Necrotizing soft tissue infections after injection therapy: Higher mortality and worse outcome compared to other entry mechanisms.

OBJECTIVES: Necrotizing Soft Tissue Infections represent a rare entity of infection associated with a high mortality. The aim of this retrospective study was to analyze patients with an iatrogenic etiology of injection or infiltration to compare the outcome with other etiologies.

METHODS: The study group consisted of 21 patients treated with a Necrotizing Fasciitis caused by injection or infiltration. Risk factors and outcome were compared to 134 patients with a Necrotizing Fasciitis caused by other entry mechanisms.

RESULTS: Overall mortality in our study group was 14 of 21 (67%) with an amputation rate of 11 of 15 (73%) if an extremity was involved. The survival rate was significantly worse after injection or infiltration (p < 0.001) as was the amputation rate (p = 0.013), the percentage of patients requiring intensive care (100% vs. 83%, p = 0.038) and vasopressors (81% vs. 54%, p = 0.02). Injection or infiltration therapy proved to be the strongest prognostic factor (p = 0.003) besides the known risk factors obesity (0.007) and renal insufficiency (0.025).

CONCLUSIONS: Our results demonstrate that patients with a Necrotizing Soft Tissue Infection after injection or infiltration therapy have a significantly worse prognosis.