M.S. General Surgery - Paper III (March/April 2017) — Model Answers

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QUESTION 1 [30 Marks]

Carcinoma Penis: Premalignant Conditions, Etiopathology, Clinical Features and Management

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I. PREMALIGNANT CONDITIONS OF THE PENIS

A. Penile Intraepithelial Neoplasia (PeIN) / Carcinoma in Situ

• Erythroplasia of Queyrat: PeIN occurring on the glans penis. Appears as a bright red, velvety, well-demarcated plaque. Malignant transformation rate ~10%.
• Bowen's disease: PeIN on the shaft of the penis. Appears as a scaly, erythematous plaque. Considered a squamous cell carcinoma in situ.

B. Leukoplakia of the Glans

• White, thickened patches on the glans penis, similar to oral leukoplakia.
• Represents hyperkeratosis and dysplasia; considered premalignant.

C. Lichen Sclerosus (LS) / Balanitis Xerotica Obliterans (BXO)

• A chronic inflammatory dermatosis causing whitish, atrophic plaques on the glans and prepuce.
• Strongly associated with carcinoma of the penis (Figure 85.23 in Bailey & Love shows early penile cancer in a patient with lichen sclerosus).

D. Condyloma Acuminata (Buschke-Lowenstein Tumour)

• Giant condylomata associated with HPV types 6 and 11.
• Although histologically benign, these are locally invasive; the giant form is considered a verrucous carcinoma variant.
• Carries malignant transformation potential.

E. Chronic Balanoposthitis

• Recurrent inflammation under the foreskin due to poor hygiene or phimosis.
• Long-standing inflammation creates a carcinogenic environment.

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II. ETIOPATHOLOGY

• Circumcision performed soon after birth confers near-complete immunity. Late circumcision does not confer the same benefit, implying smegma is in some way carcinogenic.
• Two pathways exist: (1) HPV-related (verrucous/warty subtype), (2) HPV-unrelated (keratinising/flat invasive type, arising from lichen sclerosus or leukoplakia). (Bailey and Love, p. 1573; Robbins Pathologic Basis of Disease)

• Squamous cell carcinoma (SCC) is the most common type (~95%)
• Other types: verrucous, basaloid, papillary, warty, sarcomatoid

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III. PATHOLOGY AND STAGING

• Flat/infiltrating type: starts as leukoplakia or PeIN
• Warty/exophytic type: arises from existing papilloma

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IV. CLINICAL FEATURES

• Age: Usually >50 years; ~10% are under 40 years of age
• Site: Most commonly the glans penis (48%) and prepuce (21%)
• Primary lesion: May present as a papule, nodule, ulcer, or warty growth. Often the prepuce is non-retractile (phimosis), hiding the lesion and causing delay in diagnosis.
• Discharge: Foul, bloody discharge from under a tight prepuce is a common presentation
• Pain: Typically little or no pain, even with large lesions
• Advanced disease: Fungating/ulcerative growth replacing the glans
• Lymph nodes: ~50% have inguinal lymphadenopathy at presentation, but this often reflects infection rather than metastasis
• Late complications: Inguinal nodes may erode the skin of the groin; erosion of the femoral or external iliac vessels can be fatal in rare cases.

• Biopsy: Mandatory for diagnosis
• MRI: For local staging of the primary tumour
• Ultrasound-guided FNA: Of palpable inguinal nodes to confirm metastasis
• CT scan: For pelvic and distant lymph node assessment (Bailey and Love, p. 1573-1574)

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V. MANAGEMENT

A. Treatment of the Primary Tumour

B. Treatment of Inguinal Lymph Nodes

• Timing: Lymph node management should be delayed by at least 3 weeks after local treatment of the primary, to allow resolution of reactive infection-related lymphadenopathy.
• Palpable nodes: Ultrasound-guided FNA confirms metastasis; if positive, bilateral block dissection of the groins is performed.
• Non-palpable nodes: Sentinel lymph node biopsy (SLNB) followed by inguinal node dissection if SLNB is positive.

C. Management of Pelvic (Iliac) Nodes

• When involved on CT scanning, surgery has limited role.
• When iliac nodes are not enlarged in the presence of N2 disease, options include: observation, pelvic lymphadenectomy, or radiotherapy.

D. Radiotherapy

• Useful for small T1-T2 lesions as primary treatment (organ-preserving).
• Used for pelvic nodes when surgery is not feasible.

E. Chemotherapy

• Relatively ineffective; reserved for palliation in metastatic disease.
• Regimens: Cisplatin-based (e.g., TIP - paclitaxel, ifosfamide, cisplatin).

F. Prognosis

• Tumours confined to the penis: 5-year survival >80%
• With nodal involvement: 5-year survival ~40% (Bailey and Love, p. 1574)

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QUESTION 2 [20 Marks]

Painless Haematuria: Causes, Differential Diagnosis and Investigations

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I. DEFINITION

• Visible (VH) / Gross haematuria: blood visible to the naked eye
• Non-visible (NVH) / Microscopic haematuria: detectable only on dipstick or microscopy (>3 RBCs/HPF)

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II. CAUSES (Mnemonic: TIN - Trauma, Infection, Neoplasm)

A. Neoplastic (Most Important for Painless Haematuria)

B. Trauma

• Renal trauma (blunt or penetrating)
• Bladder trauma
• Catheter trauma (iatrogenic)

C. Infective/Inflammatory

• UTI (cystitis, urethritis) - usually associated with dysuria
• Pyelonephritis
• Genitourinary tuberculosis (haematuria with dysuria and frequency)
• Schistosomiasis (Schistosoma haematobium)
• Filarial involvement of retroperitoneal lymphatics (chyluria + haematuria)

D. Calculi

• Ureteric/renal calculi (usually associated with pain - renal colic; occasionally painless)
• Bladder calculi

E. Glomerular Disease

• IgA nephropathy (Berger's disease) - episodic macroscopic haematuria
• Post-streptococcal glomerulonephritis
• Alport syndrome
• Thin basement membrane disease

F. Coagulopathy and Drugs

• Anticoagulant therapy (warfarin, heparin, DOACs)
• Thrombocytopenia
• Haemophilia
• Drugs: cyclophosphamide (haemorrhagic cystitis), NSAIDs

G. Benign Prostatic Hyperplasia (BPH)

• Can cause haematuria in older men - diagnosis of exclusion after excluding all other causes

H. Vascular Causes

• Arteriovenous malformation (AVM) of kidney
• Renal vein thrombosis

I. Others

• Polycystic kidney disease
• Sickle cell disease/trait
• Exercise-induced haematuria ("march haematuria")

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III. DIFFERENTIAL DIAGNOSIS

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IV. INVESTIGATIONS

A. Basic Workup

1. Urine Dipstick: Confirms haematuria; detects protein, leucocytes, nitrites
2. Urine Microscopy: Confirms RBCs; dysmorphic RBCs (acanthocytes) suggest glomerular origin; casts suggest nephropathy
3. Urine Culture and Sensitivity: To exclude infection
4. Urine Cytology: To detect malignant cells in urothelial cancer
5. Blood Tests:
   • Full blood count (FBC)
   • Renal function tests (serum creatinine, BUN)
   • Coagulation profile (PT, aPTT, INR)
   • PSA (for prostate cancer screening in men >50 years)
   • Serum calcium (for calculi workup)

B. Imaging

C. Endoscopic Evaluation

• Cystoscopy: Mandatory when no aetiology found on imaging; directly visualises the bladder mucosa; allows biopsy of suspicious lesions; flexible cystoscopy used in outpatient setting.
• Ureteroscopy: When upper tract pathology is suspected

D. Special Investigations

• Renal biopsy: When glomerular disease is suspected (dysmorphic RBCs, proteinuria, casts)
• MCUG (Micturating cystourethrogram): In children with recurrent UTI

• Visible haematuria: ~20% will have underlying malignancy
• Non-visible haematuria: <5% will have malignancy (Bailey and Love, p. 1470)

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QUESTION 3 [20 Marks]

Management of Thyrotoxicosis

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I. INTRODUCTION

• Graves' disease (diffuse toxic goitre) - most common (TSH-receptor antibody [TSH-RAb] mediated)
• Toxic nodular goitre (Plummer's disease)
• Toxic adenoma (solitary toxic nodule)
• Thyroiditis (subacute, Hashimoto's thyroiditis - transient thyrotoxicosis)
• Exogenous thyroid hormone excess
• Rare: struma ovarii, TSH-secreting pituitary adenoma, iodine-induced (Jod-Basedow)

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II. PRINCIPLES OF TREATMENT

1. Antithyroid drugs (ATDs)
2. Surgery (thyroidectomy)
3. Radioiodine (radioactive iodine, RAI, ¹³¹I)

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III. ANTITHYROID DRUGS (ATDs)

• Inhibit thyroid peroxidase (TPO), reducing oxidation and organification of iodine
• Block coupling of iodotyrosines to form T3/T4
• PTU also inhibits peripheral conversion of T4 to T3 (additional advantage in thyroid storm)
• Carbimazole/methimazole have an immunosuppressive effect on TSH-RAb production in Graves' disease

• Initial carbimazole: 30-40 mg/day until euthyroid (8-12 weeks), then reduced to 5 mg 8-hourly
• Initial PTU: 100-200 mg three times daily
• Block-and-replace regimen: High-dose carbimazole continued + thyroxine 0.1-0.15 mg/day added to prevent hypothyroidism

• Prolonged treatment; high relapse rate (>55%)
• Cannot cure toxic nodule (autonomous tissue; recurrence certain on stopping)
• Side effects: agranulocytosis (0.1% with carbimazole; 0.4% with PTU - patient warned to report sore throat/fever immediately), hepatotoxicity (PTU), teratogenesis

• Pregnancy (1st trimester): PTU preferred over carbimazole (fewer teratogenic effects)
• 2nd-3rd trimester: Carbimazole acceptable (Harrison's Internal Medicine 22E; Bailey and Love, p. 883)

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IV. SURGERY (Thyroidectomy)

Indications for Surgery

• Large goitre (especially toxic nodular goitre)
• Compressive symptoms (dysphagia, stridor)
• Patient preference or refusal of radiation
• Progressive ophthalmopathy (eye signs)
• Pregnancy (if drugs fail, 2nd trimester)
• Suspicious nodule (possible concurrent malignancy)
• Relapse after ATD therapy

Preoperative Preparation (Critical)

1. Carbimazole 30-40 mg/day for 8-12 weeks until euthyroid
2. Alternatively, propranolol 40-80 mg three times daily (block adrenergic effects rapidly - euthyroid state achieved in days rather than weeks; also inhibits peripheral T4→T3 conversion)
3. Lugol's iodine for 10 days preoperatively - reduces vascularity of the gland, minimising intraoperative bleeding; given in addition to carbimazole or beta-blocker
4. Beta-blockers must be continued for 7 days postoperatively (hormone levels remain elevated for several days)

Extent of Resection

Complications of Thyroidectomy

• Recurrence of thyrotoxicosis: ~5% after subtotal thyroidectomy
• Hypothyroidism: Immediate after total thyroidectomy; delayed after subtotal
• Recurrent laryngeal nerve (RLN) injury: Transient (5%) or permanent hoarseness
• Hypoparathyroidism: Tetany due to parathyroid injury/removal
• Haemorrhage: Can cause tracheal compression (surgical emergency)
• Thyroid storm (crisis): Rare; prevented by adequate preoperative preparation (Bailey and Love, p. 884)

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V. RADIOIODINE (¹³¹I)

• Recurrence after surgery or ATD failure
• Elderly patients (especially with toxic adenoma)
• Patients unfit for surgery

• No surgery
• No prolonged drug therapy
• Effective for toxic adenoma (suppressed normal tissue does not take up iodine, minimising risk of hypothyroidism)

• Requires isotope facilities and specialised infrastructure
• Patient must be quarantined until radiation levels are safe
• Must avoid pregnancy for 6-12 months after treatment
• Must avoid close contact with children
• Eye signs (ophthalmopathy) may be aggravated - important consideration in Graves' disease
• Risk of delayed hypothyroidism (10-20% at 10 years; ~50% at 25 years)
• Cannot be given during pregnancy

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VI. CHOICE OF THERAPY

• Most patients: initial course of ATDs; radioiodine for relapse
• Exceptions: refusal of radiation, large goitre, progressive eye signs, pregnancy - surgery preferred
• Total thyroidectomy is increasingly preferred to eliminate risk of recurrence and simplify follow-up

• Large goitres: Surgery preferred (do not respond as well to RAI or ATDs; ATDs may enlarge goitre further)
• Small goitres: Radioiodine

• Surgery (hemithyroidectomy) or radioiodine (>45 years)
• ATDs cannot cure - recurrence certain on stopping

• Surgery or thyroid ablation with ¹³¹I

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VII. MANAGEMENT OF THYROID STORM

1. High-dose PTU or methimazole (blocks synthesis AND peripheral conversion)
2. Lugol's iodine (1 hour AFTER ATDs - blocks hormone release)
3. Propranolol IV/oral (controls adrenergic features)
4. Dexamethasone/hydrocortisone (blocks T4→T3 conversion; treats relative adrenal insufficiency)
5. Supportive care: cooling, IV fluids, antipyretics (not aspirin - displaces T4 from binding proteins)
6. Treat precipitating cause (infection, surgery, trauma)

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QUESTION 4 [30 Marks]

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Q4(a): GLASGOW COMA SCALE (GCS) [15 Marks]

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I. INTRODUCTION

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II. THE THREE COMPONENTS

1. EYE OPENING (E) - Maximum score: 4

2. VERBAL RESPONSE (V) - Maximum score: 5

3. MOTOR RESPONSE (M) - Maximum score: 6

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III. TOTAL GCS SCORE AND INTERPRETATION

• GCS = E + V + M
• Maximum score: 15 (fully conscious and oriented)
• Minimum score: 3 (no response in any domain)

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IV. HOW TO APPLY PAINFUL STIMULUS

• Supraorbital ridge pressure
• Sternal rub / trapezius squeeze
• Nail-bed pressure

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V. CLINICAL APPLICATIONS

1. Trauma assessment (ATLS): GCS recorded as part of primary survey (ABCDE)
2. Head injury management: GCS ≤8 mandates definitive airway management
3. Serial monitoring: Identifies neurological deterioration (falling GCS = urgent CT head)
4. Prognostication: Lower GCS at presentation correlates with worse outcome
5. ICU monitoring: Guides management of ventilated patients

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VI. LIMITATIONS

• Cannot be reliably scored in: intubated patients (V component), periorbital oedema (E component), spinal cord injury (M component), alcohol/drug intoxication
• Does not assess brainstem reflexes (unlike the FOUR score)
• Subjective element in intermediate scores
• Does not directly indicate the cause of unconsciousness

• A - Alert
• V - Responds to Voice
• P - Responds to Pain
• U - Unresponsive (AVPU "P" roughly corresponds to GCS 8)

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Q4(b): NSV (No-Scalpel Vasectomy) [15 Marks]

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I. INTRODUCTION

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II. PREOPERATIVE CONSIDERATIONS

• Male partner who has completed family
• Counselling about permanence (irreversibility must be assumed)
• Discussion of failure rate, complications, need for postoperative semen analysis
• Physical examination: palpability of the vas deferens bilaterally, absence of scrotal pathology (hydrocele, varicocele, previous surgery)

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III. INSTRUMENTS (Specific to NSV)

1. Ring-tipped (cantilevered) vas deferens fixation clamp: Atraumatically grasps and elevates the vas through the scrotal skin; cantilevered design prevents vessel injury
2. Sharp, curved mosquito haemostat (dissecting forceps): Used to puncture and spread the skin overlying the vas (Campbell-Walsh-Wein Urology, p. 2466)

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IV. ANAESTHESIA

• Conventional: Skin wheal + vasal nerve block with 1-2% lidocaine using a needle
• No-needle technique (NNV): Uses a jet-injector device (MadaJet) to deliver local anaesthetic without a needle; further reduces patient anxiety and pain

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V. SURGICAL TECHNIQUE

1. Positioning: Patient supine; scrotum shaved, cleaned, and draped
2. Vas identification: The vas is palpated at the raphe of the scrotum and brought to the midline (most superficial, subcutaneous position)
3. Fixation: The ring-tipped clamp grasps the vas through the scrotal skin, fixing it in place
4. Skin puncture: The sharp curved mosquito haemostat punctures the scrotal skin, subcutaneous tissue, and vasal sheath over the most prominent part of the vas (single midline puncture vs. bilateral)
5. Spreading manoeuvre: The haemostat is opened in a spreading motion (not cutting) to dilate the opening
6. Delivery of the vas: The anterior wall of the vas is pierced and the vas is lifted through the skin opening; the posterior wall is then dissected to strip the vas of its fascial sheath - delivering a clean segment of bare vas
7. Vas occlusion (separate from NSV technique - see below)
8. Skin closure: The puncture wound is typically <10 mm; may be closed with an absorbable suture or left open (heals by secondary intention)

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VI. VAS OCCLUSION METHODS

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VII. ADVANTAGES OF NSV OVER CONVENTIONAL VASECTOMY

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VIII. POSTOPERATIVE CARE

• Scrotal support for 2-3 days
• Avoid heavy lifting/intercourse for 1 week
• Postvasectomy semen analysis (PVSA): Performed 8-16 weeks postoperatively, after at least 10-20 ejaculations
• Azoospermia or RNMS (≤100,000 non-motile sperm/mL) = procedure successful = can stop other contraception
• If motile sperm persist at 6 months PVSA = failure; repeat procedure indicated

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IX. COMPLICATIONS

X. CONTRAINDICATIONS

• Scrotal pathology (unresolved hydrocele, varicocele, prior surgery - relative)
• Active genital infection
• Bleeding diathesis (relative)
• Single testis (absolute)
• Patient uncertainty about decision

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XI. FAMILY WELFARE PROGRAMME (India)

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• Bailey and Love's Short Practice of Surgery, 28th Edition (pp. 883-884, 1470, 1573-1574)
• Campbell-Walsh-Wein Urology, 12th Edition (pp. 2465-2467)
• Harrison's Principles of Internal Medicine, 22nd Edition
• Robbins & Cotran Pathologic Basis of Disease
• Plum and Posner's Diagnosis and Treatment of Stupor and Coma
• Park's Textbook of Preventive and Social Medicine
• Katzung's Basic and Clinical Pharmacology, 16th EditionAll four questions are now answered comprehensively. Here is a summary of what's covered, weighted by marks:

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Summary of Coverage

Q1 - Carcinoma Penis (30 marks) ✓

Q2 - Painless Haematuria (20 marks) ✓

Q3 - Management of Thyrotoxicosis (20 marks) ✓

Q4(a) - Glasgow Coma Scale (15 marks) ✓

Q4(b) - NSV (15 marks) ✓