Case Presentation: 77-year-old Caucasian male with history of Stage IV mantle cell lymphoma, multiple myeloma, atrial fibrillation, presented to the emergency department with 5-day history of progressively worsening ataxia & generalized weakness. He reported a black legged deer tick bite 10 days prior and was on doxycycline for this. He reported tremors in his bilateral upper extremities, neck stiffness, neck pain, headache, photophobia & confusion. There was no associated fever, rash, or focal weakness. On admission, patient was hemodynamically stable. Initial basic labs were unremarkable. Tickborne panel was negative. Physical examination was notable for bilateral upper extremity tremulousness, cogwheel rigidity & gait instability. MRI of the brain with and without IV contrast did not show any acute ischemic event or metastatic disease. MRI of cervical spine with IV contrast did not show any cord pathology. Lumbar puncture showed lymphocytic pleocytosis, elevated protein of 78, but normal glucose. CSF meningitis/encephalitis panel, fungal culture, gram stain & culture, paraneoplastic autoantibodies, cytology, flow cytometry were negative. Neurology was consulted. Aseptic meningitis and subsequent postencephalitic parkinsonism was postulated. After therapy with Carbidopa/Levodopa, patient’s symptoms improved. He was eventually discharged on this regimen.

Discussion: Parkinsonism is a clinical syndrome presenting with any combination of bradykinesia, resting tremors, rigidity, and postural instability. Parkinson disease (PD) is its most common form. There are a variety of conditions that can cause secondary parkinsonism, including drugs, toxins, and infections. There are no diagnostic tests that have been developed to distinguish PD from other forms. Distinguishing secondary parkinsonism from other primary syndromes is based on the clinical history, associated features, and laboratory or radiologic findings. Our patient had new onset Parkinsonism in the setting of his aseptic meningitis/encephalitis, making post-encephalitic parkinsonism the most likely diagnosis. This is believed to be caused by a viral illness triggering degeneration of nerve cells in the substantia nigra.

Conclusions: A wide array of conditions besides PD can cause parkinsonism. Post-encephalitic parkinsonism is an uncommon cause and diagnosis requires detailed clinical history, physical examination, and laboratory findings to distinguish it from other parkinsonian syndromes.