A man with diabetes and a swollen leg
Authors: Manish Sagar, William M Bowerfind, Fredrick M Wigley
Journal: The Lancet (1999)

A 31-year-old man with hypertension and insulin-dependent diabetes was admitted, in August, 1997, to hospital with pain and swelling in both legs. His oedema was thought to be due to diabetic nephropathy. 5 months after discharge from that hospital he was readmitted with swelling of both thighs and chills. He did not smoke, take alcohol, or use illicit drugs. He did not inject insulin into his thighs. He was taking diltiazem, enalapril, clonidine, and doxazosin. A muscle biopsy sample was reported as showing "non-specific inflammation consistent with myopathy." Tissue cultures were negative. He was treated with corticosteroids for 2 weeks and improved. 3 months later, he returned to hospital with a painful swelling of his left thigh. There was no evidence of deep-vein thrombosis on ultrasonography of his legs. Magnetic resonance imaging (MRI) showed marked enlargement of the left vastus lateralis without signs of haemorrhage. Triple-phase bone scan suggested there was no osteomyelitis. Ciprofloxacin and cefazolin were started empirically because of fever (38·4°C) and leucocytosis of 17·8×109/L. He was transferred to the Johns Hopkins Hospital because he did not get better. His left thigh was red, swollen, and indurated with a 12×3×4 cm mass above and medial to the patella. He was unable to bear weight on his left leg because of pain. General examination was unremarkable except for fever (38·5°C) and marked bilateral proliferative diabetic retinopathy. His white blood cell count was 21·9×109/L, creatine kinase level was 917 IU/L, serum creatinine was 300 μmol/L, and he had 4·5 g per 24 h urinary protein. Repeat MRI showed a diffuse high-signal intensity on T2 weighting in the vastus lateralis muscle without distinct fluid collection or mass (figure). A diagnosis of invasive pyomyositis was considered and he was given piperacillin and tazobactam. A surgeon did a muscle biopsy. Bacterial, viral, fungal, and acid-fast-bacillus cultures were negative. The biopsy specimen showed diffuse muscle necrosis without acute muscle inflammation. A vessel showed evidence of arteriosclerosis, which supported a diagnosis of diabetic muscle infarction. Antibiotics were discontinued on the seventh hospital day and he received conservative treatment with bed rest and control of his pain, hypertension, and diabetes. Over the next month he continued to have intermittent high fevers (maximum 38·8°C) and associated leucocytosis. Gradually, as his leg swelling improved, his fever subsided and his leucocytosis resolved. When last seen, in May, 1998, he was dialysis dependent but had recovered full function of his left leg. Diabetic muscle infarction is a well described but rare complication of insulin-dependent diabetes mellitus. This patient may be the first reported to present with fever and pain with leucocytosis, suggesting an infectious process or focal inflammatory myositis. His clinical course along with the culture and biopsy results were inconsistent with an infectious or autoimmune cause. The usual presentation for diabetic muscle infarction is an atraumatic swelling of the leg developing gradually over several weeks without associated systemic symptoms or signs.1Umpierrez GE Stiles RG Kleinbart J Krendel DA Watts NB Diabetic muscle infarction.Am J Med. 1996; 101: 245-250Summary Full Text PDF PubMed Scopus (105) Google Scholar The swelling is secondary to microvascular disease and is associated with other organ damage including diabetic retinopathy and renal disease.1Umpierrez GE Stiles RG Kleinbart J Krendel DA Watts NB Diabetic muscle infarction.Am J Med. 1996; 101: 245-250Summary Full Text PDF PubMed Scopus (105) Google Scholar, 2Rocca PV Alloway JA Nashel DJ Diabetic muscle infarction.Semin Arthritis Rheum. 1993; 22: 280-287Summary Full Text PDF PubMed Scopus (68) Google Scholar The clinical history, computed tomography scanning, or MRI can help make the diagnosis.3Chason DP Fleckenstein JL Burns DK Rojas G Diabetic muscle infarction: radiological evaluation.Skeletal Radiol. 1996; 25: 127-132Crossref PubMed Scopus (76) Google Scholar, 4Van Slyke MA Ostrov BE MRI evaluation of diabetic muscle infarction.Magn Reson Imaging. 1995; 13: 325-329Summary Full Text PDF PubMed Scopus (59) Google Scholar Biopsies can further support the diagnosis, but can prolong the course of the disease.5Banker BQ Chester CS Infarction of thigh muscle in the diabetic patient.Neurology. 1973; 23: 667-677Crossref PubMed Google Scholar Recognition that diabetic muscle infarction can mimic an infectious process is most important because surgical treatment is unnecessary and may lead to a poor outcome. Although the cause remains unclear, treatment consists of strict control of blood glucose, rest, and appropriate analgesia.