Abstract
Background
Mycobacterium chelonae is a rapidly growing non-tuberculous mycobacteria that can be isolated from water, soils and aerosols. Localised infection has been reported associated with surgical and cosmetic procedures. Disseminated infection is rare and usually occurs in individuals who are immunocompromised. We present a patient with severe SLE on immunosuppressive therapy who developed localised severe cutaneous infection of the foot.
Methods
A 69-year-old lady with complex SLE - RNP+, Raynaud's, arthritis, stable for several years had deteriorated within the last year with cardiac myositis and, peripheral neuropathy. Three months pulsed intravenous cyclophosphamide (EUROLUPUS regime) was completed in November 2018. Five weeks later she developed severe pain, inability to weight-bear and extensive erythema and swelling of the right ankle and lower leg. An MRI showed extensive skin thickening especially dorsally in the R foot and anteriorly in distal leg. There was also increased signal in the distal achilles tendon. Orthopedic review confirmed no evidence of septic arthritis or osteomyelitis. A skin biopsy was performed, cultures from which grew Mycobacterium chelonae. She was admitted and started on tobramycin, on which she developed long QTc, linezolid which caused thrombocytopenia and clarithromycin. In March 2019 she was re-admitted with confusion, weakness and AKI, secondary to clarithromycin. She was, then switched to clofazimine and low dose clarithromycin, on which she was stabilized. MRI brain scan was normal, lumbar puncture was negative for M chelonae PCR and MRI spine confirmed cervical cord compression and cervical and lumbar canal stenosis due to osteophytes and disc disease.
Results
The infection improved considerably after 5 months of successful mycobacterial treatment. It was then possible to treat with rituximab for a deteriorating peripheral neuropathy confirmed on EMG and cardiac myositis. Sadly, whilst awaiting rehabilitation, the patient died unexpectedly in April 2019 from an arrhythmia.
Conclusion
Mycobacterium chelonae is an uncommon cause of soft tissue infection, which is resistant to all anti-tuberculous drugs. It is susceptible to a wider range of antimicrobial agents including tobramycin, imipenem, clarithromycin, linezolid, co-trimoxazole. A high index of suspicion is necessary for diagnosis, particularly in immunocompromised patients. The incidence may be increasing, possibly due to enhanced detection. Infection can mimic MSK presentations including capsulitis, tendonitis and tenosynovitis. Close monitoring is required as anti-microbial therapy complications are common including prolongation of QTc on tobramycin. Vigilance for disseminated multiorgan involvement is essential due to high mortality, particularly with CNS and lung involvement. Atypical infections should always be considered in the immunocompromised, particularly mycobacteria, nocardia & fungi.
Disclosures
S. Rasool None. A. Afifi None. D. De Lord None.
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