Fungal ArthritisDz

ICD-9 Codes: Arthropathy associated with mycoses, 711.8 (code underlying disease first: sporotrichosis, 117.1; Candida arthritis, 112.9; coccidioidomycosis, 114.9; blastomycosis, 116.0; cryptococcosis, 117.5; histoplasmosis, 115.9).

Demographics: With the exception of those with sporotrichosis and histoplasmosis, most with serious fungal bone or joint infection are immunocompromised from systemic illnesses (e.g., HIV), malignancy, chronic disease (diabetes), chronic inflammatory disorders, or drugs (e.g., corticosteroids, TNF inhibitors).

Specific Infections

Sporotrichosis: Osteoarticular infections may be caused by Sporothrix schenckii, which has worldwide distribution. Exposure is through the skin, often secondary to plant thorn injury in gardeners and agricultural or other outdoor workers. Infection begins in the skin as a painful skin nodule. Indolent unifocal arthritis most commonly involves the knee but also can affect the wrist, hand, ankle, and elbow. Tenosynovitis is also possible. Polyarticular arthritis is rarely seen in disseminated skin and bone infection occurring in immunocompromised hosts. Diagnosis is made by culture from skin, synovial fluid, or bone. Amphotericin B is being superseded by oral itraconazole for lymphocutaneous, articular, and osseous disease, with 70% to 100% cure rates. Surgical resection is sometime necessary.

Candida Arthritis: Commonly caused by Candida albicans, infection is owing to direct seeding of a joint or by hematogenous spread, often from an indwelling transcutaneous catheter. It manifests as a monarthritis in 60% to 75% of patients, most commonly affecting the knee. Diagnosis is established by culture of synovial fluid and/or blood. The preferred treatment is systemic amphotericin B. Prognosis is poor, and mortality rates are high because of comorbidities and frequent, concurrent candidemia.

Coccidioidomycosis: Infection with Coccidioides immitis is commonly seen in the western and southwestern United States, with a higher incidence in summer months. Primary respiratory infection occurs after inhalation of spores and may be associated with constitutional and systemic manifestations, including erythema nodosum and migratory arthritis. Disseminated infection is rare (except in immunocompromised hosts) and is associated with frequent bone involvement and monarthritis, particularly of the knee. It can progress to an indolent arthritis with pannus. Histologic examination reveals noncaseating granulomas with fungal spores. Diagnosis is suggested by a positive skin test result that is seen in 80% of patients within 1 to 3 weeks of infection. Synovial fluid culture is difficult but occasionally positive. Serologies are positive in diffuse disease. Chest radiographs may also be abnormal. Treatment options include itraconazole or fluconazole for limited to moderate disease. Amphotericin B is recommended for disseminated infection.

Blastomycosis: Blastomyces dermatitidis causes an uncommon infection in the Mississippi and Ohio River valleys and Middle Atlantic states of the United States. Primary respiratory infection occurs after inhalation of spores. Acutely, arthralgias and myalgias are common. Uncommonly, there is lymphatic or hematogenous dissemination to bone, joints, and skin. Joints are less commonly involved than bone and may be owing to direct extension from adjacent osteomyelitis. Skeletal involvement is occasionally asymptomatic. Long bones, ribs, and vertebrae are most commonly affected and appear osteolytic on radiographs. Soft tissue or vertebral abscesses may occur. Fungi may be detected in synovial fluid after KOH preparation. Culture on Sabouraud medium is confirmatory. Serologic tests are available, sensitive, but nonspecific and are not routinely recommended. Itraconazole may be effective with mild to moderate disease. Amphotericin B is reserved for severe infection in immunocompromised hosts.

Cryptococcosis: Infection with Cryptococcus neoformans is seen worldwide, especially in the immunocompromised host. Primary respiratory infection occurs after inhalation of spores (ubiquitous, found in pigeon droppings). Bone involvement is uncommon (<10% of cases), and infectious arthritis is rare. The latex agglutination test for cryptococcal antigen is generally positive. Limited disease may be treated with fluconazole alone. Amphotericin B with 5-fluorocytosine is recommended for severe cases.

Histoplasmosis: Infection with Histoplasma capsulatum is most commonly seen in the Mississippi and Ohio River valleys of United States but is also found worldwide. Primary respiratory infection is usually asymptomatic. Spores tend to grow and persist in soil contaminated with avian or bat excreta. Histoplasmosis is usually a benign, self-limited, respiratory illness. Acute infections may be heralded by erythema nodosum, arthralgia, or acute oligo- or polyarthritis. Chronic infection is very rare. The diagnosis is confirmed by histopathology (caseating granulomas) or by culture. Itraconazole is indicated for mild to moderate disease. Amphotericin B, with or without surgical debridement, may be necessary with severe disease or if the host is severely immunocompromised.

BIBLIOGRAPHY

Hansen BL, Andersen K. Fungal arthritis. A review. Scand J Rheumatol 1995;24:248–250.PMID:7481591