Aims

Diabetes mellitus is the most common co-morbidity associated with necrotising fasciitis. This study aims to compare the clinical presentation, investigations, Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score, microbiology and outcome of management of this condition in diabetic and non-diabetic patients.

The Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score was developed in 2004 to risk-stratify patients with soft tissue infections using common blood tests when the clinical picture is equivocal. A score ≥ 6 conferred a positive predictive value (PPV) of 92% and negative predictive value of 96% for necrotising fasciitis. We retrospectively calculated LRINEC scores for Orthopaedic patients admitted to ITU in our hospital with limb soft-tissue infection and confirmed Group-A Streptococcus or Staphylococcus in fluid, blood, tissue or swab culture between 2010–2017 (n=10). Mean age = 57.4 and 60% were female. Half of all patients died during admission. Mean LRINEC score of all patients was 5.3±3.1 (median = 6). Mean score in deceased patients was 4.8±2.8 (scores: 0,5,6,6,7; median = 6); in discharged patients mean = 5.8±3.7 (scores: 0,5,7,7,10; median = 7). 6 patients had a score ≥6, making our PPV 60%. 4 patients had necrotising fasciitis confirmed on histology (LRINEC scores = 0,5,7,10). Our PPV of 60% is less than the figure obtained in the original paper. 2 patients with a LRINEC score <6 died during admission, including a patient with a score of 0. Furthermore, a patient with necrotising fasciitis confirmed on histology also had a LRINEC score of 0. We conclude that LRINEC scores should not delay surgery when clinical suspicion is high, and should be used as an adjunct to clinical decision-making, rather than a replacement, as patients with low LRINEC scores can also have confirmed necrotising fasciitis and poor outcomes

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases.

The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.