Hepatic encephalopathy (HE) is a neurologic complication of advanced liver disease, causing impaired functioning, reduced quality of life (QOL), and increased hospitalisation and mortality. This review discusses HE burden, precipitating risk factors, and strategies to reduce overt HE (OHE) recurrence. Key precipitants include medications, constipation, dehydration, uncontrolled diabetes, electrolyte imbalances, GI bleeding, infection, and sarcopenia. Management involves education, nutritional support, pharmacotherapy, and nonpharmacologic interventions (shunt embolisation, transplantation). Guidelines recommend lactulose as secondary prophylaxis; rifaximin is added when further episodes occur. PEG and LOLA may have roles in certain patients. Investigational approaches include nitazoxanide, FMT, and AI‑based technologies.
Introduction
HE affects ~20% of US adults with cirrhosis (projected ~697,000 by 2030). It is classified by underlying disease (type A: acute liver failure; B: shunting; C: cirrhosis) and West Haven criteria (covert: minimal/grade I; overt: grades II–IV). OHE manifests as lethargy, disorientation, confusion, asterixis, and coma. Course may be episodic, recurrent (≥2 episodes/6 months), or persistent. Diagnosis is clinical, excluding other causes.
Burden of HE
HE profoundly impairs QOL—affecting daily activities, work, independence—and causes anxiety, social isolation, and sleep disturbances. Caregivers also experience significant psychosocial burden (depression/anxiety in 28–39%). Employment is markedly reduced (13% vs. 81% without HE). Recurrent episodes may cause cumulative, irreversible cognitive impairment. Hospitalisation and readmission are common: 43.6% rehospitalised within one year; HE is the leading cause of 90‑day readmissions (~41%). HE‑related hospitalisation costs average $77,699 per episode; total annual US inpatient charges exceed $11 billion. Mortality is significantly higher with HE and increases with severity.
Pathophysiology
OHE arises from gut dysbiosis, hyperammonaemia, systemic inflammation, oxidative stress, altered neurotransmission, manganese deposition, zinc deficiency, and elevated bile acids/lactate. Liver fails to clear toxins; portosystemic shunting redirects them systemically. Toxins cross the blood–brain barrier, causing astrocyte swelling/dysfunction, neuroinflammation, and neuronal damage. Systemic inflammation enhances ammonia neurotoxicity and increases barrier permeability, creating a positive feedback loop. Sarcopenia reduces muscle ammonia clearance and releases amino acids that generate ammonia.
Precipitating and Associated Risk Factors
Key precipitants include sedatives, opioids, statins, constipation, dehydration, uncontrolled diabetes, electrolyte imbalances, GI bleeding, infection, and sarcopenia. TIPS causes HE in 30–60%; risk factors include older age, higher MELD, prior HE, sarcopenia, renal impairment, diabetes, and stent diameter >10 mm. Nonadherence to treatment is common (only 35% adherent to lactulose) and strongly associated with recurrence (nonadherence increased OHE odds 3.3‑fold). Barriers include unpleasant taste, dose titration, and GI adverse effects.
Reducing the Risk of HE Recurrence
Education and Precipitant Correction: Correcting precipitants is critical. A 15‑min educational intervention reduced HE‑related hospitalisations (HR 0.14). Education on medication, dosing, adverse events, and early signs improves adherence.
Nutritional Support: Daily intake of 35–40 kcal/kg and 1.2–1.5 g/kg protein is recommended; protein restriction should be avoided. Nutrition therapy reduced OHE episodes (13.3% vs. 48.0%) and hospitalisations. Zinc improves cognition but may not reduce recurrence. BCAA improves HE symptoms and may prevent recurrence. Sleep hygiene and mindfulness improve QOL; sedatives should be avoided.
Pharmacotherapy:
Lactulose (titrated to 2–3 bowel movements/day) is first‑line secondary prophylaxis. Recurrence reduced vs. no therapy (19.6% vs. 46.8%; 26.5% vs. 56.9%). Adverse effects: diarrhoea, distaste, bloating.
Rifaximin 550 mg BID is added when further episodes occur. Phase 3 trial: reduced breakthrough HE by 58% (HR 0.42) and HE‑related hospitalisations by 50% (HR 0.50). Meta‑analysis confirmed reduced recurrence (RR 0.49). Adverse effects: peripheral oedema, nausea, dizziness, fatigue, diarrhoea; rare C. difficile reported. Cost‑effective due to reduced healthcare utilisation. Emerging antimicrobial resistance concerns warrant further study.
PEG not studied as secondary prophylaxis but may be an alternative in acute HE or poor lactulose response.
LOLA reduced OHE recurrence in one RCT (12.3% vs. 27.8%; HR 0.39).
Nonpharmacologic Interventions:
SPSS embolisation for recurrent/persistent HE, MELD <11, and large shunts.
TIPS reduction for recurrent/persistent HE refractory to pharmacotherapy.
Liver transplantation for recurrent/persistent HE despite adequate treatment.
Investigational Approaches:
Nitazoxanide reduced ammonia and prolonged time to recurrence vs. rifaximin.
FMT showed promising results (post‑hoc: recurrence 9.1% vs. 40.0% with placebo).
AI, apps, and wearables may facilitate adherence monitoring, stool tracking, and early detection.
Barriers to Care
Poor health literacy is associated with covert HE. Caregiver burden is substantial. Cost barriers and racial/ethnic disparities exist in rifaximin prescribing and subspecialty referral. Treatment gaps (delays, interruptions) are common and associated with increased hospitalisations and costs.
Conclusions and Future Directions
A proposed algorithm emphasises precipitant correction, lifestyle interventions, and pharmacotherapy. Lactulose is first‑line; rifaximin added for breakthrough. Recurrent/persistent HE should be evaluated for SPSS embolisation, TIPS reduction, or transplantation. Patient/caregiver education is essential. Future priorities include predictive models (e.g., AMMON‑OHE), primary prevention, and large prospective international RCTs.
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The study was recently published in the Journal of Clinical and Translational Hepatology .
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