Dear doctor(s)
Hi thanks for asking question. Here according to history provided by you here all viral markers are negative. Hepatitis an is not cause here.it might be false positive report, or it is cured now. Here patient having high ammonia suggest progression toward chronic liver disease or chronic hepatitis or cirrhosis. The cause can be you are right is cryogenic hepatitis which can be idiopathic ... Rule out alcohol history as it can lead chronic hepatitis and cirrhosis. If possible after decrease in ammonia level liver biopsy can take.Meanwhile, instruct patient for less fat, less protein diet...fruits more. Papaiya seed with lemon juice good herbal remedy. Take care. Chat Doctor.