Case Presentation: Diabetic myonecrosis is a rare and under-recognized disorder observed in poorly controlled long-standing diabetes mellitus (1). Typical presentation includes acute pain and swelling of the affected muscle group in the absence of local injury due to spontaneous ischemic necrosis of the skeletal muscles. We present a case of a 48-year old female with insulin-dependent type 2 diabetes mellitus, hypothyroidism and breast cancer who presented with a 7-week history of severe, acute onset shooting left thigh pain, fevers and fatigue. Initial vital signs were stable and imaging including Computerized Tomography of the femur and lumbar spine showed L5/S1 lumbar radiculopathy and degenerative disc disease. Lower extremity ultrasound did not reveal deep venous thrombosis. She was treated with symptomatic pain management. She subsequently presented after 6-weeks without any improvement in her pain symptoms. Her investigations revealed HbA1c 12.4%, glucose ranging between 250-400 mg/dL, CK 531 U/L, ESR 113 mm/h, ferritin 255 and a negative serologic workup including RF, ANA and myositis autoantibody panel. Additionally, she had a markedly elevated TSH 97.86uIU/mL with free T4 0.6ng/dL. However, clinically there was no focal weakness and sensations were intact thus inconsistent with the proximal myopathy of hypothyroidism. A bone scan was performed and was normal thus excluding concerns for breast cancer related bone metastasis. Ultimately, T1 and T2 weighted Magnetic Resonance Imaging(MRI) demonstrated abnormal signal in the vastus lateralis, medialis and quadriceps femoris muscle bellies with irregular peripherally enhancing fluid collections upon administration of Dotarem contrast, consistent with a diagnosis of diabetes myonecrosis. The patient was managed with intense glycemic control, initiated on low-dose aspirin and physical therapy to assist with safe mobilization, leading to a gradual improvement in symptoms over several weeks. The patient did not follow with physical therapy as advised. Subsequent MRI in 2 months demonstrated the presence of persistent inflammatory changes and mild extension to the biceps femoris. Clinically, the patient continued to improve with optimization of diabetic control achieving reduced HbA1c of 8.4% at 3-month follow-up.
Discussion: The hurdles to diagnosis pivot around non-specific presentations and wide differential diagnoses thus necessitating a high diagnostic suspicion in a diabetic patient. Typical presentation is with acute onset non-traumatic muscular pain with laboratory work up revealing high inflammatory markers, supportive MRI findings and exclusion of local infection and thromboembolic disease (2,3). Muscle biopsy is not routinely performed and conservative treatment offers good short-term prognosis with the resolution of symptoms. However, long term prognosis remains poor with high recurrence rates in over one-third of the cases specifically with end-stage renal disease patients. Conservative treatment includes rest, analgesia, and intense glycemic control. Aspirin and NSAIDs are recommended due to antithrombotic effects and improvement of endothelial dysfunction. Surgical intervention is not routinely advised.
Conclusions: Diabetic myonecrosis is a rare disorder and we are yet to identify any factors or comorbidities that contribute to the development or eventual prognosis. In all diabetic patients presenting with acute atraumatic focal muscular pain, the diagnosis of diabetic myonecrosis should be considered.