Hepatic encephalopathy 

1. HEPATIC ENCEPHALOPATHY
By- Dr. Armaan Singh

2. Hepatic encephalopathy (also known as portosystemic
encephalopathy) is the occurrence of confusion, altered level
of consciousness, and coma as a result of liver failure. In the
advanced stages it is called hepatic coma or coma
hepaticum. It may ultimately lead to death.
It is caused by accumulation in the bloodstream of toxic
substances that are normally removed by the liver. The
diagnosis of hepatic encephalopathy requires the presence of
impaired liver function and the exclusion of an alternative
explanation for the symptoms. Blood tests (ammonia levels)
may assist in the diagnosis. Attacks are often precipitated by an
intercurrent problem, such as infection or constipation

3. COMMON PRECIPITANTS
 Renal failure.
 Electrolyte imbalance.
 Gastrointestinal bleeding.
 Infection.
 Constipation.
 Sedative drugs, eg opiates,
benzodiazepines,antidepressants and antipsychotic drugs.
 Diuretics. High protein intake.

4. GRADING OF HEPATIC ENCEPHALOPATHY
 Grade 0: subclinical; normal mental status, but minimal changes in
memory, concentration, intellectual function, co-ordination. This is
also termed minimal hepatic encephalopathy.
 Grade 1: mild confusion, euphoria or depression, decreased
attention, slowing of ability to perform mental tasks, irritability,
disorder of sleep pattern such as inverted sleep cycle.
 Grade 2: drowsiness, lethargy, gross deficits in ability to perform
mental tasks, obvious personality changes, inappropriate behaviour,
intermittent disorientation.
 Grade 3: somnolent but rousable, unable to perform mental tasks,
disorientation to time and place, marked confusion, amnesia,
occasional fits of rage, speech present but incomprehensible.
 Grade 4: coma, with or without response to painful stimuli.

5.  Patients with very mild hepatic encephalopathy
may have normal memory, language and motor
skills, but may have impairment of attention and
decision-making, and may have impaired fitness
to drive. These patients usually have normal
function on standard mental state testing but
abnormal psychometric testing.
 Patients with mild and moderate hepatic
encephalopathy show decreased short-term
memory and concentration with testing of mental
state. They may also have a flapping
tremor (asterixis), fetor hepaticus (a sweet musty
aroma of the
breath),hyperventilation and hypothermia

6. INVESTIGATIONS:-
 Psychometric tests - this are becoming increasingly useful in
the the diagnosis of minimal hepatic encephalopathy.
 Arterial or serum ammonia levels are raised and can help
with diagnosis.
 Electroencephalogram (EEG): may show high-amplitude low-
frequency waves and triphasic waves, but these findings are
not specific for hepatic encephalopathy although recent work
suggests EEG may be useful prognostically.
 MRI/CT scanning can help to exclude other causes of altered
mental function such as intracranial lesions.
 Visual evoked responses show classic patterns associated
with hepatic encephalopathy.

7. DIFFERENTIAL DIAGNOSIS
 Intracranial lesions, eg hemorrhage, cerebrovascular
event, tumor.
 Infection, eg meningitis, encephalitis, intracranial abscess.
 Metabolic, eg hypoglycaemia, electrolyte imbalance, anoxia,
renal failure.
 Other causes of hyperammonaemia, eg
ureterosigmoidostomy, inherited urea cycle disorders.
 Toxic, eg substance abuse, alcohol-related problems.
 Drugs, eg sedative hypnotics, antidepressants, antipsychotic
agents and salicylates.
 Post-seizure.