Generalized tonic clonic fits precipitated by drotaverine as initial presentation of acute intermittent porphyria: a case report

Acute intermittent porphyria is caused due to deficiency of porphobilinogen deaminase and usually presents with classic triad of neurologic dysfunction, abdominal pain and psychiatric disturbances. A 16 -year old unmarried girl presented with 1 -day history of recurrent episodes of generalized tonic clonic fits. There was history of mild diffuse abdominal pain for 15 days partially relieved by taking drotaverine. On examination, she was vitally stable and afebrile. Once the fits had stopped, there was no focal motor, sensory or cerebellar neurologic deficit and negative signs of neck rigidity. Initial investigations revealed microcytic anemia and a low normal sodium. Her ESR, CRP, CSF analysis, MRI scan (brain), EEG and aerobic cultures were normal. Urine had a pinkish red color and her 24 -hour urine porphobilinogen were raised at 23 mg/24 h (normal range 0-3.4 mg/24 h) with normal fecal porphyrin levels. A diagnosis of Acute Intermittent Porphyria (AIP) was made and 10% dextrose infusion was stared which resulted in recovery. Her attack was most likely precipitated by drotaverine and it was withdrawn. Counseling and education about her diagnosis and possible triggering factors was done. She was asymptomatic at discharge and remained stable on follow-up at 4 weeks.