Case: A comatose teenager

July 1, 2008

A comatose teenager and a differential diagnosis of hyperammonemia eventually points to a genetic origin for the condition.

Hyperammonemia-now what to do?

The patient arrives to the PICU unconscious with stable vital signs. His parents report that he was in his usual state of health until two days prior to admission, when he started to experience acute gastroenteritis-like symptoms. Since both parents had recently gone through similar episodes of vomiting and diarrhea, the family did not seek medical attention immediately. One day prior to transfer, his mother found the patient in the shower, curled in a fetal position, disoriented; he was immediately taken to the emergency department (ED).

There was no fever or seizure activity; however, in the ED there were two transient episodes of agitation and "stiffening" of the right arm that progressed to the entire body. These were treated with lorazepam. Per report, the patient was also kicking, screaming, and hitting personnel, behavior that is unusual for him.

In the review of his past medical history, you find out that the patient has Asperger syndrome, mild developmental delay, and ADHD. He has been receiving physical, occupational, and speech therapy. He currently takes methylphenidate and bupropion, and in the past two days was given loperamide once, and four doses of ibuprofen 200 mg. Birth history was significant only for c-section due to maternal HSV infection. Also, you learn from his parents that the patient lives in a boarding school in Virginia.

As you go back to the patient, nurses are reporting his vital signs: temperature: 98.4, heart rate (HR) of 108, respirations 21, blood pressure (BP) 128/90, O2 saturation 100% on room air. Weight is at 5th percentile, and height at 75th percentile.