A rare case of diabetic myonecrosis: an uncommon complication of a commondisease

Abstract

Introduction: Diabetic myonecrosis is a rare complication of diabetes mellitus associated with long-standing suboptimal glycaemic control. Usually it is self-limiting and responds well to conservativetreatment It affects both type 1 (T1DM) and type 2 (T2DM) diabetic patients who have long duration of diabetesand frequently have other microvascular complications.1 We report a case of diabetic myonecrosisadmitted to our hospital Case report:A 55-year-old male presented with sudden onset of pain and swelling in his right thigh after dialysis.He did not have any trauma to the thigh. He had a history of T2DM with micro- and macro-vascularcomplications, diabetic nephropathy leading to end-stage renal failure and ischaemic heart disease On examination, his right thigh was significantly bigger than his left and it was tender to palpationparticularly on the inner and anterior side. Mild erythema was present, the skin was hot to touch andhe was unable to flex his thigh. His investigations showed Hb 139g/L, WCC 7.0 x10^9/L, CRP 27 mg/Land CK 200 unit/L. He was treated with antibiotics to cover infection. Ultrasound Doppler of his rightlower limb did not show any evidence of thrombosis; MRI T2W and STIR sequences displayed highsignal heterogeneous intensity within the muscles of the anterior and medial compartments of the rightthigh with relative sparing of the posterior compartment muscles, suggesting myonecrosis. Antibioticswere stopped and he was treated conservatively with clopidogrel, analgesics and physiotherapy for afew months. Unfortunately, the patient passed away with a cardiac arrest a few months after thepresentation Discussion: Diabetic myonecrosis, or diabetic muscle infarction, is a rare manifestation of long-standing and poorly controlled diabetes mellitus. Most patients have long duration of diabetes (meanduration 14.3 years) and poor glycaemic status. In a systemic review of all reported cases of diabeticmyonecrosis, it was found to be more common in women (61.5% of all cases), in T1DM (59% of allcases) and in long-standing diabetes (mean duration of disease 14.3 years).1 The exact pathogenesis is not well known but may involve atherosclerotic occlusion, hypoxia-reperfusion injury, vasculitis and thrombosis.2 The usual presentation is sudden onset of pain in the involved muscle. The thigh muscles are themost commonly affected, followed by the calf muscles are the most affected Routine laboratory investigations are not helpful. There is a lack of correlation between muscleinvolvement and creatine phosphokinase level. Evidence shows that medical diagnosis is usuallydelayed by approximately 4 weeks. MRI is the best investigation for diagnosis. The characteristicfeatures of diabetic myonecrosis in MRI are an increased signal from the affected muscle area in T2-weighted, inversion-recovery and gadolinium enhanced images, and isointense or hypointense areason T1-weighted images.3 CT and ultrasound are less specific, and biopsy is not recommended because of potentialcomplications of delayed recovery Diabetic myonecrosis is a self-limiting disease that responds well to conservative management.Patients who undergo surgery have delayed improvement compared to those managedconservatively.4 Although the short-term prognosis of diabetic myonecrosis is good, the long-term prognosis is poorand most patients die within five years.