# Case Report: Concurrent Babesiosis and GCA/PMR

## TL;DR

This case report describes the first known instance of a 63-year-old man diagnosed with both babesiosis and GCA/PMR, highlighting a rare co-occurrence of these conditions.

## Contribution

The paper presents the first documented case of concurrent babesiosis and GCA/PMR, offering new clinical insights.

## Key findings

- The patient exhibited symptoms and lab results consistent with both babesiosis and GCA/PMR.
- Babesia microti was confirmed via blood smear and PCR, while GCA/PMR was indicated by elevated inflammatory markers and PET-CT findings.
- The case suggests a need for further research into the interaction between babesiosis and the immune system.

## Abstract

Babesiosis is a tick‐transmitted illness caused by intraerythrocytic protozoa of the genus babesia. The severity of babesiosis ranges from asymptomatic infection to fatal disease. Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are common interrelated inflammatory disorders that almost occur in people aged over 50 years. This report presents the first case of concurrent babesiosis and GCA/PMR in an old person.

A 63‐year‐old man was admitted to the hospital with a 1‐month history of fevers, accompanied by headache, muscle pain and fatigue. Laboratory tests revealed hemolytic anemia, with elevated C‐reactive protein, serum IL‐6 and erythrocyte sedimentation rate. FDG positron‐emission tomography‐computed tomography (PET‐CT) scan exhibited increased uptake in aortic wall, multiple medium‐to‐large arteries and soft tissues. A blood smear revealed Babesia microti intracellular ring forms. Babesia microti infection was further confirmed by polymerase chain reaction (PCR) test. This patient was diagnosed as concurrent babesiosis and GCA/PMR. He was treated with glucocorticoid and antimicrobial therapy.

Concurrent babesiosis and GCA/PMR is rare. Further studies are needed to understand the mechanism of interaction between babesiosis and human immune system.

Babesiosis is a tick‐transmitted infectious disease caused by parasites of the genus Babesia. Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are common interrelated inflammatory disorders. This report presents the first case of concurrent babesiosis and GCA/PMR.