Comprehensive Study Guide for Surgery and Essentials of General Surgery (Churchill's Mastery of Medicine Series)

Learning Philosophy and Examination Strategy

Philosophy of Learning: * Medical knowledge is a continuous process; boundaries cannot be easily drawn. * Students should discern knowledge into three categories: knowledge that must be understood, areas one needs to know about, and topics to simply be aware of. * Principles and mechanisms are prioritized over rote memorization of disconnected facts.
Revision Approach: * Categorize individual topics into strong, reasonable, and weak areas. * Be ruthless with time allocation: allocate less time to strong areas to focus on weaknesses. * Active learning is required; passive reading should be replaced with summarization in note form and ongoing self-assessment. * Avoid large reference books during late revision; use medium-sized textbooks combined with lecture notes and past papers. * Outlining topics helps activate existing knowledge and reveals gaps. * Assign revision time based on the likelihood of the topic appearing in the exam ('Commonest things are usually commonest').
Examination Types and Techniques: * Multiple Choice Questions (MCQs): Pay extreme attention to 'little' words (only, rarely, usually, never, always). Note the difference between "may occur" and "characteristic" (the latter implies a requirement for diagnosis). Check if marking is negative; avoid being too cautious, as negative marking might prevent a pass if too few questions are answered. * Short Notes: Aim for ordered, concise facts. No marks are gained for style; predetermined marks are assigned per key fact. * Essays: Marks are awarded for the logical development of an argument. Aim for equal weight across all essays; do not compensate for a missed essay with a long answer in another. * Data Interpretation: Translate numbers into descriptions (e.g., $2.8\,mmol/litre$ potassium is "low"). Do not leave blanks if not negatively marked. * Slide/Picture Quizzes: Use a systematic approach (e.g., in CXR, check breast shadows, bony skeleton, soft tissues, retrocardiac space). Use data tags to distinguish condition mimics. * Patient Management Problems (PMPs): Designed as evolving case histories. A wrong response in one part does not preclude marks in subsequent parts. * Vivas: Control the questioning by guiding examiners toward topics you know well. Use "I would do this" rather than "the book says this." It is better to say "I don't know" than to guess wildly.

Preoperative Management and Surgical Principles

Initial Preoperative Preparation: * Key step: Thorough history and physical examination, including drug history and allergies. * Biochemical/haematological screening: Required for all major surgeries and older patients undergoing minor surgery. * Chest X-ray and ECG: Mandatory for patients over 50 years of age and younger patients with respiratory/cardiovascular abnormalities. * Informed Consent: Should be obtained by the surgeon performing the operation, involving a logical explanation of the procedure and alternatives.
Medical Problems in Surgical Patients: * Respiratory Disease: Elective surgery should be postponed until the resolution of upper respiratory tract infections to avoid bacterial secondary infection. Patients with COAD/Asthma must stop smoking $1\text{--}2$ weeks prior to surgery. Regional anaesthesia may be superior to general in these cases. * Cardiovascular Disease: Risks of reinfarction are minimized if surgery is delayed > 6 months after a myocardial infarction (post-6-month risk is approx. $5\%$ ). Congestive heart failure requires preoperative optimization of diuretics and inotropic support. Valvular disease requires antibiotic prophylaxis to prevent endocarditis. * Diabetes Mellitus: Managed with continuous GKI (Glucose, Potassium, Insulin) infusion in $10\%$ dextrose. Infusion is adjusted based on regular blood sugar monitoring. This regimen applies to insulin-dependent and those on oral hypoglycaemics, continued until they resume a normal diet. Unsuspected glycosuria is a reason for deferment to confirm the diagnosis.
Fluid and Electrolyte Balance: * Standard Daily Turnover (70 kg individual): * Water: $2500\,ml$ ( $2000\,ml$ food/liquid + $500\,ml$ metabolism). * Output: Urine ( $1500\,ml$ ), Sweat ( $500\text{--}750\,ml$ ), Expired air ( $250\,ml$ ), Stools ( $250\,ml$ ). * Sodium intake/output: $100\,mmol$ . * Potassium intake: $100\,mmol$ . Output: Urine ( $60\,mmol$ ), Metabolism ( $40\,mmol$ ). * Fluid Regimen: $2500\,ml$ daily (approx. $2\,litres$ of $5\%$ dextrose with $40\,mmol$ K + $500\,ml$ of $0.9\%$ saline). * Ongoing Loss Replacement: Nasogastric aspirates and other losses should be replaced volume-for-volume with normal saline or balanced salt solutions (Hartmann's or Ringer's). Fever requires an extra $500\,ml$ of $5\%$ dextrose for insensible losses. * Long-standing Deficits: In cases like bowel obstruction or burns, replace sequesters slowly over days. Rapid replacement risks heart failure and gross oedema.

Surgical Nutrition and Analgesia

Nutritional Status Assessment: Based on dietary history, weight loss (> 5\,kg is significant), anthropomorphic muscle/fat measurements, and serum albumin.
Dietary Requirements: $2500\,kcal/day$ for a $70\,kg$ human; $1\,g/kg$ protein. Nitrogen-to-calorie ratio should be $150\,kcal : 1\,g$ nitrogen. At least half of calories should be glucose to stimulate insulin for protein synthesis.
Enteral vs. Parenteral: * Enteral: Uses the GI tract (oral supplements, nasogastric/nasojejunal, gastrostomy). Required at least $300\,cm$ of small bowel. Feeds are hypertonic and may cause abdominal cramps or diarrhea. * Parenteral: Intravenous route via a large central vein (SVC). Thrombogenic risk requires high flow. Restricted to those with non-functional guts (Crohn’s, high fistulae, short gut syndrome).
Analgesia: * Opioids: Morphine is the cornerstone. Patient-Controlled Analgesia (PCA) is considered the optimum technique with a 'lock-out' safety mechanism. * Epidural Opioids/Local Anaesthetics (e.g., bupivacaine): Block afferent nerves. Risk of severe orthostatic hypotension due to vasomotor blockade. * NSAIDs: Useful for minor surgery or lowering opioid doses. * Mild Analgesics: Paracetamol should be given regularly rather than "as required."

Postoperative Complications

Pulmonary Problems: * Atelectasis/Pneumonia: Caused by alveolar collapse. Early postoperative fever is a respiratory complication until proven otherwise. Risk is higher in smokers and upper abdominal incisions that inhibit breathing. * Pulmonary Aspiration: High-risk groups include pregnant women, bowel obstruction, and non-fasted emergencies. Aspiration of gastric acid causes chemical pneumonitis followed by bacterial infection. * ARDS: Characterized by radiological opacification and progressive hypoxaemia. Requires identification of cause (sepsis, fat embolus) and mechanical ventilation.
Postoperative Shock (Failure of tissue perfusion): * Hypovolaemic Shock: Most common. Hallmarked by JVP $0\text{--}5\,cm\,H_2O$ , tachycardia (> 100), cold clammy skin, urine output < 30\,ml/hour. Treated with whole blood and balanced salt solutions. * Septic Shock: Early stage is hyperdynamic (warm vasodilated periphery, bounding pulse). Late stage leads to peripheral vasoconstriction and anuria. * Cardiogenic Shock: Elevated JVP (> 10\,cm\,H_2O), basal crepitations, gallop rhythm. Differentiate from hypovolaemic shock via CVP: CVP is elevated in cardiogenic, reduced in hypovolaemic. Response to fluid challenge distinguishes the two; it aggravates cardiogenic shock.
Wound Complications: * Infection: Usually presents on day 5 with fever, tenderness, and erythema. Pack loosely and heal by secondary intention. * Dehiscence (Burst Abdomen): Typically occurs $7\text{--}10$ days after surgery, characterized by leakiage of serosanguinous fluid. Risk factors: malnutrition, jaundice, obesity, suture failure.
Postoperative Renal Failure: * Prerenal: Kidney underperfusion (most common). * Renal: Parenchymal damage (e.g., myoglobinuria, incompatible blood transfusion). * Postrenal: Catheter blockage or bilateral ureteric ligation (rare, usually pelvic surgery).
Thromboembolic Disorders (Virchow's Triad: Stasis, hypercoagulability, vessel wall damage): * Deep Vein Thrombosis (DVT): Higher risk with age, obesity, malignancy, and pelvic surgery. 1 in 200 major surgery patients die from pulmonary embolus. Prophylaxis uses graduated elastic stockings and low-dose subcutaneous heparin. * Pulmonary Embolism (PE): Massive embolus causes collapse and cardiac arrest. Smaller PE presents with pleuritic pain, haemoptysis, and tachycardia. ECG characteristic: S waves in lead 1, Q waves and T wave inversion in lead 3. Best test is isotope ventilation/perfusion (V/Q) scanning showing a mismatched defect.

Surgical Gastroenterology

Oesophageal Disease: * Hiatus Hernia: Sliding (most common, causes reflux) and Rolling (paraoesophageal, risks incarceration). Barrett's Oesophagus is columnar epithelium replacement; it is premalignant for adenocarcinoma. * Carcinoma: Progressing dysphagia and weight loss. 5-year survival is < 10\%. Treatment options: surgery, radiotherapy, or palliative tubes (Nottingham pulson, Celestin traction). * Achalasia: Idiopathic degeneration of Auerbach’s myenteric plexus; failure of Lower Oesophageal Sphincter (LOS) to relax. Diagnosis by manometry; treat with Heller’s cardiomyotomy. * Boerhaave's Syndrome: Spontaneous perforation above the LOS on the left side following violent vomiting.
Stomach and Duodenum: * Peptic Ulcer Disease: Mainstay is H2 receptor antagonists/proton pump inhibitors. Surgery involves truncal vagotomy (with drainage like pyloroplasty) or highly selective vagotomy (no drainage). * Postgastrectomy Syndromes: Early dumping (vasomotor) occurs shortly after eating; late dumping (hypoglycaemia) caused by insulin rebound. * Gastric Carcinoma: Peak in 6th decade, men > women. Pathology: ulcerative, polypoid, linitis plastica, or superficial spreading ( $90\%$ 5-year survival if early; others $10\%$ ). Metastasize to ovaries (Krukenberg tumours).
Biliary and Pancreatic Disease: * Gallstones: Symptoms overlap between biliary colic and acute cholecystitis. Murphy's sign (subcostal tenderness). Treat complications like gallstone ileus or empyema. * Obstructive Jaundice: Palpable gallbladder suggests malignant obstruction (Courvoisier’s Law). Jaundiced patients risk coagulopathy (correct with Vitamin K) and hepatorenal failure. * Acute Pancreatitis: $70\%$ caused by gallstones or alcohol. Symptoms include agonizing epigastric pain spreading to the back. Serum amylase is diagnostic. Complications: pseudocysts (often in lesser sac), pancreatic abscesses. * Carcinoma of Pancreas: Jaundice common in head cancer. Surgery: Whipple’s operation or total pancreatectomy. Survival very poor for ductal adenocarcinoma ( $1/3$ survival for periampullary).
Liver and Spleen: * Hepatocellular Carcinoma: Linked to Hepatitis B and aflatoxins. Prognosis: < 20\% 5-year survival. * Portal Hypertension/Cirrhosis: Causes oesophageal varices. Acute bleeding treated with Sengestaken-Blakemore tube (balloon tamponade) or sclerotherapy. Porta-systemic shunts (End-to-end, Side-to-side, or Distal spleno-renal) decompress high-pressure portal blood. * Splenectomy: Indications: trauma, hypersplenism, or malignancy staging. Risk: severe postsplenectomy infection (usually Streptococcus pneumoniae). Lifelong penicillin and preoperative pneumococcal vaccine required.
Small Bowel and Appendix: * Obstruction: Adhesions and hernias are leading causes. Strangulation implies compromised blood supply; presents with constant pain and fever. * Crohn’s Disease: Transmural inflammatory disease with non-caseating granulomas and 'skip lesions'. Diagnosis by barium follow-through (cobblestone mucosa, rose thorn fissures). * Acute Appendicitis: Localized tenderness at McBurney’s point. Retrocaecal type mimics renal colic; pelvic type lacks abdominal signs. * Appendicular Carcinoid: Usually found incidentally. Carcinoid syndrome occurs with liver metastases; release of 5-hydroxytryptamine causes flushing and diarrhea.
Large Intestine, Rectum, and Anus: * Large Bowel Obstruction: Usually colon cancer. Competent ileocaecal valve creates a closed-loop system, increasing caecal perforation risk. * Colorectal Cancer: Duke's staging: A (bowel wall only, $80\%$ survival), B (extending through wall, $60\%$ ), C (nodes, $30\%$ ), D (distant metastases, $10\%$ ). * Diverticular Disease: Linked to low-fibre diet. Acute diverticulitis treated with Hartmann’s procedure if complicated. * Ulcerative Colitis: Mucosal/submucosal inflammation only. 'Lead pipe' appearance on barium enema. Complication: toxic dilatation, malignant change ( $10\text{--}20\%$ chance after 10 years). * Haemorrhoids: Classified into degrees: 1st (bleeding), 2nd (prolapse, spontaneous reduction), 3rd (manual reduction required), 4th (permanent prolapse).

Hernias

Types: * Inguinal: Indirect (congenital, via patent processus vaginalis) or Direct (weak posterior wall, medial to inferior epigastric artery). 1 in 20 recur. * Richter's Hernia: Part of the intestinal wall incarcerated; no obstruction, but risks strangulation. * Sliding Hernia: Caecum or bladder forms part of the sac wall. * Femoral Hernia: Below and lateral to pubic tubercle. High risk of strangulation due to tight neck; more common in women. * Incisional Hernia: Risk increased by obesity, vertical incisions, and infection.

Trauma and Emergencies

Trauma Care (ATLS): * The 'Golden Hour' is the window for life-saving assessment. * Order of Priority: Airway (A), Breathing (B), Circulation (C), Dysfunction (D), Exposure (E). * Cervical stabilizer (collar) must remain until X-ray excludes fracture. * Thoracic injuries: Cardiac tamponade needs pericardiocentesis; tension pneumothorax needs needle decompression. * Vascular injuries: Avoid tourniquets where possible; use direct compression.
Acute Abdomen Pain Location: * Foregut (Stomach/Liver): Epigastrium. * Midgut (Small bowel/Appendix): Periumbilical. * Hindgut (Lower colon): Hypogastrium. * Radiation: Retroperitoneal (aorta/pancreas) to back; biliary system to shoulder tip.

Urology

Infections and Stones: * Proteus mirabilis increases pH, favoring 'triple phosphate' (staghorn) calculi. * ESWL (Shockwave lithotripsy) and PCNL are preferred treatments over open surgery.
Tumours: * Wilm's tumour ( $80\%$ 5-year survival protocol-driven). * Renal Adenocarcinoma: Presents with flank pain, mass, and haematuria. * Prostate Cancer: PSA > 100\,\mu g/litre suggests metastases. Treat early disease with radical surgery/radiotherapy; advanced disease via androgen deprivation (orchiectomy or LHRH analogues).

Cardiac and Thoracic Surgery

Ischaemic Heart Disease: Annual mortality without surgery: 1 vessel disease ( $2\%$ ), 3 vessel ( $8\text{--}11\%$ ), Left Main Stem ( $9\text{--}11\%$ ). Grafts used: Saphenous vein (reversed) and Internal Mammary Artery.
Aortic Disease: Aortic coarctation shows rib 'notching' on X-ray. Sternal fractures (seat-belt injuries) require monitoring for myocardial contusion.
Congenital: Tetralogy of Fallot includes VSD, overriding aorta, RV outflow obstruction, and RV hypertrophy.

Neurosurgery

Head Injury Outcomes: $1/3$ good recovery, $1/3$ disability, $1/3$ die.
Subarachnoid Haemorrhage: Ruptured 'berry' aneurysms. Nimoldipine prevents vasospasm-induced ischemia.
Spinal Cord Compression: Emergency window for rescue after loss of bladder control is only $24$ hours.

Plastic Surgery

Burns: Rule of Nine (Head $9\%$ , Arm $9\%$ , Trunk $36\%$ , Leg $18\%$ , Perineum $1\%$ ). Full thickness burns are insensitive to pain. Inhalation damage indicated by carboxyhaemoglobin > 15\%. Marjolin's ulcer is a squamous carcinoma in a chronic burn scar.
Skin Tumours: Basal Cell Carcinomas (pearly, rolled margins, very slow growth); Squamous Cell (rapid growth, metastasize); Malignant Melanoma (prognosis linked to Breslow thickness).