Immunosuppression and Opportunistic Infections: A Rare Case Report of Nocardia Osteomyelitis of the Pelvis

Patients with a long-standing history of immunosuppression are at significantly increased risk of opportunistic infections. One such group of organisms that may cause these types of infections includes the Nocardia genus, a gram-positive, filamentous rod that demonstrates a branching pattern, is urease-producing and has acid-fast properties. The disease profile of Nocardia varies with manifestations ranging from cutaneous infection to severe pulmonary or central nervous system (CNS) infections, and rarely, osteomyelitis. In this case report, we present an 87-year-old female with persistent left gluteal and lumbar pain, generalized body aches, chills, and fevers diagnosed with Nocardia asiatica osteomyelitis of the pelvis, likely secondary to dissemination from pulmonary cavitary disease in an immunosuppressed host with chronic neutropenia. On magnetic resonance imaging (MRI), the patient was found to have heterogeneous enhancement, central necrosis, and loss of cortical margins of the left iliac wing, alongside a rim-enhancing soft tissue mass from the left iliac bone into the left gluteal soft tissues and left paraspinal musculature representing an abscess. She was promptly treated with surgical irrigation and drainage with surgical wound cultures growing Nocardia asiatica. She received treatment with trimethoprim-sulfamethoxazole antibiotics with symptom improvement and is following up with an infectious disease physician outpatient. Management of osteomyelitis, like in this case, involves long-term antibiotics with the potential need for surgical intervention. There are few reported cases of extrapulmonary Nocardia infections, particularly osteomyelitis, demonstrating the importance of their inclusion in the literature to better serve patients to allow for timely intervention for rare and life-threatening conditions. In immunocompromised hosts, the differential diagnosis should include opportunistic infections and less common pathogens, especially in those with atypical presentations, including gluteal and leg pain.