Fungal Arthritis

Fungal arthritis is inflammation of a joint by a fungus  which  either spreads through the bloodstream to reside in the joint[hematogenous spread] or exogenous inoculation in form of contaminated injection.

Normal person is quite resistant to fungal infection. Fungal infection occurs when immunity of the person is low due to some reason.
Joint involvement is an unusual complication of sporotrichosis among gardeners and other persons who work with soil or sphagnum moss.

Articular sporotrichosis is six times more common among men than among women, and alcoholics and other debilitated hosts are at risk polyarticular infection.

Fungal arthritis is also called mycotic arthritis

Organisms and Risk of Infection

Candida infection involving a single joint, usually the knee, hip, or shoulder, results from surgical procedures, intraarticular injections, or among critically ill patients with debilitating illnesses such as diabetes mellitus or hepatic or renal insufficiency and patients receiving immunosuppressive therapy.

Candida infections in intravenous drug users typically involve the spine, sacroiliac joints, or other fibrocartilaginous joints. Unusual cases of arthritis due to Aspergillus species, Cryptococcus neoformans, Pseudallescheria boydii, and the dematiaceous fungi have also resulted from direct inoculation or disseminated hematogenous infection in immunocompromised persons.

Conditions that may cause fungal arthritis include

• Blastomycosis
• Candidiasis
• Coccidioidomycosis
• Cryptococcosis
• Histoplasmosis
• Sporotrichosis
• Exserohilum rostratum
• Aspergillus

Fungal arthritis in people with normal immune systems is rare. Fungal arthritis has been reported in past with use of contaminated injections in the past but otherwise fungal infection is quite rare in healthy people.

People with abnormally suppressed immune systems are at risk for fungal infections, including fungal arthritis. This includes people with severely low white blood counts (neutropenia), HIV infection, injection drug abusers, and those taking chronic cortisone medication.

Presentation

Fungal arthritis is considered when a patient whose immune system is compromised develops inflammation of a joint. Symptoms of fungal arthritis include pain, heat, swelling, warmth, redness, and loss of range of motion of the affected joint. The most common joint to develop fungal arthritis is the knee joint. Fever may or may not be present.

Symptoms of fungal arthritis typically become manifest weeks to months after the initial infection of the joint.

Lab Investigations

Blood tests can include testing the blood for the white blood count, inflammation markers like ESR, and  CRP, and cultures of the blood. Joint fluid is aspirated from the joint with a needle and syringe and this fluid is analyzed in the laboratory to culture the precise fungal organism and establish the diagnosis.

The synovial fluid in fungal arthritis usually contains 10,000 to 40,000 cells/µL, with about 70 percent neutrophils. Stained specimens and cultures of synovial tissue often confirm the diagnosis of fungal arthritis when studies of synovial fluid give negative results.

Imaging

Routine xrays, CT scanning and MRI can tell about character and extent of joint damage.

Treatment of Fungal Arthritis

Treatment consists of drainage and lavage of the joint and systemic administrations of amphotericin B, fluconazole, or itraconazole (the exact drug depending on the species involved). The doses and duration of therapy are the same as for disseminated disease. Intraarticular instillation of amphotericin B has been used in addition to intravenous therapy.

The outlook for fungal arthritis is directly related to how much damage occurs to the cartilage and bone of the joint. Earlier treatment leads to optimal outcomes.