System-based surgical diagnosis and management
Domain 2 - System-based surgical diagnosis and management
Questions here present a symptom or syndrome and expect you to build the differential in the right order, choose the discriminating investigation and commit to the next management step. The organ system matters less than the pattern: pain character and timing, fever or jaundice, and the haemodynamic state usually decide the answer.
Core rules
- RUQ pain: biliary colic is postprandial, constant, settles within 6 hours and has no fever; acute cholecystitis adds Murphy's sign, fever and leucocytosis (ultrasound: wall >3 mm, pericholecystic fluid); cholangitis adds jaundice with hypotension or confusion (Reynolds' pentad) and needs urgent biliary drainage; pancreatitis gives epigastric pain radiating to the back with lipase >3× the upper limit.
- Obstructive jaundice with a palpable, non-tender gallbladder is Courvoisier's law - suspect periampullary or pancreatic head malignancy. Ultrasound first, then pancreas-protocol CT; CA19-9 supports but does not diagnose.
- Acute limb ischaemia: the six Ps (pain, pallor, pulselessness, paraesthesia, paralysis, perishing cold). Give IV heparin immediately; Rutherford IIb (paralysis or anaesthesia) goes straight to theatre.
- Testicular pain in a boy or young man is torsion until excluded - do not wait for Doppler; fix both testes at exploration.
- Bowel obstruction: adhesions and hernia in small bowel; sigmoid volvulus (coffee-bean) and colorectal cancer in large bowel. CT defines the transition point and viability.
- Breast and neck lumps: triple assessment (clinical, imaging, cytology/histology); for thyroid, TSH plus ultrasound-guided FNA reported by Bethesda category.
Worked example
A 68-year-old woman has 3 weeks of painless jaundice, pruritus and 6 kg weight loss, with a palpable gallbladder. Courvoisier's law points to malignant distal obstruction: order CA19-9 and a pancreas-protocol CT, then staging laparoscopy and pancreaticoduodenectomy if resectable. If she instead arrives with fever and rigors, cholangitis dominates and ERCP drainage precedes any oncological work-up.
Traps
Calling jaundice haemolytic without a reticulocyte count and bilirubin split; ordering ultrasound before reducing a torsion; forgetting that cholangitis is an emergency of drainage, not antibiotics alone; missing an incarcerated hernia as the cause of obstruction.