Diabetic myonecrosis is a rare complication of diabetes. It is caused by infarcted muscle

Muscle

Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 tissue, usually in the thigh.

Epidemiology

The mean age at presentation is thirty-seven years with a reported range of nineteen to sixty-four years. The mean age of onset since diagnosis of diabetes is fifteen years. The female:male ratio is 1.3:1. Other diabetic complications such as nephropathy

Nephropathy

Nephropathy refers to damage to or disease of the kidney. An older term for this is nephrosis.-Causes:Causes of nephropathy include administration of analgesics, xanthine oxidase deficiency, and long-term exposure to lead or its salts...

, neuropathy, retinopathy

Retinopathy

Retinopathy is a general term that refers to some form of non-inflammatory damage to the retina of the eye. Frequently, retinopathy is an ocular manifestation of systemic disease.-Pathophysiology:Causes of retinopathy are varied:...

 and hypertension

Hypertension

Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

 are usually present. Its major symptom is the acute onset muscle pain, usually in the thigh, in the absence of trauma. Signs include exquisite muscle tenderness and swelling.

Investigations and diagnosis

Tissue biopsy

Biopsy

A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

 is the gold standard

Gold standard (test)

In medicine and statistics, gold standard test refers to a diagnostic test or benchmark that is the best available under reasonable conditions. It does not have to be necessarily the best possible test for the condition in absolute terms...

. Macroscopic

Macroscopic

The macroscopic scale is the length scale on which objects or processes are of a size which is measurable and observable by the naked eye.When applied to phenomena and abstract objects, the macroscopic scale describes existence in the world as we perceive it, often in contrast to experiences or...

ally this reveals pale muscle tissue. Microscopic

Microscopic

The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye and which require a lens or microscope to see them clearly.-History:...

ally infarcted patches of myocytes. Necrotic muscle fibers are swollen and eosinophilic

Eosinophilic

Eosinophilic refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

 and lack striations and nuclei. Small-vessel walls are thickened and hyalinized

Hyaline

The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...

, with luminal

Luminal

Luminal may refer to:* A trade name for the anti-epileptic drug phenobarbital* Luminal , a 2004 film by Italian director Andrea Vecchiato starring Denis Lavant* In biology, pertaining to the lumen, the interior of a hollow structure...

 narrowing or complete occlusion. Biopsy cultures for bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, fungi, acid-fast bacilli and stains are negative in simple myonecrosis.

Creatine kinase

Creatine kinase

Creatine kinase , also known as creatine phosphokinase or phospho-creatine kinase , is an enzyme expressed by various tissues and cell types. CK catalyses the conversion of creatine and consumes adenosine triphosphate to create phosphocreatine and adenosine diphosphate...

 is found to be normal. ESR

Erythrocyte sedimentation rate

The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...

 is elevated. Planar X-ray reveals soft tissue swelling and bone scan

Bone scan

A bone scan or bone scintigraphy is a nuclear scanning test to find certain abnormalities in bone which are triggering the bone's attempts to heal. It is primarily used to help diagnose a number of conditions relating to bones, including: cancer of the bone or cancers that have spread to the bone,...

 shows non specific uptake. CT

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

 shows muscle oedema with preserved tissue planes (non-contrast enhancing). MRI shows increased signal on T2 weighted images within areas of muscle oedema. Arteriography reveals large and medium vessel arteriosclerosis occasionally with dye within the area of tissue infarction . Electromyography

Electromyography

Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...

 shows non specific focal changes.

Treatment

Treatment includes supportive care with analgesics and anti-inflammatory

Anti-inflammatory

Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids, which affect the central nervous system....

 agents. Exercise should be limited as it increases pain and extends the area of infarction. Symptoms usually resolve in weeks to months, but fifty percent of sufferers will experience relapse in either leg. The majority diagnosed with diabetic myonecrosis die within 5 years.http://www.metrohealth.org/documents/patient%20services/MedPeds/DiabeticMyonecrosis.pdf

Pathophysiology

The pathogenesis of this disease is unclear. Arteriosclerosis

Arteriosclerosis

Arteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries It should not be confused with "arteriolosclerosis" or "atherosclerosis".Also known by the name "myoconditis" which is...

 obliterans has been postulated as the cause, along with errors of the clotting and fibrinolytic pathways such as antiphospholipid syndrome

Antiphospholipid syndrome

Antiphospholipid syndrome or antiphospholipid antibody syndrome , often also Hughes syndrome, is an autoimmune, hypercoagulable state caused by antibodies against cell-membrane phospholipids that provokes blood clots in both arteries and veins as well as pregnancy-related complications such as...

.

Differential Diagnosis

A large number of conditions may cause symptoms and signs similar to diabetic myonecrosis and include: deep vein thrombosis

Deep vein thrombosis

Deep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...

, thrombophlebitis

Thrombophlebitis

Thrombophlebitis is phlebitis related to a thrombus . When it occurs repeatedly in different locations, it is known as "Thrombophlebitis migrans" or "migrating thrombophlebitis".-Signs and symptoms:...

, cellulitis

Cellulitis

Cellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,...

, fasciitis

Fasciitis

In medicine, fasciitis refers to an inflammation of the fascia. In particular, it often refers to one of the following diseases:* Necrotizing fasciitis* Plantar fasciitis* Eosinophilic fasciitis* Paraneoplastic fasciitis...

, abscess

Abscess

An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...

, haematoma, myositis

Myositis

Myositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...

, pseudothrombophlebitis

Pseudothrombophlebitis

Pseudothrombophlebitis syndrome is a clinical condition where there are signs and symptoms of phlebitis in the absence of a thrombophlebitis lesion. Symptoms include pain, swelling, erythema and tenderness evolving over hours or days...

 (ruptured synovial cyst), pyomyositis

Pyomyositis

Pyomyositis, also known as tropical pyomyositis or myositis tropicans, is a bacterial infection of the skeletal muscles which results in a pus-filled abscess. Pyomyositis is most common in tropical areas but can also occur in temperate zones....

, parasitic myositis, osteomyelitis

Osteomyelitis

Osteomyelitis simply means an infection of the bone or bone marrow...

, calcific myonecrosis, myositis ossificans, diabetic myotrophy, muscle strain or rupture, bursitis

Bursitis

Bursitis is the inflammation of one or more bursae of synovial fluid in the body. The bursae rest at the points where internal functionaries, such as muscles and tendons, slide across bone. Healthy bursae create a smooth, almost frictionless functional gliding surface making normal movement painless...

, vasculitis

Vasculitis

Vasculitis refers to a heterogeneous group of disorders that are characterized by inflammatory destruction of blood vessels. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis...

, arterial occlusion, haemangioma, lymphoedema, sarcoidosis

Sarcoidosis

Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...

, tuberculosis

Tuberculosis

Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

, cat-scratch disease, amyloidosis

Amyloidosis

In medicine, amyloidosis refers to a variety of conditions whereby the body produces "bad proteins", denoted as amyloid proteins, which are abnormally deposited in organs and/or tissues and cause harm. A protein is described as being amyloid if, due to an alteration in its secondary structure, it...

, as well as tumours of lipoma

Lipoma

A lipoma is a benign tumor composed of adipose tissue. It is the most common form of soft tissue tumor. Lipomas are soft to the touch, usually movable, and are generally painless. Many lipomas are small but can enlarge to sizes greater than six centimeters. Lipomas are commonly found in adults...

, chondroma

Chondroma

A chondroma is a benign cartilaginous tumor, which is encapsulated with a lobular growing pattern.Tumor cells resemble normal cells and produce the cartilaginous matrix ....

, fibroma

Fibroma

Fibromas are benign tumors that are composed of fibrous or connective tissue. They can grow in all organs, arising from mesenchyme tissue. The term "fibroblastic" or "fibromatous" is used to describe tumors of the fibrous connective tissue...

, leiomyoma

Leiomyoma

A leiomyoma is a benign smooth muscle neoplasm that is not premalignant. They can occur in any organ, but the most common forms occur in the uterus, small bowel and the esophagus.- Etymology:* Greek:** λεῖος leios "smooth"...

 and sarcoma

Sarcoma

A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...

.