liver acute liver failure 15 01 14

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Acute liver failure Hepatic encephalopathy and coagulopathy within 12 to 26 wks of jaundice in a patient without preexisting liver disease

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Acute viral hepatitis

Most common cause – 70 %

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Other causes

Amanita phalloides (mushroom) poisoning

Paracetamol toxicity – common in Europe and North America

Reye's syndrome Acute fatty liver of pregnancy Wilson's disease Shock Malignant disease of the liver

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HELLP Syndrome Hemolysis, Elevated Liver

enzymes, Low Platelets Severe, life-threatening

complication of PET Delivery - only known

treatment

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INVESTIGATIONS - cause

IgM anti-HBc IgM anti-HAV Anti-HCV, cytomegalovirus, herpes

simplex, Epstein-Barr virus Caeruloplasmin, serum copper, urinary

copper, slit-lamp eye examination Autoantibodies: ANA, ASMA, LKM Doppler ultrasound of liver

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COMPLICATIONS Encephalopathy and cerebral edema Hypoglycemia Metabolic acidosis Infection (bacterial, fungal) Renal failure Multi-organ failure (hypotension and

respiratory failure)

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Hepatic encephalopathy

Cerebral disturbance›Cardinal manifestation

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Ammonia Synthesized predominantly

› Gut microorganisms Detoxified in astrocytes to

osmotically active glutamine Contribute to

› Hepatic encephalopathy› Cerebral edema

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Hyperammonemia treatment

Lactulose Nonabsorbable oral antibiotics

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Cerebral edema

Causes intracranial hypertension

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Cytotoxic cerebral edema

Results from astrocyte swelling rather than a leaky blood brain barrier (vasogenic cerebral edema)

Corticosteroids are not recommended

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Manifestations

Decreasing consciousness Hyperventilation Systemic hypertension Pupillary abnormalities Decerebrate posturing, Uncal herniation and death

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ICP monitoring

Gold standard for measuring and monitoring ICH› < 25 mm Hg

Neuroimaging - not reliable in diagnosing early ICH› To exclude other problems (e.g.,

intracranial bleeding or stroke)

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ICP transducer

Requires correction of underlying coagulopathy

Portal of entry for infectious organisms

Can precipitate intracranial hemorrhage

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Mannitol First-line therapy for intracranial hypertension

Elevate head of the bed to 30 degrees

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Refractory cerebral edema

IV hypertonic saline

IV thiopental

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Hypothermia (e.g., 32° to 33°C)

External cooling blankets

In refractory cerebral edema

Require an ICP monitor

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Infection

Main cause of death in ALF

Signs - frequently absent

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Most common sites

Lung Urinary tract Blood

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Most common organisms

Gram-positive cocciStaphylococciStreptococci

Enteric GNB Candida

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Sedation Propofol and benzodiazepines

are most commonly used Propofol decreases cerebral

blood flow and lowers intracranial pressure

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Parenteral vitamin K

Recommended empirically in all patients

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Cryoprecipitate In patients who have significant hypofibrinogenemia (100 mg/dL)

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Antifibrinolytic agents

Aminocaproic acid in hyperfibrinolytic state › Diffuse mucosal and puncture wound oozing

› Increased clot lysis time

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rFVIIa Recombinant factor VIIa

› when FFP has failed to correct PT/INR

› Volume overloaded Given before invasive

procedures with a high risk of bleeding

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H2 receptor antagonists/PPI

Incidence of upper GI bleeding decreased

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Blood glucose

Checked every 1–2 hrs High risk for hypoglycemia Hyperglycemia exacerbate

intracranial hypertension Insulin infusions - glucose

levels < 50 mg/dL

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Maintain CPP of 50–80 mm Hg

CPP = Mean arterial pressure – ICP Correct hypovolemia before

vasopressors › Norepinephrine preferred to

dopamine› Hydrocortisone improve the

vasopressor response to norepinephrine

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Fever

Exacerbates ICP Treat aggressively with cooling

blankets, fans, or other noninvasive devices

NSAIDs and acetaminophen are not recommended

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Renal function Urine sodium

› low (10 mEq/L) in prerenal azotemia and functional renal failure (hepatorenal syndrome)

› high in acute tubular necrosis Casts and renal tubular cells in the

urine suggest ATN IV fluid challenge (1L) to exclude

prerenal azotemia

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Serum electrolytes

Monitor once or twice daily

Hyponatremia ›Exacerbate edema›Avoided strictly

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Mechanical Ventilation

May be needed

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Etiology-specific therapy

Paracetamol poisoning - NAC Amanita - Penicillin G and NAC HSV – Acyclovir AIH - Methylprednisolone HBV - Lamivudine AFLP/HELLP - Delivery of fetus

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Amanita mushroom poisoning

Reduce the toxin load› Gastric lavage› Instillation of charcoal

Hemodialysis - remove toxins from the serum

Lower entero-hepatic toxin load - Uncertain › pencillin, cytochrome c, and silymarin

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Liver transplantation

Life-saving