Hepatic Failure/GI/Endocrine Emergencies
viii.
The pattern of liver injury may also help identify drug causes. Hepatocellular injury
(characterized by a marked elevation in transaminases with marginal increase in bilirubin
and alkaline phosphatase) is associated with certain drug causes, whereas cholestatic injury
(characterized by a marked elevation in bilirubin and alkaline phosphatase with only minimal
increases in transaminases) is associated with other drug causes of DILI. Other drug causes of
DILI exhibit a mixed pattern of liver injury in which both hepatocelluar injury and cholestatic
injury will be present. See Appendix 1 for a list of medications linked to DILI and associated
pattern of liver injury.
Viral
Infection with hepatitis A, B, or E is the primary etiology of ALF in the developing world and
has become a relatively infrequent cause of ALF in the United States (about 12%).
ii.
Hepatitis A
| (a) | Accounts for about 2% of ALF cases in the United States |
|---|---|
| (b) | Transmission is usually by the fecal-oral route. |
iii.
Hepatitis B
| (a) | Rates of hepatitis B–induced ALF have fallen significantly in the past few decades; |
|---|
however, hepatitis B is still the cause of about 7% of ALF cases per year.
| (b) | ALF secondary to hepatitis B is often caused by reactivation of chronic or inactive hepatitis |
|---|
B during times of immunosuppression (e.g., chemotherapy and high dose steroids). To
prevent reactivation, patients who are positive for HBsAg (hepatitis B surface antigen)
and who are to begin immunosuppressive regimens require antiviral prophylaxis with
a nucleos(t)ide analog, typically entecavir, lamivudine, or tenofovir. Treatment, which
is usually initiated before immunosuppression, continues during immunosuppressive
therapy and for 6 months thereafter.
iv.
Hepatitis E
| (a) | Rare cause of ALF in the United States; however, hepatitis E–induced ALF is a significant |
|---|
cause of ALF in countries where it is endemic, such as Russia, Pakistan, Mexico, and India.
| (b) | Hepatitis E–induced ALF tends to be more severe in pregnant women, and hepatitis E can |
|---|
be transmitted to neonates during acute infections in pregnant women.
Herpes simplex virus (HSV)
| (a) | HSV is rarely a cause of ALF; however, cases have been reported, particularly in |
|---|
immunocompromised and pregnant patients (usually in the third trimester).
vi.
Viral hepatitis–induced ALF generally presents as acute or subacute liver failure with an onset
of symptoms greater than 1 week after onset of jaundice.
vii.
Globally, mortality rates are greater than 50% because of ALF from hepatitis A and E in the
developing world; however, mass vaccination and better public health standards have helped
reduce the incidence of viral infections in the developed world.
Acute ischemic injury
Often called “shock liver,” acute ischemic injury may lead to ALF after cardiac arrest, any
period of significant hypovolemia or hypotension, or during severe congestive heart failure.
ii.
Documented hypotension is not always evident with acute ischemic injury. Drug-induced
hypotension or hypoperfusion may also cause acute ischemic injury, such as with cocaine and
methamphetamine.
iii.
Typical laboratory presentation includes markedly elevated aminotransferase concentrations. In
addition, simultaneous renal dysfunction and other markers of hypoperfusion may be present.
iv.
Acute ischemic injury is classified as a hyperacute ALF, which generally resolves with
resolution of the circulatory problem.