Abstract Details

Title Establishing Ammonia Levels in Acute Onset Encephalopathy May Provide Rapid Diagnosis of Treatable Causes

Topic General Neurology

Presentation(s) P1 - Poster Session 1 (12:00 PM-1:00 PM)

Poster/Presentation
Number 6-013

Objective To report a case of an adult female patient with delayed diagnosis of ornithine transcarbamylase (OTC) deficiency, exhibiting a sudden-onset of encephalopathy with hyperammonemia.

Background

Hyperammonemia is a treatable cause of (sub)acute encephalopathy and often under-assessed in altered mental status evaluation. Inborn urea cycle disorders (UCD), may present as hyperammonemia without hepatic dysfunction. X-linked OTC deficiency is the most common UCD. While the majority of patients present in the pediatric age group, almost 20% manifest with initial symptoms after age 16. It can present in adulthood as acutely altered mental status with hyperammonemia and associated abnormal motor function, vomiting, stroke or seizures. Patients may have a history of protein intolerance and chronic daily headaches. Select environmental stressors such as a high-protein diet or a catabolic state may precipitate the onset of symptomatic hyperammonemia. Rapid management with ammonia scavengers, protein restriction, and dialysis is life-saving.

Design/Methods A case report of an adult female patient with acute onset altered mental status after starting high dose steroid therapy.

Results A 51 year-old female patient was admitted for further management of worsening chronic rheumatoid arthritis. High dose steroid therapy was initiated. On the second day of treatment, the patient became unarousable with myoclonus of lower extremities. Urgent diagnostic testing excluded stroke or infectious causes. Hyperammonemia (>700 µmol/L) was noted and dialysis was initiated. Ultimately, the patient developed seizures and cerebral edema. In the meantime, a workup for metabolic causes pointed to UCD. Due to persisting hyperammonemia and progressive cerebral edema, a fatal outcome ensued on the sixth day of hospitalization. Eventually, a urine analysis showed an increased orotic acid concentration.

Conclusions

Ammonia levels should always be assessed in patients with encephalopathy. In the setting of persisting hyperammonemia, prompt diagnosis of X-linked OTC allows for rapid treatment and the provision of appropriate genetic counseling in potentially presymptomatic family members.

Authors/Disclosures
Karlo Toljan, MD (Cleveland clinic) PRESENTER	Dr. Toljan has nothing to disclose.
Ahmad Mahadeen, MD (University of Mississippi Medical Center)	Dr. Mahadeen has nothing to disclose.
Sumit Parikh, MD (Cleveland Clinic Neurological Institute)	Dr. Parikh has received personal compensation in the range of $0-$499 for serving as a Consultant for Epirium. The institution of Dr. Parikh has received research support from CHAMP. The institution of Dr. Parikh has received research support from Mitochondrial Medicine Society. The institution of Dr. Parikh has received research support from Minovia. The institution of Dr. Parikh has received research support from Acadia. The institution of Dr. Parikh has received research support from Stealth. Dr. Parikh has received publishing royalties from a publication relating to health care.