Spontaneous Muscle Hematoma in Patients with COVID-19: A Systematic Literature Review with Description of an Additional Case Series

Coagulation abnormalities, thrombosis, and endothelial dysfunction have been described in COVID-19 patients. Spontaneous muscle hematoma (SMH) is a rare complication in COVID-19. The aims of this study are to: (1) perform a systematic review of the literature to better define the clinical SMH characteristics, (2) describe the prevalence and the clinical characteristics of SMH in COVID-19 patients referring to a Department of Internal Medicine (IM) (Federico II University of Naples), a Department of Sub-Intensive Care Medicine (SIM) (Ospedale Del Mare), and a Department of Intensive Care Unit (ICU) (Federico II University). The systematic review was performed according to PRISMA criteria. The local prevalence of SMH in COVID-19 was evaluated retrospectively. The medical records of all COVID-19 patients referring to IM and ICU from March 11th, 2020, to February 28th, 2021 were examined for SMH occurrence. In our retrospective analysis, we describe 10 cases of COVID-19 patients with SMH not previously reported in literature, with a prevalence of 2.1%. The literature review, inclusive of our case series, describes a total of 50 SMHs in COVID-19 patients (57.4% males; mean age 68.8 +/- 10.0 years). The SMH sites were ileo-psoas, vastus intermedius, gluteus, sternocleidomastoid, and pectoralis major muscles. Males developed SMH earlier than females (9.5 +/- 7.8 vs. 17.1 +/- 9.7 days). Ileo-psoas hematoma was more frequent in males (69.2 vs. 30.8%), while pectoralis major hematoma occurred only in females. The in-hospital mortality rate of SMH in COVID-19 patients was 32.4%. SMH is a rare but severe complication in COVID-19 hospitalized patients, associated with high mortality. A gender difference seems to be present in the clinical presentation of the disorder.