Reversible Pisa Syndrome Induced by Rivastigmine in a Patient With Early-Onset Alzheimer Disease.

Pisa syndrome (PS) is a state of dystonic muscle contraction with a marked truncal deviation to one side. It is an uncommon adverse effect of antipsychotic drugs, but is rarely reported in patients receiving acetylcholinesterase inhibitors, especially rivastigmine. We present a 57-year-old female patient with Alzheimer disease who began to develop symptoms of dementia at the age of 51 years. She was observed to have symptoms of PS after continuous use of rivastigmine (9 mg/d) for nearly 2 years. The PS symptoms improved after the dose of rivastigmine was reduced but recurred when the dose was added back to 9 mg/d. Finally, after we decreased the dose to 4.5 mg/d, her PS symptoms were remitted. This report reminds us that clinicians need to be cautious about the risk of PS when prescribing rivastigmine in a patient with early-onset Alzheimer disease.