215 - Infectious Shakes: Legionella as a precipitating factor to Parkinson’s Disease

Case Diagnosis: Exacerbation of cogwheel rigidity secondary to Legionella pneumonia in a dopaminergic agent–naïve patient with Parkinson’s disease, in the setting of an acute traumatic left intertrochanteric fracture, status post open-reduction internal fixation.

Case Description:

A 68-year-old male with Parkinson’s disease presented to the emergency department after a ground-level fall, with imaging confirming a left intertrochanteric femoral fracture. He was alert, oriented, and physically active, including marathon running, until his Parkinson’s diagnosis four months prior, at which time he had not initiated dopaminergic therapy. He underwent open reduction and internal fixation. Postoperatively, he developed severe cogwheel rigidity and encephalopathy. Brain CT was unremarkable, while chest CT revealed pneumonia, and urine antigen testing was positive for Legionella. He was treated with azithromycin and initiated on donepezil. Discharged to an inpatient rehabilitation facility, he completed the antibiotics. After three weeks of intensive rehabilitation, his cogwheel rigidity improved, and he regained independence in activities of daily living, requiring only contact-guard assistance for ambulation and stair navigation.

Discussions:

Parkinson’s disease is characterized by bradykinesia, rigidity, resting tremor, and postural instability, which serve as clinical hallmarks for diagnosis. Parkinsonian rigidity reflects increased muscle tone from progressive loss of dopaminergic neurons in the substantia nigra. Akinetic crisis, often triggered by abrupt withdrawal of dopaminergic therapy or systemic infections, is rare, occurring in about 0.3% of patients annually. While infections can exacerbate motor symptoms, Legionella is rarely implicated. Herein, we report a male patient with Parkinson’s disease who developed significant cogwheel rigidity in the setting of Legionella pneumonia.

Conclusions: Legionella pneumonia precipitating Parkinsonian rigidity is a rare phenomenon in clinical practice. Early recognition and diagnosis of infection with tailored pharmacologic and rehabilitative strategies are fundamental to improving patient outcomes. Further investigation into the relationship between Legionella infection and Parkinson’s disease is essential for optimizing neurologic prognoses and guiding future therapeutic strategies.