Rabbit syndrome

A rare movement disorder characterized by involuntary, rapid movements of the mouth

Rabbit syndrome is a rare movement disorder characterized by involuntary, rapid, rhythmic movements of the mouth, resembling the chewing motions of a rabbit. This condition is often associated with long-term use of antipsychotic medications, particularly the older, typical antipsychotics.

Presentation

The primary symptom of rabbit syndrome is the repetitive, involuntary movement of the mouth and lips, which is distinct from tardive dyskinesia, another movement disorder associated with antipsychotic use. Unlike tardive dyskinesia, rabbit syndrome does not typically involve the tongue or other parts of the body. The movements are usually rapid and rhythmic, resembling the chewing or twitching motions seen in rabbits.

Causes

Rabbit syndrome is most commonly caused by the long-term use of typical antipsychotics, such as haloperidol and chlorpromazine. These medications are known to block dopamine receptors in the brain, which can lead to various movement disorders. The exact mechanism by which these drugs cause rabbit syndrome is not fully understood, but it is believed to involve an imbalance in the dopaminergic pathways of the brain.

Diagnosis

The diagnosis of rabbit syndrome is primarily clinical, based on the characteristic movements and the patient's medication history. It is important to differentiate rabbit syndrome from other drug-induced movement disorders, such as tardive dyskinesia and parkinsonism. A thorough neurological examination and a detailed review of the patient's medication history are essential for accurate diagnosis.

Treatment

The primary treatment for rabbit syndrome involves discontinuing or reducing the dose of the offending antipsychotic medication, if possible. In some cases, switching to an atypical antipsychotic with a lower risk of movement disorders may be beneficial. Additionally, anticholinergic medications, such as benztropine or trihexyphenidyl, may be used to alleviate symptoms. These medications help to restore the balance of neurotransmitters in the brain and reduce involuntary movements.

Prognosis

With appropriate treatment, the symptoms of rabbit syndrome can often be managed effectively. In many cases, reducing or discontinuing the offending medication leads to a significant improvement in symptoms. However, some patients may continue to experience mild symptoms even after treatment.

Related pages

• Tardive dyskinesia
• Parkinsonism
• Antipsychotic
• Dopamine receptor