Necrotising myositis - learnings for a plastic surgeon

Background: Necrotising myositis (NM) is a life-threatening emergency. Prompt treatment is associated with more favourable outcomes, but early diagnosis is challenging. The initial absence of cutaneous signs and symptoms coupled with delayed recognition commonly result in higher rates of morbidity and mortality.

Objectives: Analyse data regarding demographics, epidemiology, aetiology, clinical manifestations, diagnosis and treatment of previously reported cases. This publication is intended for plastic surgeons in training to help them look out for this disease.

Search methods/criteria: Publications reporting necrotising myositis between 1974 to January 2020 were identified from Embase, Medline All, Web of Science Core Collection, Google Scholar and Cochrane Central Register of Controlled Trial.

Data collection and analysis: Identified studies were exported to an end note library. In animal studies, studies relating to statin-induced myotoxicity and auto-immune myositis were excluded. The quality of included case reports was assessed using JBI Critical Appraisal Checklist for Case Reports.

Main results: The most common initial presentation was a few days of antecedent prodromal flu-like symptoms associated with muscle pain. The mean age was 43.3 years and 82% had no significant medical history. The most frequent misdiagnoses were muscle strain (11%), deep vein thrombosis (10%) and viral illness (9%). Seventy-four per cent of presentations were due to Group A Streptococcus infections and only 3.5% of cases were polymicrobial. The most common clinical course following the initial presentation was rapid deterioration into profound sepsis and progression into multi-organ failure. The overall mortality rate was 36.5%.

Conclusions: NM is a life-threatening muscle infection. It is a diagnostic conundrum as initial presentation is often only myalgia without features of preceding trauma. We propose that a high index of suspicion and increased awareness will reduce morbidity.

Other: PROSPERO (registration number CRD42018087060). Nil funding/conflict of interest.