Ischaemic Hepatitis and Shock Liver
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Direct answer
Ischaemic hepatitis, also called shock liver, is acute centrilobular hepatocellular necrosis after sudden hypoperfusion, producing very high transaminases that peak early and fall quickly once circulation is restored. The commonest triggers are cardiac failure, cardiac arrest, severe hypotension and septic shock. The key diagnostic feature is a sharp rise and fall of ALT, usually above 1000 U/L, in a patient with a clear haemodynamic insult.
What you must remember
- Zone 3 injury: centrilobular necrosis occurs because perivenous hepatocytes are the most vulnerable to low oxygen supply.
- Transaminase pattern: ALT and AST rise sharply, typically above 1000 U/L, then fall rapidly over days once perfusion is restored.
- Bilirubin and INR: bilirubin usually rises only modestly, although a prolonged INR and synthetic failure can develop.
- Common triggers: acute cardiac failure, cardiac arrest, severe hypotension, septic shock and profound hypoxia, such as respiratory failure.
- Laboratory clue: LDH is often disproportionately raised in ischaemic injury, and a high LDH supports ischaemia.
- Complications: acute kidney injury is common, and renal support is often needed alongside liver care.
- Treatment: there is no specific drug therapy, so the aim is restoring perfusion and oxygenation and correcting the trigger.
- Prognosis: the liver usually recovers within days to weeks if the insult is corrected, but the underlying shock often dominates outcome.
Where the exam tries to catch you
The exam tests whether you recognise shock liver from its tempo and whether you exclude co-existing toxins.
- Trap: assuming an ALT of several thousand means viral hepatitis or paracetamol Correct: ischaemic hepatitis can produce comparable values, but its rapid fall and clear shock history distinguish it.
- Trap: delaying the paracetamol level in a shocked patient with raised ALT Correct: paracetamol toxicity can coexist and needs its own antidote decision, so the level is checked.
- Trap: treating ischaemic hepatitis with steroids or antivirals Correct: no specific therapy exists, and the fix is restoring perfusion and treating the trigger.
Frequently asked questions
What transaminase level suggests ischaemic hepatitis?
Ischaemic hepatitis typically shows ALT or AST above 1000 U/L, often much higher, with a sharp rise and a rapid fall. The level alone is not diagnostic, so a history of shock or hypoxia must support it.
How does ischaemic hepatitis differ from paracetamol toxicity?
Ischaemic hepatitis follows a clear haemodynamic insult and peaks early before falling quickly. Paracetamol toxicity follows an ingestion and its transaminases typically peak around two to four days, so the two can coexist and a paracetamol level should be checked.
Is there a specific treatment for ischaemic hepatitis?
There is no specific drug treatment for ischaemic hepatitis. Management restores perfusion and oxygenation, corrects the cause such as heart failure or sepsis, and supports complications such as acute kidney injury.
Why does ischaemic hepatitis affect the centrilobular zone?
Ischaemic hepatitis affects the centrilobular zone, also called zone 3, because it is the region furthest from the portal and hepatic arterial blood supply. This makes perivenular hepatocytes the most vulnerable to hypoperfusion.