Positive Pyramidal Sign as an Unexpected Presentation in Antipsychotic-Induced Acute Dystonia: Case Reports and Literature Review.

Background: Acute drug-induced dystonia (DID) is an extrapyramidal side effect triggered by certain medications, primarily antipsychotics. It presents as acute involuntary muscle contractions, causing twisting, repetitive movements, or abnormal postures. Pyramidal signs, typically from upper motor neuron damage, are characterized by positive pathological reflexes, increased muscle tone, and hyperactive tendon reflexes.

Procedures: This study describes 2 cases of acute DID following antipsychotic treatment, both presenting with positive pyramidal sign. A literature review was conducted to find reports of abnormal pyramidal signs in acute DID cases, focusing on medical tests for differential diagnosis and neurological assessments related to DID.

Results: After reviewing the detailed medication history and conducting comprehensive tests, it was concluded that risperidone and haloperidol caused DID. Adjusting the medication and providing symptomatic treatment led to significant improvement.

Conclusions: These cases highlight the importance of being alert to the possibility of acute DID when using antipsychotics and pyramidal signs appear, providing insights for future research into the mechanisms of these unusual symptoms.