Microsporidial myositis in adult-onset immunodeficiency: case-based review

Arthritis related to parasitic infections

Various parasitic infections can manifest with symptoms resembling inflammatory rheumatic diseases. Parasitic arthritis is uncommon, and the literature concerning rheumatic manifestations of specific parasitic infections tends to be limited to case reports. Despite its rarity, parasitic infections should always be included in the differential diagnosis of rheumatic presentations when there is a history of risk factors, particularly in patients from endemic regions and in atypical rheumatic presentations. Specific treatment of the parasitic infection often leads to significant improvement or resolution of symptoms. This account discusses various parasites that have been reported to be associated with arthritis and other related musculoskeletal manifestations.

Microsporidia, a Highly Adaptive Organism and Its Host Expansion to Humans

Emerging infectious disease has become the center of attention since the outbreak of COVID-19. For the coronavirus, bats are suspected to be the origin of the pandemic. Consequently, the spotlight has fallen on zoonotic diseases, and the focus now expands to organisms other than viruses. Microsporidia is a single-cell organism that can infect a wide range of hosts such as insects, mammals, and humans. Its pathogenicity differs among species, and host immunological status plays an important role in infectivity and disease severity. Disseminated disease from microsporidiosis can be fatal, especially among patients with a defective immune system. Recently, there were two Trachipleistophora hominis, a microsporidia species which can survive in insects, case reports in Thailand, one patient had disseminated microsporidiosis. This review gathered data of disseminated microsporidiosis and T. hominis infections in humans covering the biological and clinical aspects. There was a total of 22 cases of disseminated microsporidiosis reports worldwide. Ten microsporidia species were identified. Maximum likelihood tree results showed some possible correlations with zoonotic transmissions. For T. hominis, there are currently eight case reports in humans, seven of which had Human Immunodeficiency Virus (HIV) infection. It is observed that risks are higher for the immunocompromised to acquire such infections, however, future studies should look into the entire life cycle, to identify the route of transmission and establish preventive measures, especially among the high-risk groups.

Myositis Caused by Trachipleistophora hominis in a Person With Human Immunodeficiency Virus: The First Case in Thailand

Background

To date, cases of extraintestinal micro-sporidiosis have been increasingly reported in both otherwise healthy and immunocompromised individuals. Among them, microsporidial myositis is very rare. To the best of our knowledge, this is the first report of microsporidial myositis caused by Trachipleistophora hominis in a patient with human immunodeficiency virus (HIV) in Thailand.

Case report

A Thai man with HIV presented with fever and muscle pain at both anterior thighs and left arm for 3 months. Muscle biopsy was performed, and pathology exhibited neutrophil infiltration and focal aggregations of microsporidial spores. The 18S ribosomal RNA sequence revealed the species of this microsporidium as T hominis, and albendazole of 800mg/day was initiated. He gradually improved, and was discharged home 6 weeks after hospitalization.

Conclusions

To the best of our knowledge, this is the first report of microsporidial myositis caused by Trachipleistophora hominis in a person with HIV in Thailand.

Insights into the knowledge, attitude and practices for the treatment of idiopathic inflammatory myopathy from a cross-sectional cohort survey of physicians

The idiopathic inflammatory myopathies (IIM) are heterogeneous and lead to high morbidity and mortality. Knowledge deficits among healthcare professionals could be detrimental to clinical care. Identifying areas of deficient Knowledge, Attitude and Practice (KAP) of IIM can improve physician education and patient outcomes. To assess the proportion of physicians treating IIM with poor KAP and identify the key areas of deficit. An anonymised and validated e-survey (57 questions) was circulated among physicians treating IIM (purposive sampling). Responses were evaluated using the Likert scale for good (> 70% correct response), poor (> 20% chose > 2 answers) and the rest as intermediate consensus. Descriptive statistics were used. Intergroup comparisons were done using non-parametric tests. Of 80 (9.1% of 883) respondents, 90% were rheumatologists and 37.5% academicians. The knowledge base of treating physicians was good in specific domains such as triggers (80-90%), clinical presentation (MDA5, statin myositis, steroid myopathy, anti-synthetase syndrome) (82-92%), IIM mimics (41-89%), investigations (23-92%) and risk of osteoporosis in IIM (79%). There is also an intermediate knowledge base/consensus for outcome measures (30-56%) and response criteria (30-53%). There was poor knowledge and consensus on trials (27-34%), EULAR/ACR criteria (31%) and exercise-based interventions (17-62%). While 90% agree on the need for muscle biopsy to diagnose polymyositis, only one-third advocated it for juvenile and adult DM. Physicians have a good understanding of the triggers, clinical presentation and mimics of IIM. Poor to intermediate knowledge and consensus exists regarding muscle biopsy, outcome measures, response criteria and exercise-based interventions, which could be addressed through future focussed educational initiatives.