Evaluation of Serum Ammonia in Hepatic Encephalopathy Patients and Its Correlation with Clinical Severity

Abstract

AIM: To study serum ammonia levels and its correlation with clinical status in patients of hepatic encephalopathy.

METHODS: A total number of 84 patients diagnosed clinically as Hepatic encephalopathy (HE) were grouped into 3 groups, due to cirrhosis of liver (n = 40), due to acute viral hepatitis (n = 34), due to drug induced hepatitis (n = 10). The diagnosis of HE was based on clinical criteria, and its severity was graded according to the West Haven Criteria for grading of mental status. Serum ammonia levels were estimated using enzymatic UV-method (RANDOX LABS). Ammonia levels were correlated with the severity of hepatic encephalopathy in all the three groups. All data obtained were assessed and statistically analyzed. ANOVA (ANalysis Of VAriance between groups) was used to find the statistical significance between the groups. TUKEY–KRAMER multiple comparison testswere used to compare meanbetween the groups.

RESULTS: The mean serum ammonia levels in each study group were found to be as follows [(μg/dL) ± SD]: 118.12 ± 48.87 in cirrhosis, 222.76 ± 74.73 in acute viral hepatitis, 134.6 ± 37.8 in drug induced hepatitis. Serum ammonia levels in acute viral hepatitis group were significantly higher than cirrhosis group (q= 10.59, p ≤ 0.001).In all 3 groups, an increase in mean serum ammonia levels were associated with worsening clinical status. Out of 84 patients, 12 patients (14.29%) of cirrhosis group, 18(21.43%) of acute viral hepatitis group, 4 (4.76%) of drug induced hepatitis expired during the course of illness. A higher risk of mortality was observed with an increase in serum ammonia levels. In cirrhosis group, 100% mortality was found with serum ammonia > 200 µg/dL. In acute viral hepatitis, 70% mortality was observed with serum ammonia levels > 200µg/dL. In drug induced hepatitis, 100% mortality was observed with serum ammonia values > 150 µg/dL.

CONCLUSION: An elevated serum ammonia level is an important laboratory abnormality in patients with HE. Both the mortality and severity of HE increases with an increase in serum ammonia levels. This could be useful in identifying patientswith higher grades of HE, suggesting that estimation of serum ammonia could be a useful tool in assessing the severity of illness and to plan for aggressive detoxification measures.