Acute Abdomen in the ICU

• ICU peritonitis is blunted; watch for fever, rising pressor needs, feeding intolerance, and lactate.
• Find the source with CT abdomen; a perforated viscus needs source control plus broad-spectrum antibiotics, while suspected ischemia (lactate, AF, pressors) needs urgent CTA and vascular/surgical review; peritonitis/necrosis → immediate surgery, otherwise consider endovascular revascularization.
• Sustained intra-abdominal pressure >20 mmHg associated with new organ dysfunction defines abdominal compartment syndrome; begin urgent medical/percutaneous decompression and escalate to surgery for persistent dysfunction or deterioration.
• Keep pancreatitis, cholecystitis (calculous vs acalculous), C. diff colitis, and Ogilvie in the differential.
• Measure intra-abdominal (bladder) pressure in ventilated patients with abdominal distension.

First tests: Urgent surgical assessment, Full blood count, Sodium, potassium, bicarbonate, urea and creatinine, Blood lactate.

Only if indicated: Contrast CT abdomen/pelvis, Blood cultures, Pregnancy test.

Repeat monitoring: Repeated abdominal and perfusion assessment.

• Diagnosing and Managing Acute Abdominal Pathology in the Intensive Care Unit