Hepatic Encephalopathy

Meet the patient

A 62-year-old man with known alcohol-related cirrhosis is brought in by his wife because for two days he has been sleeping by day and awake and irritable by night, could not draw the clock face she asked him to, and this morning held his outstretched hands with a fine irregular flap at the wrists. He has not opened his bowels for five days.[1][8]

Two questions are now live and they frame the whole topic: what grade is this, and what precipitated it? The grade (West Haven II — asterixis and disorientation) sets the urgency; the precipitant (here, constipation, but always hunt SBP, a GI bleed, sedatives, electrolytes, TIPS) is the single most important thing to find and treat, because in Type C cirrhotic HE an overt episode is almost always triggered.[1]

What HE is — and the three principles that frame every answer

Hepatic encephalopathy is a reversible syndrome of impaired brain function occurring in patients with advanced liver disease or portosystemic shunting, in the absence of other identifiable neurological disease. It runs a spectrum from subtle cognitive impairment detectable only on psychometric testing (covert HE) through disorientation, somnolence and asterixis (overt HE) to deep coma.[1][6]

Three principles define the clinical problem and frame every answer:[1]

1. It is a diagnosis of exclusion. A cirrhotic with new confusion has HE only after sepsis, hypoglycaemia, an intracranial lesion, electrolyte disturbance, drug effect, Wernicke encephalopathy and delirium tremens have been considered and excluded.
2. In cirrhosis (Type C), an overt episode is almost always precipitated. The single most important clinical act is to hunt and treat the precipitant — empirically, while the workup proceeds.[1]
3. It is potentially reversible with treatment of the precipitant and ammonia-lowering therapy, but each episode signals decompensated cirrhosis with a poor prognosis (1-year mortality up to 40 to 50 percent after the first overt HE) — so refer for liver transplantation.[6]

Classification — three axes, all examinable

HE is classified along three independent axes: underlying disease (Type A, B, C), severity (covert versus overt, West Haven grade I to IV), and time course. Examiners ask for all three.[1][6]

By underlying disease — Type A, B, C

[1]

By severity — covert versus overt (West Haven)

The West Haven classification grades mental state from minimal cognitive change to deep coma. The split that matters clinically is covert (grades 0 to I) versus overt (grades II to IV) — the syndrome that prompts admission.[1]

[1]

Covert HE (minimal HE, grade 0, plus grade I) affects 30 to 60 percent of cirrhotics, impairs driving and quality of life, and predicts the first overt episode — yet is invisible at the bedside without formal testing.[3]

By time course

• Episodic — a single acute episode over hours to days; almost always precipitated.
• Recurrent — two or more episodes within 6 months without prophylaxis.
• Persistent — continuous cognitive or behavioural abnormality that fluctuates but never returns to baseline; seen in advanced cirrhosis and large spontaneous shunts.[1]

How common, and the precipitants examiners test

HE is a major complication of decompensated cirrhosis and a leading cause of hospital admission in cirrhosis.[6]

• Prevalence of overt HE at first decompensation — about 10 to 20 percent of cirrhotics.
• Lifetime cumulative risk of overt HE in cirrhosis — 50 to 70 percent.
• Covert (minimal) HE — present in 30 to 60 percent of cirrhotics with an apparently normal mental state; high-yield because it is invisible at the bedside and predicts the first overt episode.[3]
• Recurrence — about 40 percent at 1 year after a first overt episode despite standard therapy; this is the rationale for secondary prophylaxis with rifaximin.[1]

Mortality after first overt HE — 1-year mortality approaching 40 to 50 percent, 3-year mortality over 70 percent; the episode signals transition to a decompensated state and is an independent indication for transplant evaluation.[6]

The precipitants — the high-yield mnemonic list. In Type C, an overt episode is almost always triggered, so hunt the precipitant from the moment of admission:[1]

[1]

Why it happens — the ammonia-astrocyte cascade

The core insight examiners want: HE is a multifactorial syndrome of gut-derived neurotoxins (chiefly ammonia) acting on a brain made vulnerable by portosystemic shunting, inflammation and oxidative stress. No single toxin explains all of HE.[6]

Ammonia is produced in the gut by bacterial degradation of dietary protein and urea (the urease-positive organisms — Klebsiella, Proteus, E. coli) and by glutaminase in enterocytes.[1]

In health, portal venous ammonia is detoxified in the liver — by the urea cycle in hepatocyte mitochondria (to urea, excreted by the kidney) and by glutamine synthetase in periportal hepatocytes (ammonia plus glutamate to glutamine). In cirrhosis both routes fail: reduced hepatocyte mass cuts urea-cycle capacity, and portosystemic shunting diverts ammonia-rich portal blood straight into the systemic circulation.[6]

At the blood-brain barrier, ammonia crosses as NH3 gas (the uncharged form favoured by alkalosis) and is taken up almost exclusively by astrocytes, the only brain cell expressing glutamine synthetase. There it is converted to glutamine, which is osmotically active — it accumulates, draws in water, and causes astrocyte swelling (the histological hallmark is the Alzheimer type II astrocyte).[1][6]

The swollen astrocyte cannot regulate extracellular glutamate (normally cleared via EAAT-2 transporters), so glutamate accumulates and drives NMDA-receptor excitotoxicity; it cannot maintain the GABA-glutamate balance, producing a relative GABA-ergic tone increase (the basis of the GABA hypothesis and the reason benzodiazepines worsen HE); and in severe cases it progresses to cerebral oedema and intracranial hypertension.[1]

Other contributors (the synergistic toxin hypothesis):[6]

• Systemic inflammation — sepsis disrupts the BBB and sensitises the brain to ammonia; inflammation and ammonia act synergistically, not additively, which is why a mild infection can trigger overt HE.
• GABA and endogenous benzodiazepine-like substances — increased GABA-ergic tone produces the somnolence, ataxia and asterixis; flumazenil produces transient improvement in some patients but is not used clinically (low response rate, seizure risk).
• Manganese — deposited in the basal ganglia in chronic portosystemic shunting; produces extrapyramidal signs and the T1-weighted hyperintensity of the globus pallidus on MRI.
• Mercaptans (methanethiol, from methionine bacterial metabolism) — contribute to fetor hepaticus (the sweet musty breath).
• Zinc deficiency — zinc is a cofactor for glutamate dehydrogenase and the urea cycle; cirrhotics are often deficient.[1]

The bedside signs — named and reproduced

The presentation depends on grade and on whether the episode is covert or overt. The classical teaching emphasises the progression: sleep reversal, then mild confusion, then asterixis and disorientation, then somnolence, then coma. Most patients present with known cirrhosis and a precipitant; rarely, HE is the first manifestation of cirrhosis.[8]

The named bedside signs, reproduced verbatim:[8]

• Asterixis (flapping tremor) — ask the patient to hold the arms outstretched with wrists dorsiflexed and fingers spread for 30 seconds; a rapid, irregular, non-rhythmic flexion-extension (flap) at the wrist and metacarpophalangeal joints appears, with brief silent lapses of sustained posture. It is the sign of loss of sustained motor tone in a metabolic encephalopathy. Bilateral in HE (unilateral asterixis suggests a focal structural lesion). Also seen in uraemia, hypercapnia (CO2 narcosis), and severe heart failure.[8]
• Constructional apraxia — the patient cannot copy a five-pointed star, a clock face, or intersecting pentagons. Sensitive for grade I to II HE.
• Fetor hepaticus — sweet, musty, faecal breath (volatile mercaptans, methanethiol) blown off from portosystemic shunting of gut-derived substances. High-yield exam pearl.
• Hyperreflexia, rigidity, clonus, extensor plantars in grade III.
• Signs of chronic liver disease — jaundice, spider naevi, palmar erythema, gynaecomastia, testicular atrophy, ascites, caput medusae, clubbing, leukonychia, Dupuytren contracture, parotid enlargement — establish the underlying cirrhosis and portal hypertension.[1]

Covert (minimal) HE — grade 0 — has no bedside signs by definition. Diagnosis requires psychometric testing (PHES — Psychometric Hepatic Encephalopathy Score) or specialist tools (critical flicker frequency, ICT, EncephalApp smartphone Stroop). Patients report impairment in driving, sleep, attention and work; family may note personality change. Affects 30 to 60 percent of cirrhotics and predicts the first overt episode.[3]

The differential — a cirrhotic with new confusion is not always HE

A cirrhotic with new confusion has HE only after other causes are considered and excluded. Name and distinguish the mimics:[1]

[1]

The practical rule: if the working diagnosis is HE but the patient is not improving after 48 to 72 hours of adequate lactulose and precipitant treatment, re-examine the diagnosis — obtain a CT brain, EEG, repeat the septic screen, and reconsider Wernicke and metabolic causes.[1]

Bedside assessment — grade, hunt the precipitant, exclude mimics

Bedside assessment serves three purposes: grade the severity (West Haven), identify the precipitant, and exclude mimics. All three run in parallel.[1]

Mental state and grade: orientation (time, place, person); attention (serial subtraction of 7 from 100; digit span); asterixis (hold posture 30 seconds); construction (copy a star or draw a clock at 11:10); conscious level (GCS if grade III to IV or deteriorating).[1]

Hunt the precipitant: vitals (fever — infection; tachypnoea — acidosis, sepsis, aspiration; hypotension — sepsis or GI bleed; hypothermia — severe sepsis); abdomen (ascites — tap it for SBP; tenderness or peritonism; hepatomegaly or a mass for HCC); rectal examination (melaena or bright blood for a GI bleed; hard stool or a loaded rectum for constipation); signs of alcohol withdrawal (tremor, sweating, hallucinations); hydration (over-diuresis); focal neurological deficit (image the brain); the drug chart (benzodiazepines, opioids, diuretics).[1]

Confirm the underlying cirrhosis: the stigmata of chronic liver disease (jaundice, spider naevi, palmar erythema, gynaecomastia, ascites, caput, clubbing, leukonychia, parotid enlargement) and portal hypertension (splenomegaly, ascites, caput) confirm the substrate.[1]

Investigations — support the diagnosis, find the precipitant, exclude mimics

HE is a clinical diagnosis. Investigations support it, identify the precipitant, exclude mimics, and stage the underlying liver disease.[1]

[1]

Serum ammonia — what it does and does not do. A venous ammonia, sampled on ice and processed within 20 minutes, supports the diagnosis and helps distinguish HE from non-HE causes (a normal ammonia in a confused cirrhotic argues against HE). Levels do not correlate well with West Haven grade — a patient may be in deep coma with a modestly raised ammonia, and vice versa. Levels correlate better with hepatic synthetic function than with neurological state. Arterial ammonia is not required routinely. Falsely elevated by delayed processing, haemolysis, a high-protein meal, exercise, smoking, muscle activity (tourniquet), valproate, and carbamazepine.[3]

Confirming covert HE requires formal testing: PHES (five paper-and-pencil tests; a score under minus 4 defines covert HE); critical flicker frequency (a fused light appears to flicker; below 39 Hz indicates covert HE); ICT and EncephalApp (smartphone Stroop) as bedside screening tools.[1]

Neuroimaging. CT brain (non-contrast) is first-line to exclude structural lesions. MRI brain may show T1-weighted hyperintensity of the basal ganglia (globus pallidus) from manganese deposition (a hallmark of chronic portosystemic shunting, not of acute HE). MRI is not diagnostic of HE — it excludes other causes and shows supportive signs.[1]

Electroencephalogram. The classic finding is generalised slowing (theta and delta waves) with, in advanced cases, triphasic waves — high-amplitude, bilaterally synchronous, symmetric, frontal-dominant waves at 1.5 to 3 Hz with a phase lag. Triphasic waves are NOT specific — also seen in uraemia, hyponatraemia, anoxia and other metabolic encephalopathies. EEG is rarely needed at the bedside but useful to exclude non-convulsive status epilepticus in unexplained coma.[1]

Severity scoring. West Haven (Conn-Lieberthal) is the clinical score. Child-Pugh stages the underlying cirrhosis (encephalopathy is one of its five components: none = 1 point, grade I to II = 2, grade III to IV = 3; class C has a 1-year mortality around 45 percent). MELD or MELD-Na governs transplant prioritisation — a rising MELD in a cirrhotic with new HE mandates transplant referral.[1][6]

Management — resuscitation and ABCDE

ABCDE first. HE is rarely an immediate airway threat at grade I to II, but grade III to IV coma risks airway obstruction, aspiration and respiratory arrest.[1]

• Airway — protect the airway in grade III to IV; consider intubation if GCS under 8, inability to protect the airway, or aspiration risk. Lateral position plus suction.
• Breathing — oxygen to keep SpO2 at 94 to 98 percent (88 to 92 percent if a CO2 retainer). Treat hypoxaemia from aspiration pneumonia, sepsis, or hepatic hydrothorax.
• Circulation — IV access; treat hypovolaemia (GI bleed, over-diuresis, sepsis) with balanced crystalloids; transfuse for a GI bleed per a restrictive strategy. Avoid hyponatraemic fluids — use saline cautiously.
• Disability — finger-prick glucose immediately; if low, give IV dextrose. Give parenteral thiamine BEFORE any glucose in suspected alcohol misuse, to avoid precipitating Wernicke. Check GCS, pupils, focal signs.
• Exposure — hunt the precipitant. Treat sepsis empirically if there is any clue — blood cultures then a broad-spectrum antibiotic. For SBP, a third-generation cephalosporin (cefotaxime) plus IV albumin 1.5 g/kg at diagnosis and 1 g/kg on day 3 reduces renal impairment and death (Sort 1999 NEJM).[10]

Do not delay the precipitant workup and treatment while awaiting ammonia or neuroimaging. A septic cirrhotic with new confusion needs bloods, paracentesis, cultures, empiric antibiotics and lactulose started within the first hour of admission.[1]

Definitive management — the four pillars, run in parallel

The four pillars: treat the precipitant, lower gut ammonia, prevent recurrence, and supportive care and nutrition. All four run in parallel from admission.[1][6]

Pillar 1 — Identify and treat the precipitant

| Precipitant | Specific treatment |[1] |---|---| | SBP | Diagnostic paracentesis (PMN over 250); third-generation cephalosporin (e.g. cefotaxime) plus IV albumin 1.5 g/kg at diagnosis, then 1 g/kg on day 3 to prevent renal impairment and death (Sort 1999)[10] | | GI bleed | Resuscitate, restrict transfusion (Hb 70 to 80), terlipressin plus antibiotics (e.g. ceftriaxone 1 g IV daily), urgent endoscopy with band ligation; clear gut blood with lactulose (blood in the gut is a high ammonia load) | | Constipation | Lactulose to achieve soft stools daily; an enema if impacted | | Hypokalaemia or alkalosis | Replace potassium (oral and IV); correct the alkalosis by treating the cause | | Hyponatraemia | Slow correction — water restriction, stop diuretics; avoid rapid Na correction (risk of osmotic demyelination); hypertonic saline only if severe symptoms or seizures | | Sedatives or drugs | Stop the offending agent; consider reversal agents — flumazenil for benzodiazepines (only if severe, with monitoring — seizure risk) and naloxone for opioids | | Infection (other than SBP) | Culture, source control, targeted antibiotics | | TIPS-related HE | Optimise lactulose plus rifaximin; if refractory, shunt embolisation or reduction | | Hepatic decompensation or ACLF | Treat the underlying cause; consider transplant evaluation |

[1]

Pillar 2 — Lower gut ammonia

[2] [9] [11] [14] [15]

Lactulose (a non-absorbable synthetic disaccharide) is the standard first-line agent for HE, working by three actions:[13]

1. Catharsis — an osmotic laxative that reduces gut transit time and contact of ammonia with the mucosa.
2. Acidification of the colon — bacterial fermentation produces lactic and acetic acid, lowering colonic pH to under 5, which converts diffusible NH3 to non-absorbable NH4 plus (ion trapping) — ammonia is trapped in the lumen and excreted in stool.
3. Favours urease-negative flora — the acidic pH suppresses urease-positive organisms (Klebsiella, Proteus).[2]

Dose — titrate to stool frequency, not to a number. In minimal HE, lactulose 30 to 60 mL per day improved psychometric testing and lowered venous ammonia in a randomised trial of 190 cirrhotics.[15] In overt HE give lactulose orally, or via a nasogastric tube in coma, titrated to soft stools daily; the endpoint is stool frequency and consistency, NOT a target ammonia level. The Als-Nielsen 2004 BMJ systematic review of 22 randomised trials found that versus placebo or no intervention, non-absorbable disaccharides seemed to reduce the risk of no improvement (relative risk 0.62), but high-quality trials showed no significant effect, mortality was unaffected, disaccharides were inferior to antibiotics in improving HE, and the review concluded there was insufficient evidence to support or refute their use.[2]

Rifaximin — a minimally absorbed antibiotic with activity against ammonia-producing gut flora. Dose 550 mg orally twice daily, ADDED to lactulose, not replacing it — more than 90 percent of patients in the landmark trial received concomitant lactulose. The Bass 2010 NEJM trial randomly assigned 299 patients in remission from recurrent HE to rifaximin 550 mg twice daily or placebo for 6 months: breakthrough HE occurred in 22.1 versus 45.9 percent (hazard ratio 0.42) and HE-related hospitalisation in 13.6 versus 22.6 percent (hazard ratio 0.50).[9] The Cochrane 2023 review found rifaximin alone likely has no overall effect on mortality versus non-absorbable disaccharides (RR 0.99), but rifaximin plus a non-absorbable disaccharide, versus a disaccharide alone, likely reduces mortality (RR 0.69) and may reduce serious adverse events and HE recurrence.[7]

L-ornithine L-aspartate (LOLA) provides substrates (ornithine, aspartate) that enhance residual urea-cycle and glutamine-synthetase activity, converting ammonia to urea and glutamine. In a double-blind randomised trial in grade III to IV overt HE, IV LOLA 30 g over 24 hours for 5 days added to lactulose and rifaximin improved HE grade (92.5 versus 66 percent) and lowered 28-day mortality (16.4 versus 41.8 percent).[14] A network meta-analysis found LOLA effective for reversing minimal HE and, with lactulose, among the most effective agents for preventing overt HE.[13] Used in some countries where rifaximin is costly.

Branched-chain amino acids (BCAA) — leucine, isoleucine, valine — compete with aromatic amino acids for BBB transport and promote muscle glutamine synthesis (ammonia disposal in skeletal muscle). May reduce recurrence and improve nitrogen balance; not first-line.[1]

Other agents with limited evidence: polyethylene glycol — in the HELP randomised trial, PEG 3350-electrolyte solution achieved improvement of one grade or more at 24 hours in 91 versus 52 percent with lactulose, with faster resolution (median 1 versus 2 days)[12]; probiotics — effective for minimal HE in a network meta-analysis, and lactulose, probiotics and the combination were equally effective in a randomised trial[13][15]; zinc — zinc acetate 150 mg per day for 3 months reduced blood ammonia in hypozincemic cirrhotics in a small randomised trial[16]; shunt embolisation for refractory Type B or large spontaneous portosystemic shunt HE.

Agents that do NOT work and should not be used: branched-chain ketoanalogues; dopamine agonists (bromocriptine); flumazenil (transient only, seizure risk); sorbitol and other osmotic laxatives (no ammonia-lowering beyond catharsis; lactulose preferred for its acidification).[1]

Pillar 3 — Prevent recurrence (secondary prophylaxis)

After a first overt HE episode, breakthrough occurs in nearly half of patients within 6 months without rifaximin (45.9 percent on placebo over 6 months in the Bass trial). Standard secondary prophylaxis:[9]

• Continue lactulose titrated to soft stools daily, indefinitely.[13]
• Add rifaximin 550 mg twice daily indefinitely — reduces breakthrough HE and HE-related hospitalisation.[9]
• Treat and prevent precipitants — avoid constipation, treat infections early, avoid sedatives.
• Refer for liver transplant evaluation — a first overt HE episode marks decompensation and carries high early mortality.[6]

Pillar 4 — Supportive care and nutrition

Nutrition is the single most under-prescribed intervention in HE.[1]

• Do NOT restrict dietary protein. The older dogma of protein restriction is wrong — the Córdoba 2004 RCT in episodic HE showed a normal-protein diet can be administered safely, that protein restriction has no beneficial effect, and that the low-protein group showed higher protein breakdown, worsening the sarcopenia that robs cirrhosis of its major extrahepatic ammonia-disposal site.[4]
• Recommended intake — 1.2 to 1.5 g/kg/day of protein, with 35 to 45 kcal/kg/day (ISHEN nutritional consensus). Vegetable and dairy protein is preferred — "diets rich in vegetables and dairy protein may be beneficial and are therefore recommended".[11]
• A late-night snack of complex carbohydrates (with small meals evenly distributed through the day) minimises overnight protein utilisation.[11]
• Vitamin supplementation — short-term multivitamin supplementation should be considered in patients admitted with decompensated cirrhosis.[11]
• Avoid sedatives where possible — they can worsen encephalopathy; if a sedative is unavoidable, use the lowest effective dose.[6]
• Supportive basics — aspiration precautions in coma, DVT and pressure-area care in immobile patients, and a stool chart to titrate lactulose.[6]

The special subtypes and scenarios

Covert (minimal) HE. Affects about half of cirrhotics (55 percent in a series of 190) — impairs quality of life and work and predicts progression to overt HE. Diagnose with psychometric tests (results vary with age and education) or specialist computerised tests. Treatment: a network meta-analysis found rifaximin (OR 7.53) and lactulose (OR 5.39) the most effective agents for reversing minimal HE, with LOLA and lactulose best for preventing overt HE and probiotics also effective; in a randomised trial, lactulose 30 to 60 mL per day and probiotics were equally effective and both improved psychometry and venous ammonia.[3][13][15] Address quality of life and work disability.

Post-TIPS HE. New or worsening HE in 20 to 50 percent within the first year after TIPS, especially with prior HE, older age, a large shunt, or sarcopenia. Most episodes respond to lactulose plus rifaximin; refractory cases need shunt embolisation or reduction. Pre-TIPS prophylaxis with rifaximin reduces incidence.[1]

Recurrent and persistent HE. Recurrent — two or more episodes within 6 months; add rifaximin to lactulose and search for an occult large spontaneous shunt. Persistent — continuous cognitive impairment; consider large portosystemic shunt embolisation and transplant evaluation.[1]

Type A HE (acute liver failure). HE and cerebral oedema are the central and most important clinical events of ALF and, with superadded infection, determine its outcome (INASL ALF consensus). Management is a different paradigm: ammonia plays a crucial role in pathogenesis and several therapies aim to correct it; patients are best managed with aggressive intensive medical care at a centre with liver transplantation, which is the only effective therapy for patients with poor prognostic factors.[17]

ACLF-related HE. Acute decompensation of cirrhosis with extrahepatic organ failure; high short-term mortality. Treat the HE precipitant and the ACLF in parallel; consider NAC and transplant.[1]

Complications and the classic pitfalls

Complications of HE itself: aspiration of gastric contents in coma (aspiration pneumonia); falls and trauma (confusion plus ataxia plus a subdural in a coagulopathic patient); pressure sores, decubitus ulcers, DVT and PE in immobile patients; cerebral oedema (rare in Type C, common in Type A) with hypertension, bradycardia, abnormal pupils, decerebrate posturing; progression to coma and death if untreated; recurrence (40 percent at 1 year); and the chronic irreversible neurological complications of long-standing shunting — hepatic myelopathy and acquired hepatocerebral degeneration.[1]

Complications of treatment: protein restriction — restriction of dietary protein has no beneficial effect during an episode of HE and the low-protein group showed higher protein breakdown in the Córdoba randomised study[4]; hyponatraemia — may itself worsen HE and must always be corrected slowly[11].

The classic pitfalls (exam favourites): treating the ammonia without finding the precipitant (SBP missed, patient deteriorates); restricting protein (sarcopenia, worse ammonia disposal); attributing confusion to HE in an alcoholic without excluding Wernicke (give thiamine); giving IV dextrose before thiamine (precipitates Wernicke); rapidly correcting Na (osmotic demyelination); using midazolam for ICU sedation (worsens HE — use propofol); confusing HE with delirium tremens (DTs has autonomic hyperactivity, tremor, hallucinations); forgetting to look for a subdural in a cirrhotic with falls and confusion; stopping rifaximin on discharge (breakthrough HE; secondary prophylaxis is indefinite).[1]

Prognosis and disposition

• Recovery from each episode — usually within 3 to 7 days of appropriate treatment; failure to improve by 72 hours mandates re-evaluation (CT brain, EEG, repeat septic screen).
• 1-year mortality after first overt HE — 40 to 50 percent; 3-year mortality over 70 percent.[6]
• Predictors of poor outcome — higher MELD, low albumin, a persistent precipitant (uncontrolled sepsis), older age, sarcopenia, ACLF, need for ICU.
• Recurrence — 40 percent at 1 year despite standard therapy.
• Disposition — a first overt HE episode is an indication for liver transplant evaluation; covert HE is managed as an outpatient with driving advice.[1]

Special populations

• Elderly — atypical (quiet delirium, falls); lower threshold to admit and image; multiple comorbidities; avoid benzodiazepines (excess sensitivity); watch for cumulative drug effects.[1]
• Pregnancy with cirrhosis — rare; coordinate with obstetric hepatology; intrahepatic cholestasis and HELLP can mimic; manage at a transplant centre.[1]
• Children — urea-cycle disorders, biliary atresia post-Kasai; present with vomiting, ataxia, school decline, reversible dementia. Treat precipitants; liver transplant for inborn errors.[1]
• Post-liver-transplant — HE usually resolves rapidly with restoration of hepatic function; persistent cognitive deficits reflect pre-transplant brain injury.[1]
• Immunocompromised — occult infection; lower threshold for empiric broad-spectrum antibiotics.[1]
• Anticoagulated cirrhotic — INR often already prolonged; balance bleeding risk (do not routinely transfuse FFP for INR correction unless bleeding).[1]
• Alcoholic cirrhotic — give parenteral thiamine before any glucose; screen for Wernicke and DTs; treat alcohol withdrawal concomitantly with short-acting benzodiazepines at the lowest effective dose.[1]

Evidence, guidelines and regional differences

The landmark trials:[1]

• Bass 2010 NEJM — rifaximin 550 mg twice daily (with over 90 percent on concomitant lactulose) reduced breakthrough HE over 6 months in patients in remission from recurrent HE (22.1 versus 45.9 percent; hazard ratio 0.42) and HE-related hospitalisation (13.6 versus 22.6 percent; hazard ratio 0.50); established rifaximin as standard secondary prophylaxis.[9]
• Als-Nielsen 2004 BMJ — Cochrane systematic review of 22 randomised trials of non-absorbable disaccharides: versus placebo or no intervention they seemed to reduce the risk of no improvement (RR 0.62), but high-quality trials showed no significant effect and they were inferior to antibiotics; the review concluded there was insufficient evidence to support or refute their use.[2]
• Córdoba 2004 J Hepatol — RCT showing a normal-protein diet is safe in episodic HE and protein restriction has no beneficial effect; killed the protein-restriction dogma.[4]
• Cochrane 2023 (Zacharias et al.) — versus non-absorbable disaccharides, rifaximin alone likely has no overall effect on mortality (RR 0.99), but rifaximin plus a disaccharide likely reduces mortality (RR 0.69, moderate-certainty), may reduce serious adverse events (RR 0.66, very low-certainty) and hepatic encephalopathy or its recurrence (RR 0.58, low-certainty).[7]

Current guidelines: the EASL-AASLD 2014 Practice Guideline (Vilstrup) is the international standard; it introduced the Type A/B/C and covert/overt classification. The Rose 2020 (ISHEN/WCOG consensus) added novel pathophysiology, classification and therapy, and Ferenci's 2017 review remains a widely cited teaching synthesis of the same framework.[1][6][5]

Regional differences:[1]

[1] [1]

Controversies: whether serum ammonia should be measured routinely (most guidelines: useful for trend and support, not diagnostic, not predictive of grade); whether non-absorbable disaccharides reduce mortality (no trial has; benefit is symptomatic); the long-term safety of rifaximin (no signal yet for clinically significant resistance or C. difficile, but surveillance continues); the role of embolising large spontaneous shunts in refractory HE (emerging evidence); whether albumin infusion benefits HE specifically (under investigation).[1]

The mnemonic, and the mantra

[1] [4] [9] [11]

The mantra: find the precipitant, lactulose to two to three soft stools a day, add rifaximin, keep the protein high, and keep benzodiazepines out — then refer for transplant.[1][6]

Ward-round test — three stems

Stem 1 — the man from the top of the topic (answer)

A 62-year-old cirrhotic with sleep reversal, an inability to draw a clock, and asterixis, who has not opened his bowels in five days. What is the grade, the precipitant, and the first-hour plan? Model: This is overt hepatic encephalopathy, West Haven grade II (lethargy, disorientation, asterixis, constructional apraxia) — grade it on the West Haven scale, which runs from subclinical change to disorientation and coma.[6] Always treat it as precipitated — here the obvious trigger is constipation, but you must hunt for the others: check glucose, do a full septic screen (blood, urine, chest X-ray), tap the ascites to exclude SBP, do a rectal examination for melaena, and review the drug chart for sedatives. The first-hour plan is the four pillars in parallel: start lactulose titrated to soft stools daily[13], treat any infection empirically — for SBP a third-generation cephalosporin plus IV albumin 1.5 g/kg at diagnosis and 1 g/kg on day 3 (Sort 1999)[10], correct electrolytes, and stop sedatives. Add rifaximin 550 mg twice daily[9] for recurrent disease. Keep protein high (1.2 to 1.5 g/kg/day) — do not restrict[11]. On recovery, continue lactulose plus rifaximin indefinitely and refer for transplant evaluation — HE marks advanced liver disease with considerable mortality.[6]

Stem 2 — the cirrhotic who is not improving (answer)

A cirrhotic treated for HE with lactulose and rifaximin for 72 hours is not improving. What do you reconsider? Model: HE that fails to improve after 48 to 72 hours of adequate lactulose and precipitant treatment is a diagnostic alarm, not a dosing problem. Re-examine the diagnosis. Obtain a CT brain (a subdural — cirrhotics fall and are coagulopathic), an EEG (non-convulsive status), repeat the septic screen, and reconsider Wernicke (give parenteral thiamine), hyponatraemia (correct slowly), hypoglycaemia, and drug effect. Also check the lactulose is actually working (a stool chart) and that a precipitant such as an occult GI bleed or infection has not been missed. The rule is: if HE is the working diagnosis but the patient is not waking up, the working diagnosis is probably incomplete.[1]

Stem 3 — the protein question as a viva trap (answer)

An examiner asks: "A cirrhotic with overt HE is prescribed a low-protein diet to reduce ammonia production. Is that appropriate?" Model: No — and the question is the classic trap. Do not restrict dietary protein. The older dogma of protein restriction is wrong: the Córdoba 2004 RCT showed a normal-protein diet is safe in episodic HE, that restriction has no beneficial effect, and that the low-protein group showed higher protein breakdown — worsening the catabolism and sarcopenia that cost skeletal muscle, the major extrahepatic site of ammonia disposal.[4] The recommended intake is 1.2 to 1.5 g/kg/day of protein with 35 to 45 kcal/kg/day, with vegetable and dairy protein preferred and a late-night snack of complex carbohydrates to minimise overnight protein utilisation (ISHEN consensus).[11] Lower ammonia with lactulose and rifaximin, not with starvation.

References

1. [1]Vilstrup H, Amodio P, Bajaj J, Cordoba J, Ferenci P, Mullen KD, Weissenborn K, Wong P Hepatic encephalopathy in chronic liver disease: 2014 Practice Guideline by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver Hepatology, 2014.PMID 25042402
2. [2]Als-Nielsen B, Gluud LL, Gluud C Non-absorbable disaccharides for hepatic encephalopathy: systematic review of randomised trials BMJ, 2004.PMID 15054035
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