Diabetic Myonecrosis
Diabetic myonecrosis is also known as diabetic muscle infarction, spontaneous aseptic diabetic muscle infarction and ischemic myonecrosis.8 It is an under-recognized complication of diabetes, with fewer than 200 cases reported in the literature.10 Dr. Schiopu notes that “although [diabetic myonecrosis] is rare, it is important to keep in mind.”
Patients present with acute-onset, painful swelling of an affected muscle. The thigh is most commonly involved, and a palpable mass may be present.9 Myonecrosis is distinct from diabetic amyotrophy (i.e., Bruns-Garland syndrome), in which there is muscle wasting, weakness and pain due to diabetic neuropathy, such as at the lumbosacral plexus.
“Diabetic myonecrosis should always be listed in the differential, especially if a patient has very localized, exquisitely painful swelling and poorly controlled diabetes,” says Dr. Schiopu.
Myonecrosis may be confused with idiopathic inflammatory myopathy (IIM), given the presence of fever in 10% of patients, elevated erythrocyte sedimentation rate in over 50%, creatine kinase (CK) elevations and indistinguishable changes of muscle edema on MRI.9
Sureja et al. described a case of a 59-year-old man who presented with insidious pain in both thighs, resulting in immobility and mimicking IIM.11 MRI showed symmetrical involvement of the thigh muscles with hyperintensities on short-tau inversion recovery imaging, and a CK of approximately 300 U/L. The patient had a similar prior episode and muscle biopsy that showed ischemic necrosis of muscle fibers. Thus, a diagnosis of recurrent diabetic myonecrosis was made. The patient ultimately improved with supportive management over several weeks.
Key distinguishing features from IIM are that diabetic myonecrosis tends to be acute in onset, with only mild elevations in CK, and it is often unilateral, sparing the upper extremities.9 Autoantibodies should be negative, and there will be no additional signs or symptoms of connective tissue disease, such as interstitial lung disease, inflammatory arthritis or cutaneous disease. Dr. Schiopu has found overlying erythema of the affected muscle can occur and may be confused with cellulitis.
Treatment of diabetic necrosis is “very much supportive,” says Dr. Schiopu. Like other musculoskeletal manifestations, it is unclear whether strict diabetes control will have a meaningful impact on prevention, but it is one of few options. Patients will likely need short-term pain control and should engage with physical therapy for muscle strengthening.9
Additional Musculoskeletal Findings in Diabetes
Carpal tunnel syndrome
Carpal tunnel syndrome is an entrapment neuropathy due to compression of the median nerve as it courses through the carpal tunnel. Patients may present with numbness and tingling in the thumb, index and middle finger, and sometimes weakness with thumb abduction.
