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 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 nerve A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on ...

. 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

Signs and symptoms 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 ( fasciculations) 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 microvessel disease, in which cells that support the

endothelium The endothelium 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 rest of the vesse ...

(

pericytes Pericytes (previously known as 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 c ...

) are damaged due to

high blood sugar Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...

. Pericytes regulate capillary blood flow and

phagocytosis Phagocytosis () is the process by which a 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 phagocytosis is ...

of cellular debris and ischemia of the nerves can occur if pericytes are damaged. A different potential mechanism involves an immune mechanism causing a microvasculitis 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 conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical spec ...

(NCS) and electromyography (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 partial seizures and neuropathic pain. It is a first-line medication for the treatment of neuropathic pain caused by diabeti ...

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

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 Diabetes Peripheral nervous system disorders