Histoplasma Pyomyositis in a Patient with Disseminated Histoplasmosis and Anti-Synthetase Syndrome: Case-Based Review of Literature

A systematic review and meta-analysis of mycobacterial infections in patients with idiopathic inflammatory myopathies

OBJECTIVES

Infections including tuberculosis (TB) are a leading cause of morbidity and mortality in idiopathic inflammatory myopathies (IIM). We systematically reviewed the prevalence of mycobacterial infections in patients with IIM.

METHODS

We screened PUBMED, EMBASE and SCOPUS databases and conference abstracts (2015-20) for original articles using Covidence. Pooled estimates of prevalence were calculated.

RESULTS

Of 83 studies (28 cohort studies, two case control and 53 case reports), 19 were analysed. Of 14 043 IIM patients, DM (54.41%) was the most common subset among TB. Most studies were from Asia with high prevalence (5.86%, 2.33%-10.60%). Pooled prevalence of mycobacterial infections among IIM was 3.58% (95% CI: 2.17%, 5.85%, P < 0.01). Disseminated and extrapulmonary forms (46.58%; 95% CI: 39.02%, 54.31%, P = 1.00) were as common as pulmonary TB (49.07%; 95% CI: 41.43%, 56.75%, P =0.99) both for I2=0. Muscle involvement, an otherwise rare site, was frequently seen in case reports (24.14%). M. tuberculosis (28.84%) was the most common pathogen followed by Mycobacterium avium complex (3.25%). Non-tuberculous mycobacteria were less common overall (6.25; 95% CI: 3.49%, 10.93%) I2=0, P =0.94. Subgroup analysis and meta-regression based on high vs low TB regions found prevalence 6.61% (2.96%, 11.33%) in high TB regions vs 2.05% (0.90%, 3.56%) in low TB regions. While death due to TB was occasionally reported (P =0.82), successful anti-tubercular treatment was common (13.95%).

CONCLUSION

TB is common in IIM, particularly in endemic regions though current data is largely heterogeneous. Extra-pulmonary forms and atypical sites including the muscle are frequent. Limited data suggests fair outcomes, although larger prospective studies may offer better understanding.

Neglected tropical rheumatic diseases

The complexities of dealing with rheumatic diseases in tropical countries are diverse and likely due to limited health care infrastructure, lack of diagnostic and therapeutic facilities, impact of dominant prevailing diseases, and the challenges of differentiating from infectious and non-infectious disease mimics. Several tropical diseases present with musculoskeletal and rheumatic manifestations and often pose a diagnostic dilemma to rheumatologists. The diagnosis is often delayed or the disease is misdiagnosed, leading to poor patient outcomes. Endemic tropical diseases like tuberculosis and leprosy have myriad rheumatic presentations and remain important differentials to consider in patients with rheumatic manifestations. Infection with human immunodeficiency virus is a great masquerade and can mimic manifestations of multiple diseases. The role of viral infections in triggering and perpetuating autoimmunity is well known and chikungunya arthritis is a classic example of the same. This review highlights the rheumatic manifestations of tropical diseases and aims to create awareness among the caregivers. Key Points • It is crucial to be aware and identify infectious diseases presenting with rheumatic manifestations in the tropics. • Presentations akin to classic rheumatic syndromes such as rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus and vasculitis are common.