Role of zinc in subclinical hepatic encephalopathy: comparison with somatosensory-evoked potentials

BACKGROUND AND AIM: The purpose of the present paper was to determine the role of zinc in subclinical portosystemic encephalopathy (SPSE). METHODS: The serum zinc levels were studied for 10 cirrhotic patients who did not suffer SPSE and for 10 patients who did, and the results compared with those deriving from 10 healthy volunteers. The nutritional evaluation included serum prealbumin, albumin, and transferrin levels, body mass index (BMI), mid-arm muscle circumference (MAMC), and tricep skin-fold (TSF). The occurrence of SPSE was defined as a situation when the N20-N65 interpeak latencies of median nerve-stimulated somatosensory-evoked potentials (SEP) exceeded 2.5 SD of the control mean value. RESULTS: Cirrhotic patients suffering SPSE (57.5 +/- 10.5 microg/dL) had lower serum zinc levels than those not experiencing SPSE (69.5 +/- 16.6 microg/dL, P = 0.03) and controls (77.7 +/- 6.8 microg/dL, P < 0.001). Four of the non-SPSE and nine SPSE patients had zinc levels less than the lower normal limit. Cirrhotic patients suffering SPSE had lower levels of albumin (2.8 +/- 0.4 g/dL vs 3.8 +/- 0.4 g/dL, P < 0.001), prealbumin (9.0 +/- 4.3 mg/dL vs 14.3 +/- 6.0 mg/dL, P = 0.02), and transferrin (158 +/- 56 g/L vs 218 +/- 50 g/L, P = 0.01), but a greater total bilirubin level (1.2 +/- 1.5 mg/dL vs 0.9 +/- 0.4 mg/dL, P = 0.005) than those not suffering SPSE. The serum zinc levels correlated with N20-N65 interpeak latencies (P = 0.03), serum albumin (P = 0.006), prealbumin (P < 0.001), and total bilirubin (P = 0.02) levels. CONCLUSIONS: The data show that zinc deficiency is common in cases of non-alcoholic cirrhosis with SPSE. The early assessment of malnutrition and zinc deficiency are important.