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AL-AZHAR MEDICAL COLLEGE — General Surgery 1st Internal 2023

Complete Model Answers

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SECTION I — STRUCTURED ESSAY

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Question 1 (5+5+15+5 = 30 marks)

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(a) Most Probable Diagnosis (5 marks)

• Middle-aged female (classic demographic)
• Anterior neck swelling moving with deglutition → thyroid origin
• Nodular texture on examination
• Symptoms of thyrotoxicosis: weight loss, palpitations
• Mild exophthalmos (infiltrative ophthalmopathy, less severe than Graves')
• 6-month history suggests gradual autonomous function developing in a pre-existing MNG

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(b) Differential Diagnoses (5 marks)

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(c) Investigation and Management (15 marks)

INVESTIGATIONS

• Serum T3, T4 (Free T4, Free T3) — elevated in thyrotoxicosis
• Serum TSH — suppressed (< 0.1 mU/L)
• Thyroid antibodies: Anti-TPO, Anti-TSH receptor (TSH-RAb) — may be mildly positive
• Serum calcium, phosphate (pre-op)
• CBC, LFT, RFT, coagulation profile (pre-operative workup)

• Ultrasound neck — number, size, nature of nodules; vascularity (Doppler); lymph nodes
• Radionuclide scan (Tc-99m / I-131) — hot nodules with suppressed background = toxic nodules; essential to characterise
• FNAC (Fine Needle Aspiration Cytology) — for any dominant/suspicious nodule (Bethesda classification)
• CT neck/thorax — if retrosternal extension suspected; check for tracheal compression/deviation
• Barium swallow — if dysphagia present

• ECG — atrial fibrillation, tachycardia
• Echo — if cardiac failure suspected

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MANAGEMENT

• Carbimazole 20–40 mg/day or Propylthiouracil (PTU) 300–450 mg/day for 6–8 weeks
• Propranolol 40–80 mg TDS for symptom control (palpitations, tremor, anxiety)
• Lugol's iodine (potassium iodide) × 10 days pre-operatively — reduces vascularity of gland
• Target: euthyroid state, pulse < 80/min, weight restored

1. Surgery (Total/Near-total thyroidectomy) — treatment of choice for large/compressive MNG
2. Radioiodine (I-131) — for elderly/high surgical risk patients
3. Long-term antithyroid drugs — rarely curative for toxic MNG (relapse common)

• Nodular goiter with compressive symptoms
• Failed/relapsed medical therapy
• Suspicion of malignancy in a nodule
• Patient preference
• Large goiter with cosmetic issues

• Total thyroidectomy (preferred — eliminates all abnormal thyroid tissue, avoids recurrence)
• Alternatively: near-total thyroidectomy (leaves < 1 g of tissue)
• Post-op lifelong thyroxine replacement (L-T4)

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(d) Complications of Surgery in Toxic MNG (5 marks)

Immediate (< 24 hours)

• Thyroid storm (thyrotoxic crisis) — fever, tachycardia, agitation, hyperthermia; precipitated by inadequate pre-op preparation
• Primary haemorrhage — can cause respiratory obstruction; clip remover at bedside
• Respiratory obstruction — haematoma, tracheomalacia, bilateral RLN palsy

Early (24 hours – 1 week)

• Tetany / Hypocalcaemia — inadvertent parathyroid gland removal; treat with IV calcium gluconate
• Recurrent Laryngeal Nerve (RLN) injury — unilateral → hoarseness; bilateral → respiratory obstruction
• External laryngeal nerve injury → loss of high-pitched voice (cricothyroid palsy)
• Secondary haemorrhage — infection-related
• Wound infection, seroma

Late (> 1 week)

• Hypothyroidism — most common long-term complication; requires lifelong thyroxine
• Hypoparathyroidism — permanent, requires calcium + Vitamin D supplementation
• Keloid / Hypertrophic scar — uncommon in neck
• Recurrence of MNG — if inadequate surgery done

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Question 2 — Essay (15 marks)

Primary Hyperparathyroidism: Etiopathogenesis, Clinical Features, Management & Complications

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ETIOPATHOGENESIS

• Cyclin D1 gene rearrangement — inversion on chromosome 11 places CCND1 gene adjacent to PTH gene regulatory elements → abnormal cyclin D1 overexpression → uncontrolled cell cycle progression
• MEN1 tumor suppressor gene mutations — loss of menin protein; found in ~30–35% of sporadic parathyroid adenomas and familial MEN1 syndrome (parathyroid + pituitary + pancreatic tumors)

• Sporadic (most common)
• MEN1 (Wermer syndrome): primary HPT + pituitary + pancreatic islet tumors
• MEN2A (Sipple syndrome): primary HPT + medullary thyroid carcinoma + phaeochromocytoma
• Radiation to neck
• Lithium therapy

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CLINICAL FEATURES

• Osteitis fibrosa cystica (advanced/classic)
• Brown tumors, pathological fractures
• Subperiosteal bone resorption (radial aspect of middle phalanx — on X-ray)
• "Salt and pepper" skull on X-ray
• Bone pain, tenderness

• Nephrolithiasis (calcium oxalate / phosphate stones) — most common presenting feature
• Nephrocalcinosis, polyuria, polydipsia, nephrogenic DI

• Nausea, vomiting, constipation, anorexia
• Peptic ulcer disease (calcium stimulates gastrin)
• Acute pancreatitis

• Depression, anxiety, cognitive impairment
• Muscle weakness, fatigue, hypotonia

• Hypertension
• Band keratopathy (corneal calcium deposits — slit lamp)
• Most cases today are asymptomatic, detected incidentally on routine calcium screening

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INVESTIGATIONS

• Serum calcium ↑ (> 10.5 mg/dL)
• Serum phosphate ↓ (PTH inhibits renal phosphate reabsorption)
• Serum PTH ↑ (intact PTH assay) — diagnostic when simultaneously elevated with high calcium
• Urinary calcium ↑ (24-hour urine)
• ALP ↑ (if bone involvement)
• Serum creatinine (renal function)
• Chloride/phosphate ratio > 33 (suggestive)
• Vitamin D levels (exclude secondary HPT)

• Sestamibi scan (Tc-99m MIBI) — gold standard for pre-operative localisation
• Neck ultrasound — identifies adenoma (most common: lower pole of posterior thyroid)
• 4D CT scan — for localisation in re-operative cases
• MRI — if ectopic gland suspected
• X-ray hands, skull, abdomen — bone and renal changes
• Renal ultrasound — nephrolithiasis

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MANAGEMENT

• Parathyroidectomy — only curative treatment
• Indications for surgery (even in asymptomatic patients):
  • Serum Ca > 1 mg/dL above normal upper limit
  • Age < 50 years
  • T-score < −2.5 (osteoporosis)
  • Creatinine clearance < 60 mL/min
  • Renal stones/nephrocalcinosis
  • Symptomatic disease

• Focused/minimally invasive parathyroidectomy (MIP) — for single adenoma localised pre-op; with intraoperative PTH monitoring (Miami criterion: 50% fall in PTH levels)
• Bilateral neck exploration — for hyperplasia, MEN, failed localisation
• Subtotal parathyroidectomy (3.5 glands) or total parathyroidectomy + autotransplantation — for hyperplasia

• For asymptomatic patients not meeting surgical criteria:
  • Hydration, bisphosphonates (reduce bone resorption)
  • Cinacalcet (calcimimetic) — activates calcium-sensing receptors → ↓ PTH secretion; for patients unfit for surgery
  • Avoid: thiazide diuretics (worsen hypercalcemia), dehydration, immobilisation

• IV 0.9% saline (3–4 L/day) — first line
• Loop diuretics (furosemide) after rehydration
• IV bisphosphonate (pamidronate/zoledronic acid)
• Calcitonin (rapid but short-acting)
• Haemodialysis (refractory cases)

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COMPLICATIONS

• Hungry bone syndrome — sudden fall in calcium post-op as bones remineralise rapidly; treated with IV/oral calcium + calcitriol
• Hypocalcaemia — tetany, Chvostek's/Trousseau's signs
• Recurrence — if inadequate resection
• Persistent HPT — missed adenoma (ectopic location: mediastinum, thyroid, retroesophageal)
• RLN injury, haemorrhage (as with any neck surgery)

• Severe osteoporosis and pathological fractures
• Renal failure (nephrocalcinosis)
• Cardiovascular disease (hypertension, calcification)
• Pancreatitis

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SHORT ESSAYS (2×5 = 10 marks)

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Question 3 — Applied Anatomy of the Adrenal Gland and Surgical Relevance (5 marks)

ANATOMY

• Right: triangular/pyramidal, overlying upper pole right kidney
• Left: semilunar/crescentic, overlying medial upper border left kidney + left kidney upper pole
• Weight: 4–6 g each; 3 × 5 cm

• Cortex (80%) — mesodermal origin; 3 zones:
  • Zona Glomerulosa → Aldosterone (mineralocorticoid)
  • Zona Fasciculata → Cortisol (glucocorticoid)
  • Zona Reticularis → Androgens (DHEA)
• Medulla (20%) — neuroectodermal (neural crest) origin; Chromaffin cells → Adrenaline + Noradrenaline (catecholamines)

• Arterial (three sources — critical for surgery):
  • Superior suprarenal artery — from inferior phrenic artery
  • Middle suprarenal artery — directly from aorta
  • Inferior suprarenal artery — from renal artery
• Venous (single, large — key surgical landmark):
  • Right adrenal vein — short (< 1 cm), drains directly into inferior vena cava (IVC); most dangerous in surgery
  • Left adrenal vein — longer, drains into left renal vein (+ left inferior phrenic vein)

SURGICAL RELEVANCE

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Question 4 — Planning and Conduct of Surgical Audit (5 marks)

DEFINITION

THE AUDIT CYCLE

1. Select a topic/problem (identify a standard or clinical question)
2. Set criteria and standards (gold standard, evidence-based guidelines)
3. Observe and collect data (current practice)
4. Compare with standards (identify gaps)
5. Implement change and re-audit ("closing the loop")

PLANNING A SURGICAL AUDIT

• High volume procedure (e.g., appendicectomy, cholecystectomy)
• High risk / high cost area
• Known problem area (e.g., SSI rates, anastomotic leak)
• Multidisciplinary interest

• Based on NICE guidelines, RCSE standards, hospital protocols
• E.g., "90% of appendicectomies should be completed within 24 hours of admission"

• Retrospective: case notes review, hospital records, operation registers
• Prospective: data collection forms, electronic records (preferred)
• Data collected: patient demographics, operative details, complications, outcomes, readmissions, mortality

CONDUCT OF A SURGICAL AUDIT

• Theatre registers, discharge summaries, histopathology reports, morbidity/mortality meetings
• National databases (e.g., CEPOD — Confidential Enquiry into Peri-operative Deaths)

• Process audit — was the procedure performed correctly?
• Outcome audit — morbidity, mortality, length of stay, readmission rates
• Structure audit — availability of facilities, staffing, equipment
• Morbidity and mortality (M&M) meetings — regular audit of deaths and complications

• Statistical analysis of outcome indicators
• Comparison against standard (benchmark)
• Identify variance and root cause

• Present findings to department
• Implement corrective measures (education, protocol change, resource allocation)
• Re-audit after 6–12 months to close the loop

• Confidentiality maintained
• Non-punitive, educational environment
• Leadership support essential
• Linked to continuing medical education (CME)

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SHORT NOTES (4×5 = 20 marks)

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Question 5 — Etiopathogenesis of Thyroid Swellings + Diagram of Types of Goiter (5 marks)

ETIOPATHOGENESIS

• Low iodine → ↓ T3/T4 → ↑ TSH → follicular hyperplasia → colloid accumulation → goiter
• Diffuse initially, then multinodular with time

• Dietary: cassava, cabbage, soya (inhibit iodine organification)
• Drugs: lithium, PAS, carbimazole

• Graves' disease: TSH-receptor stimulating antibodies → diffuse goiter + thyrotoxicosis
• Hashimoto's thyroiditis: anti-TPO + anti-thyroglobulin → lymphocytic infiltration → firm goiter + hypothyroidism

• Inherited enzyme defects in thyroid hormone synthesis (peroxidase deficiency, etc.) → compensatory TSH rise → goiter

• Benign: follicular adenoma
• Malignant: papillary, follicular, medullary, anaplastic carcinoma

• De Quervain's thyroiditis (viral, painful)
• Riedel's thyroiditis (fibrotic, woody goiter)

• Puberty, pregnancy, lactation (↑ demand for thyroid hormones)

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DIAGRAM: CLASSIFICATION OF GOITER

GOITER
│
├── By PATHOLOGY
│     ├── Diffuse (Parenchymatous / Colloid)
│     └── Nodular
│           ├── Solitary nodule
│           └── Multinodular goiter (MNG)
│
├── By FUNCTION
│     ├── Euthyroid (non-toxic)
│     ├── Hypothyroid (e.g., Hashimoto's)
│     └── Hyperthyroid (toxic)
│           ├── Toxic MNG (Plummer's)
│           ├── Toxic adenoma
│           └── Graves' (diffuse toxic)
│
└── By STRUCTURE
      ├── Simple / Colloid goiter
      ├── Cystic degeneration
      ├── Haemorrhagic
      ├── Calcified
      └── Malignant transformation

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Question 6 — Fascial Planes of the Hand and Hand Infections (5 marks)

FASCIAL PLANES OF THE HAND

• Palmar aponeurosis — central thick triangular fascia, apex at flexor retinaculum, base forms four digital slips; thickening = Dupuytren's contracture
• Medial (hypothenar) fascia — covers hypothenar muscles
• Lateral (thenar) fascia — covers thenar muscles

• Bounded: laterally by thenar muscles, medially by septum attached to 3rd metacarpal
• Related to: index and middle fingers, flexor tendons
• Infection here → thumb adducted (thenar bulge), index/middle finger semi-flexed

• Bounded: anteriorly by flexor tendons (ring & little fingers), posteriorly by 4th and 5th metacarpals
• Infection here → loss of palmar concavity, ring and little finger semi-flexed

• Located in forearm, above pronator quadratus, beneath flexor tendons
• Communicates with ulnar and sometimes radial bursa
• Infection spreads from U-shaped bursa

• Radial bursa — surrounds FPL tendon
• Ulnar bursa — surrounds flexor tendons to all fingers; both communicate at Parona's space → "horseshoe abscess"

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HAND INFECTIONS

1. Uniform (fusiform) swelling of the finger
2. Semi-flexed posture of the finger (position of rest)
3. Extreme pain on passive extension of the finger
4. Tenderness along the entire flexor tendon sheath

• Paronychia: warm soaks if early; incision along nail fold; partial nail avulsion if subungual
• Felon: hockey stick/fish-mouth incision over pulp space (avoid neurovascular bundles)
• Tenosynovitis: urgent surgical drainage — closed tendon sheath irrigation (catheter method); open incision if severe
• Deep space abscess: surgical incision and drainage, with counter-drainage
• Antibiotics: flucloxacillin ± metronidazole; MRSA cover if needed
• Elevation and splinting

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Question 7 — Burns Management (5 marks)

ASSESSMENT

• Rule of Nines (Wallace, adults):
  • Head & neck: 9%
  • Each upper limb: 9%
  • Anterior trunk: 18%
  • Posterior trunk: 18%
  • Each lower limb: 18%
  • Perineum: 1%
• Lund & Browder chart — more accurate; adjusts for age (especially in children)
• Palm method — patient's palm = ~1% TBSA; useful for small/scattered burns

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MANAGEMENT

IMMEDIATE (First Aid / Pre-hospital)

• Stop the burning process — remove clothing, cool running water (15–20 min, within 3 hours)
• Do NOT use ice (causes vasoconstriction and deepens burn)
• Cover with clean non-adherent dressing
• Keep patient warm (prevent hypothermia)
• Analgesia (IV morphine)

PRIMARY SURVEY (ABCDE)

• Airway: Assess for inhalation injury — hoarseness, stridor, facial burns, singed nasal hair, carbonaceous sputum → early intubation
• Breathing: Circumferential chest burns → escharotomy
• Circulation: IV access × 2 large bore, commence fluid resuscitation

FLUID RESUSCITATION

Total fluid in first 24 hours = 4 mL × body weight (kg) × % TBSA burned

• Use Hartmann's (Ringer's Lactate) solution
• Give 50% in first 8 hours (from time of burn, not admission)
• Give 50% in next 16 hours
• Monitor: urine output 0.5–1 mL/kg/hr (adults), 1 mL/kg/hr (children)
• For burns > 20% TBSA in adults / > 15% in children / > 10% in elderly

WOUND CARE

• Gentle cleaning, debridement of loose skin
• Topical antimicrobials: Silver sulfadiazine (most common), Mafenide acetate, Silver nitrate
• Modern dressings: Biobrane, Mepilex (negative pressure, silver)
• Escharotomy — for circumferential full-thickness burns; releases constriction → restores distal perfusion

SURGICAL

• Split-thickness skin grafting (STSG) — for full-thickness and deep partial-thickness burns after excision (tangential or full excision)
• Early excision and grafting (within 48–72 hrs) reduces infection, mortality
• Donor site: thigh most common

NUTRITIONAL SUPPORT

• High calorie, high protein (burns = hypermetabolic state)
• Enteral feeding preferred (NG tube); start early

SPECIAL BURNS

• Chemical burns: Copious water irrigation × 30 min; alkali burns deeper than acid
• Electrical burns: Cardiac monitoring (arrhythmias); myoglobinuria (IV fluids, alkalinise urine)
• Inhalation injury: Humidified O₂, bronchodilators, N-acetylcysteine; intubation if needed

COMPLICATIONS

• Early: Shock, inhalation injury, sepsis
• Late: Hypertrophic scar, contracture, Marjolin's ulcer (SCC in scar), psychological trauma

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Question 8 — Difference Between Hypertrophic Scar and Keloid (5 marks)

• Intralesional corticosteroids (triamcinolone acetonide) — first line; softens, reduces pruritus
• Silicone gel sheeting — prophylaxis and treatment
• Pressure garments
• Surgical excision + post-op intralesional steroids / radiation — for bulky keloids
• Pulsed dye laser
• Intralesional chemotherapy (5-FU, bleomycin) — for refractory cases
• Radiation (post-excision) — highly effective to prevent recurrence but limited by radiation risks

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Summary of All Answers