Page 1483 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1022 PART 9: Gastrointestinal Disorders

CHAPTER Acute Liver Failure in volume; splenomegaly is a feature and ascites may be present. This
group has a very poor chance of spontaneous survival while the acute/
106 Julia Wendon fulminant presentations have a greater chance of spontaneous recovery
despite having a greater manifestation of extrahepatic organ failure.
The etiology of ALF syndromes can be seen in Table 106-1.
The table does not provide an exhaustive list of etiologies; rather, it lists
the common aetiologies. The category “other” provides for the descrip-
5
tion of various diseases, which may be categorized as ALF but have cer-
KEY POINTS
tain unique features. Wilson disease is, by definition, a chronic disease
• Acute liver failure is a syndrome with sudden loss of liver function process with features of cirrhosis and splenomegaly at presentation.
denoted by coagulopathy and encephalopathy in a patient without Patients, children and young adults, present with acute coagulopathy
previous liver disease. and encephalopathy, often with no previous diagnosis of any disease
• Etiologies vary greatly, with viral hepatitis infections and acet- process. In some, this may represent an intercurrent viral illness with
aminophen toxicity among the most common. hepatic presentation of ALF and in others it may relate to a discontinu-
• Shock, kidney failure, and encephalopathy are common complica- ation of chelating therapy. The characteristic features are those of a low
alkaline phosphate level, often a hemolytic anemia (not direct antiglobu-
tions of acute liver failure. lin test [DAT] positive) and features of splenomegaly with or without
• Severe sepsis is a common complication of acute liver failure. Kayser-Fleischer rings on slit lamp examination of the eyes. The devel-
• Aggressive supportive care in a center that performs liver trans- opment of high level encephalopathy (grade III/IV) and coagulopathy
plantation will optimize patient outcomes. in this disease presentation effectively always requires transplantation.
Lymphoma can present with a picture of ALF as can other malignan-
cies causing diffuse infiltration of the liver. Such etiologies should always
be considered as secondary ALF and not suitable for consideration for
SUMMARY transplantation. An elevated LDH and alkaline phosphate are character-
istic features of lymphoma.
The term acute liver failure is frequently used as a generic expression Auto-immune liver disease may rarely present as an acute or subacute
to describe a large and diffuse cohort of patients presenting with or presentation, often but not always with elevated globulin fraction and
developing an acute episode of liver dysfunction, usually manifested by positive autoantibodies.
deterioration in liver blood tests and other organ dysfunction. Acetaminophen causes ALF (acute) in a dose dependent manner with
This chapter largely addresses a cohort of patients with primary acute toxicity being seen in doses above 150 mg/kg although lower ingested
liver failure (ALF), that is patients with acute liver dysfunction mani- doses have also been reported as causing severe hepatotoxicity espe-
fested by transaminitis, coagulopathy, and encephalopathy in the setting cially in the face of chronic alcohol abuse and chronic use of enzyme-
6
of a previously normal liver. The etiology of these disturbances should inducing drugs. Presentation and treatment with the antidote (N-acetyl
be primarily liver in aetiology and as such, the coagulopathy and altered cysteine) within 16 hours of presentation normally prevents progression
7,8
conscious level should be attributable to the liver failure as opposed to to ALF. Later presentations and staggered ingestion are associated with
other etiologies such as systemic disease processes or sepsis. The later a worse prognosis.
processes are typically described in the context of a secondary liver injury. Many drugs can cause ALF or acute liver injury and the categories are
9
Management of patients with ALF should focus upon prevention and described as hepatotoxic, cholestatic, or mixed. Withdrawal of putative
removal of any potentiating agents and support of the liver and other drugs should always be considered and scoring systems are available
organs to facilitate regeneration and recovery. A small proportion of to aid this decision process. Guidelines have been issued by various
patients with ALF will have a liver injury that does not have the capacity thoracic societies for management and withdrawal of antituberculous
to repair and regenerate and as such will need the option of emergent chemotherapy in patients who develop transaminitis or jaundice. 10
liver transplantation. Recreational drugs such as ecstasy may result in ALF from a heat
■ ALF: DESCRIPTION AND AETIOLOGY shock type injury or as a more indolent course. Cocaine may similarly
result in ALF with an ischemic aetiology.
ALF describes a syndrome incorporating sudden loss of liver function Budd-Chiari may present as ALF, either with an acute or sub-
denoted by the features of coagulopathy and encephalopathy in a patient acute presentation albeit usually with ascites. The routine screening
without previous liver disease. The disease process should result from
primary liver insult, and the coagulopathy and altered conscious level
should occur as a result of liver failure as opposed to a systemic process TABLE 106-1 Etiology and Nature of Acute Liver Failure
such as sepsis. 1,2 Precipitant Examples Presentation
ALF was subdivided, by O’Grady and colleagues, into hyperacute,
acute and subacute, while previous descriptions had utilized fulminant Viral hepatitis A, hepatitis E, hepatitis B (less frequent CMV, Acute
and subfulminant terminologies, with times lines of up to 8 weeks and HSV, hepatitis C)
8 to 24 weeks, respectively. For practical reasons acute and hyperacute Drugs/toxins Acetaminophen, Phosphorous, Acute
3
have been merged to describe management. Disease processes resulting Amanita phalloides
in encephalopathy after 24 weeks are categorized as chronic liver disease Antituberculous chemotherapy, statins, NSAIDs, phenytoin, Acute and subacute
and fall outside the scope of this chapter. carbamazepine, ecstasy, flucloxacillin and others
Similarities of disease process and complications are seen for
hyperacute, acute, and fulminant groups; while the subacute and Vascular Budd-Chiari Acute and subacute
subfulminant groups have different presentations and characteristics. 4 Hypoxic hepatitis, ecstasy Acute
The acute type presentations demonstrate severe coagulopathy, trans- Pregnancy Preeclamptic liver rupture, HELLP syndrome, fatty liver Acute
aminitis, and initially only moderate, if any, increases in bilirubin; by of pregnancy
contrast, the subfulminant/subacute often present with minor transami-
nitis, deep jaundice, and mild to moderate coagulopathy. Their disease Others Wilson disease, autoimmune, lymphoma,
process is often such that they present with a liver that is shrinking hemophagocytic lymphohistiocytosis (HLH)

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