encephalopathy - hepatic; hepatic coma
A group of symptoms that may occur when there is damage to the
brain and nervous system as a complication of liver disorders, characterized
by various neurologic symptoms including changes in consciousness, behavior
changes, and personality changes.
Causes, Incidence and Risk Factors
Hepatic encephalopathy is caused by disorders affecting the
liver. These include disorders that reduce liver function (such as cirrhosis
or hepatitis) and conditions where blood circulation bypasses the liver. The
exact cause of the disorder is unknown. The liver cannot properly metabolize
and detoxify substances in the body. Accumulation of toxic substances causes
metabolic abnormalities that lead to damage in the central nervous system
(brain and spinal cord). The most common toxic substance is ammonia, which
is produced by the body when proteins are digested, but normally is
detoxified by the liver. Many other substances also accumulate in the body
and damage the nervous system.
In people with otherwise stable liver disorders, hepatic
encephalopathy may be triggered by episodes of gastrointestinal bleeding,
excessive dietary protein, or electrolyte abnormalities (especially decrease
in potassium, which may result from vomiting or treatments such as diuretics
or paracentesis). The disorder may also be triggered by any condition that
results in alkalosis (alkaline blood pH), low oxygen levels in the body, use
of medications that suppress the central nervous system (such as
barbiturates or Benzodiazepine tranquilizers), infections including viral
hepatitis, bile duct obstruction, surgery, or any coincidental illness.
Disorders that mimic or mask symptoms of hepatic encephalopathy
include Reye's syndrome, alcohol intoxication, sedative overdose,
complicated alcohol withdrawal, Wernicke-Korsakoff syndrome, subdural
hematoma, meningitis, metabolic abnormalities such as low blood glucose, and
Hepatic encephalopathy occurs in approximately 4 out of 100,000
people. It may occur as an acute, potentially reversible disorder or as a
chronic, progressive disorder.
a.. changes in mental state, consciousness, behavior,
b.. confusion, disorientation
c.. delirium (acute, severe confusion with fluctuating level
d.. dementia (loss of memory, intellect, reasoning, and
e.. changes in mood
f.. decreased alertness, daytime sleepiness
g.. decreased responsiveness, progressive stupor
b.. decreased self-care ability
c.. deterioration of handwriting or loss of other small hand
d.. coarse muscle tremors
e.. muscle stiffness or rigidity
f.. seizures (rare)
g.. yellow skin, jaundice
h.. speech impairment
i.. movement, uncontrollable
j.. movement, dysfunctional
k.. breath odor
l.. gynecomastia (breast development in males)
n.. positive Babinski's reflex
o.. decerebrate posture
Signs And Tests
Neurologic symptoms may fluctuate. Asterixis (coarse "flapping"
muscle tremor) may be observed during voluntary movement, such as when the
person attempts to hold the arms out in front of the body. Liver disease may
be known or may be suspected. Skin may be jaundiced (yellow skin and eyes).
Ascites (fluid collection in the abdomen) may be noted because of increased
body weight, abdominal enlargement, and abdominal examination that shows
free fluid in the abdomen. Occasionally, there is a characteristic musty
odor to the breath and the urine.
Blood tests may be nonspecific, or may show liver failure.
a.. Blood chemistry may show low albumin, high bilirubin, or
b.. Serum ammonia levels are commonly high.
c.. Prothrombin time may be prolonged and not correctable with
d.. CT scan of the head may be normal, or may show general
atrophy (loss of tissue).
e.. EEG (electroencephalogram, a reading of electrical
activity in the brain) shows characteristic abnormalities.
Hepatic encephalopathy is an acute medical condition that may
become a medical emergency. Hospitalization is required.
The goals of treatment include life support, elimination or
treatment of precipitating factors, and removal or neutralization of ammonia
and other toxins. Life support including support of breathing or circulation
may be required, particularly if coma develops. Cerebral edema (brain
swelling) may occur and may be life threatening.
Precipitating factors must be identified and treated.
Gastrointestinal bleeding must be stopped. This often requires endoscopy
(use of a scope) and cauterization or other means to control bleeding. The
intestines must be emptied of blood. Blood breaks down into protein
components that are converted to ammonia. Magnesium citrate or other
laxatives, and/or enemas are used to evacuate the intestines.
Reduced or no protein in diet is prescribed to reduce ammonia
production. Vegetable protein may be tolerated better than animal protein.
Specially formulated intravenous or enteric feedings (tube feedings) may be
Lactulose prevents absorption of ammonia from the intestines and
acts as a laxative to evacuate blood from the intestines. Neomycin may be
given by mouth to reduce ammonia production by intestinal bacteria.
Sedatives, tranquilizers, or any other medication that is metabolized or
excreted by the liver should be avoided. Medications containing ammonium
(including certain antacids) should be avoided. Other medications and
treatments may be recommended, with variable results.
Acute hepatic encephalopathy may be reversible, while chronic
forms of the disorder are often progressive. Both forms may result in
irreversible coma and death, with approximately 80% fatality if coma
develops. Recovery and recurrence are variable.
a.. cerebral edema (brain swelling)
b.. brain herniation
c.. progressive, irreversible coma
d.. permanent neurologic losses (movement, sensation, or
e.. increased risk of:
b.. respiratory failure
c.. cardiovascular collapse
d.. kidney failure
f.. side effects of medications (see the specific medication)
Calling Your Health Care Provider
Call your health care provider if any change in mental state or
other neurologic function occurs, particularly if there is known or
suspected liver disorder. Hepatic encephalopathy can rapidly progress to
become an emergency condition!
Treatment of liver disorders, particularly when that treatment
includes restriction of dietary protein (a primary source of ammonia), may
prevent some cases of hepatic encephalopathy.
Any neurologic symptoms in a person with known or suspected
liver disease should be referred to the health care provider immediately.
Dr Sharat C Misra MD,DM,FACG
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