Acute-on-Chronic Liver Failure (ACLF) - Clinical Guidelines

Definition & Overview

• Underlying chronic liver disease (almost always with cirrhosis)
• An identifiable or cryptic precipitating event
• Hepatic and/or extrahepatic organ failure
• Excessive systemic inflammatory response

Definitions Across Major Guidelines

EASL-CLIF Grading System

• Liver: Bilirubin ≥12 mg/dL
• Kidneys: Creatinine ≥2.0 mg/dL (or renal replacement therapy)
• Brain: HE grade 3-4 (West Haven)
• Coagulation: INR ≥2.5
• Circulation: Vasopressor use
• Respiratory: PaO2/FiO2 <200 or SpO2/FiO2 <214

Precipitating Events

• Alcohol-associated hepatitis (most common in the West)
• HBV reactivation or new viral hepatitis (HEV, HAV) - most common in Asia
• Drug-induced liver injury (DILI)
• Autoimmune hepatitis flare

• Bacterial/fungal infection and sepsis (most common overall)
• GI bleeding
• Post-operative state
• Large-volume paracentesis without albumin

Diagnostic Workup

1. Assess organ failure: CLIF-C OF score, SOFA score
2. Prognostic scoring: CLIF-C ACLF score (best validated), MELD/MELD-Na, NACSELD-ACLF score, Child-Pugh
3. Look for precipitants: Blood/urine/ascitic fluid cultures, viral hepatitis serology, alcohol history, drug review
4. Imaging: Abdominal US with Doppler (portal vein thrombosis, hepatic architecture), CXR
5. Diagnostic paracentesis: If ascites present (cell count, culture, albumin, total protein)

Management - General Principles (EASL 2023 / AASLD 2024)

1. Triage and ICU Admission

• All ACLF-2 and ACLF-3 patients should be admitted to ICU
• ACLF-1 may be managed in high-dependency unit with close monitoring
• Reassess organ failure status daily for the first 3-7 days
• If no improvement or deterioration after 3-7 days of full ICU support with 4+ organ failures and no transplant option - consider transition to palliative care

2. Treat the Precipitating Event

3. Infection Prophylaxis and Management (EASL 2023 - Strong Recommendations)

• Infections trigger/worsen ACLF in up to two-thirds of cases
• Routine cultures on admission (blood, urine, ascitic fluid)
• Empiric antibiotics should be started within 1 hour of suspected infection
• Norfloxacin (or rifaximin) for SBP prophylaxis in high-risk patients (low ascitic protein <1.5 g/dL + advanced disease)
• IV albumin 1.5 g/kg day 1, then 1 g/kg day 3 in SBP reduces risk of renal failure and death

4. Organ-Specific Management

• Stop nephrotoxins (NSAIDs, aminoglycosides, contrast)
• Volume resuscitation with albumin (preferred colloid)
• Terlipressin (0.5-1 mg IV q4-6h) + albumin for hepatorenal syndrome type 1 (HRS-AKI) - first-line (EASL Grade A1)
• Norepinephrine may be used as alternative if terlipressin unavailable
• Renal replacement therapy (CRRT preferred) if AKI/HRS unresponsive or volume overload/hyperkalemia/acidosis
• Avoid diuretics in oliguric HRS

• Identify and treat precipitants (infection, bleeding, constipation, sedatives)
• Lactulose 2-3 soft stools/day (titrate dose)
• Rifaximin 550 mg BD for recurrent/persistent HE
• Airway protection/intubation for grade 3-4 HE
• Limit sedation; use dexmedetomidine or propofol over benzodiazepines
• Zinc supplementation (adjunctive)
• Avoid protein restriction (counter-productive)

• Vasopressor of choice: norepinephrine (target MAP ≥65 mmHg)
• Screen for adrenal insufficiency (AASLD 2024) - treat with hydrocortisone 200-300 mg/day if confirmed
• Volume resuscitation: albumin preferred over crystalloids
• Vasopressin/terlipressin as adjuncts in refractory shock

• High-flow nasal oxygen (HFNO) as first-line for moderate hypoxemic respiratory failure
• Non-invasive ventilation (NIV) if tolerated (caution in encephalopathy)
• Invasive mechanical ventilation for severe ARDS or failure of above; lung-protective strategy (6 mL/kg tidal volume)

• Do NOT correct coagulopathy prophylactically (INR not reliable indicator of bleeding risk in cirrhosis - balances pro- and anticoagulant deficits)
• FFP, platelets, cryoprecipitate only for active bleeding or before invasive procedures
• Thromboprophylaxis with LMWH for DVT prevention unless active bleeding or platelets <50,000

5. Nutrition

• Target 35-40 kcal/kg/day, protein 1.2-1.5 g/kg/day (do NOT restrict protein)
• Enteral nutrition preferred; nasogastric feeding if needed
• Small frequent meals + late-evening snack
• BCAA supplementation may be considered
• Early enteral nutrition in ICU patients within 24-48 hours

6. Specific Pharmacological Therapies

• Granulocyte colony-stimulating factor (G-CSF): Promising - shown to decrease mortality in decompensated cirrhosis in some trials; under investigation specifically for ACLF. Some APASL guidance supports its use.
• Albumin infusions: Beyond SBP, chronic albumin administration (PILOT/ATTIRE/ANSWER trials) - role evolving; currently standard in specific indications (HRS, SBP, post-paracentesis)
• NAC: Evidence limited in ACLF; used in DILI-associated precipitants
• Liver support devices (MARS, PROMETHEUS, ELAD): Not yet proven to reduce mortality in RCTs; consider as bridge to transplant in selected centres

Liver Transplantation

Indications (EASL 2023)

• ACLF-1 and ACLF-2: Strong candidates; early listing recommended
• ACLF-3 (3+ OF): Carefully selected patients; short-term post-LT mortality higher but still beneficial vs. no transplant
• Patients with ACLF who fail to improve or deteriorate after 3-7 days of medical therapy but have <3 organ failures should be prioritized for LT

Contraindications / Futility Criteria

• ACLF-3 with ≥4 organ failures: Very high peri-operative mortality; individual assessment required
• CLIF-C ACLF score ≥64 with 3+ organ failures - daily reassessment; if does not improve, transplant may not confer survival benefit
• Active uncontrolled sepsis, multidrug-resistant organisms without coverage
• Severe extra-hepatic disease incompatible with LT
• Alcohol-associated hepatitis: Selected patients without adequate sobriety period (early LT for severe AH shows good outcomes in specialized centers per multiple RCTs)

Scoring for LT listing

• MELD-Na: Primary allocation tool in USA/Europe
• CLIF-C ACLF score: Better short-term mortality predictor in ACLF than MELD
• NACSELD-ACLF: Predicts 30-day mortality based on number of OFs

When to Consider Palliative Care

"If after 3-7 days of ICU support, there continue to be four or more organ failures and liver transplantation is not an option, consideration for a transition to palliative care is recommended."

Monitoring and Reassessment

• Reassess CLIF-C ACLF score daily for first 7 days
• Patients who improve by day 3-7 (reduction in organ failures) have significantly better prognosis
• ACLF resolution (reversal to no ACLF state by day 28) is associated with near-normal survival
• Discharge planning should include:
  • Alcohol cessation counseling and treatment
  • Rifaximin for secondary HE prophylaxis
  • Outpatient LT evaluation if eligible
  • Infection surveillance

Summary of Key Guideline Sources

• ACLF is a medical emergency requiring rapid diagnosis, ICU triage, and multidisciplinary team management
• Identify and aggressively treat precipitants (infection first, then alcohol, viral hepatitis)
• Organ-specific support (terlipressin + albumin for HRS, norepinephrine for circulatory failure, lactulose + rifaximin for HE)
• Refer early for liver transplantation - it is the only definitive therapy
• After 3-7 days of maximal ICU care with 4+ organ failures and no transplant option, transition to comfort-focused care is appropriate
• Reassess daily - trajectory of organ failure is as important as the grade at admission

Snakebite Envenomation - Clinical Guidelines

Epidemiology & Global Burden

• ~5.4 million bites/year worldwide; 2.7 million envenomations
• 83,000-138,000 deaths/year; ~400,000 permanent disabilities (amputations, blindness)
• Most deaths in South Asia, sub-Saharan Africa, and Latin America
• USA: 7,000-8,000 venomous bites/year; <6 deaths/year (due to antivenom availability)
• 20-25% of pit viper bites and up to 75% of sea snake bites are "dry bites" (no venom injected)

Snake Families of Medical Importance

Venom Syndromes

1. Cytotoxic / Hemotoxic (Vipers)

• Local: Pain, swelling, erythema, ecchymosis, hemorrhagic bullae, tissue necrosis
• Systemic: Coagulopathy (DIC pattern), thrombocytopenia, spontaneous bleeding (gums, IV sites), hematuria
• Renal: Myoglobinuria, acute kidney injury (Russell's viper especially)
• Shock: Hypovolemia from third spacing

2. Neurotoxic (Elapids)

• Pre-synaptic (kraits, taipans, some mambas): Irreversible - block acetylcholine release; antivenom less effective once bound
• Post-synaptic (cobras, most elapids): Reversible by antivenom + neostigmine
• Features: Ptosis (earliest sign), dysarthria, diplopia, bulbar palsy, progressive descending paralysis, respiratory failure (the killer)
• Minimal local effects (except cobras, which also cause necrosis)
• Onset may be delayed 12+ hours after bite

3. Compartment Syndrome

• Particularly with rattlesnake/viper bites on digits or confined spaces
• Distinguish from simple envenomation swelling - requires pressure measurement
• True compartment syndrome (compartment pressure >30 mmHg) requires fasciotomy

Warning Signs of Severe Envenomation

• Snake identified as highly dangerous species
• Rapid early spread of local swelling beyond the bitten segment
• Early tender lymphadenopathy (regional nodes)
• Early collapse, hypotension, shock
• Ptosis, ophthalmoplegia, inappropriate drowsiness
• Spontaneous systemic bleeding (gums, nose, GI, IV sites)
• Dark brown/black urine (hemoglobinuria/myoglobinuria)

First Aid (Field Management)

DO:

1. Move patient away from the snake (stay beyond striking distance)
2. Keep calm and still - movement accelerates venom absorption
3. Immobilize the bitten limb in neutral position at approximately heart level (splint like a fracture)
4. Remove rings, watches, bracelets, tight clothing near the bite
5. Clean the wound with soap and water; apply a sterile dressing
6. Rapid transport to a facility with antivenom - this is the single most important step
7. Take a photo of the snake from a safe distance (for identification)

For Elapid bites ONLY (cobras, kraits, coral snakes, sea snakes):

• Pressure-immobilization bandage (PIB): Wrap the entire bitten limb with an elastic bandage (snug, not tight - finger should slip under), then splint and immobilize
• Bandage pressure: 40-70 mmHg upper limb; 55-70 mmHg lower limb
• The victim must be carried, not walk - muscle pumping disperses venom
• Removes once antivenom is running

DO NOT:

• Incise or suck the bite - damages tissue, no venom removed, increases infection risk
• Apply tourniquets - cause ischemia and worsen local necrosis
• Apply ice/cold water - worsens venom injury
• Give alcohol - vasodilator, increases venom absorption
• Use electric shock - ineffective, causes electrical burns
• Try to capture the snake - risk of second bite
• Give aspirin or NSAIDs - worsen coagulopathy/bleeding

Hospital Assessment

History

• Time of bite, snake description/photo
• Geographic location (narrows likely species)
• First aid applied (note if tourniquet placed - remove carefully after antivenom starts)
• Symptoms since bite (syncope, vomiting, numbness, weakness)

Physical Examination

• Vital signs (BP, HR, RR, SpO2, temperature)
• Fang marks, wound extent, swelling measurement (circumference q1h)
• Neurological: ptosis, eye movements, bulbar function, limb power
• Bleeding: IV sites, gums, urine, stool

Investigations

Antivenom - The Cornerstone of Treatment

Indications for Antivenom

• Evidence of coagulopathy (20WBCT non-clotting, spontaneous bleeding)
• Neurotoxicity (ptosis, bulbar weakness, limb paralysis)
• Cardiovascular compromise (hypotension, arrhythmia)
• Renal failure (oliguria, rising creatinine, hematuria)
• Rhabdomyolysis/myotoxicity
• Thrombocytopenia (<100,000 with bleeding)

• Swelling extending beyond adjacent joint (beyond wrist for hand bite; beyond knee for foot bite)
• Rapid progressive swelling after bite
• Lymphangitis spreading proximally

• Any definite bite by a neurotoxic elapid - give antivenom prophylactically; do not wait for symptoms (symptoms may be irreversible)
• Ptosis = antivenom NOW (indicates imminent respiratory failure)

Antivenom - How to Give

Antivenom Types

• Polyvalent antivenom (India, Africa, Australia): Covers multiple species; does not require species identification
• Monovalent antivenom: Species-specific, used in some regions
• Fab fragment antivenoms (USA): CroFab (Crotalidae Polyvalent Immune Fab, Ovine); longer-acting F(ab')2 now available, reduces recurrent coagulopathy

Antivenom Dosing (General Principles)

• Children receive the same dose as adults (same volume of venom injected)
• Repeat dose in 6 hours if: coagulopathy persists, neurotoxicity worsens, swelling continues to progress, or vital signs do not stabilize
• USA rattlesnake (CroFab): Initial 4-6 vials IV; repeat 2 vials q6h x 3 doses to prevent recurrent coagulopathy
• Coral snake (USA): 3-5 vials prophylactically for any definite bite
• India polyvalent: 10 vials IV initially; repeat as needed based on 20WBCT at 6 hours

Antivenom Reactions

Organ-Specific Management

Coagulopathy / DIC

• Antivenom is the treatment - FFP does not work until venom is neutralized
• After antivenom, FFP/cryoprecipitate/platelets for persistent bleeding
• Repeat 20WBCT at 6 hours; if still non-clotting, repeat antivenom dose
• Do NOT use heparin for viper-induced DIC

Neurotoxic Paralysis

• Airway and ventilation are paramount - intubate early if ptosis + swallowing difficulty
• Anticipate need for prolonged mechanical ventilation (days to weeks with krait bites)
• Anticholinesterase test: Give atropine 0.6 mg IV then neostigmine 1.5-2 mg IM; if improvement in 30 min, continue neostigmine 0.5 mg IM q30min (effective for post-synaptic block - cobras; ineffective for pre-synaptic block - kraits)
• Monitor spirometry and vital capacity serially (intubate if VC <15 mL/kg or <1 L)
• SpO2 monitoring unreliable alone - use ETCO2 or arterial blood gas

Acute Kidney Injury

• Common with Russell's viper, sea snakes, and some African vipers
• Maintain hydration; avoid nephrotoxins (aminoglycosides, NSAIDs, contrast)
• Furosemide for oliguria only if volume-replete
• Early dialysis (CRRT preferred) if AKI persists or severe electrolyte disturbance
• AKI from Russell's viper may recover fully with dialysis support

Hypotension / Shock

• IV fluid resuscitation (0.9% saline or Hartmann's 250-500 mL bolus)
• Vasopressors (norepinephrine) if fluid-refractory
• Watch for pulmonary edema (some vipers cause increased capillary permeability)

Local Wound Care

• Mark the margin of swelling with a pen every 30-60 min with time noted
• Elevate the limb after antivenom is given
• Fasciotomy ONLY for confirmed compartment syndrome (direct pressure measurement >30 mmHg with clinical features) - do not do prophylactically
• Debridement of necrotic tissue when demarcated (days to weeks later)
• Tetanus prophylaxis
• Antibiotics: Not routinely indicated; use only if wound infection signs develop (antibiotic stewardship - routine prophylaxis is not evidence-based per Brenes-Chacon et al., Toxins 2024)

Pain

• Paracetamol (acetaminophen) - preferred
• Codeine phosphate for moderate pain
• Avoid aspirin and NSAIDs (worsen bleeding)

Antivenom Is NOT Indicated When:

• Dry bite (no signs of envenomation after 6-12 hours observation)
• Minor, purely local swelling confined to the bite area without progression
• Non-venomous snake confirmed
• Psychological symptoms only (fright response)

Monitoring Protocol

Disposition

• Observation minimum 12 hours for all suspected venomous bites (even if initially asymptomatic) - elapid envenomation may be delayed
• ICU for: respiratory compromise, shock, severe coagulopathy, renal failure, multi-organ involvement
• Discharge criteria: Swelling resolving, coagulopathy resolved, ambulatory and eating/drinking, no neurological deficits
• Instruct on serum sickness symptoms before discharge

Special Situations

Ophthalmia (Spitting Cobras)

• Venom spat directly into eyes causes intense pain, conjunctivitis, corneal ulceration
• Immediate copious irrigation with water (or any bland fluid)
• Do NOT rub the eye
• Antivenom is NOT instilled into the eye
• Ophthalmology review for corneal injury

Pregnancy

• Antivenom is NOT contraindicated - benefits outweigh risks
• Premature labor and fetal loss are recognized complications of envenomation
• Obstetric monitoring mandatory

Pediatric Considerations

• Same antivenom dose as adults
• Higher risk of severe envenomation relative to body mass (children receive same volume of venom)
• Rapid deterioration possible; lower threshold for ICU

WHO 2026 Update: Novel Therapeutics

Key Guideline Sources