Parkinsonism-Hyperpyrexia Syndrome and Dyskinesia-Hyperpyrexia Syndrome in Parkinson's Disease: Two Cases and Literature Review.

Parkinsonism-hyperpyrexia syndrome (PHS) and dyskinesia-hyperpyrexia syndrome (DHS) are rare but exhibit life-threatening complications in Parkinson's disease (PD). We herein presented two cases of PD patients and performed a comprehensive and comparative literature review for these two syndromes. The first case was diagnosed as PHS with cerebral salt wasting syndrome caused by abrupt withdrawal of antiparkinsonian medication. Her symptoms were gradually remitted with reinstitution of the medication. The second one was an early-stage PD patient diagnosed as DHS in association with abuse of antiparkinsonian drugs. Her symptoms were gradually remitted with reduced dosage of dopaminergic drugs. Results of literature reviews revealed a total of 56 and 13 cases of PHS and DHS, respectively, and they were more likely to occur in elderly and long-term PD patients. These two syndromes showed different female-to-male ratio, similar mortality, and different recovery time. There were stark differences between PHS and DHS, including triggers (abrupt drug stoppage versus drug abuse), symptoms (worsened tremor and rigidity versus continuous dyskinesia), and treatment (drug reinstitution versus drug reduction). In summary, our reports and the review provide new insights into PHS and DHS in association with PD and may facilitate rapid discrimination of the syndromes for timely and proper treatment to reduce mortality.