Acute Pisa syndrome in a 4-year-old child with autism spectrum disorder: The youngest reported case of risperidone-induced extrapyramidal reaction.

A 4-year-old boy with autism taking risperidone for behavior issues developed a rare side effect called Pisa syndrome, causing his trunk to bend sideways painfully. This was the youngest case ever reported. Doctors treated him with medication that immediately fixed the problem, stopped the risperidone, and he fully recovered. Parents should know that even young children can experience unusual side effects from autism medications.

This case report describes the youngest documented case of risperidone-induced Pisa syndrome in a 4-year-old child with autism spectrum disorder. Pisa syndrome is a rare extrapyramidal side effect characterized by sustained lateral trunk flexion, typically associated with antipsychotic medications. The child was receiving risperidone 0.5 mL twice daily for behavioral management alongside behavioral therapy when he developed acute onset painful lateral trunk flexion. Treatment with intravenous pheniramine maleate provided immediate symptom resolution.

Following risperidone discontinuation, no recurrence occurred. Causality assessment using the Pediatric Naranjo Scale scored 7, indicating probable drug causation. This case highlights the importance of recognizing rare extrapyramidal reactions in young children receiving atypical antipsychotics.

Clinicians should monitor for extrapyramidal side effects in very young children receiving risperidone, maintain high clinical suspicion for rare reactions like Pisa syndrome, and be prepared with appropriate treatment protocols including antihistamine therapy.

Single case report limits generalizability. No information provided about dosing duration before onset or long-term follow-up outcomes. Sample size and specific risperidone dose unclear from the abstract.

Pisa syndrome is a rare extrapyramidal disorder characterized by sustained lateral flexion of the trunk, typically associated with antipsychotic medications. Though well-described in adult populations, its occurrence in children is exceedingly rare, with no previously reported cases in children under 12 years of age for drug-induced etiology. We report the case of a 4-year-old boy with autism spectrum disorder (ASD), receiving risperidone (0.5 mL BID) for behavioural issues, on continued behavioural therapy, who developed acute onset painful lateral flexion of the trunk-clinically consistent with Pisa syndrome. He was promptly treated with intravenous pheniramine maleate, with immediate resolution of symptoms.

Risperidone was discontinued, and no recurrence was noted on follow-up. Causality assessment using the Pediatric Naranjo Adverse Drug Reaction Probability Scale yielded a score of 7, indicating a probable adverse drug reaction to risperidone. This case underscores the importance of early recognition of rare extrapyramidal side effects such as Pisa syndrome in children on atypical antipsychotics. Clinicians should maintain a high index of suspicion, even in very young children, and be aware of effective management strategies.