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Q17. Etiopathogenesis of Thyroidal Swellings

Classification

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A. Diffuse & Multinodular Goitre

1. ↓ iodine intake → impaired T₃/T₄ synthesis
2. ↓ T₃/T₄ → compensatory ↑ TSH
3. ↑ TSH → hypertrophy and hyperplasia of follicular cells
4. Recurrent cycles → irregular multinodular goitre with fibrosis, hemorrhage, calcification

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B. Autoimmune Thyroid Diseases

• Most common cause of hyperthyroidism (85%)
• Pathogenesis: IgG autoantibodies (TSI) bind and stimulate TSH receptor → unregulated T₃/T₄ production
• Ophthalmopathy: TSH receptors on orbital fibroblasts → T-cell cytokines → retroorbital tissue expansion
• Morphology: Symmetrical enlargement, tall columnar epithelium, papillary projections, scalloped colloid, lymphoid follicles

• Female:Male = 10–20:1
• Pathogenesis: CD8+ cytotoxic T cells destroy thyroid epithelium; anti-TPO and anti-thyroglobulin antibodies (complement-mediated)
• Morphology: Lymphocytic infiltrate with germinal centres, Hürthle cell metaplasia, follicular atrophy

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C. Thyroid Neoplasms

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Q18. Applied Anatomy of Parathyroid

General

• Number: Usually 4 (2 superior, 2 inferior); 5% have >4 glands
• Weight: 30–50 mg each
• Colour: Yellow-tan-brown (brighter yellow fat helps distinguish them intraoperatively)

Embryology

Surgical Positions

Key surgical rule: Superior = dorsal to RLN; Inferior = ventral to RLN

Ectopic Sites

Blood Supply

• Both glands primarily supplied by inferior thyroid artery (branch of thyrocervical trunk)
• 10% of inferior glands supplied by superior thyroid artery branch
• Right adrenal vein → IVC directly; rich anastomotic network protects against ischaemia

Histology

• Chief cells — small, pale; secrete PTH
• Oxyphil cells — large, eosinophilic; rich in mitochondria; function uncertain
• Fat content increases with age

Surgical Significance

• Transient hypoparathyroidism: up to 20% after total thyroidectomy
• Permanent hypoparathyroidism: ~5% after adenoma surgery
• Inadvertently removed tissue → autotransplantation into sternocleidomastoid or brachioradialis
• Intraoperative PTH assay confirms adequate resection (>50% fall in PTH)

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Q19. Clinical Features of Hypo- and Hyperparathyroidism and Management

A. HYPERPARATHYROIDISM

Types

• Primary HPT: Autonomous PTH overproduction (adenoma 85–95%, hyperplasia 5–10%, carcinoma 1%)
• Secondary HPT: Compensatory — chronic renal failure → hypocalcaemia → ↑ PTH
• Tertiary HPT: Secondary HPT becomes autonomous with hypercalcaemia

Clinical Features — Mnemonic: "Bones, Stones, Groans, Psychic Moans"

Most common cause of asymptomatic hypercalcaemia = Primary HPT; Most common cause of symptomatic hypercalcaemia = Malignancy

Management — Hyperparathyroidism

1. IV normal saline (↑ urinary calcium excretion)
2. Loop diuretics (furosemide) — inhibit renal calcium reabsorption
3. Bisphosphonates (zoledronic acid/pamidronate) — inhibit osteoclasts
4. Calcitonin — rapid ↓ Ca²⁺ within hours
5. Dialysis in renal failure

• Serum Ca²⁺ >1 mg/dL above upper limit of normal
• 24h urine Ca²⁺ >400 mg/day
• T-score ≤ −2.5 (osteoporosis)
• Age <50 years
• Creatinine clearance <60 mL/min

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B. HYPOPARATHYROIDISM

Causes

1. Post-surgical — most common (inadvertent removal during thyroidectomy/neck dissection)
2. Autoimmune — AIRE gene mutations (APS type 1)
3. Congenital — DiGeorge syndrome (22q11.2 deletion — absent parathyroids + thymus + cardiac defects)
4. Hypomagnesaemia — functional hypoparathyroidism

Clinical Features (all from hypocalcaemia)

• Perioral and fingertip tingling/paraesthesiae
• Carpopedal spasm / tetany
• Facial grimacing
• Seizures, cardiac arrhythmias

• Cataracts
• Basal ganglia calcification (Fahr's disease)
• Dental abnormalities, papilloedema

• Chvostek's sign: Tapping facial nerve → ipsilateral facial muscle twitch
• Trousseau's sign: BP cuff inflation → carpopedal spasm (more specific)
• ECG: Prolonged QT interval

Management — Hypoparathyroidism

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Q20. Applied Anatomy of Adrenal Gland

General

Anatomical Relations

Blood Supply

1. Superior adrenal arteries — from inferior phrenic arteries
2. Middle adrenal arteries — direct from aorta
3. Inferior adrenal arteries — from ipsilateral renal artery

⚠️ The short right adrenal vein is the most dangerous structure in right adrenalectomy — risk of IVC avulsion

Lymphatics

• Right → paracaval nodes
• Left → para-aortic nodes

Innervation

• Medulla: Direct preganglionic sympathetic fibres (unique — chromaffin cells = modified sympathetic neurons)
• Cortex: Postganglionic splanchnic fibres

Embryology

Cortical Zones — Mnemonic: GFR = ACE

Surgical Significance

• Pheochromocytoma: 10% bilateral, 10% extra-adrenal (paraganglioma), 10% malignant ("Rule of 10s")
• Adrenal incidentaloma: 1–4% of abdominal CT scans
• Laparoscopic adrenalectomy: lateral transabdominal or posterior retroperitoneoscopic approach

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Q21. Planning and Conduct of Surgical Audit

Definition

A. Planning the Audit

• Choose procedure/condition (e.g., appendicectomy, thyroidectomy)
• Define whether it is a process audit (was care delivered correctly?) or outcome audit (what were the results?), or both
• Set time period and eligible patient population

• Evidence-based guidelines (ERAS, WHO Safe Surgery Checklist, NICE guidelines)
• Measurable indicators:
  • Process: antibiotic prophylaxis timing, VTE prophylaxis, normothermia
  • Outcome: 30-day morbidity/mortality, wound infection rate, readmission rate, length of stay

• Surgeon, anaesthesiologist, nurses (ward + OR), pharmacist, physiotherapist, administrator/audit coordinator

• Prospective > retrospective
• Use standardised tools: ACS-NSQIP, ERAS Interactive Audit Tool, WHO surgical safety checklist
• Define key variables: patient demographics, ASA grade, comorbidities, operative details, postoperative outcomes

B. Conduct of the Audit

• All eligible cases; trained data abstractor reviews records
• NSQIP: 8-day sampling blocks; 30-day outcome follow-up

• Use observed-to-expected (O:E) ratio via multivariate logistic regression
• Prevents penalising high-acuity centres

• Compare against peer institutions, national standards, or own previous performance (temporal trends)

• Share results openly with all stakeholders
• Regular multidisciplinary review meetings (monthly/quarterly)

• Identify system errors (most common) vs. provider errors
• Develop targeted improvement interventions

• Repeat after implementing changes to assess whether improvements are sustained

Key Quality Frameworks

Surgical "Never Events"

• Wrong site/wrong patient/wrong procedure surgery
• Retained foreign object
• Postoperative death after elective low-mortality procedure

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Q22. Tissue Injuries and Their Management

Phases of Wound Healing

Haemostasis → Inflammation → Proliferation → Remodelling

Phase 1: Haemostasis (Minutes)

• Vascular injury → vasoconstriction → platelet aggregation → fibrin clot
• Platelets release PDGF, TGF-β, EGF → initiate cascade
• Provisional fibrin matrix = scaffold for cell migration

Phase 2: Inflammation (Hours – Day 4)

Phase 3: Proliferative (Day 3 – Week 3)

• Granulation tissue = capillary bed + fibroblasts + macrophages + loose collagen + fibronectin
• Angiogenesis (VEGF-driven)
• Fibroplasia: fibroblasts synthesise type III collagen (later replaced by type I)
• Epithelialisation: keratinocyte migration

Phase 4: Remodelling (Week 3 – 1 Year)

• Fibroblasts → myofibroblasts → wound contraction
• Type III collagen → cross-linked type I collagen
• Maximum tensile strength = only 70–80% of unwounded skin (never 100%)

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Abnormal Wound Healing

Hypertrophic Scar vs. Keloid

Chronic Wounds

• Fail to progress within 3 months
• Stuck in inflammatory phase; high MMP activity, ↓ growth factors, ↑ bacterial load
• Types: diabetic foot ulcers, venous leg ulcers, pressure ulcers

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Factors Impairing Wound Healing

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Management

1. Haemostasis (pressure, ligation, cautery)
2. Wound cleansing — saline irrigation, debridement
3. Closure:
   • Primary intention — immediate closure (clean wounds, <6 h)
   • Delayed primary — closure at 4–5 days (contaminated)
   • Secondary intention — granulation (infected/large wounds)
4. Tetanus prophylaxis
5. Antibiotics only if infected

1. Treat underlying cause (glycaemic control, compression therapy, pressure relief)
2. Wound bed preparation — debridement, moisture balance, infection control
3. Appropriate dressings (hydrocolloids, foam, silver-impregnated)
4. Advanced therapies: PDGF (becaplermin), negative pressure wound therapy (VAC), hyperbaric oxygen, skin grafts

• Silicone sheeting + pressure garments (prevention/first line)
• Intralesional triamcinolone acetonide (10–40 mg/mL every 2–4 weeks)
• 5-Fluorouracil intralesional injections
• Keloid excision + immediate radiation → <10% recurrence

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Q23. Biohazard and Hospital Waste — Appropriate Methods of Disposal

Classification of Hospital Waste (WHO/CPCB)

Key Principles

• Segregation at source — colour-coded bags/bins at the point of generation
• Never overfill bags (>¾ full)
• Labelling — generator identity, date, category on all bags
• Safe handling — PPE (gloves, aprons, face shields) for handlers
• Transport — designated routes; covered trolleys; no hand-carrying of sharps
• Record keeping — waste manifest system (chain of custody)

Disposal Methods

• High-temperature two-chamber incinerators (850–1100°C)
• Destroys pathogens, reduces volume by 90%
• Produces toxic dioxins/furans → requires gas scrubbers

• 134°C at 2 bar for 18 min (or 121°C for 30 min)
• For microbiological waste (Category II)
• After autoclaving → treated waste can go to landfill

• Liquid chemical waste and effluents
• Hypochlorite, glutaraldehyde
• Not for solid waste

• Never recap needles (one-handed scoop if necessary)
• Puncture-proof containers; fill to ¾ only
• Sealed containers → incineration

• Separate high-temperature incineration (>1000°C)
• Never with general infectious waste

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Q24. Principles of Ethics in General Surgery

Four Pillars of Medical Ethics (Beauchamp & Childress)

Informed Consent

1. Voluntariness — free of coercion or undue influence
2. Information — procedure, alternatives, risks, benefits explained in understandable language
3. Capacity — patient must have the mental capacity to understand, retain and weigh information
4. Authorisation — explicit agreement (verbal or written)

• Emergency/life-threatening situations
• Waiver by patient
• Therapeutic privilege (very rarely applicable)

Specific Ethical Issues in Surgery

• Requires discussion with patient/family
• Does not mean "do not treat" — only cardiac arrest; full palliative/comfort care continues

• Giving adequate analgesia/sedation knowing it may hasten death is ethically permissible if the intent is relief of suffering, not death

• Surgeons are not obligated to provide treatment that will not benefit the patient
• Requires open, compassionate communication with patient/family

• Patient information must not be disclosed without consent
• Exceptions: Public health reporting (infectious diseases), court orders, imminent risk to others

• Ethical obligation to disclose errors (even near-misses) transparently
• "Never events" must be disclosed and investigated

Specific Surgical Ethics Scenarios

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Q25. Anaesthesia and Pain Management

Types of Anaesthesia

General Anaesthesia — Components (TRIAD)

1. Hypnosis (unconsciousness) — inhalational/IV agents
2. Analgesia — opioids, NSAIDs, ketamine
3. Muscle relaxation — NMBs

Inhalational Agents

• Volatile agents: Isoflurane, sevoflurane, desflurane
• MAC (Minimum Alveolar Concentration): Concentration required to prevent movement in 50% of patients in response to surgical incision (standard measure of potency)
• Nitrous oxide (N₂O): Weak anaesthetic; used as carrier gas; analgesic

Intravenous Agents

Neuromuscular Blocking Drugs (NMBs)

Succinylcholine contraindicated in burns (>48h), denervation injuries, hyperkalaemia risk

Regional Anaesthesia

Pain Management

WHO Analgesic Ladder (3 Steps)

1. Mild pain: Non-opioids (paracetamol, NSAIDs)
2. Moderate pain: Weak opioids (codeine, tramadol) + non-opioids
3. Severe pain: Strong opioids (morphine, fentanyl, oxycodone) + non-opioids

Multimodal Analgesia (Gold Standard in Postoperative Pain)

• Paracetamol (regular, around the clock)
• NSAIDs/COX-2 inhibitors (unless contraindicated)
• Gabapentinoids (gabapentin/pregabalin — preoperative and postoperative)
• Ketamine low-dose infusion (opioid-sparing, especially in chronic pain/opioid tolerance)
• Regional anaesthesia (nerve blocks, epidural)
• Opioids (for breakthrough/rescue only)

Acute Pain Service (APS)

• Dedicated team managing postoperative/acute pain
• Patient-controlled analgesia (PCA) — IV morphine; set dose + lockout interval
• Epidural analgesia — superior for thoracic/abdominal surgery

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Q26. Anatomical Basis of Enlarged Axillary Lymph Nodes

Groups of Axillary Lymph Nodes

Berg's Levels (for Breast Cancer Surgery)

Causes of Enlarged Axillary Lymph Nodes

• Breast cancer — most important surgical cause; ipsilateral axillary LN metastasis
• Infections of upper limb, shoulder, chest wall (pyogenic, cat-scratch disease)
• Melanoma/SCC of ipsilateral upper limb

• Lymphoma (Hodgkin's / Non-Hodgkin's)
• Leukaemia
• Sarcoidosis
• HIV infection
• Infectious mononucleosis (EBV)

Clinical Significance

• Hard, fixed, matted nodes → malignancy
• Soft, tender, mobile → reactive/infective
• Sentinel Lymph Node Biopsy (SLNB): Preferred over ALND for early breast cancer; identifies first draining node; if negative → spares full dissection
• Rotter's nodes (interpectoral) — located between pectoralis major and minor; may be missed in standard axillary dissection

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Q27. Anatomical Basis of Venepuncture of Cubital Veins

Anatomy of the Cubital Fossa

• Lateral: Brachioradialis
• Medial: Pronator teres
• Base (superior): Imaginary line between medial and lateral epicondyles
• Roof: Deep fascia + bicipital aponeurosis + skin

• Tendon of biceps brachii (central)
• Brachial artery (medial to tendon)
• Median nerve (medial to brachial artery)
• Radial nerve (lateral, in radial fossa)

Veins Used for Venepuncture

Why the Bicipital Aponeurosis is Critical

• The bicipital aponeurosis runs from the biceps tendon medially to blend with the deep fascia
• It separates the superficial veins from the underlying brachial artery and median nerve
• During venepuncture: as long as the needle stays superficial to the bicipital aponeurosis, the brachial artery and median nerve are protected
• Danger: Excessive depth of needle → brachial artery puncture → haematoma, arterial thrombosis; median nerve injury

Clinical Points

• The median cubital vein is preferred for blood sampling (large calibre, relatively fixed)
• Cephalic vein is preferred for IV cannula insertion (less likely to be valved; no nearby nerves)
• Anatomical snuffbox veins (cephalic) used as alternative for IV access
• Femoral vein in cubital fossa region — not applicable; femoral venepuncture is at the femoral triangle

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Q28. Anatomical Basis of Claw Hand

Definition

Causative Nerve: Ulnar Nerve

Normal Function of Ulnar Nerve in the Hand

• All interossei (4 dorsal, 3 palmar)
• 3rd and 4th lumbricals (ring and little fingers)
• Hypothenar muscles
• Adductor pollicis

The Biomechanics

• MCP flexion — by interossei and lumbricals (intrinsic muscles)
• IP extension — by interossei acting via lateral bands of extensor expansion

• Interossei + 3rd/4th lumbricals LOST → no MCP flexion or IP extension via intrinsics
• Intact: Long flexors (FDP/FDS — median/ulnar) and long extensors (radial nerve)
• Net result: MCP hyperextension (by unopposed extensor digitorum) + IP flexion (by unopposed FDP/FDS)
• = Classic claw deformity

Why Mainly Ring and Little Fingers?

• Index and middle fingers have 1st and 2nd lumbricals supplied by the median nerve → partially compensated → less clawing
• Ring and little fingers rely on 3rd and 4th lumbricals (ulnar nerve) → more severe clawing
• = Ulnar paradox

Ulnar Paradox

• Low ulnar nerve lesion (at wrist) → more severe claw deformity (FDP intact → stronger IP flexion)
• High ulnar nerve lesion (at elbow) → less severe claw (FDP also paralysed → less IP flexion)

Other Causes of Claw Hand

Froment's Sign

• Ask patient to hold a piece of paper between thumb and index finger
• Ulnar nerve injury: Adductor pollicis weak → patient compensates by flexing FPL (median nerve) = flexed IP joint of thumb = positive Froment's sign

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Q29. Infections of Fascial Spaces of Palm

Fascial Spaces of the Hand

Collar-Button Abscess

• Dumbbell-shaped abscess: superficial component + deep component connected through a narrow isthmus in the palmar fascia
• Web space infections are the most common type
• Must drain both components

Clinical Features of Palmar Space Infection

• Painful, tense swelling of palm
• Dorsal oedema (often more marked than palmar swelling)
• Fingers held in partial flexion
• High fever, systemic toxicity
• Pointing — localises toward palmar aspect

• Thenar: swelling in thenar eminence; index finger held in extension/abduction; "ballooned thumb web"
• Midpalmar: loss of normal palmar concavity; ring/middle finger involvement

Spread

• Deep space infections can spread:
  • Via lumbrical canals to web spaces (and vice versa)
  • Into Space of Parona → forearm
  • Via ulnar and radial bursae — "horseshoe abscess" (if both bursae involved)

Management

1. IV antibiotics — broad-spectrum (Staph. aureus most common organism; cover MRSA if suspected): flucloxacillin ± metronidazole; vancomycin for MRSA
2. Surgical Incision and Drainage (I&D) — definitive treatment

1. Post-drainage: irrigation, loose packing with gauze, elevation
2. Physiotherapy early to prevent stiffness
3. Repeat surgery if inadequate drainage

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Q30. Important Muscle Groups of the Hand

Classification: Extrinsic vs. Intrinsic

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A. Extrinsic Muscles (Origin in forearm; act on hand)

Flexors (Anterior Compartment of Forearm)

Extensors (Posterior Compartment — Radial Nerve)

The radial nerve has no intrinsic hand muscles — only extrinsic extensors and brachioradialis

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B. Intrinsic Muscles (Origin AND insertion within the hand)

1. Thenar Muscles (Median Nerve, C8–T1 via recurrent branch)

2. Hypothenar Muscles (Ulnar Nerve, C8–T1, deep branch)

3. Lumbricals (Four muscles)

4. Interossei

• Nerve: Ulnar (deep branch)
• Abduct fingers from the middle finger axis
• Also flex MCP and extend IP joints

• Nerve: Ulnar (deep branch)
• Adduct fingers toward the middle finger axis

5. Adductor Pollicis

• Nerve: Ulnar (deep branch)
• Two heads (oblique + transverse)
• Adducts thumb toward palm
• Tested by Froment's sign

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Summary Table — Nerve Supply of Hand Muscles

"All intrinsic hand muscles are either median or ulnar nerve. Radial nerve = zero intrinsic hand muscles."

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