Study guide
12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
ABIM Neurocritical Care Subspecialty Certification Exam
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility, Practice Pathway, and the IM Training Route 1.3 Format, Scoring, Pearson VUE, and Score Reports 1.4 How to Use This Independent Study Guide
2 ICU Neurologic Exam, Cerebral Physiology, and CSF
2.1 Neurological Examination in the ICU 2.2 Cerebral Physiology, ICP, CBF, and Autoregulation 2.3 CSF Physiology
3 Core Neuropharmacology
3.1 Osmotic Agents 3.2 Anti-Seizure Drugs 3.3 Anesthetics, Sedatives, Analgesia, and Paralytics 3.4 Antihypertensives, Vasopressors, and Inotropes
4 Reperfusion Drugs, Airway, and Ventilation
4.1 Thrombolytics, Anticoagulants, and Antiplatelets 4.2 Reversal of Anticoagulation After Acute Hemorrhage 4.3 Airway Management and Tracheostomy 4.4 Mechanical Ventilation
5 Hemodynamics and Shock
5.1 Hemodynamic Monitoring 5.2 IABP, Temporary VADs, LVAD, and ECMO 5.3 Diagnosis and Management of Shock
6 Nutrition, Temperature, and ICU Prophylaxis
6.1 Nutrition (01.J) 6.2 Temperature Control (01.K) 6.3 ICU Prophylaxis, Delirium, and Early Mobility (01.L)
7 General Trauma
7.1 Emergency Evaluation of Polytrauma, Chest, and Abdominal Trauma 7.2 Long-Bone Fractures and Fat Embolism 7.3 Burns, Electrical Injury, and Hanging/Strangulation
8 Pulmonary Critical Care
8.1 Pulmonary Physiology and ARDS (01.N.1–2) 8.2 PE, Pneumonia, and Pulmonary Edema (01.N.3, 7–8) 8.3 COPD, Asthma, PAH, and Bronchoscopy Basics (01.N.4–6, 9)
9 Cardiovascular Critical Care
9.1 Cardiovascular Physiology, Stress Cardiomyopathy, ACS, and Valves 9.2 Arrhythmias and Pacing 9.3 Acute Aortic Dissection and Cardiac Ultrasound
10 Renal and Infectious Disease
10.1 AKI, RRT, and Renal Drug Dosing 10.2 Acid-Base and Electrolyte Disorders 10.3 Severe Sepsis, Septic Shock, and Infective Endocarditis 10.4 Antimicrobial Use and Infection in the Immunosuppressed
11 Endocrine and Salt-Water Disorders
11.1 Pituitary Apoplexy, DI, and Panhypopituitarism (01.R.1–4) 11.2 SIADH and Cerebral Salt Wasting (01.R.5–6) 11.3 Thyrotoxicosis, Myxedema, Adrenal Crisis, and Dysglycemia (01.R.7–9)
12 Gastrointestinal Critical Care
12.1 GI Physiology, Acute Abdomen, Bleed, Ileus, and Perforation (01.S.1–5) 12.2 Mesenteric Ischemia and Abdominal Compartment Syndrome (01.S.6–7) 12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
13 Hematologic Disorders
13.1 Anemia, Transfusion, Thrombocytopenia, Coagulopathy, and DIC (01.T.1–4) 13.2 VTE in the Neuro ICU (01.T.5) 13.3 Chemo/Immune, SCT, CAR-T, Sickle Cell, and TMA (01.T.6–10)
14 Neuroimaging
14.1 CT of Brain and Spine 14.2 MRI and CT/MR Perfusion 14.3 Noninvasive Angiography and Catheter Angiography
15 EEG, EMG, and CSF Analysis
15.1 EEG, Standard and Processed (02.B) 15.2 Basic EMG Interpretation (02.G) 15.3 CSF Analysis (02.H)
16 ICP, TCD, and Multimodality Monitoring
16.1 ICP Monitoring (02.C) 16.2 Transcranial Doppler (02.D) 16.3 Brain-Tissue Oxygen and Multimodality Monitoring (02.E–F)
17 Brain Death and Bedside Procedures
17.1 Brain Death Prerequisites and Clinical Exam (02.I) 17.2 Apnea Testing and Ancillary Studies (02.I) 17.3 Vascular Access, Thoracic Echo, and Lung Ultrasound (02.J–L)
18 Coma, Anoxia, and Intracranial Hypertension
18.1 Coma and Other States of Altered Consciousness (03.A) 18.2 Global Anoxia-Ischemia and Post-Resuscitation Encephalopathy (03.A.1) 18.3 Toxidromes, ICU Delirium, and Hypertensive Encephalopathy (03.A.2–4) 18.4 Intracranial Hypertension as a Disease State (03.B)
19 Acute Ischemic Stroke
19.1 IV Reperfusion Therapy (03.C.3) 19.2 Mechanical Thrombectomy Windows and Imaging Selection (03.C.3) 19.3 Malignant Hemispheric Infarction and Basilar Artery Occlusion (03.C.1–2)
20 Intraparenchymal Hemorrhage
20.1 Intracerebral Hematoma (03.D.1) 20.2 Cerebellar Hematoma (03.D.2) 20.3 Intraventricular Hemorrhage (03.D.3)
21 SAH, CVST, and Spinal Cord Infarction
21.1 Aneurysmal Subarachnoid Hemorrhage (03.E.1) 21.2 Non-Aneurysmal SAH (03.E.2) 21.3 Cerebral Venous Sinus Thrombosis (03.F) 21.4 Spinal Cord Infarction (03.G)
22 Vascular Anomalies and Traumatic Brain Injury
22.1 Unruptured Aneurysm, Cavernoma, AVM, and Dural AVF (03.H) 22.2 Diffuse Axonal Injury and Cerebral Contusions (03.I.1–2) 22.3 Epidural Hematoma, Subdural Hematoma, and Penetrating Injury (03.I.3–4, 7) 22.4 Arterial Dissection and Carotid-Cavernous Fistula (03.I.5–6)
23 Spine, Hydrocephalus, and CNS Infection
23.1 Spinal Cord Injury, Central Cord, and Neurogenic Shock (03.J) 23.2 Unstable Spine Fractures (03.K) 23.3 Hydrocephalus and CSF Diversion (03.L) 23.4 Acute CNS Infections (03.M)
24 Seizures and Neuromuscular Emergencies
24.1 Status Epilepticus and Seizures (03.N) 24.2 Guillain-Barré Syndrome (03.O.1) 24.3 Myasthenic Crisis (03.O.2) 24.4 Motor Neuron Disease, Acute Myopathies, Rhabdomyolysis, and CINM (03.O.3–6)
25 Inflammatory Disease, Neuro-Oncology, and Special Populations
25.1 Fulminant Demyelinating Diseases (03.P) 25.2 Autoimmune Encephalitis and Acute Autonomic Hyperactivity (03.Q–R) 25.3 Neuro-Oncology and Treatment Complications (03.S) 25.4 Pregnancy/Post-Partum, Post-Transplant, and Pediatric Patients (03.T–U)
26 Neurosurgical and Perioperative Complications
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H) 26.2 Infection, CSF Leak, and Pneumocephalus (04.B, E, F) 26.3 Complications of EVD and Lumbar Drain (04.G, I)
27 Ethics, Prognostication, and Organ Donation
27.1 Communication, Decision-Makers, Advance Directives, and DNR (05.A, B, G) 27.2 Uncertainties of Prognostication and the Self-Fulfilling Prophecy (05.C) 27.3 Palliative Care, Withdrawal, Withholding, and Futility (05.D–F) 27.4 Donation After Cardiac Death and Care of the Organ Donor (05.H–I)
12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
Key Takeaways Explain This Topic AI
Acute liver failure is coagulopathy plus encephalopathy without cirrhosis and with an illness shorter than 26 weeks; hyperacute (especially acetaminophen) disease is an ammonia-driven cerebral-edema emergency.
Arterial ammonia >150 μmol/L marks high intracranial-hypertension risk; grade III/IV encephalopathy is an intubation and transplant-referral trigger. Avoid hypotonic fluids.
Intravenous N-acetylcysteine is indicated for acetaminophen ALF even after delayed presentation and is often continued until recovery or transplant.
Cirrhosis decompensation on this examination is SBP (ascitic PMN ≥250/µL), hepatic encephalopathy plus a precipitant hunt, HRS-AKI vasoconstrictors with albumin, and a variceal-bleed bundle — not acute herniation physiology.
Avoid high-dose midazolam infusions in liver failure; prefer levetiracetam over valproate; fosphenytoin free fraction rises when albumin is low or bilirubin is high, so measure a free level.
Last updated: September 2026
Liver failure reaches this examination because it is a brain disease as much as a hepatic one. In acute liver failure (ALF) the brain has no time to buffer ammonia, astrocytes swell, and herniation is a leading cause of death. In cirrhosis the brain has adapted; the emergencies are infection, bleeding, and kidney failure, not usually acute herniation. Drug dosing sits on top of both. Independent ExamFinch teaching here follows fulminant hepatic failure, cirrhosis complications, and hepatic dosing topics in the ABPN Content Specifications. It is not an AASLD document.
Acute liver failure: definition and tempo
ALF is coagulopathy (typically INR ≥1.5 ) plus any degree of hepatic encephalopathy in a patient without preexisting cirrhosis , with an illness duration <26 weeks . Wilson disease, vertically acquired hepatitis B, and autoimmune hepatitis can blur that “no chronic disease” rule when they present as ALF; the examination still wants you to treat the cerebral-edema risk.
Tempo predicts the neurology:
Category Jaundice-to-encephalopathy interval Typical cause Brain risk Transplant-free survival
Hyperacute ≤7 days Acetaminophen, some ischemia Highest cerebral edema Relatively better if the liver regenerates
Acute 8–28 days Viral, drug Intermediate Intermediate
Subacute >4 weeks to 26 weeks Idiosyncratic drug, indeterminate Less edema, more portal hypertension Worse without transplant
Acetaminophen is the prototype hyperacute toxin in North America. Measure a level, but do not withhold N-acetylcysteine (NAC) if the history is plausible, the time of ingestion is unknown, or aminotransferases are already rising. The conventional 21-hour intravenous protocol is 150 mg/kg over 1 hour, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours (total 300 mg/kg). Many transplant centers continue NAC as an infusion until the INR is clearly falling or the patient is transplanted. Late presentation is not a reason to skip NAC. NAC is also often started empirically in non-acetaminophen ALF while the workup runs; some data show better transplant-free survival in early-grade encephalopathy.
Other treatable causes to start while you wait: intravenous acyclovir if herpes simplex hepatitis is possible (pregnancy, immunocompromise, fever, anicteric ALF), nucleoside analog for hepatitis B, steroids only when autoimmune hepatitis is the working diagnosis after infection is considered, and delivery planning for acute fatty liver of pregnancy / HELLP. Ischemic (“shock”) liver has astronomical aminotransferases that fall quickly once perfusion is restored and is not primarily a transplant disease.
Ammonia, cerebral edema, and grade III/IV encephalopathy
Ammonia is detoxified to glutamine in astrocytes. Glutamine is an osmolyte. In ALF that osmotic load appears in hours, not months, so cytotoxic cerebral edema and intracranial hypertension follow. Arterial ammonia >150 μmol/L identifies patients at high risk for intracranial hypertension; values >200 μmol/L are associated with herniation in classic series. Venous samples on ice are acceptable if an arterial line is not yet in, but trend the same source.
West Haven grade III (somnolent, marked confusion) and grade IV (coma) encephalopathy in ALF are airway and ICP events . Cerebral edema is uncommon in grades I–II, rises to about 25–35% in grade III , and 65–75% or more in grade IV (AASLD ALF guidance). Intubate for airway protection and controlled ventilation. Head of bed 30 degrees, neutral neck, minimize stimulation, treat fever, and keep the head uncongested (the ACS physiology from the prior section applies). Avoid hypotonic fluids (D5W, 0.45% saline): they drop serum sodium and worsen astrocyte swelling. In the highest-risk group (ammonia >150 μmol/L, grade III/IV, renal failure, vasopressors), prophylactic hypernatremia with hypertonic saline to 145–155 mEq/L is the AASLD-supported osmolar strategy. Mannitol 0.5–1 g/kg is first-line rescue for a herniation spike if the serum osmolality allows; do not give mannitol prophylactically to every ALF patient. Continuous renal replacement therapy can lower ammonia when the kidney fails or ammonia stays high.
ICP monitors are used in some transplant centers for high-risk coma; they are not mandatory in every hospital and they bleed more when INR is 4. Noninvasive optic-nerve sheath and transcranial Doppler trends help when a bolt is not placed. Do not flood the patient with fresh frozen plasma to “correct” INR for a number unless there is bleeding or a procedure: INR is a prognostic marker (King’s College-type listing uses coagulopathy, acidosis, renal failure, and high-grade encephalopathy). Extra plasma volume raises ICP.
Refer to a liver transplant center as soon as ALF is recognized , not after the first herniation. Listing criteria are center-specific; your job is airway, sodium, NAC, glucose, infection surveillance, and a telephone call. Hypoglycemia from failed glycogenolysis is common and mimics herniation — check a glucose before you stack osmotherapy.
Worked example: a 28-year-old presents 36 hours after a large acetaminophen ingestion. INR 4.2, grade III encephalopathy, sodium 132 mEq/L on D5W, arterial ammonia 170 μmol/L . Stop the hypotonic infusion, start hypertonic saline toward 145–155 mEq/L , start NAC now , intubate, and transfer to a transplant center. Do not load valproate for possible seizures. Do not wait for the 4-hour acetaminophen nomogram; the ingestion is already late and the liver is failing.
Cirrhosis decompensation: a different brain
Chronic hyperammonemia allows osmotic adaptation. Hepatic encephalopathy (HE) in cirrhosis is a neurotransmitter and inflammation problem more than acute herniation. Treat it as a precipitant hunt plus ammonia-lowering therapy, not as ALF osmotherapy. Precipitants: gastrointestinal bleed , infection (especially spontaneous bacterial peritonitis ), constipation, hypokalemia, alkalosis, benzodiazepines, hypoxia, and TIPS. Lactulose (titrate to about 3 soft stools daily) and rifaximin are the usual pair. Do not use benzodiazepines to “calm” HE; they worsen it. Flumazenil is not standard HE therapy.
Spontaneous bacterial peritonitis (SBP)
Any cirrhotic with ascites and unexplained fever, pain, HE, ileus, or AKI needs a diagnostic paracentesis . SBP is an ascitic fluid polymorphonuclear (PMN) count ≥250 cells/µL , with or without a positive culture (usually a single enteric organism). Do not wait for the culture to start antibiotics. Community-acquired SBP is typically a third-generation cephalosporin (cefotaxime or ceftriaxone). Nosocomial SBP needs broader coverage based on local resistance. Albumin 1.5 g/kg on day 1 and 1 g/kg on day 3 reduces renal failure and death in SBP when creatinine, blood urea nitrogen, or bilirubin is high — this is not cosmetic volume. Secondary peritonitis (polymicrobial culture, very high ascitic protein, glucose <50 mg/dL, high LDH) is perforation until proven otherwise; that is a surgical CT, not another dose of ceftriaxone alone.
Hepatorenal syndrome, conceptually
Hepatorenal syndrome–acute kidney injury (HRS-AKI) is kidney failure from splanchnic vasodilation and renal vasoconstriction after volume has been restored and structural kidney disease, shock, and nephrotoxins have been excluded. A typical sequence is albumin 1 g/kg/day for two days as a diagnostic volume challenge, then a vasoconstrictor plus albumin. Terlipressin plus albumin reversed HRS more often than albumin alone in the CONFIRM trial ( NEJM 2021) and was FDA-approved in 2022; it increases respiratory failure (about 14% versus 5% in CONFIRM) and is a poor choice in hypoxia, volume overload, or creatinine already >5 mg/dL . In the ICU, norepinephrine plus albumin is the usual alternative. Midodrine plus octreotide is a ward-level stopgap, not the preferred ICU regimen. Transplant remains definitive. Dialysis is a bridge, not a cure of the physiology.
Variceal bleeding in the cirrhotic ICU patient
The bundle from the prior section still applies: restrained transfusion, octreotide (or terlipressin where used for bleeding), antibiotics, and banding. Gastric fundal varices may need glue or TIPS rather than bands. After a large-volume bleed, HE often follows because the gut protein load becomes ammonia; lactulose starts after the airway is safe. Do not attribute every post-bleed coma in a cirrhotic to HE until you have considered aspiration, seizure, and intracranial hemorrhage — especially if the patient was thrombocytopenic and fell.
Problem Diagnostic clue First-line ICU therapy Do not
ALF cerebral edema Hyperacute course, NH3 >150, grade III/IV Intubate, Na 145–155, NAC if acetaminophen, transplant referral Hypotonic fluids, VPA, delaying transfer
Cirrhotic HE Precipitant + asterixis, adapted brain Lactulose, rifaximin, treat bleed/infection Standing midazolam, assuming herniation first
SBP PMN ≥250 Cephalosporin now, albumin 1.5 then 1 g/kg Waiting for culture
HRS-AKI AKI after albumin challenge, no shock/nephrotoxin Terlipressin or norepinephrine + albumin Terlipressin in pulmonary edema
Variceal bleed Hematemesis in portal hypertension Vasoactive drug, antibiotic, endoscopy Transfusion to Hb 10, waiting on INR
Hepatic dosing that hits the neuro ICU
The liver clears high-extraction drugs (flow-dependent) and low-extraction drugs (enzyme- and protein-binding-dependent). In ALF and decompensated cirrhosis both flow and CYP activity collapse, albumin falls, and bilirubin occupies binding sites. The three examination favorites are midazolam, valproate versus levetiracetam, and fosphenytoin.
Midazolam is a CYP3A4 substrate with an active metabolite ( 1-hydroxymidazolam ) that accumulates when renal function also fails. Infusion context-sensitive half-time stretches from hours to days in cirrhosis. High-dose midazolam infusions for status epilepticus or for “comfort” produce a patient who cannot be examined, cannot wean, and looks like irreversible coma. Prefer propofol or ketamine for short-term anesthetic-range sedation in status, with the usual propofol-infusion-syndrome limits, and use the lightest possible sedation for ventilation. Bolus midazolam for seizures still has a role in the first minutes of status; the trap is the unmonitored high-dose infusion left on for days.
Valproate is hepatotoxic, causes hyperammonemia even with therapeutic levels (carnitine depletion), and is contraindicated in ALF and in urea-cycle disorders. It is a poor maintenance choice in decompensated cirrhosis. Levetiracetam is renally cleared , not hepatically metabolized, is not protein-bound in a clinically important way, and was equivalent to fosphenytoin and valproate for benzodiazepine-refractory convulsive status in ESETT (load conceptually 60 mg/kg , maximum 4500 mg). In liver failure, levetiracetam is the preferred antiseizure drug among those three. Adjust the maintenance dose for creatinine clearance and for CRRT.
Fosphenytoin / phenytoin is about 90% albumin-bound . In hypoalbuminemia and hyperbilirubinemia , the free fraction rises , so a “therapeutic” total level of 15 µg/mL can be toxic free phenytoin. The Sheiner–Tozer approximation (corrected total ≈ measured / [(0.2 × albumin) + 0.1]) is a crude alert, not a substitute for a free phenytoin level . Hepatic CYP2C9/2C19 failure also slows elimination, so levels climb over days. Do not empirically “give more fosphenytoin because the total level is 8” in a patient with albumin 1.8 g/dL and bilirubin 12 mg/dL — measure free drug, watch for nystagmus and arrhythmia, and consider levetiracetam instead.
Other practical hepatic-dosing notes that appear in stems: lacosamide has mixed renal/hepatic clearance but is still more usable than valproate; phenobarbital accumulates and sedates for days; propofol has extrahepatic clearance but still causes hypotension; dexmedetomidine is hepatically cleared and lingers; nimodipine is CYP3A4-metabolized — in Child–C cirrhosis the hypotensive effect is exaggerated. For analgesia, morphine-6-glucuronide accumulates more from kidney failure than from liver failure; hydromorphone and fentanyl still require titration.
Drug Hepatic problem Safer pattern in ALF/cirrhosis
Midazolam infusion CYP3A4 + active metabolite; prolonged coma Avoid high-dose infusions; shortest possible benzodiazepine exposure
- Valproate Hepatotoxicity, hyperammonemia Avoid; not for ALF seizures
- Levetiracetam Minimal hepatic metabolism Preferred antiseizure drug; renal dose
Fosphenytoin 90% protein bound; CYP clearance falls Free level; do not chase a low total level in hypoalbuminemia
Propofol Hemodynamics, PRIS at high dose Acceptable short-term anesthetic if blood pressure allows
Exam traps: treating cirrhotic HE with 3% saline as if it were hyperacute ALF herniation; giving hypotonic maintenance fluid to grade-IV acetaminophen ALF; holding NAC because the ingestion was “too late”; waiting for ascitic culture to treat a PMN of 400; starting terlipressin in pulmonary edema; loading valproate for seizures in ALF; and raising the fosphenytoin dose because the total level is low while albumin is 1.6 g/dL.