The importance of serum creatine phosphokinase level in the early diagnosis and microbiological evaluation of necrotizing fasciitis

Background  Necrotizing fasciitis (NF) due to group A β-haemolytic streptococci (GAS) is a rare but still life-threatening soft-tissue infection characterized by rapidly spreading necrosis of the muscle fascia and of the surrounding tissues. NF other than that due to GAS involves the participation of one or more anaerobes and/or of non-group A streptococci, Staphylococcus aureus, enteric organisms, and may be associated with a better outcome. Early diagnosis and treatment, consisting of surgical debridement along with appropriate antibiotic therapy, are required to reduce morbidity and mortality rates. Objectives  The aim of the study was to analyse the clinical and laboratory findings of patients with GAS NF and with non-GAS NF, and to identify which characteristics could help to diagnose NF in the early stages of infection. Methods  We retrospectively analysed the clinical and laboratory findings of 43 cases of GAS and non-GAS NF that occurred in Belgium (n = 32) and at Saga Medical School (Japan) (n = 11) between May 1984 and December 2001. Results  GAS NF more frequently occurred in previously healthy individuals than NF due to other pathogens (P < 0.05) but was associated with a poorer prognosis. Both for patients with GAS NF and with non-GAS NF, the first clinical manifestations often suggested a diagnosis of erysipelas or cellulitis and rarely evoked the correct diagnosis (12% and 15% of the cases, respectively). However, we found that creatine phosphokinase (CPK) values were far higher in patients with GAS NF than in those with non-GAS NF. Conclusions  Our data suggest that GAS may exert particular tropism and/or toxicity for muscle, responsible for early muscle necrosis. This indicates that elevated levels of CPK in a patient with erysipelas or cellulitis-like symptoms should clearly prompt the clinician to exclude the diagnosis of GAS NF.