Article Text
Abstract
Serotonin syndrome associated with clozapine withdrawal and concurrent selective serotonin reuptake inhibitor (SSRI) use has previously been reported.
A 56-year-old female with schizophrenia was admitted for pyrexia, rigidity, and altered mental state after her second dose of clozapine restart. She had discontinued her long-term clozapine 2 weeks prior. She developed ventilatory failure, reduced consciousness, eye deviation, and worsening rigidity, requiring ICU support. Examination showed a right upper motor neurone syndrome with absent ankle reflexes.
She had raised inflammatory markers and creatine kinase. Serum neuropathy, encephalitis screen, and COVID PCR were negative. Respiratory investigations were unfruitful. MRI head and spine did not show brain or cord signal change to correlate to signs. Lumbar puncture showed a quiet CSF, negative culture, viral PCR, and encephalitis antibodies. EEG showed bihemispheric background slowing.
Despite clinical improvement, repeat examination showed persistent signs. She was diagnosed with serotonin syndrome after developing a bilateral tremor. Treatment with cyproheptadine correlated with an improvement in her signs, cognitive state, and EEG.
Serotonin syndrome can present with reversible neuromuscular signs. With clozapine withdrawal, it can require a prolonged time course of recovery in contrast with classical serotonin syndrome. Cyprohepta- dine can cause agranulocytosis and this delays clozapine restart.