Role of bone scan in the assessment of polymyositis/dermatomyositis

Diagnostic role of technitium-99m bone scan in severe COVID-19-associated myositis

Coronavirus disease 2019 (COVID-19), initially appreciated as a respiratory illness, is now known to affect many organs in the human body. Significant data has become available on muscle involvement, with creatinine kinase elevations present in a significant percentage of patients. For those with suspected COVID-19-associated myositis, the imaging modality of choice has been gadolinium-enhanced magnetic resonance imaging; however, the use of technitium-99 m bone scan has not been previously reported. Here, we report two cases of COVID-19 patients with severe elevation in creatinine kinase who underwent technitium-99 m bone scan. The resulting images showed diffuse symmetrical muscle involvement. Both patients developed acute renal injury due to rhabdomyolysis. To our knowledge, this is the first report of bone scan as a diagnostic imaging modality for COVID-19-associated myositis.

AST/ALT ratio as a predictor of mortality and exacerbations of PM/DM-ILD in 1 year-a retrospective cohort study with 522 cases

OBJECTIVE

To assess the associations between aspartate transaminase/alanine transaminase ratio (DRR) and mortality in patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD).

PATIENTS AND METHODS

This was a retrospective cohort study, which included 522 patients with PM/DM-ILD whose DRR on admission were tested at West China Hospital of Sichuan University during the period from January 1, 2008, to December 31, 2018. Cox regression models were used to estimate hazard ratios for mortality in four predefined DRR strata (≤ 0.91, 0.91-1.26, 1.26-1.73, and > 1.73), after adjusting for age, sex, DRR stratum, diagnosis, overlap syndrome, hemoglobin, platelet count, white blood cell count, the percentage of neutrophils, neutrophil/lymphocyte ratio, albumin, creatine kinase, uric acid/creatinine ratio, triglycerides, or low-density lipoprotein.

RESULTS

Higher DRR (> 1.73) was an independent predictor of 1-year mortality in multivariate Cox regression analysis (hazard ratio 3.423, 95% CI 1.481-7.911, p = .004). Patients with higher DRR more often required the use of mechanical ventilation and readmission for acute exacerbation of PM/DM-ILD at 1-year follow-up.

CONCLUSION

Higher DRR on admission for PM/DM-ILD patients are associated with increased mortality, risk of mechanical ventilation, and hospitalization in 1-year follow-up. This low-cost, easy-to-obtain, rapidly measured biomarker may be useful in the identification of high-risk PM/DM-ILD patients that could benefit from intensive management.