Pisa Syndrome

Pisa syndrome is a sustained lateral flexion of the trunk of at least 10 degrees that improves with passive mobilisation or lying down. It is a form of axial dystonia.

It is reported in under one in ten patients with Parkinson disease and is a recognised adverse effect of antipsychotics and cholinesterase inhibitors in older adults, particularly in dementia.

Pathophysiology. Asymmetric basal ganglia dopaminergic and cholinergic imbalance causes unilateral truncal dystonia. Other proposed mechanisms include asymmetric rigidity and altered body schema. Drugs implicated are antipsychotics, metoclopramide, donepezil and other cholinesterase inhibitors, some antidepressants and lithium.

The patient leans to one side while sitting or standing, sometimes with trunk rotation, back pain, falls and difficulty in walking or eating. In Parkinson disease, the lean is usually towards the side with more severe parkinsonism. Onset can follow a drug start or dose change within weeks to months.

Measure the lateral flexion angle standing, seated and lying. Review the timing of drug changes. Exclude structural scoliosis with spine radiographs, and spinal pathology or paraspinal myopathy with MRI when examination suggests it. Look for other extrapyramidal signs.

Differential diagnosis.

• Camptocormia and fixed scoliosis.
• Stroke with hemiparesis and hemispatial neglect.
• Vestibular disorders and pain related antalgic posture.

Stop or reduce the offending drug (antipsychotic, cholinesterase inhibitor, metoclopramide) where possible, since early withdrawal often reverses the posture. In Parkinson disease, optimise dopaminergic therapy, noting that either increasing or decreasing doses can help. Offer physiotherapy for postural re-education and trunk strengthening. Botulinum toxin injection to paraspinal muscles may help selected patients. Deep brain stimulation is rarely used.

Monitoring. Posture after each drug change, and pain and falls.