Diabetic Diabetic MyonecrosisMyonecrosis

Krista Fajman, MDKrista Fajman, MDJanuary 29, 2010January 29, 2010

Diabetic MyonecrosisDiabetic Myonecrosis Also known as diabetic muscle infarctionAlso known as diabetic muscle infarction Usually affects longstanding poorly Usually affects longstanding poorly

controlled type I diabeticscontrolled type I diabetics In literature reviews, ages ranged from In literature reviews, ages ranged from

18-91 years. Average age at 18-91 years. Average age at presentation is 44.presentation is 44.

Equal distribution between males and Equal distribution between males and females.females.

Not related to trauma.Not related to trauma.

Signs and SymptomsSigns and Symptoms Acute or subacute onset of pain and swelling. Acute or subacute onset of pain and swelling.

Can be mild or severe. May have palpable mass.Can be mild or severe. May have palpable mass. Occurs in the quadriceps > 80% of the time. Occurs in the quadriceps > 80% of the time.

Calf muscles 20% of the time. Rare in upper Calf muscles 20% of the time. Rare in upper extremities.extremities.

Bilateral involvement in 10-30% of cases, Bilateral involvement in 10-30% of cases, recurrence in occurs in 50%.recurrence in occurs in 50%.

May have fever or leukocytosis.May have fever or leukocytosis. CK and ESR elevated in 50% of patients. CK and ESR elevated in 50% of patients.

Elevation does not correlate with disease Elevation does not correlate with disease activity.activity.

Rare if any reports of associated adenopathy, compartment syndrome or gangrene.

Differential DiagnosisDifferential Diagnosis Pyomyositis (due to Pyomyositis (due to Staph aureusStaph aureus)) Spontaneous gangrenous myonecrosis (due to Spontaneous gangrenous myonecrosis (due to Strep Strep

pyogenespyogenes)) Ischemic muscle necrosisIschemic muscle necrosis Clostridial myonecrosisClostridial myonecrosis Necrotizing fasciitisNecrotizing fasciitis DVT, superficial venous thrombosisDVT, superficial venous thrombosis Intramuscular hematomaIntramuscular hematoma Neoplasm (sarcoma or lymphoma)Neoplasm (sarcoma or lymphoma) Focal or systemic myositisFocal or systemic myositis Localized abscessLocalized abscess OsteomyelitisOsteomyelitis CellulitisCellulitis

Diagnostic ImagingDiagnostic Imaging MRI – T2 weighted images show MRI – T2 weighted images show

high intensity signal in affected high intensity signal in affected muscles. T1 images show muscles. T1 images show subcutaneous edema, subfascial subcutaneous edema, subfascial fluid, loss of normal fatty fluid, loss of normal fatty intramuscular septaintramuscular septa Gadolinium can help but caution in Gadolinium can help but caution in

this patient group – likely have this patient group – likely have some degree of renal dysfunction. some degree of renal dysfunction.

X-rays usually unhelpfulX-rays usually unhelpful Ultrasound may show hypoechoic,

well defined intramuscular lesion which may help differentiate from a necrotic mass or abscess but no studies comparing modalities have occurred.

Needle electromyography - may show fibrillation potentials, small motor unit potentials and positive sharp waves, some areas of muscle can by silent indicating replacement of muscle by fibrous tissue.

Muscle BiopsyMuscle Biopsy Grossly presents as nonhemorrhagic, pale,

whitish muscle Light microscopy shows large areas of muscle

necrosis and edema, phagocytosis of necrotic muscle fibers, granular tissue and collagen. May also see occlusion of arterioles and capillaries by fibrin.

At later stages you have replacement of necrotic muscle fibers by fibrous tissue, myofiber regeneration, and mononuclear cell infiltration.

PathogenesisPathogenesis Etiology unclear but thought that muscle infarction arises Etiology unclear but thought that muscle infarction arises

from vascular disease including atherosclerosis and diabetic from vascular disease including atherosclerosis and diabetic microangiopathymicroangiopathy

Chester and Banker – initial ischemic event (?embolic) leads Chester and Banker – initial ischemic event (?embolic) leads to ischemia that causes tissue swelling which through mass to ischemia that causes tissue swelling which through mass effect and swelling compromises blood flow. effect and swelling compromises blood flow.

Small thrombotic/emoblic event leads to ischemic muscle Small thrombotic/emoblic event leads to ischemic muscle damage, causes an inflammatory response, reperfusion with damage, causes an inflammatory response, reperfusion with generation of reactive oxygen species causes further muscle generation of reactive oxygen species causes further muscle damage, muscle edema.damage, muscle edema.

Long standing hyperglycemia may affect arterial Long standing hyperglycemia may affect arterial vasculature, platelets, thrombolytic factorsvasculature, platelets, thrombolytic factors

Some authors feel that abnormality in the coagulation-Some authors feel that abnormality in the coagulation-fibrinolysis system leading to hypercoagulability leads to fibrinolysis system leading to hypercoagulability leads to venous occlusion leading to increased plasma levels of venous occlusion leading to increased plasma levels of plasminogen activatory inhibitor and thrombomodulin.plasminogen activatory inhibitor and thrombomodulin.

TreatmentTreatment No ideal treatment plan.No ideal treatment plan. Rest and analgesics – anti-inflammatory agents Rest and analgesics – anti-inflammatory agents

ideal but caution with NSAIDS depending on ideal but caution with NSAIDS depending on renal function. May need narcotics.renal function. May need narcotics.

Antiplatelet agents. Daily ASA.Antiplatelet agents. Daily ASA. Daily activity okay but may be painful. Physical Daily activity okay but may be painful. Physical

therapy may be harmful.therapy may be harmful. Glycemic controlGlycemic control GlucocorticoidsGlucocorticoids PentoxyfillinePentoxyfilline Surgical excision – not recommended, associated Surgical excision – not recommended, associated

with complicationswith complications

Short term prognosis good. Usually resolves Short term prognosis good. Usually resolves over weeks to months but overall poor prognosis.over weeks to months but overall poor prognosis.

ReferencesReferences Hordon, Lesley. UpToDate Online. “Diabetic Muscle Infarction”Hordon, Lesley. UpToDate Online. “Diabetic Muscle Infarction” Morcuende, J. et al. “Diabetic Muscle Infarcation” The Iowa Morcuende, J. et al. “Diabetic Muscle Infarcation” The Iowa

Orthopaedic Journal. 2000; 20: 65-74.Orthopaedic Journal. 2000; 20: 65-74. Silberstein et al. “An unexpected cause of muscle pain in Silberstein et al. “An unexpected cause of muscle pain in

diabetes”. Annals of Rheumatologic Disease. 2001; 60: 310-312.diabetes”. Annals of Rheumatologic Disease. 2001; 60: 310-312. Trujillo-Santos, A.J. “Diabetic Muscle Infarcation. An Trujillo-Santos, A.J. “Diabetic Muscle Infarcation. An

underdiagnosed complication of long-standing diabetes.” underdiagnosed complication of long-standing diabetes.” Diabetes Care. January 2003. Vol 26. No 1. 211-215.Diabetes Care. January 2003. Vol 26. No 1. 211-215.

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