AUTHOR=Xu Zhangling , Lv Xia , Xu Wenwen , Ye Yan , Wang Xiaodong , Ye Shuang , Ding Huihua , Wu Wanlong 

TITLE=Spontaneous Intramuscular Hemorrhage in Anti-MDA5 Positive Dermatomyositis: A Case Series and Literature Review

JOURNAL=Frontiers in Medicine

VOLUME=Volume 8 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.802753

DOI=10.3389/fmed.2021.802753

ISSN=2296-858X

ABSTRACT=Objectives: Spontaneous intramuscular hemorrhage (SIH) is a rare but life-threatening complication associated with dermatomyositis (DM). This study reported a case series of SIH associated with DM. In addition, the characteristics and prognostic factors for this complication were analyzed based on literature review. 
Methods: We reported 7 cases of anti-melanoma differentiation-associated gene 5 positive dermatomyositis (MDA5+DM) complicated with SIH in our single-center cohort and a comprehensive literature review was performed. The clinical characteristics, treatment and outcome data of all eligible reported cases were summarized. The potential prognostic factors were identified by comparisons between the deceased and survivors. 
Results: Among cumulatively reported DM patients with SIH, the overall mortality was 60.9% (14/23) (including our cases). Fourteen out of nineteen (73.7%) hemorrhagic events occurred within 6 months since disease onset. Anti-MDA5 antibody predominated in those myositis-specific antibodies available cases (8/10), although patients with positive anti-NXP2 and anti-Mi2 have also been documented. Iliopsoas (52.2%, 12/23) was the most frequently involved bleeding location. Bleeding in deep muscles was identified to be associated with poorer prognosis. The mortality of DM patients with deep muscular hematoma (non-palpable) (80%,12/15) was significantly higher than those only with superficial muscular hematoma (palpable) (25%, 2/8) (p=0.023). 
Conclusion: Spontaneous hematoma in non-palpable deep muscles including iliopsoas probably leads to excess mortality in dermatomyositis, particularly for those with anti-MDA5 antibody and often within 6 months of disease onset. Clinicians should be vigilant for this rare but potentially fatal complication and carefully balance the risk-benefit of prophylactic anti-thrombotic treatment.