A young female patient, who was otherwise well, presented with acute hemiparesis, dysphasia and confusion after a night out in town. She was febrile and developed focal motor seizures that were difficult to control, culminating in secondary generalisation and status epilepticus. She required intubation and ventilation on ITU. Blood and CSF testing revealed no evidence of infection, drugs, or toxins. MRI brain scans and angiography showed subtle left hemisphere swelling associated with cerebral vasoconstriction, and a degree of cerebellar atrophy. EEG found delta waves over the left hemisphere. After extubation the patient developed delusional and paranoid thoughts about the medical team. All symptoms resolved rapidly after treatment with steroids and three anticonvulsants, and the patient recovered to baseline. The underlying diagnosis proved to be a rare variant of Familial Hemiplegic Migraine type I (CACNA1A I1709T) of which there are two previous reports in the literature, and which seems to have a characteristically severe phenotype.
The de novo CACNA1A pathogenic variant Y1384C associated with hemiplegic migraine, early onset cerebellar atrophy and developmental delay leads to a loss of Cav2.1 channel function