Surgery Skin - Last-Minute Exam Tricks 🩺

SKIN & SOFT TISSUE INFECTIONS

🔑 The BIG 3 to distinguish:

• Antibiotics IV broad-spectrum
• Broad debridement urgently
• Careful re-look surgery (multiple times)
• Don't delay for imaging
• Escalate to ICU

BURNS

Rule of 9s (must memorize):

• Head = 9%, Each arm = 9%, Chest front = 9%, Chest back = 9%, Each leg front = 9%, Each leg back = 9%, Perineum = 1%
• Palm = 1% (useful for irregular burns)

Parkland Formula trick:

"4 × kg × %TBSA" - Half in first 8 hrs, half over next 16 hrs

• 1st = Epidermis only = Erythema (sunburn)
• 2nd = Blisters = Better feel pain (partial thickness, very painful)
• 3rd = Leathery/white = Lost sensation (full thickness, PAINLESS)

Chemical Burns - Key rule:

"Dilute, don't neutralize" - Irrigation only, never try to neutralize acid with base.

Electrical Burns - Remember the triad:

"ECG + CK + Urine" - Arrhythmias, muscle damage, myoglobinuria (dark urine). Aim urine >1 mL/kg/hr.

Inhalation Injury - Red flags:

"Soot, Hoarse, Facial burns" = secure airway EARLY before swelling closes it.

PLASTIC / RECONSTRUCTIVE

Skin Graft Rule:

"SPLIT for LARGE, FULL for SMALL/FACE"

• Split-thickness graft = large area coverage
• Full-thickness graft = small, cosmetically important areas

Wound healing failure causes - mnemonic "DIPS":

• Diabetes
• Infection
• Poor blood supply / Pressure
• Starvation (malnutrition)

CARDIAC SURGERY

CABG vs Valve - Key distinction:

• CABG = for coronary artery disease (blocked arteries) → use grafts (IMA or saphenous vein)
• Valve surgery = rheumatic/degenerative → repair > replacement; if mechanical valve → lifelong anticoagulation

Aortic Dissection - Type A vs B trick:

"A = Ascending = Always surgery" "B = Below = Beta-blockers first"

• Type A (ascending) = emergency op
• Type B (descending) = medical (IV beta-blockers), surgery only if complications

TOF - "Boot-shaped heart" = 4 defects:

"PROVE" - Pulmonary stenosis, RVH, Overriding aorta, VSD + Examine CXR for boot shape

THORACIC SURGERY

Pneumothorax vs Hemothorax - percussion trick:

"P = Pneumo = Ping (hyperresonant)" "H = Hemo = Hollow dull"

Tension Pneumothorax - DON'T wait for X-ray:

"Needle decompression NOW, then chest tube" - 2nd intercostal space, midclavicular line

Empyema vs effusion - pleural fluid:

• Effusion: clear fluid → Light's criteria (transudate vs exudate)
• Empyema: PUS → IV antibiotics + chest drain + VATS if loculated

ARTERIAL DISEASE

6 Ps of Acute Limb Ischemia - must memorize:

Pain, Pallor, Pulselessness, Paresthesia, Paralysis, Poikilothermia (cold)

PAD vs Acute Limb Ischemia:

• PAD = chronic, claudication, ABI <0.9 → lifestyle + antiplatelets + statins
• Acute = sudden 6Ps → IV heparin → embolectomy

Carotid disease - "FAST" = TIA warning:

Face, Arm, Speech, Time → carotid endarterectomy if >70% symptomatic stenosis

VENOUS / LYMPHATIC

DVT - Virchow's Triad (OSCE gold):

"SHE" - Stasis, Hypercoagulability, Endothelial injury

Varicose Veins vs CVI vs DVT:

• Varicose = dilated superficial veins, valve incompetence
• CVI = long-standing varicose/DVT → skin changes + venous ulcers
• DVT = acute, unilateral swelling + Doppler confirms

Lymphoedema trick:

"Non-pitting" = lymphoedema (vs pitting = venous/cardiac)

GI SURGERY

GERD → Barrett's → Cancer chain:

GERD → Barrett's → Adenocarcinoma - surveillance endoscopy mandatory

Achalasia - "Bird-beak" on barium:

Manometry = GOLD standard. Treatment: Balloon → Botox → Heller myotomy

Peptic Ulcer Disease - H. pylori triple therapy:

"PPA" = PPI + Amoxicillin + Clarithromycin (C sneaks in but remember 2 antibiotics)

Gastric outlet obstruction - electrolytes:

Vomiting → Hypokalemia + Metabolic alkalosis (losing HCl in vomit)

Perforation signs:

"Free air under diaphragm on erect CXR" = perforation until proven otherwise

APPENDIX & BOWEL OBSTRUCTION

Appendicitis - signs to know:

• McBurney's point = 1/3 from ASIS to umbilicus = RLQ tenderness
• Rovsing's sign = RLQ pain when pressing LLQ
• Psoas sign = pain on hip extension
• Obturator sign = pain on internal rotation of flexed hip

SBO vs LBO:

Volvulus X-ray:

Sigmoid volvulus = "Coffee-bean sign" on AXR

Strangulated bowel = surgical emergency:

Pain + peritonism + fever + shock = laparotomy NOW, no delay

OSCE MAGIC PHRASES (say these in EVERY station)

1. "I will wash my hands, introduce myself, confirm patient identity, and check vital signs."
2. "I will perform an ABCDE assessment."
3. "I will involve a senior/specialist early."
4. "This is a surgical/medical emergency - I will call the surgical team immediately." (for NF, dissection, perforation, ischemia)
5. "I will arrange multidisciplinary team discussion." (for any cancer)

HIGH-YIELD DIFFERENTIALS SUMMARY

• 50 management boxes - every blue "MANAGEMENT / TREATMENT PLAN" from the PDF, compressed into bullet steps
• 5 columns across one A4 page, organized in reading order
• Blue header bars on each box (matching the original style) with a light blue background for the steps
• Covers everything: skin infections, burns, plastic surgery, cardiac, thoracic, arterial, venous, esophagus, stomach, small bowel, colon, rectum, appendix

• All 50 conditions from the PDF, each with 4-6 key differentials
• Color-coded by system so you can instantly spot which category you're in:
  • 🔵 Blue = Skin/Soft Tissue
  • 🔴 Red = Burns
  • 🟢 Teal = Plastic/Reconstructive
  • 🟣 Purple = Cardiac
  • 🟠 Orange = Thorax
  • ...and so on for Arterial, Venous, Esophagus, Stomach, Small Bowel, Colon, Appendix
• Color legend at the bottom of the page
• 5-column layout, fits on 1 A4 page

THE GOLDEN RULE FOR ANY DDx

"Same symptom, different mechanism" - Always think: Infection? Vascular? Neoplasm? Congenital? Autoimmune? Trauma?

• Vascular, Infective, Trauma, Autoimmune, Metabolic, Iatrogenic, Neoplastic, Congenital, Degenerative

SKIN & SOFT TISSUE

The "Red Leg" trio - separate by ONE sign:

Lumps (the 5-second screen):

• Fluctuant + tender = Abscess (drain it)
• Soft + mobile + non-tender = Lipoma
• Has a PUNCTUM = Sebaceous cyst
• In natal cleft = Pilonidal sinus
• Hard + fixed = Cancer until proven otherwise

BURNS DDx

• Heat → Thermal burn
• Acid/alkali → Chemical (ongoing, no neutralize!)
• Electricity → ECG + CK + dark urine (myoglobin)
• Smoke → Inhalation (soot + hoarse + facial burns)

CHEST PAIN DDx - the BIG 6 killers

• Pneumothorax
• Aortic dissection (tearing, back radiation, pulse deficit)
• Tension pneumothorax
• Cardiac tamponade
• Hemothorax
• MI (crushing, radiation to jaw/arm)
• Dissection again (don't forget it)

• Dissection = pain MAXIMAL AT ONSET, radiates to BACK, pulse deficit, widened mediastinum
• MI = pain builds up, ST changes on ECG, no pulse deficit

ABDOMINAL PAIN - "pain out of proportion" rule

Pain out of proportion to exam findings = VASCULAR until proven otherwise

• Mesenteric ischemia
• Ruptured AAA
• Aortic dissection
• Strangulated bowel

DYSPHAGIA DDx

RECTAL BLEEDING DDx

BOWEL OBSTRUCTION DDx

1. Where is it? SBO vs LBO
2. What caused it?

RLQ PAIN DDx - "APPENDICITIS MIMICS"

• Appendicitis (most common)
• Mesenteric adenitis (children, viral)
• Pelvic pathology (ovarian cyst, torsion, ectopic - ALWAYS in women)
• Lymphoma (terminal ileum)
• Ectopic pregnancy (beta-hCG first!)
• Gastrointestinal - Crohn's, Meckel's
• Ovary - torsion, cyst
• Duodenal/renal - ureteric colic (renal stones, hematuria)

CARDIAC DDx - murmur tricks

LIMB ISCHEMIA DDx

LEG SWELLING DDx

THE UNIVERSAL EXAM TRICK

"Common things commonly, dangerous things always"

• "Most likely X... but I must exclude life-threatening Y."