Necrotizing fasciitis caused by diabetic foot

•Irregular hypoglycemic and diabetic foot treatment led to necrotizing fasciitis.•Necrotizing fasciitis often develops rapidly and can lead to fatal consequences.•History, symptoms and auxiliary examinations can diagnose necrotizing fasciitis in a timely manner.•Treatment of necrotizing fasciitis requires effective antibiotics and prompt surgery. A 56-year-old woman with type 2 diabetic foot came to our hospital. She had an ulcer with a diameter of about 15 cm on the medial border of her right foot. There was black necrotic tissue and purulent secretions in the ulcer and it smelled bad (Figure 1 A). The patient was diagnosed with type 2 diabetes mellitus 6 months ago at a local hospital and complained that she did not receive formal hypoglycemic treatment. Three months ago, the patient had occasional outpatient treatment at the local community clinic because of a coin-sized skin ulcer on her right foot. But the skin ulcer on the foot was getting bigger and bigger. In the early morning of the day of admission, the swelling caused by her foot ulcer spread quickly to her right thigh. She developed fever, and felt very poor in energy and appetite. Her family sent her to our hospital. After admission, her T 39.3 °C, white blood cell (WBC) count in peripheral venous blood 25.87 × 109/L, CRP 326 mg/L, IL-6 529 pg/mL, pain and swelling spread to the right thigh. X-ray, CT and MRI scan suggested soft tissue swelling and gas accumulation in right thigh, right calf and right foot (Figure 1 B, C, D). We considered necrotizing fasciitis caused by diabetic foot and urgently performed amputation and debridement on the middle of the right thigh for this patient. During the operation, we dissected the right lower limb of the amputation and saw extensive subcutaneous tissue and fascia necrosis, accompanied by malodor, but no muscle tissue was involved (Figure 1 E, F). Cultures of ulcer secretion were positive for Eggerthella lenta, but negative for Bacillus perfringens. Postoperative patients were treated with sensitive antibiotics (vancomycin, imipenem and cilastatin sodium), blood transfusions, blood sugar control, correction of hypoproteinemia, and wound dressings with autologous platelet-rich gel therapy. The patient has been treated for more than two months; the wound on the amputation site of the right thigh of the patient healed (Figure 1 G). Necrotizing fasciitis has a mortality rate of 29% and is one of the most serious infections of the musculoskeletal system (Hysong et al., 2020Hysong A.A. Posey S.L. Blum D.M. Benvenuti M.A. Benvenuti T.A. Johnson S.R. et al.Necrotizing Fasciitis: Pillaging the Acute Phase Response.J Bone Joint Surg Am. 2020; 102: 526-537Crossref PubMed Scopus (2) Google Scholar). In the early stages of disease progression, necrotizing fasciitis is often confused with cellulitis, resulting in delayed diagnosis and poor prognosis. Necrotizing fasciitis is a widespread soft-tissue infection characterized by necrosis of the subcutaneous tissue and fascia (usually occurring in the skin, superficial subcutaneous fascia layer, and superficial lymphatic vessels and lymph node), often accompanied by systemic toxic shock (Kotrappa et al., 1996Kotrappa K.S. Bansal R.S. Amin N.M. Necrotizing fasciitis.Am Fam Physician. 1996; 53: 1691-1697PubMed Google Scholar). Muscle tissue that does not involve the site of infection is an important feature. Bacterial infection spreads rapidly and extensively along the fascia tissue, causing extensive inflammation, edema and congestion in the infected tissue. Inflammatory embolism, tissue dystrophy, and ischemic necrosis of the skin occurred in the small blood vessel network under the skin and skin. This pathology could be triggered by many factors, such as a fracture, sharp instrument wound, insect bite, obesity, malnutrition and so on(Advances In Musculoskeletal et al., 2020Advances In Musculoskeletal D. Infections S. Vitiello R. Segala F.V. Oliva M.S. Cauteruccio M. et al.Ankle fracture and necrotizing fasciitis: a common fracture and a dreadful complication.J Biol Regul Homeost Agents. 2020; 34: 71-75Google Scholar). Group A Streptococcus is the most frequently isolated organism, also included are some gram-positive cocci, gram-negative bacilli and anaerobic bacteria (Hakkarainen et al., 2014Hakkarainen T.W. Kopari N.M. Pham T.N. Evans H.L. Necrotizing soft tissue infections: review and current concepts in treatment, systems of care, and outcomes.Curr Probl Surg. 2014; 51: 344-362Crossref PubMed Scopus (184) Google Scholar). X-ray, CT and MRI scan can be used to observe the scope and plane of the lesion. Laboratory tests such as C-reactive protein, WBC count, hemoglobin level, serum sodium level, serum creatinine level, and blood glucose level at admission should all be considered as diagnostic factors when the diabetic foot is infected and the patient is not receiving standard treatment. In addition, people with diabetes usually have poor immune function. Ulcers will promote the penetration of bacteria into deeper tissues (Lavery et al., 2006Lavery L.A. Armstrong D.G. Wunderlich R.P. Mohler M.J. Wendel C.S. Lipsky B.A. Risk factors for foot infections in individuals with diabetes.Diabetes Care. 2006; 29: 1288-1293Crossref PubMed Scopus (429) Google Scholar, Singh et al., 2005Singh N. Armstrong D.G. Lipsky B.A. Preventing foot ulcers in patients with diabetes.JAMA. 2005; 293: 217-228Crossref PubMed Scopus (1874) Google Scholar). The inflammation spreads rapidly and leads to necrotizing fasciitis. If this is not treated in a timely manner, it leads to a fatal outcome. Emergency surgery (including open debridement or amputation) is required to save the patient's life. At the same time, a large number of effective antibiotics and effective systemic support treatments are applied. The condition of internal organs (such as heart, lung, kidney) should also be observed. The authors declare no financial or other relations that could lead to a conflict of interest. All authors had access to the data and had a role in writing the manuscript. None.