Non-tuberculous mycobacterial infection in patients with systemic lupus erythematosus.
OBJECTIVE
Patients with systemic lupus erythematosus (SLE) are susceptible to opportunistic infections. To examine the clinical manifestations of non-tuberculous mycobacterial (NTM) infections with those of Mycobacterium tuberculosis (MTB) infections in SLE patients.


METHODS
Medical records of a cohort of 725 SLE patients were reviewed for previous NTM infections. Demographic characteristics, predisposing factors and clinical outcomes were compared with patients who had previous MTB infections (n = 39).


RESULTS
Eleven (nine female and two male) cases were identified (prevalence 1.5%). The mean +/- S.D. age at the time of infection was 42.8 +/- 13.9 yrs, 9.3 +/- 5.8 yrs after the onset of SLE. The mean +/- S.D. time taken from onset of symptoms to the diagnosis of NTM infection was 5.7 +/- 7.2 months. Sites of involvement included skin and soft tissue (n = 8), chest (n = 2) and disseminated infection (n = 1). NTM infections were more likely to involve extrapulmonary sites (P = 0.006), presented in patients with longer lupus disease duration (P < 0.001), occurred in older patients (P < 0.001) and in those who had a higher cumulative dose of prednisolone (P = 0.01) than MTB infections. Using a stepwise logistic regression, disease duration was found to be the only independent predictive factor (P = 0.005) for NTM infections. Ten (25.6%) patients with MTB infections but none of the patients with NTM infections presented concomitantly at the onset of SLE (P = 0.09). There were no differences in the recurrence rate (P = 0.64) and frequency of disseminated infections (P = 0.40) between NTM and MTB infections.


CONCLUSIONS
NTM infections tended to develop in SLE patients later in their disease course than MTB infections. A high index of suspicion is required for its diagnosis.
Mok
M Y
MY
University Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China. mymok@netvigator.com
Wong
S S Y
SS
Chan
T M
TM
Fong
D Y T
DY
Wong
W S
WS
Lau
C S
CS
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000150:complications* / Q000175:diagnosis; D009894:Opportunistic Infections / Q000150:complications* / Q000175:diagnosis; D011379:Prognosis; D012307:Risk Factors; D013997:Time Factors; D014376:Tuberculosis / Q000150:complications