What are possible precipitating factors in hepatic encephalopathy (HE)?

Updated: Apr 04, 2019
  • Author: David C Wolf, MD, FACP, FACG, AGAF, FAASLD; Chief Editor: BS Anand, MD  more...
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Answer

Some patients with a history of hepatic encephalopathy may have normal mental status while under treatment. Others have chronic memory impairment in spite of medical management. Both groups of patients are subject to episodes of worsened encephalopathy. Common precipitating factors are as follows: [25]

Renal failure: Renal failure leads to decreased clearance of urea, ammonia, and other nitrogenous compounds.

Gastrointestinal bleeding: The presence of blood in the upper gastrointestinal tract results in increased ammonia and nitrogen absorption from the gut. Bleeding may predispose to kidney hypoperfusion and impaired renal function. Blood transfusions may result in mild hemolysis, with resulting elevated blood ammonia levels.

Infection: Infection may predispose to impaired renal function and to increased tissue catabolism, both of which increase blood ammonia levels.

Constipation: Constipation increases intestinal production and absorption of ammonia.

Medications: Drugs that act upon the central nervous system, such as opiates, benzodiazepines, antidepressants, and antipsychotic agents, may worsen hepatic encephalopathy.

Diuretic therapy: Decreased serum potassium levels and alkalosis may facilitate the conversion of NH4+ to NH3. At the author’s institution, diuretic-induced hypovolemia is the most common reason for patients with previously well-controlled hepatic encephalopathy to present to the emergency room with worsening mental function.

Dietary protein overload: This is an infrequent cause of hepatic encephalopathy.


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