Epidemiology of the fungi causing bone and joint infections
|Fungi||Mode of Infection||Geographic Area|
|Histoplasma capsulatum||Inhalation; aerosolized from soil rich in bird (especially chicken) and bat feces||Worldwide, but highest in Ohio and Mississippi River valleys|
|Cryptococcus neoformans||Inhalation; aerosolized from pigeon droppings also seen in immunosuppressed||Worldwide|
|Coccidioides immitis||Inhalation; especially in dry months; also seen in immunosuppressed and HIV patients||Southwestern United States, Central and South America (especially in arid and semiarid regions)|
|Blastomyces dermatitidis||Usually inhalation, but rare case of dog-to-human, human-to-human, and inoculation reported; male to female ratio of 9:1||Mississippi and Ohio River basins, Middle Atlantic states, Canada, Europe, Africa, and northern South America|
|Sporothrix schenckii||Cutaneous disease from scratch or thorn prick; systemic disease is due to inhalation; also seen in immunosuppressed, alcohol abusers, and gardeners||Worldwide|
|Candida species||Endogenous; common in premature infants and other compromised hosts (malignancies, indwelling catheters, immunosuppression, wide-spectrum antibiotic use)||Worldwide|
|Aspergillus species||Inhalation of decaying matter or contaminated hospital air; also seen in surgical or trauma patients and immunocompromised||Worldwide|
How frequently is bone or articular involvement seen with these fungi and at what locations?
H. capsulatum —In the acute setting, large joint polyarthritis with or without erythema nodosum can be seen in ∼5% of patients with pulmonary histoplasmosis. It can resemble acute sarcoid arthritis. In the chronic setting, arthritis is very rare. Disseminated histoplasmosis is seen in immunosuppressed patients. Serologic tests, serum and urine antigen screening, and biopsy and cultures can confirm the diagnosis. Test of choice = urine antigen.
C. neoformans —Osteomyelitis occurs in 5% to 10% of infections. Arthritis is very rare and almost always involves the knee. Serum antigen screen and tissue biopsy and culture can confirm the diagnosis.
C. immitis —Bone and joint involvement is seen in 10% to 50% with extrathoracic disease. Osseous involvement may involve multiple sites. Monoarthritis of the knee is the most common arthritis. Serologic testing and tissue biopsies with stains and cultures are necessary to confirm the diagnosis. Synovial fluid cultures are rarely positive.
B. dermatitidis —Bone and joint involvement is seen in 20% to 60% of patients with disseminated disease. Osseous involvement typically affects the long bones, vertebrae, ribs, skull, and feet. Arthritis is usually monoarticular, occurring in 3% to 5%. Synovial fluid is often purulent. Serum and urine antigen screening, synovial fluid cultures, and tissue biopsy and cultures can confirm the diagnosis. Note that urine histoplasma antigen cross-reacts with blastomyces.
S. schenckii —Bone and joint involvement is seen in 80% of systemic cases. Arthritis is monoarticular or pauciarticular. Knee and all upper extremity joints are most commonly involved. Hand and wrist involvement distinguishes it from other fungal arthritides. Infection occurs by entry through the lungs with dissemination and uncommonly through skin inoculation. Most patients are immunosuppressed. Serologic testing is unreliable. Synovial fluid and tissue biopsy and culture can confirm the diagnosis.
Candida species—Rare, but the number is increasing with greater use of broad-spectrum antibiotics and indwelling catheters in immunosuppressed patients. The two common sites involved after an episode of candidemia include intervertebral discs and knee joints. A high index of suspicion is necessary as symptoms may develop weeks to months after candidemia. The arthritis may have an acute presentation with positive cultures.
Aspergillus species—Osteomyelitis and arthritis are both rare but can occur by direct spread from the lung. Serum biomarker antigen detection (galactomannan) and tissue biopsy with culture confirm the diagnosis.
Madurella species—Bone and joint involvement is common with spread of the soft-tissue infection to the bone, fascia, and joint.
Scedosporiosis species—Have a predilection for bone and cartilage after cutaneous inoculation and dissemination.