Acute pancreatitis
- Diagnosis (2 of 3): typical pain, lipase/amylase > 3× ULN, imaging features. Imaging is not needed if the first two are present.
- US on admission: gallstones and CBD (aetiology); pancreas often obscured by gas.
- CECT (pancreatic/portal phase): IOC for severity and complications, ideally 72–96 h after onset (necrosis takes time to declare); earlier only if the diagnosis is uncertain. Features: enlarged gland, indistinct margins, peripancreatic fat stranding/fluid, non‑enhancing parenchyma = necrosis. MRI better shows solid debris in collections and CBD stones.
- Plain film signs: sentinel loop (localised ileus of jejunum/duodenum), colon cut‑off sign (distended transverse colon with abrupt cut‑off at the splenic flexure, from inflammation spreading via the phrenicocolic ligament), renal halo, gasless abdomen; CXR left effusion.
- Clinical signs of retroperitoneal haemorrhage: Grey Turner (flank), Cullen (periumbilical).