Hepatic Failure/GI/Endocrine Emergencies
iv.
Spontaneous bleeding in patients with ALF, though uncommon, is capillary-type bleeding and
usually results from mucosal bleeding in the stomach, lungs, or genitourinary system. Unlike
chronic liver failure, bleeding from esophageal varices generally does not occur.
Clinically significant bleeding that requires blood transfusions is rare in ALF.
| d. | Renal |
|---|
Acute kidney injury with ALF is generally classified as either prerenal injury or acute tubular
necrosis.
| (a) | Prerenal azotemia typically is caused by vasodilatation owing to portal hypertension and |
|---|
is worsened by systemic hypoperfusion, similar to hepatorenal syndrome in patients with
cirrhosis.
| (b) | Acute tubular necrosis typically occurs secondary to drugs or toxins, such as acetaminophen |
|---|
or Amanita poisoning.
Infection
Patients with ALF are at high risk of infection because of prolonged ICU stays, the presence of
indwelling foleys and central venous catheters in addition to intrinsic monocyte and neutrophil
dysfunction. Infections are of particular concern because they may delay transplantation or be
problematic during the postoperative period.
ii.
The most common infections in ALF are pneumonia, followed by urinary tract infections
and bloodstream infections. The most commonly isolated organisms are gram-positive cocci
(e.g., Staphylococcus, Streptococcus) and enteric gram-negative bacilli. Fungal infections,
particularly those caused by Candida, occur in about one-third of patients with ALF.
Metabolic abnormalities
Lack of effective glycogenolysis and gluconeogenesis, caused by impaired hepatocyte function,
places patients at high risk of hypoglycemia.
ii.
Symptoms of hypoglycemia can often be difficult to identify in patients with severe
encephalopathy, whereas profound hypoglycemia can worsen an already altered mental state.
iii.
Hyponatremia is also common in patients with ALF, secondary to alterations in antidiuretic
hormone from tissue hypoperfusion and renal dysfunction. Avoidance of hyponatremia is
particularly important in patients with high-grade encephalopathy.
Management of ALF
Antidotes
Acetaminophen-induced ALF (see Table 4)
Although most effective if given within the first hour, GI decontamination with activated
charcoal may be of benefit for up to 4 hours after ingestion and does not reduce the effect of
acetylcysteine.
ii.
Administration of acetylcysteine is recommended in all ALF cases in which acetaminophen
is suspected as a cause.
| (a) | Acetylcysteine can be given either orally or intravenously. Studies have shown similar |
|---|
outcomes between the two routes; however, in those studies, the main efficacy outcome
of interest was development of hepatotoxicity. In patients already presenting with
hepatotoxicity (as in ALF), intravenous acetylcysteine is recommended. The U.S. Acute
Liver Failure Study Group recommends intravenous therapy for any of the following:
| (1) | Greater than grade I encephalopathy |
|---|---|
| (2) | Hypotension |
| (3) | If oral therapy cannot be tolerated (e.g., vomiting, compromised airway, ileus) |