# Sacral Osteomyelitis With Abscesses and Fistulae: An Unusual Manifestation of Disseminated Blastomycosis

## TL;DR

A rare case of blastomycosis causing sacral osteomyelitis with abscesses and a fistula is reported, highlighting the importance of considering fungal infections in difficult-to-diagnose cases.

## Contribution

This case report presents an unusual manifestation of disseminated blastomycosis involving the sacrum with abscesses and a fistula.

## Key findings

- Blastomycosis was diagnosed after multiple failed antibacterial treatments using KOH microscopy, culture, and PCR.
- The patient was successfully treated with a prolonged course of oral itraconazole.
- Sacral bone destruction due to blastomycosis is a rare clinical manifestation.

## Abstract

Blastomyces dermatitidis, the fungus responsible for blastomycosis, can cause systemic disease with clinical manifestations ranging from asymptomatic infection to acute or chronic pneumonia and extrapulmonary diseases. Here, we present a case of sacral osteomyelitis with multiple abscesses and a fistulous tract, which failed to improve after multiple courses of antibacterial therapy for presumed bacterial causes, leading to a significantly delayed diagnosis. Blastomycosis was diagnosed by potassium hydroxide (KOH) microscopy, fungal culture, and broad-range polymerase chain reaction (PCR). The patient was prescribed oral itraconazole, 200 mg three times a day for three days, followed by twice a day for one year.

The presentation of abscesses and osteomyelitis with a fistulous tract in blastomycosis is uncommon, and one of the rare instances of dissemination and destruction of the sacral bone is being reported. The key to diagnosing the disease is considering it a possibility. Treatment depends on its severity.