides, cyclophosphamide), pulmonary disease. - DIAGNOSIS: Hyponatremia + low plasma osmolality + high urine osmolality (>100) + high urine sodium (>40) + euvolemic. - WARD ERROR: Correcting hyponatremia too rapidly = CENTRAL PONTINE MYELINOLYSIS (osmotic demyelination). Correct no faster than 8-10 mmol/L per 24h. - TREATMENT: Fluid restriction (first line). Demeclocycline or vaptan (tolvaptan) if refractory. - DIABETES INSIPIDUS: - CENTRAL: Polyuria (dilute), hypernatremia, low urine osmolality. Responds to DDAVP. - NEPHROGENIC: Does NOT respond to DDAVP. Causes = lithium toxicity, hypercalcemia, hypokalemia. Treat with thiazide + low-salt diet + amiloride (for lithium-induced). - EXAM MISTAKE: Water deprivation test differentiates DI from primary polydipsia. 10. MEN SYNDROMES - MEN 1 (Wermer): 3 P's = Pituitary (prolactinoma most common) + Parathyroid (hyperparathyroidism most common endocrinopathy in MEN1) + Pancreas (gastrinoma most common = ZES, insulinoma). - MEN 2A (Sipple): Medullary thyroid carcinoma + Pheochromocytoma + Parathyroid hyperplasia. - MEN 2B: MTC + Pheo + Marfanoid habitus + Mucosal neuromas (no parathyroid). - EXAM MISTAKE: In MEN 2A/2B with pheochromocytoma - treat pheo FIRST before thyroidectomy (alpha-blockade, then surgery). - PEARL: RET proto-oncogene = MEN 2 and MTC. Prophylactic thyroidectomy based on RET mutation type. --- NEUROLOGY 1. STROKE - ISCHEMIC STROKE: - tPA CONTRAINDICATIONS (absolute): Active bleeding, recent surgery (<14d), prior intracranial hemorrhage, stroke or head trauma within 3 months, BP >185/110 (untreated), glucose <2.7 or >22.2, platelet <100,000. - TIME WINDOW: tPA up to 4.5 hours from symptom onset. Thrombectomy up to 24 hours (DAWN/DEFUSE trial) in selected patients with salvageable penumbra. - WARD ERROR: Giving aspirin within 24h of tPA = increases bleeding risk. - WARD ERROR: Lowering BP aggressively in acute ischemic stroke (unless >220/120 or tPA planned) = reduces perfusion to ischemic penumbra. - EXAM MISTAKE: "Wake-up stroke" or unknown onset = use DWI-FLAIR mismatch on MRI to determine eligibility for thrombolysis. - EXAM MISTAKE: NIHSS score for severity. Vertebrobasilar stroke = diplopia, vertigo, dysphagia, ataxia, locked-in syndrome. - HEMORRHAGIC STROKE: - tPA is ABSOLUTELY CONTRAINDICATED. - Most common cause = hypertension (putamen most common location, then thalamus, cerebellum, pons). - WARD ERROR: Allowing BP to fall too low in hemorrhagic stroke - maintain MAP <130 initially. - EYE-CATCHER: Cerebellar hematoma = surgical emergency if >3cm (hydrocephalus risk, herniation). Evacuate immediately. 2. TIA - MISDIAGNOSIS: TIA mimics - migraine aura, hypoglycemia, focal seizure (Todd's paralysis), complex migraine. Most common misdiagnosis = migraine with aura. - EXAM MISTAKE: TIA = transient neurological deficit resolving COMPLETELY within 24 hours (by old definition). New definition = no infarct on DWI. - EXAM MISTAKE: ABCD2 score (Age ≥60 = 1, BP ≥140/90 = 1, Clinical features: unilateral weakness = 2 or speech only = 1, Duration: ≥60min = 2, 10-59min = 1, Diabetes = 1). Score ≥4 = high risk of stroke within 48h. - WARD ERROR: Discharging high-risk TIA without urgent investigation (MRI, echocardiography, carotid Doppler within 24h). - PEARL: Carotid stenosis >70% = carotid endarterectomy reduces ipsilateral stroke risk by 65%. 3. MENINGITIS vs ENCEPHALITIS - BACTERIAL MENINGITIS: - MOST COMMON CAUSE: Adults = Neisseria meningitidis (young), Streptococcus pneumoniae (all ages). Elderly/immunocompromised = Listeria monocytogenes. - EMPIRIC TREATMENT: Ceftriaxone + ampicillin (for Listeria) + dexamethasone (reduces hearing loss and mortality in pneumococcal meningitis - give BEFORE or WITH first antibiotics dose). - WARD ERROR: Delaying antibiotics for LP = FATAL. If LP will be delayed >30min (CT needed first), give antibiotics IMMEDIATELY, then LP. - WARD ERROR: Not giving dexamethasone - must be given before or with first antibiotic dose, NOT after. - EXAM MISTAKE: LP in meningitis - raised WBC (neutrophils in bacterial, lymphocytes in viral/TB), raised protein, low glucose (<2/3 of blood glucose). - ENCEPHALITIS: - MOST COMMON CAUSE: Herpes simplex virus (HSV-1) - temporal lobe involvement, bizarre behavior, seizures. - TREATMENT: IV acyclovir 10mg/kg TDS empirically. Do NOT wait for CSF PCR results. - EYE-CATCHER: Anti-NMDA receptor encephalitis = young woman, psychiatric symptoms, seizures, autonomic instability, decreased consciousness. Associated with ovarian teratoma. Check anti-NMDAR antibodies. 4. EPILEPSY/SEIZURES - FIRST SEIZURE: Investigation needed. If cause found and treated, antiepileptics may not be needed. Start AEDs if: structural cause on MRI, epileptiform EEG, >2 seizures, nocturnal seizure. - STATUS EPILEPTICUS: Seizure >5 minutes or 2+ seizures without recovery. - Step 1: Lorazepam IV 0.1mg/kg (or diazepam rectal if no IV access). - Step 2 (if not broken after 10min): Levetiracetam IV, or sodium valproate IV, or phenytoin IV. - Step 3 (refractory): Phenobarbital, then general anesthesia (propofol, thiopental). - WARD ERROR: Not protecting airway in status epilepticus. - WARD ERROR: Giving phenytoin in eclampsia - use magnesium sulfate instead. - EXAM MISTAKES: - Carbamazepine = enzyme INDUCER (reduces OCP, warfarin). Also causes SIADH (hyponatremia). - Valproate = enzyme INHIBITOR, teratogenic (neural tube defects - avoid in women of childbearing age, give folic acid if used). - Lamotrigine dose must be reduced if adding valproate (doubles lamotrigine levels). - Phenytoin = zero-order kinetics (small dose increase = big rise in levels), gingival hyperplasia, teratogenic. 5. MULTIPLE SCLEROSIS - DIAGNOSIS: McDonald criteria (2017) - dissemination in space AND time. MRI = periventricular white matter lesions, juxtacortical, infratentorial. CSF oligoclonal bands (>95%). - MISDIAGNOSIS: Optic neuritis (painful loss of vision, afferent pupillary defect), Lhermitte's sign (electric shock down spine on neck flexion), internuclear ophthalmoplegia (MLF lesion) = classic MS presentations. - EXAM MISTAKE: Relapse treatment = high-dose methylprednisolone (speeds recovery, does NOT change long-term outcome). Disease modification = interferon-beta, glatiramer, natalizumab, fingolimod, ocrelizumab. - WARD ERROR: Not recognizing Uhthoff's phenomenon = worsening with heat (hot bath, fever) = does NOT mean new relapse, no steroids needed. 6. PARKINSON'S DISEASE - MISDIAGNOSIS TRAP: Drug-induced Parkinsonism = metoclopramide, haloperidol, risperidone, prochlorperazine (D2 blockers) - SYMMETRIC tremor, no response to levodopa. STOP the offending drug. - EXAM DISTINCTION: PD = resting tremor (pill-rolling), rigidity, bradykinesia, postural instability. Essential tremor = ACTION tremor, improves with alcohol. - WARD ERROR: Abruptly stopping levodopa = Neuroleptic malignant syndrome-like reaction (dopaminergic crisis) - hyperthermia, rigidity, confusion. - WARD ERROR: Giving antipsychotics (haloperidol) for PD psychosis = worsens Parkinsonism. Use quetiapine or clozapine (atypical, less D2 blockade). - EYE-CATCHER: Parkinson's-plus syndromes = multiple system atrophy (MSA), progressive supranuclear palsy (PSP - falls backward, square wave jerks), corticobasal degeneration. Poor response to levodopa. 7. MYASTHENIA GRAVIS - MISDIAGNOSIS: Ptosis + diplopia + fatigable weakness = classic. Often misdiagnosed as stroke or mitochondrial disease. - DIAGNOSIS: Anti-AChR antibodies (85%). Anti-MuSK (10%, seronegative to AChR). Tensilon (edrophonium) test = transient improvement. Repetitive nerve stimulation = decrement. - EXAM DISTINCTION - CRISIS: - Myasthenic crisis = worsening weakness, respiratory failure. Needs neostigmine/pyridostigmine INCREASE + plasmapheresis/IVIG. - Cholinergic crisis (too much anticholinesterase) = SLUDGE (Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis) + weakness. STOP neostigmine. - DIFFERENTIATE: Edrophonium test - improves in myasthenic crisis, worsens in cholinergic crisis. - EXAM MISTAKE: Thymoma in 10-15% of MG patients - ALWAYS do CT chest. Thymectomy improves outcomes even without thymoma in young patients. - WARD ERROR: Drugs worsening MG = aminoglycosides, fluoroquinolones, beta-blockers, calcium channel blockers, magnesium, procainamide. 8. GUILLAIN-BARRÉ SYNDROME - EXAM MISTAKE: DO NOT give steroids = worsen outcome (only immunopathies where steroids are CONTRAINDICATED). Use IVIG or plasmapheresis. - MOST COMMON PRECEDING INFECTION: Campylobacter jejuni (anti-ganglioside GM1 antibodies) for classic AIDP. Also EBV, CMV, Zika, COVID-19. - SPIROMETRY TRAP: Forced vital capacity (FVC) <1L or <20mL/kg = intubation. Monitor with "20-30-40 rule": FVC <20mL/kg, MIP < -30 cmH2O, MEP <40 cmH2O = intubate. - WARD ERROR: Relying on SpO2 to monitor respiratory function in GBS = falsely reassuring. SpO2 drops late. Use FVC serially. - WARD ERROR: Not giving DVT prophylaxis in paralyzed GBS patient. - EYE-CATCHER: Miller-Fisher variant = ophthalmoplegia + ataxia + areflexia. Anti-GQ1b antibodies. - PEARL: Autonomic dysfunction = cardiac monitoring required (arrhythmias, BP swings). 9. HEADACHE - "WORST HEADACHE OF LIFE" = SUBARACHNOID HEMORRHAGE UNTIL PROVEN OTHERWISE. Even if "normal" neurological exam. - CT head within 6h of onset - if negative = LP at 12h for xanthochromia. - WARD ERROR: Normal CT + not doing LP = missed SAH diagnosis. - CAUSE: Berry aneurysm rupture at Circle of Willis junctions (most common = anterior communicating artery). - MIGRAINE vs CLUSTER vs TENSION: - Migraine = unilateral, pulsating, nausea/vomiting, photophobia/phonophobia, aura (may occur). Acute = triptans (sumatriptan). Prophylaxis = propranolol, topiramate, amitriptyline. - Cluster = severe unilateral periorbital, autonomic features (lacrimation, rhinorrhea, ptosis, miosis), male, episodic. Acute = 100% O2 or sumatriptan SC. Prophylaxis = verapamil. - Tension = bilateral, band-like, no nausea/vomiting, no photophobia. Paracetamol/NSAIDs. - EXAM MISTAKE: Triptans are CONTRAINDICATED in hemiplegic migraine and migraine with brainstem aura (vasospasm risk). 10. SUBDURAL vs EPIDURAL HEMATOMA - EPIDURAL: Arterial bleed (middle meningeal artery), temporal bone fracture, LUCID INTERVAL then rapid deterioration. Biconvex (lens-shaped) on CT. Surgical emergency. - SUBDURAL: Venous bleed (bridging veins), elderly, alcoholics, minor trauma (or no trauma), CHRONIC = crescentic (concave) hypodense on CT. May present weeks later with confusion. - EXAM MISTAKE: Chronic subdural in elderly patient presenting with "dementia" = often missed. Always CT in new-onset cognitive change. - WARD ERROR: Not reversing anticoagulation immediately in traumatic intracranial hemorrhage. 11. BELL'S PALSY vs CENTRAL FACIAL PALSY - BELL'S PALSY (LMN VII): FOREHEAD SPARED? NO - entire face affected including forehead. Cause = idiopathic (HSV-1 reactivation). - CENTRAL VII PALSY (UMN lesion - stroke): FOREHEAD SPARED (bilateral cortical representation of forehead). Contralateral lower face weakness only. - EXAM MISTAKE: Bell's palsy = forehead affected (cannot wrinkle forehead). Central = forehead spared. - TREATMENT: Prednisolone within 72h (improves recovery). Add acyclovir in severe cases. 12. WERNICKE'S ENCEPHALOPATHY - CLASSIC TRIAD: Confusion + Ophthalmoplegia (nystagmus, lateral gaze palsy) + Ataxia (only 10% have all three - "iceberg" - most have only 1-2 features). - CAUSES: Thiamine deficiency - alcoholism, prolonged vomiting, malnutrition, post-bariatric surgery, hyperemesis gravidarum. - WARD ERROR: Giving IV GLUCOSE before thiamine = precipitates or worsens Wernicke's (glucose depletes remaining thiamine). - TREATMENT: IV thiamine (Pabrinex) BEFORE any glucose. Give empirically in any confused alcoholic. - EXAM MISTAKE: Korsakoff's psychosis = chronic sequel = anterograde amnesia + confabulation + relatively preserved intelligence. Thiamine-resistant (permanent damage). 13. NORMAL PRESSURE HYDROCEPHALUS - CLASSIC TRIAD: Wet (urinary incontinence) + Wobbly (gait ataxia/apraxia - "magnetic gait") + Wacky (dementia). - MISDIAGNOSIS: Most commonly misdiagnosed as Alzheimer's or Parkinson's disease. - EXAM MISTAKE: CT/MRI shows enlarged ventricles out of proportion to sulcal atrophy. Confirm with large-volume LP (30-50mL) = improvement = diagnostic and therapeutic. - TREATMENT: Ventriculoperitoneal shunt. Gait improves most, dementia least. 14. HORNER'S SYNDROME - CLASSIC: Ptosis (partial) + Miosis + Anhidrosis (same side). Enophthalmos (apparent). - ASSOCIATIONS BY LEVEL: - Central (hypothalamus to ciliospinal center): Wallenberg syndrome (lateral medullary infarct), MS, syringomyelia. - Preganglionic (T1 - stellate ganglion): Pancoast tumor (APEX lung), cervical rib, thyroid tumor. - Postganglionic (cavernous sinus - orbit): ICA dissection (neck pain + Horner's), cavernous sinus thrombosis, cluster headache. - EXAM MISTAKE: Horner's in young adult with neck pain after trauma = ICA dissection until proven otherwise = urgent MRI/MRA. Please return the FULL text of all these notes exactly as structured above for all four systems (Respiratory, GI/Hepatobiliary, Endocrinology, Neurology). Do not omit or abbreviate any section.

You are a senior clinical medicine educator compiling high-yield exam and ward notes. Produce dense, specific clinical notes for FOUR systems: Cardiology, Rheumatology, Nephrology, and Psychiatry. For EACH major topic within each system, structure your notes around these exact headings: - MOST COMMON CAUSE/ETIOLOGY (exam-relevant) - MOST COMMON MISDIAGNOSIS CAUSE - CLASSIC EXAM MISTAKES/TRAPS - WARD ERRORS (management mistakes in clinical practice) - EYE-CATCHERS (buzzword presentations, classic scenarios that appear in exams) - CLINICAL PEARLS (treatment, DDx, exam-specific) Use Harrison's Principles of Internal Medicine, Davidson's Principles and Practice, Kumar and Clark's Clinical Medicine, Oxford Handbook of Clinical Medicine, UpToDate, and Master the Wards by Conrad Fischer as reference frameworks. Be EXTREMELY specific: give drug names, doses where critical, lab values, criteria names, specific conditions. Maximum information density. This is for a medical student/resident. --- CARDIOLOGY 1. ACUTE CORONARY SYNDROME (ACS) - STEMI, NSTEMI, UA - MOST COMMON CAUSE: Atherosclerotic plaque rupture with thrombus formation. - MISDIAGNOSIS: ACS in women, diabetics, elderly = atypical presentations (fatigue, nausea, jaw pain, epigastric pain, dyspnea) - MISSED. Any unexplained dyspnea in high-risk patient = think ACS. - EXAM MISTAKE: STEMI = ST elevation in 2+ contiguous leads + new LBBB. NSTEMI = troponin rise + NO ST elevation. Unstable angina = chest pain at rest + NO troponin rise. - EXAM MISTAKE: Posterior STEMI = ST depression in V1-V4 (mirror image) + dominant R wave in V1 = do posterior leads (V7-V9). - EXAM MISTAKE: Right-sided leads (V3R, V4R) for RV infarction in inferior STEMI. RV infarction = hypotension + clear lungs + raised JVP = do NOT give nitrates (preload-dependent) or diuretics. - WARD ERROR: Giving nitrates in RV infarction = severe hypotension (RV depends on preload). - WARD ERROR: Not giving anticoagulation with NSTEMI/UA - fondaparinux preferred (OASIS-5), or enoxaparin. - WARD ERROR: Stopping beta-blockers after MI discharge = increases reinfarction risk. - STEMI MANAGEMENT: Dual antiplatelet (aspirin 300mg + ticagrelor 180mg or prasugrel), anticoagulant, O2 if SpO2 <94%, morphine, nitrates. Primary PCI within 90min (door-to-balloon). If PCI not available within 120min = thrombolysis (streptokinase or tPA). - EYE-CATCHER: Dressler's syndrome = pericarditis 2-10 weeks after MI. Fever, pleuritic chest pain, raised ESR. Treat with NSAIDs or aspirin. - EYE-CATCHER: Wellens syndrome = critical LAD stenosis, biphasic or deeply inverted T waves V2-V3 in pain-free period. High risk of anterior STEMI. Do NOT exercise test. - PEARL: Door-to-balloon time <90 minutes for STEMI PCI. If fibrinolysis: give within 30 minutes. 2. HEART FAILURE - MOST COMMON CAUSE HFrEF: Ischemic heart disease (most common), hypertension, dilated cardiomyopathy. - MOST COMMON CAUSE HFpEF: Hypertension (most common), diabetes, obesity, AF. - MISDIAGNOSIS: Cardiac cachexia, fatigue, and exertional dyspnea = often attributed to COPD, deconditioning, or depression. - EXAM MISTAKE: HFrEF (EF <40%) = ACEi/ARB + beta-blocker + MRA (spironolactone) + SGLT2 inhibitor (dapagliflozin/empagliflozin) = "the fantastic four" = ALL proven mortality benefit. HYDRALAZINE + NITRATE if ACEi/ARB intolerant (Black patients particularly benefit). - EXAM MISTAKE: HFpEF (EF >50%) = NO proven mortality benefit from any drug except SGLT2 inhibitors (empagliflozin - EMPEROR-Preserved trial 2021). Treat symptoms with diuretics. - WARD ERROR: Starting beta-blocker in acutely decompensated HF = worsens decompensation. START beta-blocker only in euvolemic, stable patients. - WARD ERROR: Giving NSAIDs in heart failure = cause fluid retention and worsen HF. Absolutely avoid. - EYE-CATCHER: Cardiogenic shock = MAP <65, cold clammy extremities, oliguria, raised JVP, S3 gallop. IABP (intra-aortic balloon pump) or LVAD as bridge to PCI/transplant. - EYE-CATCHER: Acute pulmonary edema = sit upright, IV furosemide 40-80mg, GTN infusion (if systolic >110), CPAP reduces intubation risk, morphine (controversial, causes vasodilation and reduces anxiety). - PEARL: BNP/NT-proBNP: raised in HF, also in PE, AF, renal failure, sepsis. Normal BNP has very HIGH negative predictive value for HF. - PEARL: CRT (cardiac resynchronization therapy) indicated in HFrEF + LBBB + QRS >150ms + NYHA III-IV on optimal therapy. 3. ARRHYTHMIAS - ATRIAL FIBRILLATION: - MOST COMMON ARRHYTHMIA requiring treatment. - MISDIAGNOSIS: AF mistaken for sinus tachycardia or multifocal atrial tachycardia on telemetry. - EXAM MISTAKE: CHA2DS2-VASc score for stroke risk: CHF(1) + Hypertension(1) + Age≥75(2) + Diabetes(1) + Stroke/TIA(2) + Vascular disease(1) + Age 65-74(1) + Sex female(1). Score ≥2 (men) or ≥3 (women) = anticoagulate. - WARD ERROR: Using aspirin instead of anticoagulant for AF stroke prevention - aspirin has NO significant benefit in AF. - WARD ERROR: Cardioverting AF of unknown duration without anticoagulation or TOE = risk of embolizing atrial thrombus. Must anticoagulate for 3 weeks before elective cardioversion OR exclude thrombus by TOE. - WARD ERROR: Giving digoxin as rate-control in active/exercising patients - digoxin only controls rate at rest (vagotonic), not with exertion. - EYE-CATCHER: Wolff-Parkinson-White + AF = EXTREMELY DANGEROUS - accessory pathway can conduct rapidly = VF. Do NOT give digoxin, beta-blockers, CCBs, adenosine. Use procainamide or DC cardioversion. - PEARL: Rate control (beta-blocker or diltiazem/verapamil) is preferred in most patients. Rhythm control with flecainide (only if no structural heart disease) or amiodarone. - SVTS: - AVNRT (most common SVT) = narrow complex, regular, no P waves visible (or retrograde). - TREATMENT: Vagal maneuvers → adenosine 6mg IV rapid bolus (warn patient of transient cardiac arrest feeling) → 12mg → 18mg → DC cardioversion if unstable. - EXAM MISTAKE: Adenosine contraindicated in severe asthma. Use verapamil instead. - WARD ERROR: Giving adenosine via distal IV = may not work. Use antecubital fossa or central line. - VENTRICULAR TACHYCARDIA: - VT vs SVT with aberrancy = in doubt, treat as VT (DC cardioversion if unstable, amiodarone if stable). - EYE-CATCHER: Torsades de pointes = polymorphic VT, QTc >500ms, "twisting around baseline." Causes = hypokalemia, hypomagnesemia, drugs (quinidine, sotalol, haloperidol, macrolides, TCAs). TREAT: IV magnesium sulfate 2g, remove causative drug, isoproterenol or pacing to increase rate (shortens QT). 4. HYPERTENSION - EXAM MISTAKE: Secondary causes to screen for in: age <30, resistant (≥3 drugs), sudden onset, hypokalemia (Conn's), paroxysmal (pheo), cushingoid features. - WARD ERROR: Treating hypertensive urgency (no end-organ damage) too aggressively IV = over-treatment. Oral agents, lower BP over 24-48h. - WARD ERROR: Treating hypertensive emergency too slowly - need IV treatment, lower MAP by no more than 25% in first hour, then 160/100 in 2-6h. Nitroprusside, labetalol, nicardipine. - EYE-CATCHER: Malignant hypertension = papilledema + BP >180/120 = hypertensive encephalopathy, AKI, microangiopathic hemolytic anemia. Admit, IV treatment. - PEARL: Aortic coarctation = hypertension in arms + low BP in legs, radio-femoral delay, rib notching on CXR. 5. VALVULAR HEART DISEASE - AORTIC STENOSIS: - SYMPTOMS: Angina, Syncope, Dyspnea (heart failure) - SAD. Once symptomatic, median survival: angina 5yr, syncope 3yr, dyspnea (HF) 2yr. - EXAM MISTAKE: Severe AS = valve area <1cm2, peak gradient >40mmHg, mean gradient >40mmHg. Slow-rising pulse, narrow pulse pressure, heaving non-displaced apex, soft/absent A2, ejection systolic murmur (ESM) radiating to carotids. - WARD ERROR: Giving vasodilators (nitrates, ACEi) in severe AS = dangerous hypotension (fixed cardiac output). - TREATMENT: TAVR (transcatheter aortic valve replacement) for high surgical risk. Surgical AVR for standard risk. - MITRAL REGURGITATION: - EXAM MISTAKE: Acute MR (papillary muscle rupture post-MI, chordal rupture) = no cardiomegaly, pulmonary edema, soft murmur (minimal gradient). Surgical emergency. - EYE-CATCHER: MVP (mitral valve prolapse) = young woman, mid-systolic click + late systolic murmur. Marfan's, Ehlers-Danlos associations. - MITRAL STENOSIS: - CAUSE: Rheumatic fever (most common worldwide). - EXAM MISTAKE: Opening snap - closer to S2 = more severe MS (increased LA pressure = opens valve earlier). Longer diastolic murmur = more severe. - PEARL: MS + AF = high stroke risk = anticoagulate. Pregnancy = increased blood volume worsens MS symptoms. 6. PERICARDITIS and CARDIAC TAMPONADE - PERICARDITIS: - MOST COMMON CAUSE: Viral (idiopathic). Also autoimmune (SLE, RA), TB, post-MI (Dressler's), uremia. - EXAM MISTAKE: ECG = saddle-shaped ST elevation in ALL leads except aVR and V1 (PR depression). NOT localized like in MI. - TREATMENT: NSAIDs (ibuprofen) + colchicine for 3 months (reduces recurrence). Avoid exercise. Corticosteroids only if autoimmune cause or failure of NSAIDs. - CARDIAC TAMPONADE: - BECK'S TRIAD: Hypotension + Raised JVP + Muffled heart sounds. - EXAM MISTAKE: Pulsus paradoxus (>10mmHg drop in systolic BP on inspiration) = classic finding. - WARD ERROR: Giving diuretics in tamponade = worsens hemodynamics (preload-dependent). Treatment = pericardiocentesis. - ECG: Electrical alternans (alternating QRS axis) = pathognomonic for large pericardial effusion. 7. CARDIOMYOPATHIES - HYPERTROPHIC CARDIOMYOPATHY (HCM): - EXAM MISTAKE: Murmur INCREASES with standing/Valsalva (decreases preload = outflow obstruction worsens). DECREASES with squatting/passive leg raise (increases preload). OPPOSITE of AS (which decreases with Valsalva). - WARD ERROR: Giving digoxin, nitrates, diuretics, or vasodilators = worsens outflow obstruction. - TREATMENT: Beta-blockers or verapamil (non-dihydropyridine CCB). ICD for SCD prevention. - PEARL: Most common cause of sudden cardiac death in young athletes. - DILATED CARDIOMYOPATHY: - CAUSE: Idiopathic most common, alcohol, viral myocarditis, peripartum, Chagas disease. - EYE-CATCHER: Peripartum cardiomyopathy = last month of pregnancy to 5 months postpartum. Treat as HFrEF (caution ACEi/ARB in pregnancy - use hydralazine + nitrate). 8. INFECTIVE ENDOCARDITIS - MOST COMMON ORGANISM: Streptococcus viridans (native valve, dental procedures). Staphylococcus aureus (IV drug users, prosthetic valves, most aggressive). - MISDIAGNOSIS: Fever + new murmur in IV drug user = endocarditis until proven otherwise. - DUKE CRITERIA: 2 major, 1 major + 3 minor, or 5 minor = definite IE. Major = positive blood cultures + echocardiographic evidence. - WARD ERROR: Only 1 set of blood cultures before antibiotics = inadequate. Need at least 3 sets from different sites before antibiotics. - WARD ERROR: Starting single antibiotic therapy - usually require combination (penicillin + gentamicin for streptococci, vancomycin + gentamicin for staphylococci/MRSA). - EYE-CATCHER: Right-sided IE (tricuspid) in IV drug users = septic pulmonary emboli (bilateral nodular infiltrates + cavitation). Peripheral features (Osler's nodes, Janeway lesions, Roth spots, splinter hemorrhages) are often absent. - PEARL: Osler's nodes (painful) = immune complex mediated. Janeway lesions (painless) = septic emboli. Both on hands/feet. --- RHEUMATOLOGY 1. RHEUMATOID ARTHRITIS - MOST COMMON: Symmetric small joint polyarthritis (MCP, PIP, wrists), morning stiffness >1h, RF/anti-CCP antibodies. - MISDIAGNOSIS: Palindromic rheumatism, osteoarthritis (DIP joints, Heberden's nodes), reactive arthritis, crystal arthritis. - EXAM MISTAKE: Anti-CCP (anti-cyclic citrullinated peptide) is more specific than RF for RA and predicts erosive disease. RF can be positive in: SLE, Sjögren's, endocarditis, hepatitis, elderly. - EXAM MISTAKE: Felty's syndrome = RA + splenomegaly + neutropenia. Risk of infection. - WARD ERROR: Starting DMARD without screening for TB (TB reactivation risk with methotrexate and especially anti-TNF biologics). Check CXR + Mantoux/IGRA before anti-TNF therapy. - WARD ERROR: Methotrexate without folic acid = mucositis, hepatotoxicity. ALWAYS co-prescribe folic acid 5mg weekly (not same day as MTX). - WARD ERROR: Not monitoring LFTs and FBC on methotrexate. - EYE-CATCHER: Atlantoaxial subluxation in severe RA = MUST check before general anesthesia (intubation risk = C1-C2 instability = spinal cord injury). - PEARL: Treat-to-target strategy - aim for remission (DAS28 <2.6). Step up: NSAIDs → DMARDs (methotrexate first-line) → add-on leflunomide/hydroxychloroquine → biologics (anti-TNF first: etanercept, adalimumab) → JAK inhibitors (baricitinib, tofacitinib). 2. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) - MOST COMMON DEMOGRAPHICS: Young women of reproductive age, Afro-Caribbean women most severely affected. - MISDIAGNOSIS: Multisystem disease = can mimic many conditions. Thrombocytopenia labeled as ITP. Nephritis labeled as glomerulonephritis. Serositis labeled as pleuritis/pericarditis of other cause. - EXAM MISTAKE: ACR/EULAR 2019 criteria. Classic features = malar (butterfly) rash + discoid rash + photosensitivity + oral ulcers + alopecia + serositis + arthritis + renal involvement + neurological + hematological. - EXAM MISTAKE: ANA positive in >95% (sensitive but NOT specific - also positive in RA, Sjögren's, drug-induced, normal elderly). Anti-dsDNA = specific for SLE and correlates with disease activity/nephritis. Anti-Smith = most SPECIFIC for SLE. - WARD ERROR: Not monitoring urine protein:creatinine ratio - lupus nephritis is a major cause of morbidity/mortality. - WARD ERROR: Using NSAIDs in lupus nephritis = worsen renal function. - EYE-CATCHER: Libman-Sacks endocarditis (non-infective, sterile vegetations on mitral valve, BOTH sides of leaflet). Antiphospholipid syndrome = recurrent thrombosis + miscarriage + thrombocytopenia. Anticardiolipin + lupus anticoagulant antibodies. - PEARL: Hydroxychloroquine (HCQ) given to ALL SLE patients (reduces flares, protects against nephritis, improves survival). Requires annual ophthalmology review (retinal toxicity). 3. GOUT vs PSEUDOGOUT - GOUT: - CAUSE: Hyperuricemia (urate >6.8 mg/dL) → monosodium urate crystals (needle-shaped, NEGATIVELY birefringent under polarized light = yellow when parallel to axis). - MOST COMMON SITE: First MTP joint (podagra). - WARD ERROR: Starting allopurinol during acute attack = prolongs and worsens attack. Start only 2-4 weeks after acute attack resolves. - WARD ERROR: Not giving colchicine prophylaxis when starting allopurinol = flare risk. - EXAM MISTAKE: Treat acute gout with NSAIDs (first line), colchicine, or corticosteroids. NOT allopurinol acutely. - EXAM MISTAKE: Allopurinol + azathioprine WITHOUT dose reduction = azathioprine toxicity (bone marrow suppression). Must reduce azathioprine dose by 75% or use febuxostat instead. - PSEUDOGOUT: - Calcium pyrophosphate crystals = POSITIVELY birefringent (blue when parallel), rhomboid shape. Knees/wrists most common. - Associated with: hypercalcemia, hemochromatosis, hypomagnesemia, hypothyroidism, hyperparathyroidism. - EYE-CATCHER: Chondrocalcinosis on XR = calcium in cartilage. 4. SYSTEMIC SCLEROSIS (SCLERODERMA) - LIMITED (CREST): Calcinosis + Raynaud's + Esophageal dysmotility + Sclerodactyly + Telangiectasia. Anti-centromere antibodies. LATE complication = pulmonary arterial hypertension. - DIFFUSE: Rapid skin thickening, anti-Scl-70 (anti-topoisomerase) antibodies. EARLY complication = scleroderma renal crisis (hypertensive emergency, microangiopathic hemolysis). - SCLERODERMA RENAL CRISIS: Severe hypertension + acute kidney injury in diffuse SSc. TREAT with ACEi (captopril) = LIFESAVING. Dialysis if needed. - EXAM MISTAKE: ACEi is INDICATED (lifesaving) in scleroderma renal crisis. Contrast to most AKI where ACEi is avoided. - WARD ERROR: Not starting ACEi empirically in diffuse SSc with new hypertension. 5. SJÖGREN'S SYNDROME - FEATURES: Dry eyes (keratoconjunctivitis sicca) + dry mouth (xerostomia) + arthralgia. Primary (alone) or secondary (with RA, SLE). - ANTIBODIES: Anti-Ro (SSA) and Anti-La (SSB). - MISDIAGNOSIS: Dry mouth/eyes in elderly attributed to medications or aging. - EXAM MISTAKE: Increased risk of B-cell lymphoma (especially MALT lymphoma = parotid, extranodal). - PEARL: Neonatal lupus + congenital heart block = maternal Anti-Ro antibodies crossing placenta (Sjögren's or SLE mother). 6. ANKYLOSING SPONDYLITIS / SpA - FEATURES: Young male, inflammatory back pain (worse at rest/morning, improves with exercise - opposite of mechanical), sacroiliitis on MRI/XR, HLA-B27 (90%+). - EXAM MISTAKE: Schober's test = marks 10cm above + 5cm below L5, flexion = <20cm total = reduced lumbar flexion. - EXAM MISTAKE: Bamboo spine (syndesmophytes) = late finding. Early = sacroiliitis. - WARD ERROR: NSAID avoidance in AS = mistake. NSAIDs are FIRST-LINE treatment in AS (reduce inflammation + may slow progression). Use continuously. - EYE-CATCHER: Complications = apical lung fibrosis, aortic regurgitation, anterior uveitis (most common extraarticular, acute painful red eye), cardiac conduction defects. - PEARL: Anti-TNF (etanercept, adalimumab) if NSAID failure. IL-17 inhibitors (secukinumab) also effective. DMARDs (methotrexate) do NOT work for axial disease (only peripheral arthritis). 7. VASCULITIS - GIANT CELL ARTERITIS (GCA): - PRESENTATION: Elderly woman >50yr, severe headache, temporal artery tenderness, jaw claudication, visual loss (ischemic optic neuropathy - PERMANENT if untreated). - WARD ERROR: Waiting for temporal artery biopsy before starting steroids = NEVER delay steroids. Give prednisolone 40-60mg daily IMMEDIATELY. - EXAM MISTAKE: Associated with polymyalgia rheumatica (PMR) in 50% = shoulder + hip girdle stiffness + raised ESR/CRP. - PEARL: Biopsy must be done within 2 weeks of starting steroids (skip lesions = need long segment biopsy >2cm). - GRANULOMATOSIS WITH POLYANGIITIS (GPA = Wegener's): - TRIAD: Upper respiratory (sinusitis, epistaxis, saddle-nose deformity) + Lower respiratory (cavitating nodules) + Renal (necrotizing GN). - c-ANCA (PR3-ANCA) = classic. p-ANCA (MPO-ANCA) = MPA (microscopic polyangiitis). - TREATMENT: Cyclophosphamide + high-dose steroids (induction), then azathioprine/rituximab (maintenance). - KAWASAKI DISEASE: - CHILDREN <5 years, prolonged fever >5 days + 4/5: conjunctival injection, oral changes (strawberry tongue, cracked lips), rash, extremity changes (desquamation), cervical lymphadenopathy. - TREATMENT: IV immunoglobulin (IVIG) + aspirin. IVIG reduces coronary artery aneurysm risk. - EXAM MISTAKE: Aspirin is indicated in Kawasaki's (despite being avoided in children for Reye's syndrome risk in other contexts). --- NEPHROLOGY 1. ACUTE KIDNEY INJURY (AKI) - CAUSES: Pre-renal (most common, 60% - dehydration, sepsis, cardiac failure), renal (ATN, GN, interstitial nephritis), post-renal (obstruction). - MISDIAGNOSIS: Contrast-induced nephropathy vs atheroembolism vs pre-renal after catheter. - EXAM MISTAKE: AKI KDIGO criteria = rise in creatinine ≥26.5 umol/L within 48h, OR 1.5x baseline within 7 days, OR urine output <0.5mL/kg/h for >6h. - WARD ERROR: Continuing ACEi/ARB/NSAIDs in AKI = compounds renal ischemia. - WARD ERROR: Using nephrotoxic contrast in AKI without pre-hydration (or deferring contrast when avoidable). - WARD ERROR: Not catheterizing patient to exclude post-renal cause = missed obstructive uropathy. - EXAM MISTAKE: Pre-renal vs ATN - FeNa <1% = pre-renal (kidneys retaining sodium). FeNa >2% = ATN (tubular damage, can't retain Na). HOWEVER: FeNa unreliable if diuretics given or in contrast nephropathy. - EYE-CATCHER: Hepatorenal syndrome = pre-renal picture (FeNa <1%) in cirrhotic patient with ascites. NOT truly pre-renal - does NOT respond to fluids alone. - PEARL: KDIGO AKI Staging: Stage 1 = Cr x1.5-1.9 or +26.5. Stage 2 = x2-2.9. Stage 3 = x3+ or Cr >354 or initiation of RRT. 2. GLOMERULONEPHRITIS - NEPHRITIC vs NEPHROTIC: - NEPHRITIC = hematuria (red cell casts = pathognomonic), hypertension, oliguria, proteinuria (non-nephrotic range usually). - NEPHROTIC = heavy proteinuria (>3.5g/day), hypoalbuminemia, edema, hyperlipidemia, lipiduria (fatty casts/oval fat bodies), thrombosis risk. - MOST COMMON ADULT NEPHROTIC: Membranous nephropathy (PLA2R antibody), FSGS (focal segmental glomerulosclerosis), minimal change disease (adults, but also most common in children). - MOST COMMON CHILD NEPHROTIC: Minimal change disease (responds to steroids). - MOST COMMON ADULT NEPHRITIC: IgA nephropathy (Berger's disease) = most common GN worldwide. Hematuria within 24-48h of URTI ("synpharyngitic hematuria"). Different from post-strep GN (2-3 weeks after throat/skin infection - "latent period"). - EXAM MISTAKES: - Post-streptococcal GN = low complement C3 (consumed) + raised ASO titre. Resolves spontaneously in children. - SLE nephritis = low C3 AND C4 (classical pathway activation). Class IV (diffuse proliferative) = worst, treat with cyclophosphamide + steroids. - Goodpasture's syndrome = anti-GBM antibodies, hemoptysis (pulmonary hemorrhage) + nephritis. Linear IgG on immunofluorescence. - ANCA vasculitis (GPA, MPA) = pauci-immune (no/little immunoglobulin on IF). c-ANCA or p-ANCA. 3. CHRONIC KIDNEY DISEASE (CKD) - STAGING: eGFR >90 = Stage 1, 60-89 = 2, 45-59 = 3a, 30-44 = 3b, 15-29 = 4, <15 = 5 (or on dialysis). - MOST COMMON CAUSES: Diabetic nephropathy (most common globally), hypertension, glomerulonephritis. - COMPLICATIONS: - Anemia: Normochromic normocytic, reduced EPO. Treat with ESA (erythropoietin-stimulating agents) + IV iron. Target Hb 100-120g/L. - Renal bone disease: Low Ca, high PO4, raised PTH (secondary hyperparathyroidism), low vit D (reduced 1-alpha hydroxylation). Treat: dietary phosphate restriction, phosphate binders (calcium carbonate), active vitamin D (alfacalcidol or calcitriol). - Metabolic acidosis: Sodium bicarbonate supplementation. - Hypertension: ACEi/ARB first line (reduce proteinuria, slow progression - LANDMARK REIN/IDNT/RENAAL trials). - WARD ERRORS: - Not adjusting drug doses in CKD (metformin, NSAIDs, low MW heparin, antibiotics). - Not stopping ACEi/ARB acutely in AKI superimposed on CKD. - Metformin in eGFR <30 = lactic acidosis risk. Stop at eGFR <45 if contrast planned. 4. DIALYSIS INDICATIONS (AEIOU) - A = Acidosis (pH <7.1 or refractory) - E = Electrolytes (severe hyperkalemia refractory to medical management) - I = Intoxication (certain overdoses: lithium, salicylate, methanol, ethylene glycol) - O = Overload (fluid overload refractory to diuretics) - U = Uremia (pericarditis, encephalopathy, bleeding from uremia, urea >35 mmol/L symptomatic) 5. RENAL TUBULAR ACIDOSIS (RTA) - TYPE 1 (distal) = cannot acidify urine (urine pH always >5.5), hypokalemia, nephrocalcinosis, kidney stones. Causes = SLE, Sjögren's, amphotericin B. - TYPE 2 (proximal) = cannot reabsorb HCO3 (bicarbonaturia). Fanconi syndrome (generalized tubular dysfunction). Causes = multiple myeloma, Wilson's disease, cisplatin. - TYPE 4 = hypoaldosteronism or tubular resistance to aldosterone. HYPERKALEMIA. Most common in diabetic nephropathy (hyporeninemic hypoaldosteronism). - EXAM MISTAKE: Type 4 RTA = hyperkalemia + metabolic acidosis + normal anion gap in diabetic = common and commonly missed. 6. RENAL ARTERY STENOSIS - CAUSE: Atherosclerosis (older patients, risk factors) vs Fibromuscular dysplasia (young women, "beaded" appearance on angiography). - MISDIAGNOSIS: Refractory hypertension attributed to poor compliance. - EXAM MISTAKE: Flash pulmonary edema with bilateral RAS = should be suspected. - WARD ERROR: ACEi/ARB in bilateral RAS or single functioning kidney = acute AKI (efferent arteriole dilation = drops GFR critically). Monitor creatinine closely after starting ACEi. 7. NEPHROLITHIASIS - MOST COMMON TYPE: Calcium oxalate (80%). Risk factors: hypercalciuria, hyperoxaluria, low urine volume. - URIC ACID STONES: Radiolucent (not seen on plain XR), hyperuricemia, gout. Alkalinize urine (sodium bicarbonate/potassium citrate). - STRUVITE: Infection stones (Proteus, Klebsiella), staghorn calculi, urease-producing bacteria. - CYSTINE: Cystinuria (autosomal recessive), pathognomonic hexagonal crystals on urine microscopy. - EXAM MISTAKE: Most stones pass spontaneously if <5mm. Indications for intervention: obstruction, sepsis, pain not controlled, failure to pass. - WARD ERROR: Not sending stone for analysis after passage = missed underlying metabolic cause. 8. POLYCYSTIC KIDNEY DISEASE (PKD) - AUTOSOMAL DOMINANT PKD (most common hereditary renal disease): PKD1 (chromosome 16, 85%) > PKD2. - EXTRARENAL: Berry aneurysms (Circle of Willis - SAH risk), hepatic cysts, mitral valve prolapse, diverticular disease. - EXAM MISTAKE: Tolvaptan (vasopressin V2 receptor antagonist) slows cyst growth in ADPKD. - PEARL: Annual BP monitoring + ACEi/ARB for hypertension + avoid nephrotoxins. --- PSYCHIATRY 1. DEPRESSION - MOST COMMON PRESENTATION: Low mood + anhedonia + fatigue, biological features (sleep, appetite, concentration, psychomotor changes, libido changes). - MISDIAGNOSIS: Hypothyroidism, anemia, diabetes, malignancy, Parkinson's disease causing depression. Always check TSH, CBC, fasting glucose in new-onset depression. - EXAM MISTAKE: ICD-10/DSM-5 depression = at least 2 weeks, with low mood and/or anhedonia + 4+ symptoms. - EXAM MISTAKE: Seasonal affective disorder = autumn/winter depression, hypersomnia, carbohydrate craving. Treat with light therapy + SSRI. - WARD ERROR: Not assessing suicide risk in every depressed patient - ask directly. - WARD ERROR: Stopping antidepressants after 2-4 weeks if "not working" = SSRIs take 4-6 weeks for full effect. - WARD ERROR: Stopping antidepressants too soon after remission = high relapse risk. Continue at least 6 months after remission. Second episode = 1-2 years. Third+ = long-term/lifelong. - EYE-CATCHER: Serotonin syndrome = SSRIs + MAOIs (or triptans, tramadol, fentanyl, linezolid, St John's Wort) = hyperthermia, clonus, myoclonus, agitation, autonomic instability. Treatment = cyproheptadine (serotonin antagonist). - PEARL: MAOIs + tyramine (cheese, red wine, cured meats) = hypertensive crisis. MAOIs are rarely used first-line now. 2. BIPOLAR DISORDER - EXAM MISTAKE: Bipolar I = manic episode (>7 days or any duration if hospitalized) with or without depressive episodes. Bipolar II = hypomanic episodes (4-7 days, not severe enough to impair functioning) + major depressive episodes. - MISDIAGNOSIS: Bipolar disorder with prominent depressive phases = misdiagnosed as unipolar depression. Treating with SSRI ALONE in bipolar = can precipitate mania. - WARD ERROR: Prescribing antidepressant monotherapy in bipolar = precipitates manic switch. ALWAYS add mood stabilizer. - TREATMENT: Lithium = gold standard mood stabilizer (reduces suicide risk). Valproate, olanzapine, quetiapine also used. - LITHIUM MONITORING: Narrow therapeutic index (0.6-1.0 mmol/L therapeutic; toxicity at >1.5 mmol/L). - Toxicity signs: coarse tremor, confusion, ataxia, GI symptoms, dysarthria, seizures, cardiac arrhythmias. - INTERACTIONS: NSAIDs, thiazide diuretics, ACEi = raise lithium levels (reduce renal clearance). Increase fluid intake in hot weather. - Long-term monitoring: TFTs (hypothyroidism), U&Es (nephrogenic DI, CKD), calcium (hypercalcemia). 3. PSYCHOSIS / SCHIZOPHRENIA - EXAM MISTAKE: Schizophrenia diagnosis requires symptoms >6 months. Schizophreniform = 1-6 months. Brief psychotic disorder = <1 month. - MISDIAGNOSIS: Organic causes MUST be excluded before diagnosing schizophrenia: drug-induced (cannabis, amphetamines), autoimmune (anti-NMDAR encephalitis), metabolic, thyroid, Wilson's disease. - WARD ERROR: Using high-potency typical antipsychotics (haloperidol) in elderly = high risk of extrapyramidal side effects, QTc prolongation. - EXAM MISTAKE: Clozapine = most effective for treatment-resistant schizophrenia (failure of ≥2 antipsychotics). Requires weekly then monthly FBC monitoring (agranulocytosis - 1-2%). ABSOLUTELY CONTRAINDICATED to combine with carbamazepine (both can cause agranulocytosis). - EYE-CATCHER: Neuroleptic malignant syndrome (NMS) = hyperthermia + "lead pipe" rigidity + autonomic instability + raised CK. Caused by dopamine blockade (antipsychotics, metoclopramide). Treatment: STOP drug, dantrolene, bromocriptine. - PEARL: All antipsychotics can prolong QTc - baseline ECG before starting. 4. ANXIETY DISORDERS - EXAM MISTAKE: GAD = persistent, generalized, uncontrollable worry >6 months about multiple areas. - PANIC DISORDER: Recurrent unexpected panic attacks + fear of future attacks. Agoraphobia may develop. - WARD ERROR: Prescribing benzodiazepines long-term for anxiety = dependence, tolerance. Use SSRI/SNRI first-line (long-term). Benzodiazepines for acute/short-term only. - EYE-CATCHER: Panic disorder mimics = cardiac arrhythmia, hyperthyroidism, hypoglycemia, pheochromocytoma - MUST exclude organic causes. - PEARL: SSRI is first-line for all anxiety disorders (GAD, panic, social anxiety, PTSD, OCD). CBT is equally effective. 5. DEMENTIA - MOST COMMON: Alzheimer's disease (60-70%), then vascular dementia, then Lewy body dementia, then frontotemporal dementia. - MISDIAGNOSIS: Delirium mistaken for dementia in hospitalized elderly. KEY DIFFERENCE: Delirium = acute onset + fluctuating + impaired attention. Dementia = gradual onset, stable (or slowly progressive). - EXAM MISTAKE: Lewy body dementia = fluctuating cognition + visual hallucinations + Parkinsonism (2 of 3 = probable LBD). REM sleep behavior disorder. - WARD ERROR: Antipsychotics (especially haloperidol) in Lewy body dementia = SEVERE neuroleptic sensitivity = rigidity, falls, accelerated decline, death. Use with extreme caution (quetiapine lower risk). - EXAM MISTAKE: Frontotemporal dementia = personality/behavior change + executive dysfunction BEFORE memory loss. Pick's bodies (tau). Affects frontal > temporal lobe. - EXAM MISTAKE: Vascular dementia = stepwise deterioration after TIA/strokes, associated cardiovascular risk factors. - WARD ERROR: Not assessing for reversible causes of "dementia": hypothyroidism, B12/folate deficiency, neurosyphilis, normal pressure hydrocephalus, subdural hematoma, depression (pseudodementia). - PEARL: Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) = symptomatic benefit in Alzheimer's and Lewy body dementia. Memantine for moderate-severe Alzheimer's. 6. EATING DISORDERS - ANOREXIA NERVOSA: BMI <17.5, fear of weight gain, distorted body image, amenorrhea. Medically most dangerous psychiatric disorder (highest mortality). - BULIMIA NERVOSA: Binge-purge cycles, normal or elevated BMI, dental erosions (from vomiting), parotid hypertrophy, Russell's sign (calluses on dorsum of hand from self-induced vomiting), hypokalemia + metabolic alkalosis (from vomiting) or acidosis (from laxative abuse). - EXAM MISTAKE: Refeeding syndrome in anorexia = hypophosphatemia (most dangerous - cardiac arrhythmias, respiratory failure) + hypokalemia + hypomagnesemia when refeeding starts. Monitor electrolytes, give thiamine, introduce feeding slowly (NICE guidelines). - WARD ERROR: Feeding aggressively without monitoring phosphate = refeeding syndrome. 7. SUBSTANCE USE DISORDERS - ALCOHOL WITHDRAWAL: - Timeline: Tremors (6-24h) → hallucinations (24-48h, visual) → seizures (12-48h) → delirium tremens (48-72h, up to 5 days). - WARD ERROR: Using inadequate benzodiazepine dosing = seizures. Use CIWA protocol (Clinical Institute Withdrawal Assessment) to guide benzodiazepine dosing. - WARD ERROR: Forgetting thiamine before IV glucose (Wernicke's risk). - TREATMENT: Long-acting benzodiazepine (diazepam or chlordiazepoxide). Short-acting (lorazepam) if liver failure. - OPIOID OVERDOSE: - TRIAD: Miosis + respiratory depression + decreased consciousness. - TREATMENT: Naloxone IV 0.4-2mg (short acting - may need repeat doses or infusion; morphine has longer duration than naloxone). - OPIOID WITHDRAWAL: Not life-threatening (unlike alcohol/benzo withdrawal which can be fatal). Symptoms: lacrimation, piloerection, diarrhea, myalgia, insomnia. Treat with methadone or buprenorphine/naloxone. 8. DELIRIUM - MOST COMMON CAUSE IN ELDERLY: Infection (UTI, pneumonia), drugs (especially opioids, benzodiazepines, anticholinergics), metabolic (renal failure, hyponatremia, hypoglycemia), pain, urinary retention, constipation, post-ictal, stroke. - MISDIAGNOSIS: Hypoactive delirium (quiet, withdrawn, somnolent) misdiagnosed as depression. - WARD ERROR: Giving haloperidol routinely for delirium = may worsen (especially Lewy body). Low-dose haloperidol only for agitated delirium when non-pharmacological measures fail. - WARD ERROR: Not treating the UNDERLYING CAUSE = delirium persists. - EXAM MISTAKE: CAM (Confusion Assessment Method) = (1) Acute onset + fluctuation, (2) Inattention, (3) Disorganized thinking, (4) Altered level of consciousness. Positive if 1+2 + either 3 or 4. 9. PERSONALITY DISORDERS (exam-relevant) - BORDERLINE PD = emotional dysregulation, self-harm, unstable relationships, impulsivity, identity disturbance, fear of abandonment. Associated with childhood trauma. - EXAM MISTAKE: Borderline PD patients in ED with self-harm = do NOT withhold treatment due to diagnostic label. Assess each episode independently. - WARD ERROR: Prescribing antidepressants as the "solution" for Borderline PD = limited evidence, may worsen impulsivity. DBT (Dialectical Behavior Therapy) is first-line. 10. OVERDOSE / TOXICOLOGY (exam-relevant) - PARACETAMOL OVERDOSE: - Treatment = N-acetylcysteine (NAC). Use Rumack-Matthew nomogram to determine need. - WARD ERROR: Waiting for liver function tests before starting NAC in significant overdose = delay. - WARD ERROR: Missing paracetamol overdose in patient with other drug ingestion (mixed overdose). - TRICYCLIC ANTIDEPRESSANT (TCA) OVERDOSE: - Features: Anticholinergic (dry mouth, urinary retention, dilated pupils, tachycardia), QRS widening (>100ms = severe, >160ms = arrhythmias), seizures, hypotension. - TREATMENT: IV sodium bicarbonate (alkalinize to reduce TCA binding to sodium channels). NOT flumazenil (won't help, can precipitate seizures by unmasking benzodiazepine). - WARD ERROR: Giving physostigmine (cholinesterase inhibitor) for TCA overdose = can cause seizures. - BENZODIAZEPINE OVERDOSE: - Flumazenil = antidote BUT use with caution - can precipitate seizures in chronic benzo users. Please return the FULL, COMPLETE text for all four systems: Cardiology, Rheumatology, Nephrology, and Psychiatry. Do not omit or abbreviate any section. Return ALL the bullet points and details for every topic listed.