Patient presents with signs and symptoms suggestive of hyperammonemia.  Clinical presentation includes (list presenting symptoms e.g., altered mental status, confusion, lethargy, vomiting, asterixis, seizures).  Initial evaluation reveals elevated ammonia levels (document specific level).  Differential diagnosis includes hepatic encephalopathy, urea cycle disorders, Reye's syndrome, inherited metabolic disorders, and drug-induced hyperammonemia.  Pertinent medical history includes (list relevant medical history e.g., liver disease, cirrhosis, hepatitis, use of valproic acid).  Family history is notable for (document any relevant family history of metabolic disorders).  Physical examination findings include (document relevant physical findings e.g., jaundice, ascites, hepatomegaly).  Laboratory testing includes ammonia level (document value and units), liver function tests (LFTs), complete blood count (CBC), basic metabolic panel (BMP), and coagulation studies.  Imaging studies (e.g., abdominal ultrasound, CT scan) may be considered to further evaluate the underlying cause.  Diagnosis of increased ammonia level is based on elevated serum ammonia concentration in conjunction with clinical presentation.  Treatment plan includes addressing the underlying cause of hyperammonemia and managing symptoms.  Specific treatments may include lactulose, rifaximin, protein restriction, intravenous fluids, and hemodialysis or other extracorporeal therapies in severe cases.  Patient education provided on dietary modifications, medication management, and the importance of follow-up care.  Prognosis depends on the underlying etiology and severity of the hyperammonemia.  Follow-up appointments are scheduled to monitor ammonia levels, assess treatment response, and adjust management as needed.  ICD-10 code E72.2 (disorders of ammonia metabolism) is appropriate for billing and coding purposes.