Residency · Residency · Internal Medicine

Hepatic Encephalopathy and the Acutely Decompensated Cirrhotic

Pathophysiology

Hepatic encephalopathy (HE) results from the accumulation of neurotoxins, primarily ammonia, that cross the blood-brain barrier due to impaired hepatic clearance. Within astrocytes, ammonia is converted to glutamine by glutamine synthetase, causing osmotic stress and astrocyte swelling (Alzheimer type II astrocytosis). Additional contributing factors include neuroinflammation, increased GABA-ergic tone, manganese deposition, altered gut microbiome composition, and oxidative stress. Portal-systemic shunting, whether spontaneous or TIPS-related, bypasses hepatic ammonia metabolism and contributes to the condition. Importantly, serum ammonia levels correlate poorly with HE severity in chronic liver disease, and clinicians should not trend ammonia to guide treatment.

Classification and Grading

By Underlying Disease

Type A is associated with acute liver failure, Type B with portal-systemic bypass without intrinsic liver disease, and Type C with cirrhosis (the most common form).

By Temporal Course

Episodes may be episodic (single or recurrent), persistent (continuous cognitive impairment), or minimal/covert (no overt clinical signs, detectable only by psychometric testing).

West Haven Criteria (Grade 0-4)

Grade 0 (Minimal HE) involves no clinical findings but abnormal psychometric tests such as number connection test, Stroop test, or Inhibitory Control Test. Grade 1 (Covert) manifests as trivial lack of awareness, shortened attention span, euphoria or anxiety, and impaired addition or subtraction. Grade 2 (Overt) presents with lethargy, disorientation to time, inappropriate behavior, and asterixis. Grade 3 (Overt) features somnolence to semi-stupor, responsiveness to stimuli, confusion, gross disorientation, and bizarre behavior. Grade 4 (Overt) represents coma, with variable response to painful stimuli.

ISHEN Classification

The International Society for Hepatic Encephalopathy and Nitrogen Metabolism classifies covert HE as encompassing minimal and Grade 1 (requiring specialized testing) and overt HE as Grades 2 through 4 (clinically apparent).

Precipitating Factors -- Always Search for the Trigger

Infection and sepsis are the most common precipitants, including SBP, urinary tract infection, pneumonia, and cellulitis. GI bleeding provides a protein load from blood in the GI tract. Constipation increases ammonia generation and absorption. Over-diuresis and dehydration cause hypokalemia and alkalosis, which increase NH3 diffusion across the blood-brain barrier. Hypokalemia specifically promotes renal ammoniagenesis, and metabolic alkalosis shifts NH4+ to the diffusible NH3 form. TIPS placement creates new portal-systemic shunting. Medications including benzodiazepines, opioids, sedatives, and potentially proton pump inhibitors (which alter gut flora) are common culprits. Dietary protein excess is a rare cause in practice, and protein restriction is not recommended. Hyponatremia independently worsens cerebral edema. Hepatocellular carcinoma progression and portal vein thrombosis are additional considerations.

Diagnosis

HE is a clinical diagnosis with no single laboratory test providing confirmation. Serum ammonia supports the diagnosis if elevated, but a normal ammonia level does not exclude HE, and ammonia levels should not be trended to assess treatment response. Other causes of altered mental status must be ruled out, including subdural hematoma (cirrhotics fall frequently and have coagulopathy), Wernicke encephalopathy, meningitis, hypoglycemia, medications, uremia, hyponatremia, stroke, and seizure. CT head should be considered if there are focal neurological signs, recent falls, or atypical presentation. EEG shows diffuse slowing with triphasic waves, which are suggestive but not specific. Psychometric testing is used for minimal and covert HE, including number connection tests, Stroop test, Animal Naming Test, and EncephalApp.

Treatment

Acute Overt HE -- Stepwise Approach

Step 1: Identify and Treat Precipitant

This is the most important intervention. It requires an infection workup (blood cultures, urine culture, chest X-ray, diagnostic paracentesis for SBP), correction of electrolytes (especially hypokalemia and hyponatremia), discontinuation of sedatives, benzodiazepines, and opioids, holding diuretics if over-diuresed, and evaluation and management of GI bleeding.

Step 2: Lactulose

Lactulose works as an osmotic laxative that acidifies colonic pH, converting NH3 to non-absorbable NH4+, promoting fecal nitrogen excretion and modifying gut flora. Dosing begins at 20-30 g (30-45 mL) orally every 1-2 hours until a bowel movement occurs, then is titrated to achieve 2-3 soft stools per day. For patients unable to take oral medications or with Grade 3-4 HE, rectal administration (300 mL in 700 mL water, retained 30-60 minutes) is an option. Over-use must be avoided because excessive diarrhea causes dehydration and electrolyte derangement that worsen HE. The goal is soft stools, not explosive diarrhea.

Step 3: Rifaximin

Rifaximin is a non-absorbable antibiotic that reduces ammonia-producing gut bacteria and has anti-inflammatory effects. It is dosed at 550 mg orally twice daily. Bass et al. (NEJM 2010) demonstrated that adding rifaximin to lactulose reduces HE recurrence by 58%. It is generally used as an add-on to lactulose rather than monotherapy for secondary prophylaxis. The drug is very well tolerated with minimal systemic absorption and, while expensive, is cost-effective when considering reduced hospitalizations.

Refractory/Recurrent HE

Optimization of lactulose plus rifaximin adherence is the first priority. Nutritional optimization is critical: dietary protein should not be restricted because this worsens sarcopenia and malnutrition. Recommended protein intake is 1.2-1.5 g/kg/day, with vegetable and dairy protein potentially better tolerated than animal protein due to higher fiber content and less ammoniagenic properties. A late-evening snack prevents overnight fasting catabolism. Branched-chain amino acids (BCAA) may improve HE in patients intolerant of dietary protein, though evidence is mixed. Large spontaneous portosystemic shunt embolization should be considered in patients with large shunts contributing to recurrent HE despite medical therapy. TIPS revision or reduction is appropriate when HE developed after TIPS and is refractory. Fecal microbiota transplant (FMT) is an emerging therapy with pilot studies showing reduced HE hospitalizations and improved cognition, though it is not yet standard of care. L-ornithine L-aspartate (LOLA) promotes ammonia metabolism with some evidence for benefit in overt HE and is used more commonly outside North America. Liver transplant remains the definitive treatment for recurrent HE in appropriate candidates.

Minimal/Covert Hepatic Encephalopathy

Minimal or covert HE is present in 30-80% of cirrhotics and impairs driving ability, work performance, and quality of life while predicting future overt HE episodes. Screening tools include EncephalApp (a Stroop test on smartphone), number connection tests, and the Psychometric Hepatic Encephalopathy Score (PHES). Treatment with lactulose and/or rifaximin improves psychometric testing and quality of life. Patients should be counseled about driving and occupational safety.

Prognostication in Decompensated Cirrhosis

MELD-Na Score

The MELD-Na score incorporates bilirubin, INR, creatinine, and sodium, and is used for transplant listing prioritization. Higher scores predict higher 90-day mortality. MELD 3.0 has recently been proposed, adding sex and albumin for improved accuracy.

Child-Turcotte-Pugh (CTP) Score

The CTP score uses bilirubin, albumin, INR, ascites, and encephalopathy on a 5-15 point scale. Child A (5-6) represents well-compensated disease, Child B (7-9) significant functional compromise, and Child C (10-15) decompensated disease. One-year survival rates are approximately 100% for Class A, 80% for Class B, and 45% for Class C.

Acute-on-Chronic Liver Failure (ACLF)

ACLF is a syndrome of acute decompensation with organ failure in cirrhosis, graded by the CLIF-SOFA score. Grade 1 involves single organ failure, Grade 2 two organ failures, and Grade 3 three or more. ACLF Grade 3 carries a 28-day mortality exceeding 70%, guiding futility discussions and transplant urgency.

The Acutely Decompensated Cirrhotic -- Comprehensive Inpatient Assessment

The comprehensive inpatient assessment of an acutely decompensated cirrhotic includes diagnostic paracentesis for SBP screening, infection screen with cultures (blood, urine, ascites) and chest X-ray, precipitant search for each complication, MELD-Na calculation and trending, nutritional assessment with early dietitian involvement, transplant candidacy evaluation (if not already listed), goals-of-care discussion if ACLF Grade 3 or MELD above 30 without transplant access, and screening for hepatocellular carcinoma if not done in the past 6 months.

<image> A diagnostic and treatment algorithm for hepatic encephalopathy. Start with "Altered Mental Status in Cirrhotic Patient." First branch: rule out other causes (subdural hematoma, Wernicke, hypoglycemia, medications). Then grade HE using West Haven criteria. Show precipitant search checklist (infection, GI bleed, constipation, medications, electrolytes). Treatment pathway: lactulose titration to 2-3 stools/day, add rifaximin if recurrent, nutritional optimization. Include liver transplant as definitive treatment. </image>

<image> A visual representation of the West Haven grading scale for hepatic encephalopathy. Show a spectrum from left to right: Minimal (normal appearance, abnormal psychometric tests), Grade 1 (subtle personality changes, impaired attention), Grade 2 (lethargy, asterixis, disorientation to time), Grade 3 (somnolence, confusion, gross disorientation), Grade 4 (coma). Include typical clinical findings and examination maneuvers at each stage. Use a color gradient from green (minimal) to red (coma). </image>

<image> An infographic showing the precipitants of hepatic encephalopathy as a "trigger wheel." Central hub labeled "HE Episode" with spokes radiating to: Infection/SBP (most common), GI Bleeding, Constipation, Over-diuresis/Dehydration, Hypokalemia/Alkalosis, Sedative Medications, TIPS, and Dietary (rare). Each spoke includes a brief management action. Emphasize that identifying and treating the precipitant is the most important intervention. </image>

Clinical Pearls

HE is a diagnosis of exclusion in cirrhotics with altered mental status, and clinicians must always rule out subdural hematoma, Wernicke encephalopathy, hypoglycemia, and infection first. Serum ammonia correlates poorly with HE severity in chronic liver disease, and levels should not be trended to assess treatment response; instead, the clinical picture should guide management. The most important step in managing HE is identifying and treating the precipitant, not simply administering lactulose. The lactulose goal is 2-3 soft stools per day, and excessive diarrhea causes dehydration and electrolyte disturbances that paradoxically worsen HE. Dietary protein must not be restricted in cirrhotics because this worsens sarcopenia and malnutrition, which in turn worsen HE; the recommended intake is 1.2-1.5 g/kg/day. Rifaximin combined with lactulose is more effective than lactulose alone for preventing HE recurrence, and rifaximin should be added after the first episode of overt HE. Minimal HE affects up to 80% of cirrhotics and impairs driving and work performance; screening with EncephalApp and appropriate patient counseling are important clinical responsibilities.

References

• Vilstrup H, et al. AASLD/EASL Practice Guideline: Hepatic Encephalopathy in Chronic Liver Disease. Hepatology. 2014.
• Bass NM, et al. Rifaximin Treatment in Hepatic Encephalopathy. NEJM. 2010.
• Bajaj JS, et al. Fecal Microbiota Transplant for Hepatic Encephalopathy. Hepatology. 2017.
• Bajaj JS, et al. EncephalApp Stroop Test for Covert Hepatic Encephalopathy. Am J Gastroenterol. 2013.
• European Association for the Study of the Liver. EASL Clinical Practice Guidelines on Hepatic Encephalopathy. J Hepatol. 2022.
• Moreau R, et al. CANONIC Study: Acute-on-Chronic Liver Failure. Gastroenterology. 2013.
• Amodio P, et al. ISHEN Consensus on Neuropsychological Testing. Hepatology. 2011.

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