Infectious Arthritis Due to Uncommon Pathogens

Mycobacterium tuberculosis and nontuberculous mycobacteria (NTM) are rare causes of subacute and chronic infectious arthritis, developing over months to years (1). Due to chronicity of infection, patients may present with a sinus tract communicating with the joint. Patients may also exhibit associated symptoms of night sweats, weight loss, fatigue and loss of appetite.

M. tuberculosis septic arthritis typically affects large joints (knee and hip) and less commonly small joints (2).

The most common NTM to cause septic arthritis are M. abscessus, M. kansasii, M. avium complex (MAC), and M. marinum (3). Infection may occur with dissemination or direct inoculation of the joint (1).

Mycobacterial infections are often treated with multiple antibiotics, guided by sensitivity testing results. Management of mycobacterial septic arthritis often requires coordinated decision-making between infectious disease and orthopedic teams to evaluate the need for surgical intervention in addition to antimicrobial therapy.

Viral arthritis is a rare cause of septic arthritis. A broad range of viruses can cause arthritis. The most common viral pathogens include parvovirus B19, hepatitis B and C, HIV, and alphaviruses such as chikungunya (1, 2).

Parvovirus B19 is a single-stranded DNA virus, with exposure to young children as a common risk factor for infection. In children, parvovirus B19 may present as large joint oligoarthritis. In adults, it typically manifests as symmetrical a small joint polyarthritis involving wrists and hands (3). Parvovirus B19 is typically self-limited and may be managed with NSAIDs.

Hepatitis B (HBV) is a double-stranded DNA virus. Risk factors include mother-to-child transmission, sexual contact, injection drug use, or other blood-borne exposures. Arthritis is caused by immune complex deposition in synovial tissues during an acute HBV infection, which typically presents as symmetrical polyarticular arthritis of the knees, ankles, and interphalangeal joints (4).

Hepatitis C (HCV) is a single-stranded RNA virus. Risk factors include unregulated tattoos and piercings, exposure to infected body fluids, sexual contact, and injection drug use. HCV– associated arthritis may present with symmetric polyarthritis of the small joints. Patients with HCV may also develop mixed cryoglobulinemia, which can present with intermittent polyarthralgias of the hands and knees or large joint oligoarticular, nonerosive arthritis (1, 2).

HIV is a single-stranded RNA retrovirus. Arthritis and arthralgias have been associated with early or acute HIV infection. Risk factors include men who have sex with men (MSM), individuals with multiple sexual partners, inconsistent condom use, sexual partners of persons living with HIV, and injection drug use. With untreated HIV, patients may present with mono or polyarticular arthritis. Treatment should include antiretroviral therapy for HIV. Since the antiretroviral era, the incidence of HIV-associated arthritis has been decreasing (5).

Chikungunya is a single-stranded RNA virus. Risk factors include mosquito exposure in the Americas, Southeast Asia, Africa, and islands in the Indian and Pacific oceans (6). Patients typically present with symmetric polyarthralgias and effusions of both large and small joints (1, 2). No specific antiviral treatment is available.

Fungal arthritis is a rare cause of septic arthritis, most commonly caused by Candida species, particularly Candida albicans, Candida tropicalis, and Candida parapsilosis (1). Patients typically present with an acute onset monoarticular arthritis, most commonly affecting the knee. Candida arthritis may be associated with hematogenous dissemination. Treatment includes prolonged antifungal therapy, with surgical intervention guided by coordinated decision-making between infectious disease and orthopedic specialists (2).

Other causes of fungal arthritis include Aspergillus, endemic fungi (Histoplasma, Blastomyces, Coccidioides and Cryptococcus), and Sporothrix. Infection may occur via hematogenous dissemination, direct inoculation, or less likely contiguous spread. Management of fungal arthritis often requires coordinated decision-making between infectious disease and orthopedic specialists to evaluate the need for surgical intervention in addition to targeted antifungal therapy (2).