9.4 Gastrointestinal and Hepatic Emergencies in the ICU

Gastrointestinal and Hepatic Emergencies in the ICU

Acute Variceal Hemorrhage

Variceal bleeding accounts for 10-30% of upper GI bleeds in cirrhosis and carries 15-25% 6-week mortality per episode.

Pharmacotherapy bundle (within 12 hours):

1. Octreotide 50 mcg IV bolus, then 50 mcg/hour infusion for 3-5 days — splanchnic vasoconstriction reduces portal pressure.
2. Ceftriaxone 1 g IV daily for 7 days — prophylaxis against spontaneous bacterial peritonitis; reduces mortality.
3. Albumin 1 g/kg on day 1, 0.5 g/kg day 3 if large-volume resuscitation — preferred over crystalloid in cirrhosis.
4. Proton pump inhibitor infusion — for ulcer prophylaxis.
5. Endoscopic band ligation within 12 hours.

Rescue therapy for refractory bleeding: balloon tamponade (Sengstaken-Blakemore) as bridge, transjugular intrahepatic portosystemic shunt (TIPS).

Fulminant Hepatic Failure (Acute Liver Failure)

Most common cause in US/UK: acetaminophen toxicity.

Management:

• N-acetylcysteine (NAC): 150 mg/kg IV over 1 hour, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours (21-hour protocol), or 100 mg/kg over 1 hour then 6.25 mg/kg/hour (modified). Continue until INR <1.5, hepatic encephalopathy resolved.
• Rumack-Matthew nomogram: applies only to acute single ingestion with known timing. Chronic or staggered ingestion = treat empirically.
• King's College Criteria for transplant: arterial pH <7.3, OR all of (INR >6.5, creatinine >3.4, grade III-IV encephalopathy).
• Lactulose for hepatic encephalopathy; Rifaximin 550 mg BID added for prevention.
• Avoid hepatotoxins (NSAIDs, statins during acute phase, certain antibiotics requiring hepatic dose adjustment).

Severe Acute Pancreatitis

Pharmacotherapy:

• Aggressive crystalloid resuscitation (lactated Ringer's preferred; goal BUN reduction by 24h).
• Early enteral nutrition within 48 hours reduces infected necrosis and mortality vs. NPO.
• No prophylactic antibiotics in interstitial pancreatitis; reserve for documented infected necrosis with carbapenem or ciprofloxacin + metronidazole covering gut flora.
• Pain control: hydromorphone preferred over morphine (less sphincter of Oddi spasm historically, though evidence is mixed).
• Octreotide has no mortality benefit in acute pancreatitis and is not routine.
• Ercp within 24 hours for confirmed cholangitis or biliary obstruction.

Hepatorenal Syndrome (HRS-AKI)

Defined by International Club of Ascites criteria: AKI in cirrhosis without other clear cause.

First-line: albumin 1 g/kg day 1 then 20-40 g/day plus vasoconstrictor:

• Terlipressin (FDA-approved 2023): 1-2 mg IV q4-6h or continuous infusion 2-12 mg/day until SCr reduction; monitor for ischemia. Slow taper to prevent relapse.
• Norepinephrine alternative where terlipressin unavailable.

Response criteria: SCr decrease toward <1.5 mg/dL within 14 days. Non-responders require evaluation for transplant.

Hepatic Encephalopathy

• Lactulose 15-30 mL BID-QID titrated to 2-3 soft bowel movements daily.
• Rifaximin 550 mg BID added for secondary prevention; reduces recurrence and hospitalization.
• Treat precipitants: infection, GI bleed, constipation, electrolyte disturbance, over-diuresis, CNS depressants.

Severe GI Bleeding (Non-Variceal)

• PPI infusion (e.g., pantoprazole 80 mg IV bolus, then 8 mg/hour infusion) for high-risk ulcers.
• Prokinetic erythromycin 250 mg IV 30-90 min before endoscopy improves visualization.
• Tranexamic acid is NOT recommended per current guidelines (meta-analyses show harm).
• Reversal of anticoagulants per agent-specific protocols (see 9.3).

Drug Dosing Considerations in Cirrhosis

Cirrhosis alters the pharmacokinetics of many drugs. The Child-Pugh score guides hepatic dosing adjustments for drugs with narrow therapeutic indices. Volume of distribution rises (ascites, fluid overload), protein binding falls (hypoalbuminemia raises free fraction of ceftriaxone, phenytoin, valproate), and hepatic extraction falls (reduced blood flow, shunting). General principles:

• Prefer renally cleared drugs when possible; avoid drugs requiring hepatic activation (codeine, tramadol) because CYP2D6 activity falls.
• Start low and titrate slowly for sedatives, opioids, and benzodiazepines; consider longer dosing intervals.
• Monitor for hepatotoxicity signals (rising AST/ALT, INR, bilirubin) when using drugs with known hepatic injury potential.

Spontaneous Bacterial Peritonitis (SBP)

SBP complicates cirrhotic ascites and carries 20% in-hospital mortality. Diagnosis: ascitic fluid polymorphonuclear count ≥250 cells/mm³. Empiric therapy is ceftriaxone 2 g IV daily for 5-7 days; add albumin 1.5 g/kg day 1, 1 g/kg day 3 to prevent hepatorenal syndrome (mortality benefit confirmed in meta-analyses). Secondary prophylaxis with norfloxacin 400 mg daily or TMP-SMX DS daily until ascites resolves or transplant. Patients with prior SBP, low-protein ascites (<1.5 g/dL) with renal dysfunction, or variceal bleed warrant primary prophylaxis.

Clinical Scenario

A 58-year-old with alcoholic cirrhosis (MELD 22) presents with hematemesis and syncope. BP 88/52, HR 122, Hgb 6.8 g/dL. What is the immediate pharmacotherapy bundle?

Answer: Octreotide 50 mcg IV bolus then 50 mcg/hour infusion; ceftriaxone 1 g IV daily; albumin 1 g/kg IV (60 g); pantoprazole 80 mg IV bolus then 8 mg/hour infusion; transfuse PRBC to target Hgb 7-8 g/dL; arrange urgent EGD with band ligation within 12 hours. Avoid over-resuscitation (worsens portal pressure and bleeding).