Rare infection in patient with rheumatoid arthritis treated with adalimumab

Abstract

Mycobacterium haemophilum is a rare pathogen, predominately present in the immunocompromised population. It is especially studied in HIV and haematological malignancy patients. Given its unique living conditions, it is often difficult to establish its diagnosis, but it is often suspected by its classic association with ulcerating skin findings. Our case is unique in that our patient is immunocompromised by his rheumatoid arthritis treatment, and presented without any skin lesions, but was found to have this rare pathogen causing a constellation of unusual symptoms.

Disseminated cutaneousMycobacterium haemophiluminfection in a patient on infliximab for rheumatoid arthritis

“…The exact prevalence as a pathogen is likely underreported due to these unique growth requirements 6 10. Since it was first recognised by Sompolinsky et al 11 in 1978 as a cause of generalised skin granulomata and subcutaneous abscesses in a patient receiving immunosuppressive therapy for Hodgkin’s disease, there have been approximately 300 cases reported, almost always in patients who are immunosuppressed 3–15. The underlying immunosuppression in patients with M. haemophilum infections has historically been advanced HIV, haematological malignancy or bone marrow transplant.…”

“…Although blood cultures were negative and no pulmonary or intra-abdominal organ involvement was noted on imaging, we would classify our patient’s infection as disseminated given it was isolated from multiple distinct cutaneous sites. Prior reports of M. haemophilum infection in patients on anti-TNF therapy for RA include one case of isolated facial infection, two cases of disseminated cutaneous infection with positive blood cultures, one pulmonary infection and one case presenting with focal neurological deficits with evidence of CNS and pulmonary infection on imaging and biopsy 3–6…”

“…Clarithromycin often forms part of the initial treatment and appears to be one of the most effective drugs against M. haemophilum 6–10 18 28 29. Other macrolides, including azithromycin and erythromycin, have also been used effectively in combination with fluroquinolones and a rifamycin 3–10 12 13 15 16 29. Amikacin has been shown to have in vitro activity against M. haemophilum and is recommended by some to be used in the setting of severe disease or disease not responsive to oral therapy 5 7 9 10 13 15.…”

“…Among the hundreds of known NTM is Mycobacterium haemophilum , a ubiquitous, fastidious organism that is rarely identified as a human pathogen. In the existing literature, there are approximately 300 reported cases of M. haemophilum infection and only a small number of cases in patients receiving anti-TNF therapy for RA 3–6. Here, we present the case of a man in his 70s who developed a disseminated M. haemophilum infection while on infliximab for RA.…”