20 typse mostly Important endocrine system and exocrine system diseases important disease treatment investigation findings differential diagnosis contraindications ICO management OPD prescription

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Given the budget constraints (only 1 query_library_db call remaining), I'll now provide a comprehensive, authoritative answer from my medical knowledge base covering the 20 most important endocrine and exocrine system diseases with full clinical details.

20 Most Important Endocrine & Exocrine System Diseases

ENDOCRINE DISEASES (14)

1. TYPE 2 DIABETES MELLITUS (T2DM)

Definition: Insulin resistance + progressive β-cell dysfunction → chronic hyperglycemia.

Investigations:

FPG ≥ 126 mg/dL (7.0 mmol/L) on two occasions
HbA1c ≥ 6.5%
2-hr OGTT ≥ 200 mg/dL
Random plasma glucose ≥ 200 + symptoms
Lipid profile, RFTs, LFTs, urine ACR, serum creatinine, eGFR
Fundoscopy, foot exam, ECG

Findings: Acanthosis nigricans, obesity (central), polyuria, polydipsia, polyphagia, blurred vision, peripheral neuropathy signs.

Treatment / OPD Prescription:

First-line: Metformin 500 mg BD with meals (titrate to 1000 mg BD)
Add-on: SGLT2 inhibitor (Empagliflozin 10 mg OD) or GLP-1 agonist (Semaglutide 0.5 mg SC weekly) — especially if CVD/CKD
DPP-4 inhibitor: Sitagliptin 100 mg OD
Insulin if HbA1c > 10% or symptomatic: Basal insulin (Insulin Glargine 10 units SC OD at bedtime)
Antihypertensive: ACE inhibitor (Ramipril 5 mg OD) if microalbuminuria
Statin: Atorvastatin 20–40 mg OD
Aspirin 75 mg OD if high CVD risk
Lifestyle: diet, exercise, weight loss

Differential Diagnosis: T1DM, MODY, secondary DM (Cushing's, acromegaly, pancreatitis), steroid-induced DM

Contraindications:

Metformin: eGFR < 30, severe hepatic disease, IV contrast, alcoholism
SGLT2i: eGFR < 45 (canagliflozin), DKA, UTI history
Thiazolidinediones: heart failure, liver disease, osteoporosis

ICU Management: DKA/HHS — see #2 below

2. DIABETIC KETOACIDOSIS (DKA)

Investigations: ABG (high anion gap metabolic acidosis), blood glucose, serum ketones, BMP, CBC, UA, ECG

Findings: pH < 7.3, bicarbonate < 15, glucose > 250 mg/dL, ketonemia/ketonuria, Kussmaul breathing, fruity breath

ICU Management:

IV fluids: 0.9% NaCl 1L/hr first hour, then 250–500 mL/hr
Insulin: Regular insulin 0.1 units/kg/hr IV infusion (no bolus if K⁺ < 3.5)
Potassium replacement: Add KCl 20–40 mEq/L to fluids once K⁺ < 5.5 and urine output confirmed
Bicarbonate: only if pH < 6.9
Monitor glucose hourly; transition to SC insulin when pH > 7.3, anion gap closed, patient eating

Contraindications: Do NOT give insulin without K⁺ correction if hypokalemic; avoid bicarbonate routinely.

3. TYPE 1 DIABETES MELLITUS (T1DM)

Investigations: Anti-GAD antibodies, anti-islet cell antibodies, C-peptide (low/absent), HbA1c, blood glucose

Treatment:

Basal-bolus insulin regimen:
- Basal: Insulin Glargine (Lantus) 0.2 units/kg SC at bedtime
- Bolus: Insulin Lispro/Aspart 1 unit per 10g carbs + correction dose SC before meals
Continuous glucose monitoring (CGM), carb counting
DAFNE education

OPD Prescription: Insulin Glargine 20 units SC at bedtime + Insulin Aspart 6 units SC TDS before meals; HbA1c target < 7.0%

Contraindications: Metformin alone (insufficient); sulfonylureas (not effective without β-cell function)

4. HYPOTHYROIDISM

Investigations:

TSH ↑ (primary hypothyroidism most common finding)
Free T4 ↓
Anti-TPO antibodies (Hashimoto's)
Lipid profile (hyperlipidemia), CBC (normocytic anemia), ECG (bradycardia, low voltage)

Findings: Fatigue, weight gain, cold intolerance, constipation, bradycardia, myxedema, periorbital edema, dry skin, slow-relaxing reflexes, goiter (Hashimoto's)

Treatment / OPD Prescription:

Levothyroxine (T4): Start 1.6 mcg/kg/day OD, taken 30–60 min before breakfast on empty stomach
Example: 75–100 mcg OD; titrate every 6–8 weeks based on TSH
Elderly/cardiac: Start 25 mcg OD and uptitrate slowly
Target TSH: 0.5–2.5 mIU/L

Differential Diagnosis: Secondary hypothyroidism (pituitary), sick euthyroid syndrome, drug-induced (amiodarone, lithium)

Contraindications: Calcium, iron, PPIs reduce levothyroxine absorption — take separately by 4 hours; avoid in untreated adrenal insufficiency (precipitates adrenal crisis)

ICU — Myxedema Coma:

IV Levothyroxine 200–400 mcg loading dose, then 100 mcg IV/day
Hydrocortisone 100 mg IV 8-hourly until adrenal insufficiency excluded
Warming, IV fluids, ventilatory support

5. HYPERTHYROIDISM / GRAVES' DISEASE

Investigations:

TSH ↓ (suppressed), free T3/T4 ↑
TSH receptor antibodies (TRAb) — specific for Graves'
Thyroid uptake scan: diffuse uptake (Graves') vs hot nodule (toxic adenoma)
ECG (atrial fibrillation), echo if heart failure

Findings: Tremor, heat intolerance, weight loss, palpitations, exophthalmos (Graves'), pretibial myxedema, goiter, hyperreflexia, diarrhea, AF

Treatment / OPD Prescription:

Carbimazole 20–40 mg OD (titration) OR Propylthiouracil (PTU) 100 mg TDS
Beta-blocker: Propranolol 40 mg BD for symptom control (tremor, palpitations)
Definitive: Radioiodine (I-131) or thyroidectomy
Titration regimen OR block-replace regimen

Differential Diagnosis: Thyroiditis, toxic nodular goiter, TSH-secreting pituitary adenoma, factitious hyperthyroidism

Contraindications:

PTU preferred in pregnancy (1st trimester); Carbimazole teratogenic in 1st trimester
Radioiodine contraindicated in pregnancy, active severe ophthalmopathy

ICU — Thyroid Storm:

PTU 600 mg loading, then 200 mg 4-hourly NG
Lugol's iodine 5 drops 6-hourly (1 hour AFTER PTU)
Hydrocortisone 200 mg IV then 100 mg 8-hourly
Propranolol 1–2 mg IV slowly or 60–80 mg PO 4-hourly
Cooling, IV fluids, treat precipitant

6. CUSHING'S SYNDROME

Investigations:

Screening: 24-hr urinary free cortisol (×2), overnight 1 mg dexamethasone suppression test (DST), late-night salivary cortisol
Low-dose DST: no suppression (>50 nmol/L)
High-dose DST + ACTH level: ACTH-dependent vs independent
CRH stimulation test
MRI pituitary (Cushing's disease), CT adrenal, CT chest (ectopic ACTH)

Findings: Central obesity, moon face, buffalo hump, purple striae, easy bruising, hirsutism, hypertension, hyperglycemia, proximal myopathy, osteoporosis, depression

Treatment:

Cushing's disease (pituitary): Trans-sphenoidal surgery (first-line)
Medical: Metyrapone, Ketoconazole, Cabergoline, Pasireotide
Adrenal adenoma: Laparoscopic adrenalectomy
Ectopic ACTH: Treat primary tumor; bilateral adrenalectomy if refractory

OPD Prescription: While awaiting surgery — Metyrapone 250 mg TDS titrated + monitor cortisol/electrolytes

Differential Diagnosis: Exogenous steroid use (most common), pseudo-Cushing's (alcohol, depression), ACTH-independent vs dependent

Contraindications: Ketoconazole — hepatotoxic, avoid in liver disease; caution with CYP3A4 drugs

7. ADDISON'S DISEASE (PRIMARY ADRENAL INSUFFICIENCY)

Investigations:

8 AM cortisol (< 83 nmol/L highly suspicious)
Short Synacthen (ACTH stimulation) test: peak cortisol < 500 nmol/L = insufficient
ACTH level ↑ (primary)
Electrolytes: hyponatremia, hyperkalemia
Anti-adrenal/anti-21-hydroxylase antibodies (autoimmune)
CT adrenal: calcification (TB), atrophy, hemorrhage

Findings: Fatigue, weight loss, hyperpigmentation (buccal mucosa, skin creases, scars), postural hypotension, nausea, salt craving, hypoglycemia

Treatment / OPD Prescription:

Hydrocortisone 10 mg AM, 5 mg noon, 5 mg 4 PM (physiological replacement)
Fludrocortisone 0.1 mg OD (mineralocorticoid replacement)
Sick day rules: Double/triple hydrocortisone dose during illness; IM Hydrocortisone 100 mg self-injection kit for emergencies
Medical alert bracelet

Adrenal Crisis (ICU):

Hydrocortisone 100 mg IV STAT, then 100 mg IV 6-hourly or 200 mg/24hr infusion
IV 0.9% NaCl 1L rapidly, then monitored
Treat precipitant (infection, surgery)

Contraindications: Never abruptly stop steroids; must cover for surgery/illness

8. PRIMARY HYPERALDOSTERONISM (CONN'S SYNDROME)

Investigations:

Aldosterone:Renin ratio (ARR) > 30 ng/dL per ng/mL/hr (screening)
Confirmatory: Salt loading test, fludrocortisone suppression test
CT adrenal (adenoma vs bilateral hyperplasia)
Adrenal vein sampling (AVS) — gold standard to lateralize

Findings: Hypertension (often resistant), hypokalemia, metabolic alkalosis, headache, polyuria, muscle weakness

Treatment:

Unilateral adenoma: Laparoscopic adrenalectomy
Bilateral hyperplasia: Spironolactone 25–50 mg OD (up to 400 mg), or Eplerenone 25–50 mg OD

OPD Prescription: Spironolactone 25 mg OD, increase to 50–100 mg; add potassium supplements if needed; monitor K⁺ and BP

Differential Diagnosis: Essential hypertension with diuretic use, secondary hyperaldosteronism (renal artery stenosis, heart failure), Liddle syndrome

Contraindications: Spironolactone — avoid in renal failure, hyperkalemia, pregnancy (anti-androgenic effects); Eplerenone preferred in men (avoids gynecomastia)

9. ACROMEGALY

Investigations:

IGF-1 elevated (best screening test)
Failure to suppress GH < 1 ng/mL after 75g OGTT (gold standard)
MRI pituitary (macroadenoma usually)
Visual field testing (bitemporal hemianopia)
Colonoscopy (increased colorectal cancer risk), echo (cardiomegaly), sleep study (OSA)

Findings: Enlarged hands/feet, coarsening facial features, prognathism, macroglossia, hyperhidrosis, hypertension, T2DM, OSA, carpal tunnel syndrome, bitemporal hemianopia

Treatment:

First-line: Trans-sphenoidal surgery
Medical (adjuvant): Octreotide LAR 20 mg IM monthly, or Lanreotide
Pegvisomant (GH receptor antagonist) if SSA fails
Radiotherapy for residual/recurrent disease
Cabergoline (mild-moderate, high prolactin component)

OPD Prescription: Octreotide LAR 20 mg IM every 28 days; monitor IGF-1 quarterly

Contraindications: SSA — caution with gallstones (can cause cholecystitis); pegvisomant — monitor LFTs

10. HYPERPROLACTINEMIA

Investigations:

Serum prolactin (> 200 ng/mL strongly suggests prolactinoma; rule out macroprolactin)
MRI pituitary
TFTs (hypothyroidism causes ↑ prolactin)
Beta-hCG, medications review (dopamine antagonists)
Visual fields

Findings: Women: amenorrhea, galactorrhea, infertility; Men: reduced libido, erectile dysfunction, gynecomastia, infertility; Large tumors: headache, bitemporal hemianopia

Treatment / OPD Prescription:

First-line: Cabergoline 0.5 mg twice weekly (more effective, better tolerated)
Alternative: Bromocriptine 1.25 mg nocte titrated to 2.5 mg BD/TDS
Surgery (trans-sphenoidal) if drug-resistant or large with mass effect
Monitor prolactin levels every 3 months; MRI at 1 year

Differential Diagnosis: Pregnancy, hypothyroidism, drug-induced (metoclopramide, antipsychotics, domperidone, antidepressants, opioids), physiological (stress, sleep)

Contraindications: Cabergoline — cardiac valvulopathy at high doses (used in Parkinson's); caution in pregnancy (use bromocriptine instead)

11. DIABETES INSIPIDUS (DI)

Investigations:

Urine osmolality < 300 mOsm/kg with serum osmolality > 295 (inappropriately dilute urine)
Water deprivation test: no urine concentration in central/nephrogenic DI
DDAVP response test: urine concentrates with DDAVP = central DI; no response = nephrogenic DI
MRI brain (absent posterior pituitary bright spot in central DI)
Electrolytes: hypernatremia, hyperosmoality

Findings: Polyuria (> 3L/day), polydipsia, nocturia, dilute urine (SG < 1.005), normal glucose

Treatment / OPD Prescription:

Central DI: Desmopressin (DDAVP) 10–20 mcg intranasal BD, or 0.1 mg PO TDS
Nephrogenic DI: Low-salt, low-protein diet; Thiazide diuretic (Hydrochlorothiazide 25 mg OD); Indomethacin; treat cause
Monitor sodium, urine output

Differential Diagnosis: Primary polydipsia (psychogenic), osmotic diuresis (diabetes mellitus, mannitol)

Contraindications: DDAVP — hyponatremia risk; avoid in hyponatremia; nephrogenic DI — DDAVP ineffective

12. PHEOCHROMOCYTOMA

Investigations:

24-hr urine catecholamines and metanephrines (most sensitive)
Plasma free metanephrines (best single test)
CT/MRI adrenal (MIBG scan for metastatic/extra-adrenal)
Clonidine suppression test
Genetic testing (SDHB, SDHD, VHL, RET, NF1)

Findings: Paroxysmal headache, palpitations, diaphoresis (classic triad), hypertensive crises, pallor, weight loss, hyperglycemia

Treatment:

Alpha-blockade FIRST: Phenoxybenzamine 10 mg BD titrated (irreversible) OR Doxazosin 2–4 mg OD
Add beta-blocker ONLY after adequate alpha-blockade: Propranolol 40 mg TDS
Pre-operative volume expansion (high-salt diet, IV fluids)
Laparoscopic adrenalectomy (definitive)

OPD Prescription: Phenoxybenzamine 10 mg BD (titrate to 20–40 mg BD); then add Propranolol 40 mg BD 2 weeks before surgery

Contraindications: NEVER start beta-blocker before alpha-blocker (hypertensive crisis from unopposed alpha stimulation)

13. HYPERPARATHYROIDISM (PRIMARY)

Investigations:

Serum calcium ↑, phosphate ↓, PTH ↑ (inappropriately normal or elevated)
24-hr urine calcium (↑ in primary; low in FHH)
ALP ↑ (bone involvement)
DEXA scan (osteoporosis), X-ray (subperiosteal resorption, "salt and pepper" skull, brown tumors, osteitis fibrosa cystica)
Renal US (nephrolithiasis), sestamibi scan (parathyroid adenoma localization)

Findings: "Bones, Stones, Groans, Psychic Moans" — bone pain, renal calculi, constipation/nausea, depression/confusion; often asymptomatic (incidental hypercalcemia)

Treatment / OPD Prescription:

Symptomatic/meets criteria: Parathyroidectomy (curative)
Asymptomatic (medical management): Adequate hydration, avoid thiazides, calcium ≥ 400 mg/day
Cinacalcet (calcimimetic) 30 mg BD if surgery not possible (reduces PTH and calcium)
Bisphosphonates (Alendronate 70 mg weekly) for osteoporosis

Hypercalcemic Crisis (ICU):

IV 0.9% NaCl aggressive hydration (4–6L/day)
IV Furosemide (only after adequate hydration)
IV Bisphosphonate: Zoledronic acid 4 mg IV over 15 min
Calcitonin 4 IU/kg IM/SC 12-hourly (rapid but short-acting)
Dialysis if renal failure

Contraindications: Thiazide diuretics worsen hypercalcemia; avoid immobilization

14. HYPOPARATHYROIDISM

Investigations: Calcium ↓, phosphate ↑, PTH ↓, Magnesium (check), ECG (prolonged QT)

Findings: Tetany, Chvostek's sign (facial twitch on tapping), Trousseau's sign (carpal spasm with BP cuff), perioral tingling, seizures, papilledema, cataracts (chronic)

Treatment / OPD Prescription:

Calcium Carbonate 500 mg TDS with meals
Calcitriol (active Vitamin D) 0.25–2 mcg OD (critical — PTH absent so cannot activate Vit D)
Magnesium supplementation if low
Recombinant PTH (Natpara) in refractory cases
Monitor calcium every 3–6 months; keep calcium at low-normal (8–8.5 mg/dL)

ICU (Hypocalcemic Crisis):

IV Calcium Gluconate 10% 10 mL IV over 10 min; then infusion 0.5–2 mg/kg/hr elemental calcium
Monitor ECG during IV infusion

EXOCRINE DISEASES (6)

15. ACUTE PANCREATITIS

Investigations:

Serum amylase/lipase > 3× upper limit (lipase more sensitive and specific)
LFTs, CBC, BMP, ABG, LDH, calcium
Severity: Ranson's criteria, APACHE II, BISAP score
CT abdomen with contrast (CECT) — for complications (necrosis, abscess, pseudocyst); not routinely on day 1
US abdomen (gallstones as cause)

Findings: Epigastric pain radiating to back, worse lying down, relieved sitting forward; nausea/vomiting; Cullen's sign (periumbilical ecchymosis), Grey Turner's sign (flank ecchymosis) — hemorrhagic pancreatitis; peritonism; fever

Treatment / ICU Management:

Aggressive IV fluids: Lactated Ringer's 250–500 mL/hr (preferred over NS)
NBM initially → early enteral nutrition via nasojejunal tube within 24–48 hrs (better than TPN)
Analgesia: Morphine 2.5–5 mg IV 4-hourly or PCA; avoid NSAIDs if hemodynamically unstable
Antibiotics: NOT routinely; give if infected necrosis (Imipenem/Meropenem)
ERCP: If gallstone pancreatitis with cholangitis within 24–72 hrs
Insulin infusion for hypertriglyceridemia-induced pancreatitis
Surgery/necrosectomy: Infected necrosis (delayed, after 4 weeks)

OPD (Discharge) Prescription:

Pancreatic enzyme supplementation (Creon) if exocrine insufficiency develops
Alcohol cessation; treat hyperlipidemia (Fenofibrate if triglycerides cause)
Cholecystectomy arranged if gallstone cause

Differential Diagnosis: PUD/perforated ulcer, mesenteric ischemia, aortic dissection, biliary colic, inferior MI

Contraindications: Avoid early surgical intervention in sterile necrosis; avoid prophylactic antibiotics routinely; avoid high-fat diet during recovery

16. CHRONIC PANCREATITIS

Investigations:

CT abdomen: calcifications (pathognomonic), ductal dilation
MRCP/ERCP: ductal abnormalities
Fecal elastase < 200 mcg/g (exocrine insufficiency)
HbA1c, glucose (pancreatogenic DM — type 3c)
Fat-soluble vitamin levels (A, D, E, K)
Serum IgG4 (autoimmune pancreatitis)

Findings: Recurrent epigastric pain, steatorrhea (oily, foul-smelling stools), weight loss, DM, nutritional deficiencies (fat-soluble vitamins, B12)

Treatment / OPD Prescription:

Pain: Paracetamol 1g TDS first-line; Tramadol 50–100 mg TDS; avoid long-term NSAIDs; low-dose Amitriptyline 25 mg nocte for neuropathic component
Pancreatic enzyme replacement: Creon 25,000 units (2 capsules) with each meal + 1 capsule with snacks
PPI (Omeprazole 20 mg OD) to prevent acid inactivation of enzymes
Fat-soluble vitamins: Vitamin D 800 IU OD, Vitamin A, K supplements
Pancreatogenic DM: Insulin (avoid metformin if exocrine deficiency + liver issues)
Alcohol abstinence (mandatory); smoking cessation
Endoscopic/surgical: Pancreatic duct stenting, Frey/Whipple procedure

Differential Diagnosis: Pancreatic cancer (marker CA 19-9, EUS-FNA), peptic ulcer disease

Contraindications: Opioids long-term (addiction risk); thiazides and tetracyclines can worsen; fat-restricted diet excessively can worsen malnutrition

17. PANCREATIC CANCER (Exocrine — Ductal Adenocarcinoma)

Investigations:

CT abdomen (triple phase) — mass in head of pancreas ± double duct sign
CA 19-9 (elevated; not diagnostic alone)
ERCP/MRCP (biliary obstruction)
EUS + FNA (tissue diagnosis)
Staging CT chest/abdomen/pelvis
PET scan for metastases

Findings: Painless progressive jaundice (head of pancreas), Courvoisier's sign (palpable non-tender gallbladder), weight loss, new-onset DM, epigastric pain, Trousseau's migratory thrombophlebitis, pale/oily stools, dark urine

Treatment:

Resectable: Whipple's procedure (pancreaticoduodenectomy) — only 15–20% resectable at diagnosis
Adjuvant: Gemcitabine + Capecitabine (ESPAC-4 regimen)
Unresectable/Metastatic: FOLFIRINOX (5-FU + Leucovorin + Irinotecan + Oxaliplatin) or Gemcitabine + Nab-paclitaxel
Palliative: Biliary stenting (ERCP), pain management (coeliac plexus block), Creon for malabsorption

OPD Prescription (Palliative):

Creon 25,000 units 2 caps with meals; Omeprazole 20 mg OD; Vitamin D; analgesia ladder (Morphine SR + breakthrough); antiemetics; LMWH (tinzaparin) for VTE prophylaxis/treatment

Contraindications: Whipple in unresectable disease; FOLFIRINOX only if good performance status (ECOG 0–1)

18. CYSTIC FIBROSIS (CF) — Exocrine Pancreatic Insufficiency

Investigations:

Newborn screening: immunoreactive trypsinogen (IRT) + CFTR mutation analysis
Sweat chloride test > 60 mmol/L (confirmatory)
CFTR gene mutation analysis
Fecal elastase, fat-soluble vitamins
Pulmonary function tests (FEV1/FVC), chest CT (bronchiectasis, mucous plugging)
Sputum culture (Pseudomonas aeruginosa, Burkholderia cepacia)
OGTT (CF-related diabetes)

Findings: Failure to thrive, steatorrhea, recurrent pulmonary infections, bronchiectasis, meconium ileus (neonates), nasal polyps, digital clubbing, male infertility (absent vas deferens), liver disease (biliary cirrhosis)

Treatment / OPD Prescription:

CFTR modulators: Elexacaftor/Tezacaftor/Ivacaftor (Kaftrio/Trikafta) — for eligible mutations (F508del homozygous/heterozygous) — transformative therapy
Airway clearance: Physiotherapy (chest percussion), hypertonic saline nebulization, DNase (Dornase alfa 2.5 mg nebulized OD)
Antibiotics: Inhaled Tobramycin or Colistin for Pseudomonas; oral azithromycin 250 mg TDS 3 days/week (anti-inflammatory)
Pancreatic enzyme: Creon (titrated by weight and diet)
Fat-soluble vitamins: ADEK vitamins daily
Insulin for CF-related DM (avoid metformin)
Ursodeoxycholic acid for liver disease

Contraindications: Azithromycin with QT-prolonging drugs; Ivacaftor in non-gating mutations (ineffective); avoid live attenuated vaccines in CF

19. SALIVARY GLAND DISEASES (Sialadenitis / Sialolithiasis)

Investigations:

US salivary glands (calculi, abscess)
CT sialography (ductal anatomy)
Plain X-ray (80% submandibular stones are radio-opaque)
Serum amylase (elevated in parotitis)
Anti-SSA/SSB antibodies, lip biopsy (Sjögren's syndrome)
Serum ACE, chest X-ray (sarcoidosis)
HIV, hepatitis serology

Findings:

Sialolithiasis: Sudden painful swelling of submandibular gland with eating (colicky), palpable hard lump in floor of mouth
Acute sialadenitis: Tender, erythematous swollen gland, purulent discharge from duct orifice
Sjögren's: Bilateral parotid enlargement, xerostomia, keratoconjunctivitis sicca, bilateral gland involvement

Treatment / OPD Prescription:

Small stones: Hydration, massage, sialogogues (lemon drops, chewing gum), analgesics
Infection: Amoxicillin-Clavulanate 625 mg TDS × 10 days (or Flucloxacillin if staph); warm compresses; adequate hydration
Large stones: Lithotripsy or sialoendoscopy; open surgery (submandibular gland excision) for recurrent/large stones
Sjögren's: Pilocarpine 5 mg TDS, Hydroxychloroquine, lubricant eye drops, artificial saliva

Differential Diagnosis: Parotid tumor, lymphoma, sarcoidosis, HIV parotitis, Mikulicz's disease

Contraindications: Pilocarpine in narrow-angle glaucoma, uncontrolled asthma

20. ZOLLINGER-ELLISON SYNDROME (ZES) — Gastrinoma

Investigations:

Fasting serum gastrin > 1000 pg/mL (or > 10× upper limit) is diagnostic
Secretin stimulation test: paradoxical rise in gastrin ≥ 200 pg/mL (gold standard)
Gastric pH < 2 while on PPIs
CT/MRI abdomen (tumor localization)
Somatostatin receptor scintigraphy (Octreotide scan / Ga-68 DOTATATE PET — most sensitive)
EUS (small tumors)
MEN1 screening (gastrinoma associated with MEN1 in 25%)

Findings: Multiple/refractory peptic ulcers (especially post-bulbar), chronic diarrhea, esophagitis (severe GERD), weight loss; often present with ulcer complications (hemorrhage, perforation)

Treatment / OPD Prescription:

High-dose PPI: Omeprazole 40 mg BD (or Pantoprazole 80 mg BD) — dramatically controls symptoms
Surgical resection of gastrinoma (curative intent if localized and no liver mets)
Somatostatin analogues (Octreotide LAR) for metastatic disease/MEN1
Chemotherapy: Streptozocin + 5-FU or Everolimus/Sunitinib for metastatic disease

Differential Diagnosis: H. pylori peptic ulcer disease, antral G-cell hyperplasia, retained gastric antrum post-gastrectomy, MEN1

Contraindications: H2 blockers insufficient (inadequate acid suppression); avoid NSAIDs; surgical resection contraindicated if diffuse metastases without control of disease

Quick Reference Summary Table

#	Disease	System	Key Investigation	First-line Treatment	Critical Contraindication
1	T2DM	Endocrine	HbA1c, FPG	Metformin + lifestyle	Metformin if eGFR < 30
2	DKA	Endocrine	ABG, glucose, ketones	IV fluids + insulin + K⁺	Insulin without K⁺ correction
3	T1DM	Endocrine	Anti-GAD, C-peptide	Basal-bolus insulin	Metformin alone
4	Hypothyroidism	Endocrine	TSH↑, free T4↓	Levothyroxine	Untreated adrenal insufficiency
5	Hyperthyroidism	Endocrine	TSH↓, free T3/T4↑	Carbimazole + propranolol	Radioiodine in pregnancy
6	Cushing's	Endocrine	UFC, DST, MRI	Surgery (TSS)	Abrupt steroid withdrawal
7	Addison's	Endocrine	Short Synacthen test	Hydrocortisone + Fludrocortisone	Stopping steroids abruptly
8	Conn's	Endocrine	ARR, AVS	Adrenalectomy / Spironolactone	Spironolactone in hyperkalemia
9	Acromegaly	Endocrine	IGF-1, OGTT GH	Surgery then Octreotide	SSA in gallstone disease
10	Hyperprolactinemia	Endocrine	Prolactin, MRI pit	Cabergoline	Cabergoline in cardiac valve disease
11	Diabetes Insipidus	Endocrine	Water deprivation test	DDAVP (central)	DDAVP in hyponatremia
12	Phaeochromocytoma	Endocrine	Plasma metanephrines	Alpha then beta block → surgery	Beta-blocker before alpha-blocker
13	Hyperparathyroidism	Endocrine	Calcium↑, PTH↑	Parathyroidectomy	Thiazides (worsen hypercalcemia)
14	Hypoparathyroidism	Endocrine	Calcium↓, PTH↓	Calcium + Calcitriol	Calcitriol without calcium monitoring
15	Acute Pancreatitis	Exocrine	Lipase > 3×, CECT	IV fluids + analgesia + early EN	Prophylactic antibiotics routinely
16	Chronic Pancreatitis	Exocrine	Fecal elastase, CT	Creon + analgesia + abstinence	Long-term opioids
17	Pancreatic Cancer	Exocrine	CT triple phase, CA 19-9	Whipple's / FOLFIRINOX	Whipple in unresectable
18	Cystic Fibrosis	Exocrine	Sweat chloride > 60	Kaftrio + Creon + physio	Ivacaftor in non-gating mutations
19	Sialadenitis/Sialolithiasis	Exocrine	US, plain X-ray	Hydration + antibiotics / stone removal	Pilocarpine in glaucoma
20	Zollinger-Ellison Syndrome	Exocrine	Fasting gastrin, secretin test	High-dose PPI + gastrinoma surgery	H2 blockers alone (insufficient)

Key OPD Prescription Principles:

Always write drug name, dose, frequency, duration, and special instructions (timing, food relation)
Sick-day rules for all patients on steroids (Addison's, Cushing's post-op)
HbA1c target, BP target, and lipid target must be documented for all diabetics
Titrate thyroxine every 6–8 weeks based on TSH
Medical alert bracelets for Addison's, T1DM, hypoglycemia-prone patients

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