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KembaraXtra-Medicine- Acute Liver Failure (ALF)
Acute liver failure (ALF) is the rapid onset of severe liver dysfunction causing coagulopathy and altered mentation in a patient without previously known liver disease. In practice, it is defined by acute severe hepatic injury lasting <26 weeks, synthetic dysfunction with inr>1.5, and any degree of hepatic encephalopathy in the absence of preexisting cirrhosis and excluding acute alcoholic hepatitis. ALF can also be diagnosed in certain patients with preexisting liver disorders such as Wilson disease, vertically acquired hepatitis B, or autoimmune hepatitis, as long as the diagnosis was made within the preceding 26 weeks. ALF must be distinguished from acutely decompensated cirrhosis (new ascites, encephalopathy, and/or GI bleeding in established cirrhosis) and acute-on-chronic liver failure (acute deterioration in chronic liver disease with intense systemic inflammation and potential multiorgan failure).
Several classification systems describe ALF based on timing of encephalopathy relative to symptom onset or jaundice. The British scheme categorizes by interval between jaundice and encephalopathy (hyperacute, acute, subacute, late-onset), and other systems (French classification, International Association for the Study of Acute Liver Failure) similarly emphasize time course, recognizing that more rapid presentations may behave differently clinically. Common synonyms include fulminant hepatic failure, fulminant hepatitis, fulminant hepatic necrosis, and acute hepatic necrosis. ICD-10-CM codes include K72, K72.0, K72.00 (without coma), and K72.01 (with coma).
ALF is uncommon but high-stakes. Reported incidence is about 2000 cases per year in the U.S. and 1 to 8 per million population in the U.K. It is described as occurring more often in women and often affecting younger individuals. Risk factors include intentional or unintentional drug overdose, exposures increasing risk of viral hepatitis (IV drug use, blood/body fluid exposure, transfusions, hemodialysis, intranasal cocaine use, imprisonment, travel to endemic regions), prior alcohol use, hepatotoxic medications, and critical illness.
Symptoms are often nonspecific early and vary by cause. Patients may develop fatigue, lethargy, anorexia, nausea/vomiting, pruritus, jaundice, and right upper quadrant pain or distention. More severe presentations can include hypotension, sepsis, and encephalopathy. Physical examination, by definition, includes neurologic abnormalities of encephalopathy, and may show jaundice, asterixis, hepatomegaly or decreased liver span, and ascites. In advanced cases, cerebral edema and increased intracranial pressure can occur, with concerning findings such as pupillary abnormalities, hypertension with bradycardia and respiratory depression (Cushing triad), loss of brainstem reflexes, and seizures. Vesicular skin lesions raise concern for HSV, and a family history of unexplained liver disease should prompt slit-lamp exam for Kayser–Fleischer rings suggestive of Wilson disease.
In the Western world, the most common causes include acetaminophen toxicity (~46%), indeterminate causes, idiosyncratic drug reactions, and viral hepatitis (especially hepatitis A and B). Other causes include autoimmune hepatitis, Wilson disease, ischemic hepatopathy (“shock liver”), Budd–Chiari syndrome, acute fatty liver of pregnancy, veno-occlusive disease, toxic ingestions such as Amanita phalloides mushroom poisoning, sepsis, malignant hepatic infiltration, and viral etiologies beyond hepatitis viruses (e.g., adenovirus, hepatitis E, HSV).
Laboratory findings reflect loss of synthetic and metabolic function. Coagulopathy is typical due to reduced hepatic synthesis of clotting factors (II, V, VII, IX, X), producing INR >1.5. Transaminases and bilirubin are usually elevated, and thrombocytopenia may occur. Many patients develop acute kidney injury (often cited around 30%–50%), and hypoglycemia can occur from impaired gluconeogenesis. Electrolyte disturbances are common (hyponatremia, hypophosphatemia, hypomagnesemia, hypokalemia), along with metabolic acidosis or respiratory alkalosis, elevated lactate dehydrogenase, and elevated ammonia.
The differential diagnosis includes severe acute hepatitis/acute liver injury (jaundice and coagulopathy without encephalopathy), acute-on-chronic liver failure, decompensated cirrhosis, and hepatocellular carcinoma. Distinguishing ALF from portal-systemic encephalopathy due to chronic liver disease can be aided by the clinical context: ALF is typically acute, with very high transaminases, a small tender liver, and absence of chronic stigmata early, whereas chronic disease often has cachexia, collateral circulation, ascites, and less dramatic transaminase elevation.
Workup relies on rapid severity assessment and urgent search for etiology, often with limited history due to encephalopathy. Clinicians should obtain collateral history regarding medications (including OTC and herbal agents), alcohol and recreational drugs, onset of jaundice and symptoms, psychiatric history (including self-harm), travel and exposure risks for viral hepatitis, transfusions, family history of liver disease, malignancy history, and hypercoagulable conditions. Examination should assess mental status and grade encephalopathy (from mild behavioral/sleep changes through coma). Laboratory evaluation typically includes CBC, complete liver panel and INR/PT, comprehensive metabolic panel with glucose and electrolytes, arterial blood gas and lactate, blood type and screen, acetaminophen level, ethanol level and toxicology screen, hepatitis serologies and viral loads where appropriate, HSV testing (often PCR), EBV/CMV testing, ceruloplasmin (with copper studies if suspicion is high), pregnancy test, ammonia, autoimmune markers (ANA, anti–smooth muscle, anti-LKM1, total IgG), and HIV testing. Imaging usually includes abdominal ultrasound with Doppler to assess for Budd–Chiari, congestion, portal hypertension, and steatosis, with consideration of cross-sectional liver imaging when malignancy or infiltrative disease is possible. Head CT or MRI may be used to evaluate alternative causes of altered mental status. A transjugular liver biopsy is considered when the cause remains unclear or when autoimmune hepatitis, malignancy, or HSV is strongly suspected.
Complications include cerebral edema (reported up to ~40% in some series), hypoglycemia, lactic acidosis, acute kidney injury, pancreatitis (notably with acetaminophen), infections due to impaired immune function, high-output cardiac failure, ARDS, and hypotension from poor intake and third spacing.
Treatment focuses on rapid stabilization, supportive ICU-level care when indicated, targeted therapy for the underlying cause, and early transplant evaluation. Encephalopathy grade guides level of care: grade I may be managed on a medical ward with frequent neuro checks, while grades II–IV generally require ICU management, head-of-bed elevation, and for grades III–IV, intubation and mechanical ventilation. Sedatives should be minimized because they can accumulate and obscure neurologic assessment; a low-stimulation environment is recommended. Early notification of a liver specialist and early transfer to a transplant center are essential because deterioration can later make transport unsafe.
Supportive care includes early nutrition (to prevent catabolism) and careful fluid management with crystalloids tailored to hemodynamics and metabolic needs, including dextrose-containing fluids if hypoglycemia is present. If intracranial hypertension develops, mannitol can transiently reduce cerebral edema; sodium is often maintained in a higher range (e.g., 140–150 mmol/L), and hypertonic saline may be used in highest-risk patients. Prophylactic hyperventilation is not recommended. Seizures may be treated with agents such as phenytoin; short-acting benzodiazepines can be used if necessary, but sedation is generally avoided when possible. Lactulose and rifaximin are not routinely recommended for encephalopathy in ALF, and neomycin should be avoided due to nephrotoxicity risk.
Infection management is critical: broad-spectrum antibiotics are started when infection is suspected, but routine empiric antibiotics without suspicion are not supported; antifungals may be added if there is poor response or high concern. Hemodynamic support may require norepinephrine as first-line vasopressor, with vasopressin as an adjunct; refractory hypotension should prompt evaluation for adrenal insufficiency. If renal replacement therapy is required, continuous modalities are often preferred over intermittent hemodialysis in unstable patients. Stress ulcer prophylaxis is recommended. Routine correction of INR or thrombocytopenia is not recommended without bleeding, but vitamin K is generally given because deficiency is common; plasma or clotting factors are reserved for active bleeding or high-risk procedures.
Cause-specific therapy is crucial, especially for acetaminophen toxicity. There should be a low threshold to start IV N-acetylcysteine (NAC) when acetaminophen overdose is known or suspected because it is beneficial and generally safe. A commonly used 20-hour IV regimen is a loading dose followed by staged infusions, with reassessment of acetaminophen level and ALT near the end of the protocol and extension of therapy if levels remain elevated or enzymes are rising. NAC use in non–acetaminophen ALF remains controversial and is center-specific, with inconclusive evidence for routine benefit.
Bridging and advanced therapies include extracorporeal liver support systems and high-volume plasma exchange in select contexts, but these are not routinely recommended in guidelines as definitive therapy; they may be used as a bridge to recovery or transplant in specialized centers. For patients with high-grade encephalopathy awaiting transplant, some centers use intracranial pressure monitoring when expertise is available; otherwise, frequent neurologic exams are essential. Coagulation tests and metabolic panels are monitored frequently, while avoiding unnecessary correction of INR because it interferes with prognostication.
Prognosis has improved over time but remains serious, with overall mortality often cited around 30%–40%. Outcomes vary by etiology: transplant-free survival is generally better with acetaminophen-related ALF, hepatitis A, ischemic (“shock”) liver, and pregnancy-related disease, and worse with many other causes. Higher-grade encephalopathy and renal dysfunction predict worse outcomes in non–acetaminophen ALF. Prognostic models include King’s College criteria, Clichy criteria, MELD, and APACHE II; King’s College criteria are widely used to guide transplant referral. Liver transplantation provides definitive therapy for many patients meeting criteria, though contraindications include irreversible brain injury, uncontrolled sepsis, severe comorbidities including malignancy, escalating dependence on ventilator/inotropes, active substance abuse, severe uncontrolled psychiatric illness affecting adherence, and inadequate social support.
Key practical points are that ALF requires INR >1.5 plus encephalopathy within 26 weeks in a patient without known chronic liver disease, acetaminophen accounts for a large portion of cases, early transfer to a transplant center can be lifesaving, NAC should be started early when acetaminophen is possible, and coagulopathy should not be corrected unless bleeding is present or a high-risk procedure is necessary.
Acute liver failure (ALF) is the rapid onset of severe liver dysfunction causing coagulopathy and altered mentation in a patient without previously known liver disease. In practice, it is defined by acute severe hepatic injury lasting <26 weeks, synthetic dysfunction with inr>1.5, and any degree of hepatic encephalopathy in the absence of preexisting cirrhosis and excluding acute alcoholic hepatitis. ALF can also be diagnosed in certain patients with preexisting liver disorders such as Wilson disease, vertically acquired hepatitis B, or autoimmune hepatitis, as long as the diagnosis was made within the preceding 26 weeks. ALF must be distinguished from acutely decompensated cirrhosis (new ascites, encephalopathy, and/or GI bleeding in established cirrhosis) and acute-on-chronic liver failure (acute deterioration in chronic liver disease with intense systemic inflammation and potential multiorgan failure).
Several classification systems describe ALF based on timing of encephalopathy relative to symptom onset or jaundice. The British scheme categorizes by interval between jaundice and encephalopathy (hyperacute, acute, subacute, late-onset), and other systems (French classification, International Association for the Study of Acute Liver Failure) similarly emphasize time course, recognizing that more rapid presentations may behave differently clinically. Common synonyms include fulminant hepatic failure, fulminant hepatitis, fulminant hepatic necrosis, and acute hepatic necrosis. ICD-10-CM codes include K72, K72.0, K72.00 (without coma), and K72.01 (with coma).
ALF is uncommon but high-stakes. Reported incidence is about 2000 cases per year in the U.S. and 1 to 8 per million population in the U.K. It is described as occurring more often in women and often affecting younger individuals. Risk factors include intentional or unintentional drug overdose, exposures increasing risk of viral hepatitis (IV drug use, blood/body fluid exposure, transfusions, hemodialysis, intranasal cocaine use, imprisonment, travel to endemic regions), prior alcohol use, hepatotoxic medications, and critical illness.
Symptoms are often nonspecific early and vary by cause. Patients may develop fatigue, lethargy, anorexia, nausea/vomiting, pruritus, jaundice, and right upper quadrant pain or distention. More severe presentations can include hypotension, sepsis, and encephalopathy. Physical examination, by definition, includes neurologic abnormalities of encephalopathy, and may show jaundice, asterixis, hepatomegaly or decreased liver span, and ascites. In advanced cases, cerebral edema and increased intracranial pressure can occur, with concerning findings such as pupillary abnormalities, hypertension with bradycardia and respiratory depression (Cushing triad), loss of brainstem reflexes, and seizures. Vesicular skin lesions raise concern for HSV, and a family history of unexplained liver disease should prompt slit-lamp exam for Kayser–Fleischer rings suggestive of Wilson disease.
In the Western world, the most common causes include acetaminophen toxicity (~46%), indeterminate causes, idiosyncratic drug reactions, and viral hepatitis (especially hepatitis A and B). Other causes include autoimmune hepatitis, Wilson disease, ischemic hepatopathy (“shock liver”), Budd–Chiari syndrome, acute fatty liver of pregnancy, veno-occlusive disease, toxic ingestions such as Amanita phalloides mushroom poisoning, sepsis, malignant hepatic infiltration, and viral etiologies beyond hepatitis viruses (e.g., adenovirus, hepatitis E, HSV).
Laboratory findings reflect loss of synthetic and metabolic function. Coagulopathy is typical due to reduced hepatic synthesis of clotting factors (II, V, VII, IX, X), producing INR >1.5. Transaminases and bilirubin are usually elevated, and thrombocytopenia may occur. Many patients develop acute kidney injury (often cited around 30%–50%), and hypoglycemia can occur from impaired gluconeogenesis. Electrolyte disturbances are common (hyponatremia, hypophosphatemia, hypomagnesemia, hypokalemia), along with metabolic acidosis or respiratory alkalosis, elevated lactate dehydrogenase, and elevated ammonia.
The differential diagnosis includes severe acute hepatitis/acute liver injury (jaundice and coagulopathy without encephalopathy), acute-on-chronic liver failure, decompensated cirrhosis, and hepatocellular carcinoma. Distinguishing ALF from portal-systemic encephalopathy due to chronic liver disease can be aided by the clinical context: ALF is typically acute, with very high transaminases, a small tender liver, and absence of chronic stigmata early, whereas chronic disease often has cachexia, collateral circulation, ascites, and less dramatic transaminase elevation.
Workup relies on rapid severity assessment and urgent search for etiology, often with limited history due to encephalopathy. Clinicians should obtain collateral history regarding medications (including OTC and herbal agents), alcohol and recreational drugs, onset of jaundice and symptoms, psychiatric history (including self-harm), travel and exposure risks for viral hepatitis, transfusions, family history of liver disease, malignancy history, and hypercoagulable conditions. Examination should assess mental status and grade encephalopathy (from mild behavioral/sleep changes through coma). Laboratory evaluation typically includes CBC, complete liver panel and INR/PT, comprehensive metabolic panel with glucose and electrolytes, arterial blood gas and lactate, blood type and screen, acetaminophen level, ethanol level and toxicology screen, hepatitis serologies and viral loads where appropriate, HSV testing (often PCR), EBV/CMV testing, ceruloplasmin (with copper studies if suspicion is high), pregnancy test, ammonia, autoimmune markers (ANA, anti–smooth muscle, anti-LKM1, total IgG), and HIV testing. Imaging usually includes abdominal ultrasound with Doppler to assess for Budd–Chiari, congestion, portal hypertension, and steatosis, with consideration of cross-sectional liver imaging when malignancy or infiltrative disease is possible. Head CT or MRI may be used to evaluate alternative causes of altered mental status. A transjugular liver biopsy is considered when the cause remains unclear or when autoimmune hepatitis, malignancy, or HSV is strongly suspected.
Complications include cerebral edema (reported up to ~40% in some series), hypoglycemia, lactic acidosis, acute kidney injury, pancreatitis (notably with acetaminophen), infections due to impaired immune function, high-output cardiac failure, ARDS, and hypotension from poor intake and third spacing.
Treatment focuses on rapid stabilization, supportive ICU-level care when indicated, targeted therapy for the underlying cause, and early transplant evaluation. Encephalopathy grade guides level of care: grade I may be managed on a medical ward with frequent neuro checks, while grades II–IV generally require ICU management, head-of-bed elevation, and for grades III–IV, intubation and mechanical ventilation. Sedatives should be minimized because they can accumulate and obscure neurologic assessment; a low-stimulation environment is recommended. Early notification of a liver specialist and early transfer to a transplant center are essential because deterioration can later make transport unsafe.
Supportive care includes early nutrition (to prevent catabolism) and careful fluid management with crystalloids tailored to hemodynamics and metabolic needs, including dextrose-containing fluids if hypoglycemia is present. If intracranial hypertension develops, mannitol can transiently reduce cerebral edema; sodium is often maintained in a higher range (e.g., 140–150 mmol/L), and hypertonic saline may be used in highest-risk patients. Prophylactic hyperventilation is not recommended. Seizures may be treated with agents such as phenytoin; short-acting benzodiazepines can be used if necessary, but sedation is generally avoided when possible. Lactulose and rifaximin are not routinely recommended for encephalopathy in ALF, and neomycin should be avoided due to nephrotoxicity risk.
Infection management is critical: broad-spectrum antibiotics are started when infection is suspected, but routine empiric antibiotics without suspicion are not supported; antifungals may be added if there is poor response or high concern. Hemodynamic support may require norepinephrine as first-line vasopressor, with vasopressin as an adjunct; refractory hypotension should prompt evaluation for adrenal insufficiency. If renal replacement therapy is required, continuous modalities are often preferred over intermittent hemodialysis in unstable patients. Stress ulcer prophylaxis is recommended. Routine correction of INR or thrombocytopenia is not recommended without bleeding, but vitamin K is generally given because deficiency is common; plasma or clotting factors are reserved for active bleeding or high-risk procedures.
Cause-specific therapy is crucial, especially for acetaminophen toxicity. There should be a low threshold to start IV N-acetylcysteine (NAC) when acetaminophen overdose is known or suspected because it is beneficial and generally safe. A commonly used 20-hour IV regimen is a loading dose followed by staged infusions, with reassessment of acetaminophen level and ALT near the end of the protocol and extension of therapy if levels remain elevated or enzymes are rising. NAC use in non–acetaminophen ALF remains controversial and is center-specific, with inconclusive evidence for routine benefit.
Bridging and advanced therapies include extracorporeal liver support systems and high-volume plasma exchange in select contexts, but these are not routinely recommended in guidelines as definitive therapy; they may be used as a bridge to recovery or transplant in specialized centers. For patients with high-grade encephalopathy awaiting transplant, some centers use intracranial pressure monitoring when expertise is available; otherwise, frequent neurologic exams are essential. Coagulation tests and metabolic panels are monitored frequently, while avoiding unnecessary correction of INR because it interferes with prognostication.
Prognosis has improved over time but remains serious, with overall mortality often cited around 30%–40%. Outcomes vary by etiology: transplant-free survival is generally better with acetaminophen-related ALF, hepatitis A, ischemic (“shock”) liver, and pregnancy-related disease, and worse with many other causes. Higher-grade encephalopathy and renal dysfunction predict worse outcomes in non–acetaminophen ALF. Prognostic models include King’s College criteria, Clichy criteria, MELD, and APACHE II; King’s College criteria are widely used to guide transplant referral. Liver transplantation provides definitive therapy for many patients meeting criteria, though contraindications include irreversible brain injury, uncontrolled sepsis, severe comorbidities including malignancy, escalating dependence on ventilator/inotropes, active substance abuse, severe uncontrolled psychiatric illness affecting adherence, and inadequate social support.
Key practical points are that ALF requires INR >1.5 plus encephalopathy within 26 weeks in a patient without known chronic liver disease, acetaminophen accounts for a large portion of cases, early transfer to a transplant center can be lifesaving, NAC should be started early when acetaminophen is possible, and coagulopathy should not be corrected unless bleeding is present or a high-risk procedure is necessary.
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