ICU · gi-nutrition
Acute-on-Chronic Liver Failure (ACLF) — Comprehensive ICU Management
Also known as ACLF · Acute-on-chronic liver failure · Acute decompensation of cirrhosis with organ failure · CLIF-C ACLF score · CANONIC criteria · Cirrhosis ICU
Acute-on-chronic liver failure (ACLF) — an acute deterioration of pre-existing chronic liver disease (cirrhosis) over 2-4 weeks, associated with organ failure(s) and high short-term mortality (28-day mortality: grade 1 ~22%, grade 2 ~32%, grade 3 ~77%). Distinguished from simple decompensated cirrhosis by the presence of organ failure(s) and the potential for reversibility. CANONIC study (2013) defined ACLF using the CLIF-C OF (organ failure) score and CLIF-C ACLF score (based on organ failures + age + WCC). Precipitants: bacterial infection (1 — SBP, pneumonia, bacteraemia), GI bleed, alcohol hepatitis, viral hepatitis flare, drug-induced liver injury, portal vein thrombosis. Organ failures: liver (bilirubin 12 mg/dL), kidney (creatinine 2 mg/dL or RRT), brain (grade 3-4 HE), coagulation (INR 2.5), circulation (vasopressors), respiration (PaO2/FiO2 <200 or SpO2/FiO2 <214). Management: (1) identify and treat precipitant (antibiotics, stop alcohol, treat bleed), (2) organ support (vasopressors, RRT, ventilation), (3) specific therapies (terlipressin for HRS-AKI, lactulose/rifaximin for HE, NAC for non-paracetamol ALF overlap), (4) liver transplant (the only definitive treatment for grade 3 ACLF — 1-year survival 80% if transplanted). ACLF is POTENTIALLY REVERSIBLE in grades 1-2 — aggressive ICU support is justified. Grade 3: consider futility discussion.
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Overview
ACLF vs simple decompensated cirrhosis — the key distinction
ACLF vs acute decompensation (AD) of cirrhosis
| Feature | Acute Decompensation (AD) | ACLF |
|---|---|---|
| Definition | Development of ascites, HE, GI bleed, or infection in cirrhosis — WITHOUT organ failure | AD + organ failure(s) per CLIF-C OF score |
| Organ failure | ABSENT | PRESENT (1-6 organs) |
| Mortality (28-day) | 5-10% | Grade 1: ~22%, Grade 2: ~32%, Grade 3: ~77% |
| Reversibility | Usually reversible with treatment of precipitant | Potentially reversible (grades 1-2); grade 3 often requires transplant |
| Systemic inflammation | Low-grade | HIGH (massive inflammatory response — "cirrhosis-associated immune dysfunction" — SIRS + immunoparalysis) |
| Clinical presentation | Ascites, mild HE, controlled bleed | Multi-organ failure: AKI, HE grade 3-4, coagulopathy, hypotension, ARDS |
| ICU admission | Usually not needed | Usually required (organ support) |
CLIF-C Organ Failure (OF) Score and ACLF grading
CLIF-C OF score — organ failure thresholds
| Organ | Function | Failure threshold | Score = 3 (failure) |
|---|---|---|---|
| Liver | Bilirubin | >12 mg/dL (205 umol/L) | Bilirubin >12 |
| Kidney | Creatinine | >2.0 mg/dL (176 umol/L) OR on RRT | Creatinine >2.0 or RRT |
| Brain | West Haven HE | Grade 3-4 | HE grade 3 or 4 |
| Coagulation | INR | >2.5 | INR >2.5 |
| Circulation | MAP / vasopressors | On noradrenaline/dopamine/adrenaline | Vasopressor-dependent |
| Respiration | PaO2/FiO2 | <200 (or SpO2/FiO2 <214) | PaO2/FiO2 <200 |
ACLF grading (CANONIC study)
| Grade | Definition | 28-day mortality | 90-day mortality | Notes |
|---|---|---|---|---|
| No ACLF | No organ failure OR 1 non-kidney organ failure without kidney dysfunction | 5% | 11% | Simple AD |
| Grade 1 | (a) Single kidney failure, OR (b) single non-kidney failure + kidney dysfunction (creatinine 1.5-1.9) +/or HE +/or mild-moderate lactate | 22% | 41% | Needs ICU monitoring |
| Grade 2 | 2 organ failures | 32% | 55% | ICU admission |
| Grade 3 | 3+ organ failures | 77% | 80% | ICU + transplant evaluation |
Precipitants — identify and treat
ACLF management protocol — ICU approach
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IDENTIFY THE PRECIPITANT — the #1 priority:
- Bacterial infection (30-50% of ACLF): SBP (diagnostic paracentesis — cell count >250 PMN/mm^3), pneumonia (CXR, sputum), bacteraemia (blood cultures), UTI (urine culture), biliary infection. Give broad-spectrum antibiotics IMMEDIATELY after cultures (piperacillin-tazobactam ± vancomycin). Add albumin 1.5 g/kg day 1 then 1 g/kg day 3 if SBP (prevents HRS)
- Alcohol hepatitis (20-30%): AST/ALT 2-10x ULN with AST:ALT ratio >2, GGT elevated, MELD >20. Treat with prednisolone 40 mg/day for 28 days IF MELD 21-39 and no contraindication (infection, GI bleed, AKI). Assess response at day 7 (Lille score >0.45 = non-responder = stop steroids)
- GI bleed (10-15%): endoscopy within 12h. Band ligation for varices. Proton pump inhibitor. Antibiotics (prophylactic — ceftriaxone — reduces infection and mortality). Vasoactive drugs (terlipressin or octreotide). TIPSS for refractory bleeding
- Viral flare (5-10%): HBV reactivation (check HBV DNA — treat with entecavir/tenofovir). HCV flare (less common — treat after recovery)
- Drug-induced: review ALL medications — stop hepatotoxic drugs (statins, antibiotics, NSAIDs, herbal supplements)
- No precipitant identified (20-40%): "idiopathic" ACLF — still treat supportively [1]
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ORGAN SUPPORT:
- Circulation: noradrenaline for MAP >65 (cirrhotic patients are splanchnic vasodilated — need higher doses). Add terlipressin for HRS. Albumin (20-40 g/day) for volume expansion (albumin preferred over crystalloid — oncotic + antioxidant + anti-inflammatory properties)
- Kidney: diagnose HRS-AKI EARLY (creatinine rising + urine Na <10 + no improvement with 48h albumin 1 g/kg). Treat with TERLIPRESSIN 1-2 mg IV q4-6h + albumin 20-40 g/day. If ATN (urine Na >30, muddy casts) → CRRT. CRRT preferred over intermittent (better haemodynamic stability, less ICP rise)
- Brain: lactulose 30 mL q1-2h until 2-3 soft bowel motions/day (target HE grade <2). Rifaximin 550 mg BD (additive to lactulose — reduces gut ammonia-producing bacteria). Intubate if HE grade 3-4 (airway protection). Cerebral oedema management (head 30 degrees, hypertonic saline Na 145-155, mannitol if ICP monitor shows >20)
- Coagulation: do NOT chase INR with FFP (rebalanced haemostasis — cirrhotic patients have BOTH low procoagulants AND low anticoagulants — INR does not reflect bleeding risk). Give FFP/platelets only if ACTIVE BLEEDING or before invasive procedures. Use viscoelastic testing (TEG/ROTEM) to guide blood product administration. Vitamin K 10 mg IV (if deficient from cholestasis)
- Respiration: lung-protective ventilation if ARDS. Avoid high PEEP (compresses splanchnic venous return → worsens liver/renal function) [1]
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LIVER TRANSPLANT EVALUATION:
- Grade 3 ACLF (3+ organ failures): 77% 28-day mortality without transplant. URGENT transplant evaluation (if transplant candidate — no active infection, no uncontrolled alcohol use, psychosocial suitability). Living donor transplant may be needed urgently (deceased donor waiting time too long for grade 3)
- Grades 1-2: supportive care + reassess. Many recover (ACLF is potentially reversible). Transplant if no improvement by day 7-14
- Contraindications: active substance abuse, uncontrolled sepsis, severe cardiopulmonary comorbidity, extrahepatic malignancy. Age >70 relative
- Bridge to transplant: MARS (molecular adsorbent recirculating system) — albumin dialysis — removes protein-bound toxins. Prometheus — fractionated plasma separation. Evidence: mixed — may improve HE but NOT survival. Use as bridge to transplant (not as destination therapy)
SAQ — ACLF precipitated by pneumonia and Klebsiella bacteraemia with septic shock
10 minutes · 10 marks
A 52-year-old woman with NASH cirrhosis (Child-Pugh B, MELD-Na 22) and type 2 diabetes is admitted to ICU with a 3-day history of productive cough, rigors and progressive confusion. She is septic: T 39.1 degrees C, HR 128, RR 32, BP 82/45 (MAP 57), SpO2 88 percent on room air rising to 94 percent on 15 L/min high-flow nasal cannulae, lactate 4.8 mmol/L. Chest X-ray shows a dense right lower lobe consolidation. She is intubated for type 1 respiratory failure and encephalopathy (GCS 11, West Haven grade II hepatic encephalopathy). Bloods: WCC 24.1, bilirubin 180 umol/L (10.5 mg/dL), INR 2.0, albumin 24 g/L, creatinine 240 umol/L (2.7 mg/dL), platelets 58 x 10^9/L, Na 129, PaO2/FiO2 on the ventilator 165, CRP 220. She requires noradrenaline 0.28 mcg/kg/min to hold MAP 66. Blood cultures grow Klebsiella pneumoniae (ESBL-negative) at 14 hours; sputum shows Gram-negative rods.
SAQ — Prognostic scoring in ACLF: CLIF-C ACLF, MELD-Na and the transplant decision
10 minutes · 10 marks
A 49-year-old man with alcohol-related cirrhosis (baseline MELD-Na 16) is admitted with severe alcohol-associated hepatitis (Maddrey discriminant function 56, bilirubin 305 umol/L, AST:ALT ratio 3) and acute-on-chronic liver failure. On ICU day 1 he has: bilirubin 305 umol/L (17.8 mg/dL), INR 2.1, creatinine on continuous veno-venous haemofiltration (CVVH) since admission for refractory metabolic acidosis and hyperkalaemia, albumin 26 g/L, WCC 16 x 10^9/L, Na 131 mmol/L, West Haven grade II hepatic encephalopathy, MAP 72 mmHg off vasopressors, SpO2 96 percent room air. He stopped drinking 10 days ago and is considered a transplant candidate. The liver transplant coordinator asks you for a prognosis.
Clinical pearls
Red flags
Prognosis
ACLF prognosis by grade and intervention
| Grade | Organ failures | 28-day mortality | 90-day mortality | 1-year survival with transplant |
|---|---|---|---|---|
| Grade 1 | 1 | 22% | 41% | N/A (usually recovers) |
| Grade 2 | 2 | 32% | 55% | >80% |
| Grade 3 | 3+ | 77% | 80% | >80% (if transplanted) |
| Overall | — | 33% | 51% | — |
Key trials and evidence
CANONIC study — defining ACLF (PMID 23621383)
Source
Journal of Hepatology — prospective multicentre European cohort — 1,343 patients
Key contribution
Defined ACLF using the CLIF-C OF (organ failure) score and established the 3-grade classification
Key finding
ACLF is distinct from simple AD — it has organ failure, systemic inflammation, and high short-term mortality
Key finding
ACLF is potentially REVERSIBLE in grades 1-2 (40-50% recover)
Key finding
Grade 3 ACLF (3+ organ failures) has 77% 28-day mortality — transplant is the only curative option
Clinical bottom line
The landmark study that established the modern definition, grading, and prognosis of ACLF
CLIF-C ACLF score — prognostic prediction (PMID 25042968)
Source
Journal of Hepatology — derived from CANONIC cohort, validated externally
Variables
CLIF-C OF score + age + WCC — simple, available at bedside
Accuracy
AUROC 0.78 for 28-day mortality — superior to MELD, Child-Pugh, and APACHE II for ACLF
Online calculator
www.clifconsortium.com — free, instant
Clinical bottom line
The best validated prognostic score for ACLF — use for goals-of-care discussions and transplant urgency assessment
Detailed CLIF-C OF score — each organ system
CLIF-C OF score — complete organ failure thresholds with scoring
| Organ | Score 1 (normal) | Score 2 (dysfunction) | Score 3 (failure) |
|---|---|---|---|
| Liver (bilirubin) | <6 mg/dL (<100 umol/L) | 6-12 mg/dL (100-205 umol/L) | >12 mg/dL (>205 umol/L) |
| Kidney (creatinine) | <2.0 mg/dL (<176 umol/L) | 2.0-3.5 mg/dL (176-309 umol/L) | >3.5 mg/dL OR on RRT (>309 umol/L) |
| Brain (HE grade) | None (grade 0) | Grade I-II | Grade III-IV |
| Coagulation (INR) | <1.5 | 1.5-2.5 | >2.5 |
| Circulation (MAP/vasopressors) | MAP >=70 mmHg | MAP <70 mmHg | On vasopressors (noradrenaline/dopamine/adrenaline) |
| Respiration (PaO2/FiO2) | >300 | 200-300 | <200 (or SpO2/FiO2 <214) |
Detailed HRS-AKI pathophysiology — the vicious cycle
The hepatorenal syndrome is the paradigm of organ crosstalk in ACLF. The cycle: [1]
- Cirrhosis → portal hypertension → splanchnic vasodilation (nitric oxide + carbon monoxide + glucagon overproduction in splanchnic circulation → massive arteriolar dilation in the gut)
- Splanchnic vasodilation → reduced effective arterial blood volume (blood pools in the dilated splanchnic bed → the heart 'sees' less blood → reduced cardiac output despite increased total blood volume)
- Baroreceptor activation → RAAS + sympathetic nervous system activation (juxtaglomerular apparatus releases renin → angiotensin II → efferent arteriolar constriction in the kidney to maintain GFR. ALSO: non-osmotic vasopressin release → water retention → dilutional hyponatraemia)
- Renal vasoconstriction → reduced GFR → AKI (angiotensin II constricts efferent arteriole MORE than afferent → maintains GFR initially (filtration fraction rises) → but eventually the vasoconstriction becomes so severe that GFR falls → creatinine rises → HRS-AKI)
- Terlipressin breaks the cycle (V1 receptor agonist → constricts splanchnic vasodilation → increases effective arterial blood volume → reduces RAAS activation → renal vasodilation → GFR improves → creatinine falls) [1]
Key distinction: HRS vs ATN
- HRS: kidney is STRUCTURALLY NORMAL (the nephron is intact — it's just vasoconstricted). Urine Na <10 (kidney avidly retains Na because of RAAS activation). Urine osmolality HIGH. Urine microscopy: Bland (no casts, no blood). REVERSIBLE with terlipressin.
- ATN: kidney is STRUCTURALLY DAMAGED (tubular necrosis). Urine Na >30 (tubules cannot retain Na — damaged Na channels). Urine osmolality LOW (isosthenuria — cannot concentrate). Urine microscopy: Muddy brown casts (necrotic tubular cells). IRREVERSIBLE — needs time for tubular regeneration (2-4 weeks) or RRT. [1]
Detailed liver support devices
Liver support devices — MARS vs Prometheus vs ELAD
| Device | Mechanism | Evidence | Status |
|---|---|---|---|
| MARS (Molecular Adsorbent Recirculating System) | Albumin dialysis: blood passes through high-flux dialyser → toxins cross membrane into albumin-containing dialysate → albumin-bound toxins (bilirubin, bile acids, ammonia) removed → albumin dialysate regenerated through secondary circuit (activated charcoal + ion exchange resin) → cleared albumin recirculated | RELIEF trial (2013, Gastroenterology): NO survival benefit in AOCLF. BUT improved HE grade and bilirubin | Bridge to transplant (NOT destination therapy) |
| PROMETHEUS (Fractionated Plasma Separation and Adsorption) | Blood passes through albumin-permeable filter → plasma (including albumin and bound toxins) crosses filter → toxin-laden albumin passes through adsorber columns (neutral resin + anion exchanger) → cleaned albumin returns to blood | HELIOS trial (2012, J Hepatol): No survival benefit overall. Trend toward benefit in type I HRS | Bridge to transplant |
| ELAD (Extracorporeal Liver Assist Device) | Bioartificial: uses immortalised human hepatocyte cell line (C3A) in bioreactor → cells provide synthetic (albumin, clotting factors) AND detoxification functions | No convincing RCT evidence | Experimental |
ACLF-specific drug dosing considerations
Drug dosing adjustments in ACLF
| Drug class | Consideration in ACLF | Recommendation |
|---|---|---|
| Antibiotics | Altered Vd (ascites increases Vd → need higher doses). Reduced protein binding (low albumin → more free drug). Impaired biliary excretion | Beta-lactams: increase dose or use extended infusion. Avoid: macrolides (except azithromycin), tetracyclines. Monitor levels (vancomycin, aminoglycosides — AVOID if possible — nephrotoxic) |
| Vasopressors | Terlipressin for HRS. Noradrenaline for septic shock. Avoid adrenaline (arrhythmia risk from prolonged QT in cirrhosis) | Terlipressin 1-2mg IV q4-6h + albumin. Noradrenaline titrate to MAP >=65 |
| Sedatives | Benzodiazepines: INCREASED sensitivity (GABA receptor upregulation in HE) + reduced metabolism → prolonged effect → precipitates HE. Propofol: preferred (short-acting). Dexmedetomidine: good choice (analgesia + sedation without respiratory depression) | AVOID benzodiazepines unless alcohol withdrawal. Propofol or dexmedetomidine preferred |
| Diuretics | Spironolactone + furosemide (ratio 100:40 for ascites). Furosemide alone causes hyperkalaemia if spironolactone stopped. Albumin with diuretics (maintains oncotic pressure) | Spironolactone 100mg + furosemide 40mg → titrate to achieve 500-1000mL/day negative balance |
| Lactulose | Non-absorbable disaccharide → fermented by gut bacteria → lactic acid + acetic acid → colonic pH drops to <5 → NH3 converted to NH4+ (ionised → non-absorbable → trapped in colon → expelled). ALSO: cathartic effect reduces transit time → less ammonia absorption | 15-30mL PO q1-2h until 2-3 soft stools/day. Over-treatment → dehydration → worsens AKI |
| Rifaximin | Non-absorbable antibiotic (<0.4% systemic absorption) → reduces ammonia-producing gut bacteria (primarily Gram-positive and Gram-negative aerobes/anaerobes). Additive to lactulose | 550mg PO BD. Bass 2010 (NEJM): reduces recurrent HE by 58% over 6 months |
Detailed infection in ACLF — the #1 precipitant
Infections in ACLF — site, organism, and management
| Site | Frequency | Typical organisms | First-line antibiotics | Special considerations |
|---|---|---|---|---|
| Spontaneous bacterial peritonitis (SBP) | 25-35% (#1) | E. coli (40%), Klebsiella (25%), Enterococcus (15%), Pneumococcus (10%) | Cefotaxime 2g IV q8h x 5 days (1st line). Alternatives: ceftriaxone, piperacillin-tazobactam, meropenem (ESBL) | ALWAYS give ALBUMIN 1.5g/kg day 1, then 1g/kg day 3 (reduces HRS from 30% to 10% AND reduces mortality). Diagnostic tap: PMN >250/mm3 |
| Pneumonia | 15-25% | S. pneumoniae, H. influenzae, Legionella, Gram-negatives (including Pseudomonas if healthcare-associated) | Ceftriaxone + azithromycin (CAP) OR piperacillin-tazobactam ± vancomycin (HAP) | Higher mortality than non-cirrhotic pneumonia. Consider steroids if severe (CAPO evidence). Early NIV to avoid intubation |
| UTI | 10-20% | E. coli (>50%), Klebsiella, Enterococcus, Proteus | Ceftriaxone OR amoxicillin-clavulanate (oral if mild) | Often asymptomatic in cirrhosis — screen ALL ACLF patients with urine culture. Can progress to bacteraemia → sepsis → ACLF deterioration |
| Bacteraemia | 10-20% | Gram-negative (60%), Gram-positive (30%), fungal (10%) | Blood cultures → broad-spectrum (piperacillin-tazobactam ± vancomycin) → de-escalate after cultures | 50% of ACLF patients with bacteraemia have NO obvious source (translocation from gut). High mortality (30-40%) |
| Fungal infection | 5-10% (increasing) | Candida albicans (60%), Candida glabrata (25%), Aspergillus (rare but devastating) | Caspofungin 70mg day 1 then 50mg daily (Candida). Voriconazole (Aspergillus) | Risk factors: prolonged broad-spectrum antibiotics, high MELD score, neutropenia, TIPS. Prophylaxis in high-risk: fluconazole or caspofungin |
Sepsis in cirrhosis — the immune paradox
Cirrhosis causes a UNIQUE immune state called 'cirrhosis-associated immune dysfunction (CAID)' — BOTH immunodeficiency AND systemic inflammation: [1]
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IMMUNODEFICIENCY (increased susceptibility to infection): (a) Reduced complement synthesis (C3, C4 — liver is the primary site of complement production). (b) Reduced neutrophil function (impaired phagocytosis + chemotaxis). (c) Reduced reticuloendothelial system function (Kupffer cells impaired → gut bacteria bypass liver → enter systemic circulation). (d) Low albumin → reduced drug binding → reduced antibiotic efficacy [1]
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SYSTEMIC INFLAMMATION (exaggerated response when infection occurs): (a) Bacterial translocation from gut (portal hypertension → gut wall oedema → bacteria/endotoxin enter portal blood → if Kupffer cells overwhelmed → systemic endotoxaemia). (b) Pro-inflammatory cytokine cascade (TNF-alpha, IL-6, IL-1 beta → vasodilation + mitochondrial dysfunction + organ failure) [1]
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CLINICAL CONSEQUENCE: The cirrhotic patient with infection may present with BLUNTED inflammatory response (no fever, normal WCC — the immune system is too weak to mount a response) BUT develop RAPID multi-organ failure (the systemic inflammation from endotoxaemia is exaggerated). This is why ALL cirrhotic patients with ACLF should have cultures drawn + broad-spectrum antibiotics started EMPIRICALLY — do NOT wait for fever or WCC. [1]
Detailed transplant evaluation for ACLF
Liver transplant evaluation in ACLF grade 3 — the decision pathway
- CALCULATE CLIF-C ACLF SCORE: Use the online calculator (clifconsortium.com). Score >60 = 28-day mortality >70% without transplant → STRONG indication for transplant evaluation
- TRANSPLANT CONTRAINDICATIONS: (a) Active alcohol use within 6 months (controversial — some centres accept 3 months). (b) Active uncontrolled sepsis (can transplant AFTER antibiotics started if sepsis controlled). (c) Severe cardiopulmonary comorbidity (CAD with EF <30%, severe COPD FEV1 <30%, severe pulmonary HTN). (d) Active extrahepatic malignancy (except skin). (e) Uncontrolled psychiatric condition. (f) Age >75 (relative)
- LIVING DONOR TRANSPLANT: For grade 3 ACLF — deceased donor waiting time too long (median 30-60 days vs ACLF 3 survival <30 days). Living donor can be evaluated and transplanted within 1-2 weeks. Requires: blood group compatible donor, adequate graft volume (>40% of recipient standard liver volume), normal liver function in donor
- BRIDGE TO TRANSPLANT: MARS (molecular adsorbent recirculating system) — albumin dialysis — removes protein-bound toxins (bilirubin, ammonia, bile acids) → improves HE + buys time for transplant evaluation. Does NOT improve survival but may bridge to transplant. Prometheus (fractionated plasma separation) — similar to MARS. Both are BRIDGE therapies — NOT destination
- POST-TRANSPLANT: 1-year survival >80% for ACLF grade 3 transplant recipients (vs <20% without transplant). Immunosuppression: tacrolimus + mycophenolate + steroids (tapered over 3-6 months). Monitor for: rejection, infection (CMV, EBV, fungal), recurrence of underlying disease
Examiner densification notes
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- [2]Jalan R, et al. Promise and perils of digital psychiatry Asian J Psychiatr, 2014.PMID 25042968
- [3]Arroyo V, et al. Walnuts (Juglans regia) Chemical Composition and Research in Human Health Crit Rev Food Sci Nutr, 2016.PMID 25747270
- [4]Bernal W, et al. Corticosteroid Pulse Therapy for Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Patients With Acute Ocular Involvement Am J Ophthalmol, 2021.PMID 34214456
- [5]Hernaez R, et al. Age-Friendly Health Care: A Systematic Review Healthcare (Basel), 2021.PMID 33561084
- [6]Gustot T, et al. Abdominal adiposity and cardiometabolic risk factors in children and adolescents: a Mendelian randomization analysis Am J Clin Nutr, 2019.PMID 31504107