CORRELATION OF AMMONIA LEVEL AND NEUROPSYCHOMETRIC TESTS FOR SEVERITY ASSESSMENT OF HEPATIC ENCEPHALOPATHY

Abstract

Purpose: The diagnosis of hepatic encephalopathy (HE) is based primarily on clinical criteria. Clinical grading of mental status, psychometric tests, electroencephalography, ammonia and other biochemical indices have been used in an attempt to develop objective measurements of HE severity. We prospectively evaluated the relationship between venous ammonia level, neuropsychometric tests and severity of HE as assessed by clinical examination. Methods: 15 patients with cirrhosis complicated by HE and 15 cirrhotics without HE were enrolled in the study. Clinical assessment of HE was determined using the West Haven criteria for grading mental status. Folstein's mini mental state examination (MMSE), number connection test (NCT), part A (trail test) and Isaacs set test were used as part of neuropsychometric evaluation. This was done at baseline, 48 and 96 hours. Results: Age, race, gender, etiology of liver disease and MELD score were similar in both groups. Neuropsychometric tests correlated moderately well with the clinical stage of hepatic encephalopathy; MMSE (r2 = 0.68), NCT (r2 = 0.62), Isaacs set test (r2 = 0.66) as compared to ammonia level (r2 = 0.17). Mean score on the Isaacs set test was lower than in controls (32.92 ± 6.5, P <0.01; 28.11 ± 5.2; 4.0 ± 8.9 for HE stages I, II and III respectively versus 37.80 ± 3.7 in controls). Conclusions: These results suggest that simple, and quick Bedside neuropsychometric tests done singly or in combination can provide a useful clinical and objective tool to assess severity of hepatic encephalopathy. Isaacs set test particularly appears to be useful to identify patients with early encephalopathy.