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General Surgery Notes - Acute Abdomen & Emergency Surgery

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1. THE ACUTE ABDOMEN - Overview

Approach (History + Examination)

• Site of pain at onset vs. now (migration is key - e.g., appendicitis migrates from peri-umbilical to RIF)
• Character: colicky (obstruction, ureteric) vs. constant (peritonitis, ischemia)
• Onset: sudden ("like a thunderclap") suggests perforation or ruptured AAA
• Associated symptoms: nausea, vomiting, fever, altered bowel habit, last menstrual period (always in women of reproductive age), urinary symptoms

1. General: Vitals, posture (peritonitis patient lies still; renal colic patient is restless)
2. Inspection: distension, scars, hernias, visible peristalsis
3. Palpation: tenderness, guarding, rigidity, rebound
4. Percussion: resonance (gas) vs dullness (fluid)
5. Auscultation: bowel sounds (high-pitched tinkling = obstruction; absent = paralytic ileus/peritonitis)
6. Always examine hernial orifices and do PR examination

Peritonism Signs

"If inflammation arises under the diaphragm, shoulder tip ('phrenic') pain may be felt. This is referred pain to the C5 dermatome." - Bailey and Love's Surgery, p. 1109

Categories of Peritonitis (Bailey & Love)

• Localised - e.g., appendicitis, diverticulitis (contained)
• Diffuse/generalised - e.g., perforated viscus, faecal peritonitis

• Bacterial (GI perforation, transmural translocation)
• Chemical (bile, barium, gastric acid)
• Ischaemic (strangulated bowel, vascular occlusion)
• Traumatic
• Miscellaneous (familial Mediterranean fever, starch peritonitis)

• GI perforation (ulcer, appendix, diverticulum)
• Transmural translocation without perforation (pancreatitis, ischaemic bowel)
• Exogenous contamination (open trauma, peritoneal dialysis)
• Female genital tract (PID)
• Haematogenous spread (rare)

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2. ACUTE APPENDICITIS

Pathophysiology

Clinical Features

• McBurney's point tenderness - 1/3 of the way from ASIS to umbilicus
• Rovsing's sign - pressure in LIF causes pain in RIF (cross-referred pain)
• Psoas sign - pain on extension of right hip (retrocaecal appendix)
• Obturator sign - pain on internal rotation of flexed right hip (pelvic appendix)
• Cutaneous hyperaesthesia at T10-T12 dermatomes

• Pregnancy: most common surgical emergency; appendix may be displaced upward after 3rd month (though in <25% of cases even in 3rd trimester); peritoneal signs may be diminished. Fetal mortality rises with perforation.
• Elderly: atypical presentation, higher perforation rate
• Children: perforation rate higher due to thin-walled appendix and delayed diagnosis

Investigations

• WBC raised (>10,000/mm³) - earliest marker; but normal WBC does not exclude appendicitis
• CRP >10 mg/L (useful especially in children <6 years)
• WBC + CRP combined sensitivity up to 98%; normal values of both make appendicitis unlikely in low pre-test probability
• Urinalysis: sterile pyuria or microscopic haematuria can occur in appendicitis (don't be misled)
• Urine pregnancy test in all women of reproductive age (rule out ectopic)

• Plain X-ray: not helpful; may show appendicolith (up to 50% in children)
• Ultrasound (US): first-line in children and pregnant women (graded compression technique - non-compressible appendix >6mm diameter)
• CT abdomen/pelvis: most accurate in adults (sensitivity ~94%, specificity ~95%); identifies perforation, abscess, alternate diagnoses
• MRI: preferred in pregnant women when US is inconclusive (avoids radiation)

Scoring Systems (MBBS Exam Favourite)

• Score 1-4: Low risk (observation)
• Score 5-6: Possible appendicitis (imaging/observation)
• Score 7-9: Probable appendicitis (surgical referral)

Note: Modified Alvarado has only 72% sensitivity; clinical judgment by an experienced surgeon remains more accurate. - Tintinalli's Emergency Medicine

Management

• Interval appendicectomy after abscess/phlegmon drainage (controversial)
• Antibiotics alone for uncomplicated appendicitis (growing evidence, but surgery remains standard in most centres)

• Appendicectomy - laparoscopic (preferred) or open (grid-iron/Lanz incision)
• Laparoscopic: better visualisation, fewer wound infections, faster recovery
• Open: grid-iron incision (oblique at McBurney's point); Lanz (transverse, better cosmesis)
• Drains used if perforation with soiling

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3. INTESTINAL OBSTRUCTION

Classification

• Intraluminal: gallstone ileus, meconium, foreign body, bezoar
• Intramural: tumour, Crohn's stricture, intussusception
• Extramural: adhesions (most common), hernias (2nd most common), volvulus, external compression

"It is essential that the hernial orifices should be carefully examined as incarceration in a hernia is one of the commonest causes of obstruction." - Pye's Surgical Handicraft, p. 9038

Small vs Large Bowel Obstruction

Strangulation - RED FLAGS

• Continuous pain (not just colicky)
• Localised tenderness
• Pyrexia
• Tachycardia
• Signs of peritonism
• Rapid deterioration

Investigations

• Erect AXR: multiple air-fluid levels
• Supine AXR: dilated bowel loops; valvulae conniventes (SBO) vs haustra (LBO); pneumoperitoneum (perforation)
• CT scan: investigation of choice; identifies level, cause, strangulation, perforation
• Bloods: FBC, U&E (dehydration), LFT, amylase, lactate (ischaemia), group & save

Management

• IV fluid resuscitation (crystalloid)
• NG tube (nasogastric decompression)
• Urinary catheter (monitor output)
• Analgesia (does NOT mask signs)
• Correct electrolyte imbalances (hyponatraemia, hypokalaemia)

• Strangulation
• Complete obstruction
• Failed conservative management
• LBO with caecal dilatation >9 cm (risk of perforation)

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4. PERFORATED PEPTIC ULCER

Overview

Clinical Features

• Sudden, severe epigastric pain (knife-like) - classically described as "like being shot"
• Pain spreads to whole abdomen rapidly
• Board-like rigidity - classic sign
• Patient lies still (any movement worsens peritonism)
• Referred shoulder tip pain (subphrenic gas)
• Tachycardia, hypotension (if late, septic shock)

Investigations

• Erect CXR: free gas under diaphragm (pneumoperitoneum) - present in ~70-80%
• CT abdomen: more sensitive for free gas; also identifies site of perforation, extent of peritoneal soiling
• Bloods: FBC, U&E, LFT, amylase (raised but usually <3x normal - distinguishes from pancreatitis), coagulation, group & save

Management

• Only if: haemodynamically stable, perforation radiologically sealed, no peritonitis
• Strict monitoring; if worsening → immediate surgery

"Surgery is almost always indicated for ulcer perforation, although occasionally nonsurgical treatment can be used in the stable patient without peritonitis in whom radiologic studies document a sealed perforation." - Schwartz's Surgery 11th Ed

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5. ACUTE MESENTERIC ISCHAEMIA (AMI)

Causes

Clinical Features

• Classic triad: severe central abdominal pain out of proportion to examination findings (early), vomiting, diarrhoea (may be bloody)
• Early: soft abdomen despite severe pain (visceral pain phase)
• Late: peritonism, rigidity, septic shock (transmural infarction + perforation)
• Risk factors: AF, recent MI, atherosclerosis, hypercoagulable state

Investigations

• CT angiography: investigation of choice - shows occlusion, bowel wall thickening, pneumatosis intestinalis (gas in bowel wall), portal venous gas (late ominous sign)
• Bloods: leukocytosis, raised lactate, metabolic acidosis (late)
• Plain AXR: often normal early; "thumb-printing" (mucosal oedema) late

Management

• Resuscitation + anticoagulation (heparin)
• CT angiography to confirm and plan
• Embolectomy / thrombolysis (endovascular or open)
• Laparotomy: bowel resection if necrotic; "second look" laparotomy at 24-48 hours to assess bowel viability
• Antibiotics (broad spectrum, including anaerobic cover)

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6. ACUTE PANCREATITIS (Emergency Context)

Aetiology - "GET SMASHED"

Severity Scoring - Revised Atlanta / Glasgow Criteria (MBBS Favourite)

• PaO₂ < 8 kPa
• Age > 55
• Neutrophils (WBC) > 15 × 10⁹/L
• Calcium < 2 mmol/L
• Raise in urea > 16 mmol/L
• Enzymes: LDH > 600 IU/L; AST > 200 IU/L
• Albumin < 32 g/L
• Sugar (glucose) > 10 mmol/L (Mnemonic: PANCREAS)

Management

• No oral intake (keep nil by mouth if severe/vomiting)
• Aggressive IV fluid resuscitation (Hartmann's/Ringer's lactate preferred over normal saline)
• Analgesia (IV opioids)
• Urinary catheter + fluid balance
• Blood sugar monitoring + insulin sliding scale
• ERCP within 24-72h if gallstone pancreatitis with cholangitis / biliary obstruction
• Antibiotics: not routine (no benefit in sterile necrosis); use only if infected necrosis suspected
• Surgery: step-up approach for infected necrotising pancreatitis (percutaneous drain → minimally invasive necrosectomy → open)

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7. CAUSES OF ACUTE ABDOMEN BY QUADRANT (Quick Reference)

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8. EMERGENCY LAPAROTOMY - GENERAL PRINCIPLES

• Peritonitis (generalised)
• Perforated viscus
• Strangulated bowel
• Unstable haemorrhage (e.g. ruptured AAA)
• Failed conservative management

• Resuscitate first (but do not delay surgery if unstable due to intra-abdominal bleeding)
• IV antibiotics (broad spectrum - cover gram-negative aerobes + anaerobes)
• Urinary catheter, NG tube
• Cross-match blood
• Consent
• Anaesthetic assessment

1. Control contamination and haemorrhage
2. Temporary abdominal closure
3. ICU resuscitation
4. Definitive repair at 24-48h

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Key Exam Points - Quick Summary

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Basics of Surgery - 2nd Year MBBS Notes

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UNIT 1: WOUND HEALING

Definition

Types of Wound Healing

"Healing by first intention is characterized by closure of a wound within 12-24 hours of its formation. These wounds are clean and well perfused... Wound edges are approximated using sutures, skin glue, steri-strips or other mechanical devices." - Scott-Brown's Otorhinolaryngology

Four Phases of Wound Healing (KEY EXAM TOPIC)

Phase 1: Haemostasis (Immediate - minutes)

• Vascular spasm (immediate response)
• Platelet plug formation: platelets adhere to exposed collagen via von Willebrand factor → platelet activation → aggregation (primary haemostasis)
• Coagulation cascade activated → fibrin clot formation (secondary haemostasis)
• Clot acts as scaffold for subsequent healing

Phase 2: Inflammation (Days 1-4)

• Vasodilation and increased vascular permeability
• Neutrophils arrive first (day 1-2): phagocytose bacteria and debris
• Macrophages arrive day 2-3: debridement + release of growth factors (PDGF, TGF-β, VEGF) - the "master cells" of wound healing
• Signs: rubor (redness), calor (heat), dolor (pain), tumour (swelling), functio laesa (loss of function) - Celsus's pentad
• Lymphocytes arrive later - coordinate immune response

Phase 3: Proliferation (Days 4-21)

• Fibroblasts migrate in (attracted by macrophage-derived growth factors) and synthesise collagen (initially Type III - immature)
• Angiogenesis (new blood vessel formation) - driven by VEGF; gives granulation tissue its red granular appearance
• Epithelialisation - keratinocytes migrate across wound surface
• Wound contraction - myofibroblasts (fibroblasts with smooth muscle features) contract wound edges; major in secondary healing

Phase 4: Remodelling / Maturation (Day 21 - 2 years)

• Type III collagen replaced by stronger Type I collagen
• Collagen fibres reorganise along tension lines
• Vascularity decreases (scar becomes pale)
• Maximum tensile strength: ~80% of original skin (never reaches 100%)
• Scar matures over 12-24 months

Wound Strength Timeline

Factors Affecting Wound Healing

• Infection (most important local factor)
• Blood supply (ischaemia delays healing)
• Foreign body / dead tissue (slows healing)
• Haematoma / seroma (acts as culture medium)
• Wound closure tension
• Radiation damage

• Nutrition: Protein deficiency impairs collagen synthesis; Vitamin C needed for hydroxylation of proline/lysine in collagen; Zinc cofactor for collagen synthesis
• Diabetes mellitus (poor perfusion, neuropathy, impaired neutrophil function)
• Steroids / immunosuppressives (inhibit inflammation and collagen synthesis)
• Anaemia, hypoxia
• Age (decreased healing in elderly)
• Jaundice, uraemia
• Malignancy

Abnormal Wound Healing

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UNIT 2: SHOCK

Definition

"Shock is a systemic state of low tissue perfusion that is inadequate for normal cellular respiration." - Bailey & Love's Surgery, p. 634

Pathophysiology at Cellular Level

• Reduced O₂ delivery → cells switch from aerobic → anaerobic metabolism
• Anaerobic metabolism produces lactic acid → systemic metabolic acidosis
• Na⁺/K⁺ pump failure → lysosomal enzyme release → cell lysis
• Potassium released → hyperkalaemia
• Microvascular injury → capillary leak → tissue oedema → worsens hypoxia

Systemic Compensatory Responses

Classification of Shock (4 Types - CHOD)

1. Hypovolaemic Shock (most common surgical type)

• Loss of circulating volume: haemorrhage, burns, GI losses, third-space losses
• Haemorrhagic shock classes (ATLS):

2. Cardiogenic Shock

• Primary pump failure: MI (most common), arrhythmia, valvular disease, myocarditis, blunt cardiac injury
• Features: low CO, raised JVP, pulmonary oedema
• Treatment: Inotropes (dobutamine), treat cause

3. Obstructive Shock

• Mechanical obstruction to cardiac filling/output
• Causes: Cardiac tamponade, Tension pneumothorax, massive PE, air embolus
• Each causes reduced ventricular filling → low CO
• Treatment: Remove obstruction immediately (needle decompression for tension pneumothorax; pericardiocentesis for tamponade)

4. Distributive Shock

• Maldistribution of blood flow - peripheral vasodilation with low SVR
• Subtypes:
  • Septic shock (most common distributive): endotoxin → cytokine storm → vasodilation + capillary leak + myocardial depression
  • Anaphylactic shock: histamine-mediated vasodilation; treat with IM adrenaline 0.5 mg
  • Neurogenic shock: loss of sympathetic tone (high spinal cord injury)

Summary Table: Cardiovascular Features

Management Principles (Surgical Shock)

1. Airway + O₂ (100% via non-rebreather mask)
2. 2 large-bore IV cannulae (antecubital fossa, 14-16G)
3. Bloods: FBC, U&E, LFT, coagulation, G&S / crossmatch, blood cultures (sepsis), lactate
4. IV fluid resuscitation: crystalloid bolus (500 mL Hartmann's) - reassess after each bolus
5. Urinary catheter - monitor urine output (target >0.5 mL/kg/h)
6. Identify and treat the cause
7. Blood products if haemorrhagic shock (1:1:1 ratio of PRBC : FFP : platelets in massive haemorrhage)
8. Vasopressors (noradrenaline) if distributive shock unresponsive to fluids

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UNIT 3: FLUID THERAPY & ELECTROLYTES

Body Fluid Compartments

Maintenance Fluid Requirements (Adults)

• Water: 25-30 mL/kg/day (~2000 mL/day)
• Sodium: 1 mmol/kg/day (~70 mmol/day)
• Potassium: 1 mmol/kg/day (~70 mmol/day)
• Glucose: ~50-100g/day (prevents protein catabolism)

Types of IV Fluids

Electrolyte Disturbances (Surgical Context)

• Causes: excess hypotonic fluids, SIADH (post-op), GI losses
• Symptoms: confusion, seizures (if severe)
• Treat: fluid restriction; slow correction (max 10 mmol/24h to avoid central pontine myelinolysis)

• Causes: vomiting/NG drainage (with alkalosis), diuretics, diarrhoea
• Risks: cardiac arrhythmias, ileus
• Treat: IV KCl (max 20 mmol/h via central line); oral KCl supplements

• Causes: renal failure, cell lysis, Addison's, massive transfusion
• Risks: cardiac arrest (sine-wave ECG pattern)
• Emergency treatment: IV calcium gluconate (membrane stabilisation) → insulin + dextrose → salbutamol → dialysis

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UNIT 4: SURGICAL INFECTIONS

Classification of Wounds (Surgical)

Surgical Site Infection (SSI)

• Superficial incisional SSI: skin and subcutaneous tissue
• Deep incisional SSI: deep soft tissue (fascia, muscle)
• Organ/space SSI: any part of the anatomy opened during surgery (e.g., anastomotic leak, intraabdominal abscess)

• Patient factors: diabetes, obesity (BMI >35), smoking, malnutrition, immunosuppression, ASA grade
• Operative factors: duration >2 hours, dirty/contaminated wound, inadequate prophylaxis, haematoma, dead space

• Antibiotic prophylaxis: single dose IV antibiotics 30-60 min before incision (e.g., co-amoxiclav or cefazolin); NOT extended beyond 24h
• Hair removal: clippers (not razors) on day of surgery
• Skin preparation: chlorhexidine-alcohol > povidone iodine
• Maintain normothermia and normoglycaemia intra-operatively
• Good surgical technique (minimise dead space, avoid haematoma)

Common Surgical Infections

• Rapidly spreading infection of fascia and subcutaneous fat; surgical emergency
• Type I: polymicrobial (Fournier's gangrene)
• Type II: monomicrobial (Group A Strep)
• Features: severe pain out of proportion to appearance, dusky skin, crepitus (gas-forming organisms), systemic toxicity
• Treatment: URGENT surgical debridement (often multiple washouts) + broad-spectrum antibiotics + ICU

• Clostridium perfringens - gas in tissues, brown exudate, "dishwater" fluid
• Treatment: surgical debridement + penicillin G + hyperbaric oxygen

Tetanus

• Clostridium tetani - exotoxin (tetanospasmin) blocks inhibitory interneurons → spastic paralysis
• Features: trismus (lockjaw), opisthotonus, risus sardonicus
• Prophylaxis: wound toilet + tetanus toxoid (if >5 years since last booster); add tetanus immunoglobulin (TIG) if dirty wound + unimmunised
• Treatment: TIG + metronidazole + benzodiazepines (muscle relaxation) + ICU

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UNIT 5: HAEMOSTASIS & BLOOD TRANSFUSION

Haemostasis - Overview

1. Vascular spasm
2. Platelet adhesion: vWF bridges platelet GPIb receptor to exposed collagen
3. Platelet activation: release of ADP, TXA₂ → more platelet recruitment
4. Platelet aggregation: GPIIb/IIIa receptors bind fibrinogen

• Intrinsic pathway (XII → XI → IX → X): activated by contact with subendothelial collagen; measured by APTT
• Extrinsic pathway (VII + Tissue Factor → X): activated by tissue injury; measured by PT/INR
• Common pathway (X → Xa + Va → Prothrombin → Thrombin → Fibrinogen → Fibrin)

Tests of Coagulation

Anticoagulants in Surgery

Blood Products & Transfusion

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UNIT 6: PRE-OPERATIVE & POST-OPERATIVE CARE

Pre-operative Assessment

• Current illness + planned surgery
• Past medical/surgical history
• Medications (especially anticoagulants, antiplatelets, antihypertensives, steroids, insulin)
• Allergies
• Anaesthetic history (family history of malignant hyperthermia)
• Smoking, alcohol, substance use
• Last oral intake (fasting status: 6h for solids, 2h for clear fluids - "6-4-2 rule")

Pre-operative Preparation

• Fasting: 6h solids, 2h clear fluids
• Stop anticoagulants appropriately (warfarin 5 days; DOACs 24-48h; aspirin continue for most surgery)
• Diabetic management: omit morning oral hypoglycaemics on day of surgery; start insulin sliding scale if prolonged fasting
• Prophylactic LMWH for DVT prevention (start evening before or post-op)
• TED stockings / intermittent pneumatic compression
• Antibiotic prophylaxis: single dose 30-60 min before incision
• Bowel prep (selected colorectal cases only)
• Consent and marking the site (especially for laterality)

Post-operative Monitoring

• Observations every 15-30 min initially: HR, BP, RR, SpO₂, temperature, GCS
• Urine output: target >0.5 mL/kg/h (30 mL/h in 70 kg adult)
• NEWS2 score (National Early Warning Score): triggered escalation for deteriorating patients

Post-operative Complications - Timeline

• Atelectasis (most common, days 1-2): microcollapses → fever, ↓O₂; treat with physiotherapy, incentive spirometry
• Pneumonia: cough, fever, consolidation; treat with antibiotics
• PE (day 5-10 peak): pleuritic chest pain, haemoptysis, tachycardia; CTPA to confirm; treat with anticoagulation

• DVT: calf pain, swelling; duplex USS; treat with LMWH then DOAC for 3 months
• MI: ECG + troponin; highest risk day 1-3 post-op

• Haematoma: collection of blood; usually resolves; aspirate/drain if large
• Seroma: serous fluid collection; common post-mastectomy/hernia; aspirate if symptomatic
• Wound infection (SSI): days 4-7; erythema, pus, fever; open wound + antibiotics

• Retention: common post-pelvic surgery and in elderly men; catheterise
• UTI: very common; MSSU + antibiotics

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UNIT 7: SURGICAL NUTRITION

Importance

Nutritional Assessment

• History: weight loss (>10% in 6 months = significant), reduced intake
• BMI: <18.5 kg/m² = underweight
• MUST score (Malnutrition Universal Screening Tool): BMI + weight loss + acute disease effect → low/medium/high risk
• Serum albumin (<35 g/L = hypoalbuminaemia; marker of chronic malnutrition)
• Serum prealbumin (half-life 2-3 days, better acute marker)

Nutritional Requirements (Surgical Patient)

• Calories: 25-30 kcal/kg/day (higher if sepsis/burns/major trauma: up to 35-40)
• Protein: 1-2 g/kg/day (nitrogen balance)
• Key micronutrients for healing: Vitamin C, Zinc, Vitamin A

Routes of Nutritional Support

• Maintains gut mucosal integrity (prevents bacterial translocation)
• Lower cost
• Lower infection risk (TPN associated with line infections, metabolic complications)
• Preserves gut immune function

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UNIT 8: SURGICAL ONCOLOGY BASICS

Tumour Classification

Staging (TNM System)

• T - Primary tumour (T0-T4)
• N - Regional lymph nodes (N0-N3)
• M - Distant metastasis (M0-M1)

Routes of Tumour Spread

1. Direct / local invasion - into adjacent structures
2. Lymphatic spread - most common route for carcinomas
3. Haematogenous spread - common for sarcomas; via portal vein → liver; systemic veins → lungs
4. Transcoelomic spread - across body cavities (peritoneum, pleura); e.g., gastric cancer → "Sister Mary Joseph nodule" (umbilical), Krukenberg tumour (ovary)
5. Perineural spread - along nerve sheaths (e.g., prostate cancer)
6. Implantation - port site metastasis after laparoscopy, surgical seeding

Tumour Markers (Surgical Context)

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QUICK REVISION TABLE - High Yield Points

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