Proximal Neuropathy – Causes, Signs and symptoms

Proximal neuropathy

Also called: Lumbosacral Plexus Neuropathy, Diabetic Amyotrophy, Bruns Garland Syndrome, Amyotrophy

Summary

Proximal neuropathy is a type of nerve damage that causes pain and weakness in the hips, thighs and buttocks. The symptoms may grow more severe as the condition worsens. For many people, proximal neuropathy interferes with the ability to stand from a sitting position.

Proximal neuropathy is usually asymmetrical, causing problems on only one side of the body. The pain and weakness associated with this condition is often accompanied by unexplained weight loss. The type, severity and duration of the symptoms from proximal neuropathy vary according to the specific nerve damage.

Most cases of proximal neuropathy occur as a complication of diabetes. It is less common than other forms of diabetic neuropathy, including peripheral neuropathy and autonomic neuropathy. It is most commonly found with type 2 diabetes but can also result from type 1 and other forms of diabetes.

The exact cause of proximal neuropathy is unknown. As with other diabetic nerve damage, it is believed to be linked to uncontrolled glucose (blood sugar). The longer the glucose is unstable, the greater the chance for developing neuropathy. The condition is diagnosed after a physical examination by a physician and several diagnostic tests.

There is no cure for the nerve damage of proximal neuropathy. Treatment focuses on controlling glucose to alleviate or eliminate the symptoms. Physicians frequently prescribe medications for pain relief and physical therapy for muscle strengthening. The best way to delay or prevent the onset of this condition is to control glucose and maintain a healthy lifestyle with proper diet, exercise and quitting smoking.

About proximal neuropathy

Proximal neuropathy is sensory and motor nerve damage to the peripheral nervous system (PNS) affecting primarily the hip and thigh area.

Within the body, the nervous system is made up of two main divisions: the central nervous system (CNS) and the (PNS). The CNS consists of the brain and the spinal cord. The PNS connects the brain and spinal cord to the rest of the body. These two systems control movement and sensation in the body.

Within the peripheral nervous system, the basic units are neurons (nerve cells). These cells have bundles of fibers classified as:

  • Motor fibers. These nerves carry messages from the central nervous system to organs and muscles. When the muscle receives the message it reacts with an action or movement. Motor neurons are responsible for voluntary movements (those the body can control).

  • Sensory fibers. These nerves carry messages from sensory receptors throughout the body. The messages, or nerve impulses, provide information about physical feelings such as pain and temperature. The messages are sent from the body to the central nervous system in the spinal cord and brain.

  • Autonomic fibers. These nerves are involved with the involuntary functions of the body (things that typically are not consciously controlled). These functions include breathing, regulation of blood pressure, sweating, digestion and bladder control. The autonomic nerves help control these functions whether the individual is awake or asleep.

Proximal neuropathy affects the motor or sensory nerves in the body. It does not affect the autonomic nerves that control the involuntary systems in the body. The problems from this neuropathy vary depending on which nerves are damaged. The symptoms from this condition are caused by related damage to:

  • Motor nerves (involved with muscle function). Damage to these nerves can result in muscle weakness, poor coordination and reduced movement.

  • Sensory nerves (involved with the feeling of sensations). Damage to these nerves may result in tingling, pain or numbness. These problems are less common than the motor nerve damage.

Proximal neuropathy most commonly occurs in people with diabetes over the age of 50, but can also appear in youth. It is less common than some other forms of diabetic neuropathy (e.g., peripheral, autonomic).

Diabetic neuropathy is believed to be caused by several changes in the nerves. When the nerves are surrounded by a high level of glucose (blood sugar), they adjust their inner workings to be in balance with their surroundings. To create this balance, the nerve cells produce and store a sugar called sorbitol. The sorbitol damages the nerve cells, resulting in problems such as pain, numbness or motor weakness. In addition, the nerves may be damaged when they do not receive enough oxygen from the surrounding blood vessels.

The condition is more common in people with type 2 diabetes than those with type 1 diabetes. There is no difference between males and females or ethnic groups in the risk of developing this neuropathy.

As with other neuropathies, poorly controlled glucose is considered to be a factor in the onset of proximal neuropathy. Some people with diabetes may have an underlying peripheral neuropathy that can cause additional problems. Others may have no symptoms other than those associated with proximal neuropathy. Proximal neuropathy can last from several weeks to more than a year, depending on the type and severity of the nerve damage.

According to the American Diabetes Association (ADA), individuals who have had diabetes for 25 years or more have a 60 to 70 percent chance of developing some form of neuropathy. Although proximal neuropathy is not a common form of nerve damage, it can cause considerable pain and weakness. Studies have shown that tight control of glucose can reduce or eliminate symptoms of diabetic neuropathy.

Potential causes of proximal neuropathy

Scientists do not know the exact cause of proximal neuropathy. Poorly controlled glucose (blood sugar) is known to be a contributing factor in development of all forms of diabetic neuropathy. High glucose (hyperglycemia) appears to have a chemical reaction with the nerves or cells around the nerves. This reaction damages the nerves, causing poor transmission of signals between the body parts and the brain.

Uncontrolled glucose can also directly damage the blood vessels (diabetic angiopathy). The resulting poor circulation has also been linked to neuropathy. The blood vessels carry oxygen and nutrients to the nerves, which keeps them healthy. Without proper blood flow, the nerves do not receive these elements from the blood and can die. An active lifestyle helps promote a healthy heart and good circulation. Proximal neuropathy occurs more frequently in older individuals who are not always able to remain active.

Smoking and alcohol use are associated with all diabetic neuropathies. Though modest use of alcohol has been found to have some health benefits, it is a nerve toxin, causing harm to the nerves in the body. Smoking causes damage by:

  • Lowering the amount of oxygen that reaches tissues
  • Constricting the blood vessels
  • Increasing blood pressure
  • Raising glucose levels

Although poorly controlled glucose is linked to neuropathy, proximal neuropathy often appears in people with diabetes with only mildly elevated glucose levels. In addition, significant unexplained weight loss commonly occurs with proximal neuropathy. Researches are not sure how these two factors contribute to the development of the condition. It is clear, though, that most people with diabetes with proximal neuropathy have difficulties controlling their glucose, regardless of the level.

Signs and symptoms of proximal neuropathy

Proximal neuropathy is a disabling condition which causes significant problems primarily in the legs, hips and buttocks. The first sign of this condition is usually a pain or weakness in the legs, most commonly in the thigh. It occurs on one side and gradually becomes more severe.

As the neuropathy progresses, symptoms may include:

  • One-sided pain in hip, buttock or thigh
  • Muscle weakness in the lower limb
  • Problems moving from sitting to standing or climbing stairs
  • Motor problems greater than sensory problems

The most common symptom of individuals with advanced proximal neuropathy is related to weakness of the thigh muscles. People with diabetes and this condition have particular difficulty rising up from a squatting position. They often need assistance to rise from a seated position and they may be unable to climb stairs.

Pain is a common complaint of people who have neuropathy. Individuals often require treatment for pain relief. The length of the recovery period for proximal neuropathy varies with the type of nerve damage.

Significant unexplained weight loss is also frequently reported with individuals who develop proximal neuropathy. It is not uncommon to lose 10 to 40 pounds with this neuropathy. Scientists are unsure as to the reason for the weight loss in conjunction with the proximal neuropathy.

In general, the symptoms from proximal neuropathy may last from several weeks to more than a year. For patients with diabetes, close control of glucose (blood sugar) can reduce the length and severity of symptoms.

Diagnosis methods for proximal neuropathy

Diagnosis of proximal neuropathy requires a physician’s review of an individual’s medical history, symptoms and a physical examination.

Review of the medical history includes:

  • Family history of diabetes and complications
  • Diagnosis and duration of diabetes
  • Glucose (blood sugar) levels
  • Onset of symptoms
  • Previous distal neuropathies (neuropathy in the hands and/or feet)
  • Weight history
  • Smoking and use of alcohol
  • Other medical complications

When assessing the symptoms of proximal neuropathy, the physician focuses on:

  • Type of difficulties (pain, numbness or weakness)
  • Severity of difficulties
  • Location of problems in the body
  • Slow or sudden onset of problems
  • Unexplained weight loss
  • Particular motor problems

After reviewing the medical history and symptoms with the patient, the physician conducts a physical examination. Particular attention is paid to the leg, thigh and buttock areas for motor weakness and pain. These are the parts of the body most affected by proximal neuropathy. The physician may check the reflexes in the knee or ankle as they are often absent with this condition. A nutritional assessment may be included if weight loss and glucose control are issues.

Several tests may be administered to further assess nerve and muscle damage for the diagnosis of proximal neuropathy. These tests may include:

  • Nerve conduction velocity. Small electrodes are placed on the arms and legs and an electric current is sent into the nerve. These impulses create a tingling sensation and usually are not painful. The physician checks for a slow or weak response to the current which indicates nerve damage in that area.

  • Electromyography (EMG). Small, thin needles are inserted into muscles and responses are recorded on an EMG machine. Although there may be some pain when the needle is inserted, it usually becomes less painful as the test is conducted. No electrical shocks or injections are given through the needle. The needle measures slower or weaker responses indicating muscle damage as the result of neuropathy.

  • Quantitative sensory testing (QST). Hot, cold and vibrating stimulations are placed on the body to measure sensation. The individual indicates when any sensation is felt as a result of the stimulation. There are no electrical shocks or needles in this test. The responses are used to evaluate the function of the small and large nerve endings, which may be damaged from neuropathy.

  • Nerve biopsy or skin biopsy. Minor surgical procedures remove a sample of nerve or skin tissue for laboratory analysis. A skin biopsy is common but a nerve biopsy is more complicated and used only in certain circumstances. Examination of the tissue can help identify nerve degeneration from neuropathy and confirm specific conditions.

Based on the results of the physical examination and diagnostic tests, the physician may refer the person with diabetes to specialists for further evaluation and treatment. These specialists include:

  • Neurologist (for nervous system disorders)
  • Orthopedist (for skeletal and muscle disorders)
  • Podiatrist (for foot care)
  • Registered dietician (for nutrition problems)

Treatment and prevention

As with other forms of neuropathy, treatment of proximal neuropathy first focuses on the underlying condition. For patients with diabetes, this starts with the control of glucose (blood sugar). Normal or near-normal glucose can help prevent or delay the onset of proximal neuropathy, and lessen the severity of the symptoms and the length of time that symptoms occur.

Quitting smoking has numerous benefits including improved control of glucose and blood pressure. Limiting consumption of alcohol will help protect the nerves from alcohol’s toxic effects. 

Motor weakness in the legs is the most common deficit present with proximal neuropathy. Physical therapy and occupational therapy may be prescribed by a physician. A physical therapist can address strengthening and recommend equipment, such as a cane or walker, to help an individual with movement. An occupational therapist can provide recommendations for devices around the home that can help with daily tasks. These adaptive devices may include self-rising chairs and elevated toilet seats. Because lowering and rising from squatted position is difficult for individuals with proximal neuropathy, these pieces of adaptive equipment can be helpful.

Treatment for pain relief may include:

  • Over-the-counter medications, such as aspirin or other anti-inflammatory drugs

  • Analgesic topical creams with capsaicin (numbing effect)

  • Antidepressant and antiseizure medications (shown to be effective with more severe pain from neuropathy)

  • Physical therapy

The treatment of proximal neuropathy varies according to the type and severity of nerve damage. A combination of treatment methods may be necessary to relieve pain and improve motor functioning.

Questions for your doctor

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about proximal neuropathy:

  1. Could my thigh pain, leg weakness and unexpected weight loss be due to proximal neuropathy? What else could be causing these symptoms?
  2. Do I have or am I at risk of developing proximal neuropathy?
  3. What tests might I need, and what do they involve?
  4. Is my proximal neuropathy caused by diabetes, or is it caused or exacerbated by another condition?
  5. How can proximal neuropathy affect me?
  6. How long is my condition likely to last?
  7. What treatments do you recommend for my proximal neuropathy?
  8. Is there any equipment that will improve my mobility and ability to function?
  9. Can I prevent or reduce my risk of proximal neuropathy?
  10. Do I also have any other forms of diabetic neuropathy?
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