# Unveiling the Uncommon: Rickettsial Infections Promoting Sudden-Onset Parkinsonism

## TL;DR

A rare case shows that a Rickettsial infection can cause sudden-onset parkinsonism, with successful treatment after accurate diagnosis.

## Contribution

This paper presents a rare U.S. case of Rickettsia-induced parkinsonism, expanding understanding of its global occurrence and management.

## Key findings

- A 60-year-old patient showed marked improvement after treatment for Rickettsia-induced parkinsonism.
- Rickettsial infections, though rare, can cause sudden-onset parkinsonism with symptoms like tremors and gait issues.
- Successful treatment involved a combination of doxycycline, amantadine, and clonazepam.

## Abstract

It is known that various infections can lead to neuroinflammation and parkinsonism. Parkinsonism encompasses a range of neurodegenerative disorders that can present with symptoms like tremors or muscle rigidity. The following case describes a rare instance of parkinsonism that was induced by Rocky Mountain Spotted Fever (Rickettsia rickettsii). While parkinsonism has been found to be caused by certain viruses, it is uncommon for Rickettsial infections to be the inciting agent. This case sheds light on the evidence-based management of Rickettsia-induced parkinsonism (RIP) and movement disorders.

A 60-year-old male with intellectual and developmental disabilities (IDD) presented with a shuffling gait, stooped posture, bilateral hand tremors, and minimal facial movement. Antibody testing confirmed Rickettsia, with no other clear cause. He was treated with a seven-day course of 100 mg doxycycline, plus a six-month course of 100 mg amantadine and 0.5 mg clonazepam, both twice daily. At follow-up, he showed marked improvement, with a normal gait, upright posture, clearer speech, and no tremors. This case exemplifies the intricacies associated with Rickettsial infections. However, upon accurate diagnosis, appropriate treatment can be effectively administered.

Our patient experienced sudden-onset parkinsonism following a recent Rickettsial infection. Similar cases that have been documented in the scientific literature have reported the Orientia species as the infective pathogen. Additionally, these reported cases were predominantly observed in Asia, while our patient resides in the United States. This case can guide clinicians treating movement difficulties after Rickettsial infections and raise awareness of the existence of the rare etiology, treatment, and prognosis.