Proximal diabetic neuropathy, also known as diabetic amyotrophy, is a complication of diabetes mellitus that affects the nerves that supply the thighs, hips, buttocks and/or lower legs. Proximal diabetic neuropathy is a type of

diabetic neuropathy Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Studies suggests that cutaneous nerve branches, such as the s ...

characterized by muscle wasting, weakness, pain, or changes in sensation/numbness of the leg. It is caused by damage to the nerves of the

lumbosacral plexus The anterior divisions of the lumbar nerves, sacral nerves, and coccygeal nerve form the lumbosacral plexus, the first lumbar nerve being frequently joined by a branch from the twelfth thoracic. For descriptive purposes this plexus is usually d ...

. Proximal diabetic neuropathy is most commonly seen people with type 2 diabetics.National Diabetes Information Clearinghouse (NDIC). (2009, February). ''Diabetic neuropathies: the nerve damage of diabetes''. Retrieved March 20, 2012, from http://diabetes.niddk.nih.gov/dm/pubs/neuropathies/#proximalneuropathy It is less common than distal polyneuropathy that often occurs in diabetes.

Signs and symptoms

Sign A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or me ...

s and

symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

of proximal diabetic neuropathy depend on the nerves affected. The first symptom is usually pain in the buttocks, hips, thighs or legs. This pain often starts suddenly and affects one side of the body, although may spread to both sides. This is often followed by variable weakness in the proximal muscles of the lower limbs such as the thigh and buttocks. The damage to nerves supplying specific muscles may cause muscle twitching (

fasciculation A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more seriou ...

s) in addition to the weakness. It is sometimes associated with weight loss. Diabetes most commonly causes damage to the long nerves that supply the feet and lower legs, causing numbness, tingling and pain ( diabetic polyneuropathy). Although these symptoms may also be present, the pain and weakness of proximal diabetic neuropathy often onset more quickly and affect nerves closer to the torso.

Causes

This condition most commonly affects people with type 2 diabetes, although sometimes presents in those without diabetes (nondiabetic lumbosacral radiculoplexus neuropathy). The population trends suggest that hyperglycemia likely plays a role but may not be the causative factor.Dyck P. J., Winderbank, A. J. (2002). Diabetic and non diabetic lumbosacral radiculoplexus neuropathies. New insights into pathophysiology and treatment. Muscle Nerve, 25, 477–491. The nerve damage associated with the disease was first thought to be caused by metabolic changes such as

endoneurial The endoneurium (also called endoneurial channel, endoneurial sheath, endoneurial tube, or Henle's sheath) is a layer of delicate connective tissue around the myelin sheath of each myelinated nerve fiber in the peripheral nervous system. Its comp ...

microvessel disease, in which cells that support the

endothelium The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the r ...

(

pericytes Pericytes (formerly called Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body. Pericytes are embedded in the basement membrane of blood capil ...

) are damaged due to

high blood sugar Hyperglycemia is a condition where unusually high amount of glucose is present in blood. It is defined as blood glucose level exceeding 6.9 mmol/L (125 mg/dL) after fasting for 8 hours or 10 mmol/L (180 mg/dL) 2 hours after eating. Blood gluco ...

. Pericytes regulate capillary blood flow and

phagocytosis Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs ph ...

of cellular debris and

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

of the nerves can occur if pericytes are damaged. A different potential mechanism involves an immune mechanism causing a

microvasculitis Microvasculitis refers to a range of diseases or presentations associated with a disease, where there is inflammation of small blood vessels: * Kawasaki disease * Susac syndrome Nerve microvasculitis * Non-systemic vasculitic neuropathy (NSVN) * H ...

which could lead to ischemia.

Diagnosis

Patients with diabetes and proximal (hip, thigh) pain and weakness may be suspected of having diabetic amyotrophy. More definitive diagnosis can be made with electrodiagnostic studies including

nerve conduction studies A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called ...

(NCS) and

electromyography Electromyography (EMG) 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 electromyo ...

(EMG).Diabetic Amytrophy. 2014. American Association of Neuromuscular & Electrodiagnostic Medicine. Diabetic amyotrophy is often a diagnosis of exclusion in diabetic patients with evidence of lumbosacral plexopathy on NCS and EMG studies for whom no other cause of lumbosacral plexopathy can be determined.

Treatment

Proximal diabetic neuropathy can be prevented through management of diabetes. The incidence of proximal diabetic neuropathy incidence is thought to be correlated to blood glucose control in diabetics, and is likely reversible with improved blood glucose control. Medications can help reduce the pain involved in proximal diabetic neuropathy. Common types of medication used to treat diabetic amyotrophy target the nerve directly such as

gabapentin Gabapentin, sold under the brand name Neurontin among others, is an anticonvulsant medication primarily used to treat neuropathic pain and also for partial seizures of epilepsy. It is a commonly used medication for the treatment of neuropath ...

pregabalin Pregabalin, sold under the brand name Lyrica among others, is an anticonvulsant, analgesic, and anxiolytic amino acid medication used to treat epilepsy, neuropathic pain, fibromyalgia, restless legs syndrome, opioid withdrawal, generalized anx ...

Prognosis

Proximal diabetic neuropathy is often monophasic and will improve after initial onset. However, the pain and weakness usually do not completely resolve and may lead to impairments in mobility and function.

References

External links

{{Medical resources , MedlinePlus = 000693 , ICD10 = {{ICD10, N, 312, , n, 312 , ICD9 = {{ICD9, 353.5 , OMIM = 603933 , eMedicineTopic = 1170337 Complications of diabetes Peripheral nervous system disorders