[Dyskinesia-hyperpyrexia syndrome in a patient with Parkinson's disease: a case report]

Non-physiological, excessive dopaminergic stimulation can cause dyskinesia-hyperpyrexia syndrome (DHS), which was initially reported by Gil-Navarro and Grandas in 2010. A 70-years-old woman with a 13-years history of Parkinson's disease (PD) was hospitalized due to difficulty walking, despite being treated with levodopa/carbidopa (600 mg/day), immediate-release pramipexole (3 mg/day), and selegiline (5 mg/day). Immediate-release pramipexole was changed to extended-release pramipexole without changing the dose or levodopa equivalent dose (LED). The patient's adherence to drugs was good. The parkinsonism gradually improved and the patient was discharged. One month later, the patient developed severe generalized athetotic dyskinesia with visual hallucinations and hyperpyrexia that lasted for a week, and she was readmitted to hospital. On admission, the patient was conscious but slightly disoriented. Body temperature was 40.3°C with hyperhidrosis. Leukocyte count in the peripheral blood was 1.78×10(4)/ml and serum creatine kinase was >3×10(4) U/l. Chest survey, whole-body computed tomography, and cranial magnetic resonance imaging showed no abnormalities. The patient was diagnosed with DHS and treated by tapering the oral administration of dopaminergic drugs, including extended-release pramipexole. Her clinical condition recovered without dyskinesia, and serum creatine kinase level swiftly normalized. DHS and resemblant conditions are reported to occur in long-term PD patients with motor complications. In advanced stage PD, loss of dopaminergic neurons impairs the dopamine holding capacity of the striatum and exogenous dopaminergic drugs can result in uncontrollable and excessive fluctuations in dopamine concentration. Our case recommends caution when switching to long-acting dopaminergic drugs, even if the dose is unchanged, could lead to excessive dopaminergic stimulation. This case highlights the importance of considering both the LED and the duration of action of dopaminergic drugs when adjusting medication.