An Atypical Presentation of Rocky Mountain Spotted Fever Presenting as Progressive Vision Loss: A Case Report

This case report describes a 49-year-old immunocompromised male with human immunodeficiency virus (HIV) who presented with progressive bilateral vision loss. He initially noticed blurriness and visual distortion in the right eye several months prior, which gradually progressed to involve the left eye with worsening peripheral vision and intermittent diplopia. Despite several evaluations and empiric treatment, his symptoms continued to worsen. Prior imaging and lumbar puncture (LP) were inconclusive. After extensive evaluation by ophthalmology, neurology, and infectious disease, the differential diagnosis was expanded to include infrequent causes, including infectious processes. A panel of diagnostic tests ultimately revealed Rocky Mountain Spotted Fever (RMSF). While it is typically a curable disease, RMSF can be a potentially lethal disease caused by the bacteria Rickettsia rickettsii. Human-to-human transmission is not known to occur. The patient denied tick bites or exposure risk; however, an unknown tick exposure could have occurred. At the time of diagnosis, the patient was significantly immunocompromised. Given this immunocompromised state, it is possible that the patient was more susceptible to infection transmission. Despite the absence of the classic triad of fever, rash, and headache, serological testing ultimately led to the diagnosis of RMSF, demonstrating the need for a broad differential and a high index of suspicion for this potentially life-threatening illness, especially in an immunocompromised patient.