Hepatic encephalopathy

Background

• Diagnosis of exclusion
• Due to accumulation of nitrogenous waste products normally metabolized by the liver
• Spectrum of illness ranges from chronic fatigue to acute lethargy

Precipitants

1. Increased ammonia production, absorption or entry into brain:
   1. GI Bleed
   2. Excess dietary intake of protein
   3. Infection
   4. Hypokalemia
   5. Metabolic Alkalosis
   6. Constipation
2. Dehydration
   1. Vomiting
   2. Diuretics
3. Drugs
   1. Opioids
   2. Benzodiazepines (including withdrawal)
   3. ETOH (including withdrawal)

Stages

1. Stage I - General apathy
2. Stage II - Lethargy, drowsiness, variable orientation, asterixis
3. Stage III - Stupor with hyperreflexia, extensor plantar reflexes
4. Stage IV - Coma

DDx

1. Subdural Hematoma
2. Hypoglycemia
3. Wernicke-Korsakoff Syndrome
4. Hyper/hyponatremia
5. Benzodiazepine Overdose (decreased hepatic clearance)
6. Renal Failure
7. Sepsis

Work-up

• History of any new medications or toxin ingestion
• Focus exam on looking for signs of GI bleed or hypovolemia
• Chemistry (look for metabolic and electrolyte derrangements)
• Search for source of infection:
  • CBC, UA, CXR, paracentesis in pt with ascites (r/o SBP)
  • LP if indicated
• Head CT

Treatment

1. Lactulose 20mg PO or (300mL in 700cc H2O retention enema x30min)
   1. In colon degrades into lactic acid: acidic environment traps ammonia
   2. Also inhibits ammonia production in gut wall

Disposition

Discharge

• Stage I or II w/ known ecephalopathy and who is otherwise well

Patient Information

Hepatic Encephalopathy (Medline Plus)

Source

• Tintinalli
• UpToDate