Nitrogenous compounds in the saliva and blood of cirrhotic patients: a cross-sectional study

Objectives Serum increase of nitrogenous compounds (NC) in cirrhotic patients has been associated with the development of hepatic encephalopathy (HE). However, the relation between NC in saliva and HE is unclear. The objective of this study is to measure the levels of nitric oxide and urea in the blood and saliva in 38 cirrhotic patients and correlate them with clinical characteristics and presence and grades of HE. Material and methods Automated enzymatic colourimetric assays were performed to determine the levels of NC. Diagnosis and severity of HE were determined based on the West Haven criteria and by using the inhibitory control test. Results HE was diagnosed in 89.47% of the patients, with the majority (60.50%) presenting covert HE. With regard to the measurement of NC, although nitric oxide is moderately correlated with its amount in blood and saliva ( r = 0.630; P < 0.001), only salivary levels were associated with the presence of ascites and ecchymosis ( P = 0.013 and P = 0.030, respectively). In patients with HE, the serum levels of urea were higher ( P = 0.013) than those in patients without HE or minimal HE. Conclusions Nitrogenous compounds in the saliva were correlated with neither the presence nor grades of HE, whereas in the blood, only urea was positively correlated with the severity and presence of HE. Clinical relevance Saliva is an excellent fluid for diagnosing several diseases, but it does not seem to be able to collaborate with the identification of HE.