How Diabetic Neuropathy Is Diagnosed and Treated

Diabetic neuropathy is a common complication of diabetes that develops in about 50% of people with the condition. Chronically high blood sugar levels associated with diabetes can cause nerve damage. This nerve damage can lead to burning pain, paresthesia (a feeling of pins and needles), weakness, and numbness (loss of sensation).

Diabetic neuropathy is a chronic, progressive condition. Fortunately, this condition can be managed with medication and lifestyle changes. The most effective medications are drugs that control your diabetes, which helps to slow the progression of this complication.

This article will look at how diabetic neuropathy is diagnosed and treated, including the most effective medication options and the drugs to avoid.

Types of Diabetic Neuropathy

There are four main types of diabetic neuropathy that may develop in relation to diabetes: peripheral, autonomic, proximal, and focal. Some people may experience just one type, while others may develop multiple types.

Peripheral Neuropathy

Peripheral neuropathy refers to damage of nerves that innervate (supply with nerves) the parts of the body located outside the brain and spinal cord. Damage to this vast communication network can lead to symptoms of weakness, numbness, and pain in the hands and feet, although digestion, urination, and circulation may also be affected.

Autonomic Neuropathy

Autonomic neuropathy refers to damage to the nerves that serve your internal organs. These organs help carry out daily functions like digestion, sweating, and urination. Autonomic nerves control largely involuntary functions of the body performed by the bladder, intestinal tract, and genitals, among other organs. This type of neuropathy can manifest in additional health complications, including:

Digestion problems: Damage to the nerves that serve the gut can delay the emptying of the stomach (diabetic gastroparesis) and distort the control of intestinal motility (how waste is moved through the intestines). This can lead to a variety of symptoms such as diarrhea, constipation, intestinal distension (bloating), intestinal blockages, and abdominal pain.

Diabetes neuropathy may also affect the sensory nerves of the gut, and depending on which pathways are involved, your perception of being full or not full may be increased or reduced.

Cardiovascular problems: One of the most overlooked complications of diabetes is cardiovascular autonomic neuropathy (CAN), or damage to the autonomic nerve fibers that innervate the heart and blood vessels. Damage to the nerves that serve the heart can result in abnormalities in heart rate control and vascular dynamics, as well as symptoms of light-headedness, weakness, palpitations, and syncope (loss of consciousness due to a drop in blood pressure) that occurs when standing.

CAN also represents a significant cause of morbidity and mortality in diabetic patients because it is associated with a high risk of cardiac arrhythmias (irregular heartbeats) and sudden death due to the possibility of having a silent heart attack.

Sexual and bladder problems: Damage to the small nerves that serve the genitals in men and women can lead to a wide range of problems. Sexual problems in men with diabetes include erectile dysfunction and retrograde ejaculation (this occurs when semen enters the bladder instead of emerging through the penis during orgasm), whereas sexual problems in women include vaginal dryness, painful intercourse, decreased libido, and decreased or absent sexual response.

Damage to the small nerves that serve the bladder can lead to overactive bladder, urinary retention, urinary tract infections (UTIs), and poor control of sphincter muscles that surround the urethra.

Proximal Neuropathy

Proximal neuropathy involves nerve damage to the hip, buttock, or thigh. It can cause severe pain and muscle shrinkage to the affected area. 

Focal Neuropathy

Diabetic focal neuropathy, also called mononeuropathy, involves damage to a single nerve, usually in the wrist or feet. It is less common than peripheral and autonomic neuropathy. Carpal tunnel syndrome and Bell's palsy are examples of focal neuropathy.

Symptoms of Diabetic Neuropathy

Symptoms of diabetic neuropathy vary depending on the type of neuropathy that you have. Symptoms can range from mild to disabling.

Symptoms of peripheral neuropathy include:

• Burning pain in hands and feet
• Numbness and tingling
• Loss of sensation of pain or temperature
• Sensitivity to touch
• Difficulty walking due to coordination issues
• Muscle weakness
• Sores on the feet due to an inability to notice an injury

Symptoms of autonomic neuropathy depend on the organ that is affected. Common symptoms include: 

• Rapid heart rate
• Dizziness or light-headedness when changing positions
• Bloating and nausea
• Diarrhea or constipation
• Incontinence (loss of bladder control)
• Bladder issues
• Vaginal dryness
• Erectile dysfunction
• Excessive or decreased sweating
• Inability to sense low blood sugar signs
• Double vision (seeing two images at the same time)

Proximal neuropathy can cause:

• Weakness in the affected area
• Muscle loss (atrophy) in the hip, buttock, and leg
• Pain in the hip, buttock, or thigh

Focal neuropathy can cause tingling, pain, or numbness in the body area near the affected nerve, usually in a hand, wrist, or foot.

Causes of Diabetic Neuropathy

Although the exact cause of diabetic neuropathy is unknown, chronically high blood sugar levels have been shown to be toxic to nerves around the body. 

Diagnosing Diabetic Neuropathy

If you have type 1 or type 2 diabetes, getting checked for damage to nerves in your hands, feet, and lower legs, is critical. Early diagnosis can relieve pain, protect your feet from small injuries before they become more serious, and motivate you to keep your blood sugar (glucose) within healthy limits.

Your assessment will start with a healthcare provider taking a thorough history and checking your vitals. Next, they will perform a physical exam. 

A physical exam that emphasizes an assessment of your neurological function, including checking your muscle strength, reflexes, and ability to move, is the first step in assessing your nerve health. 

A healthcare provider may also order some blood tests to rule out other causes of nerve damage. This may include:

• Thyroid hormone levels
• Test for vitamin levels like vitamin B6 and B12 
• Comprehensive metabolic panel 
• Tests for minerals and metals like lead, mercury, and zinc
• Test for markers of inflammation like erythrocyte sedimentation rate and C-reactive protein (CRP)
• Test for markers of autoimmune conditions such as antinuclear antibodies (ANA) that can indicate systemic lupus erythematosus (SLE) and Sjögren’s antibodies that can indicate Sjögren’s syndrome

If your nerve pain cannot be explained by other causes, it becomes more likely that your nerve pain is the result of diabetic neuropathy. 

Other tests that may be used to confirm the diagnosis include a nerve conduction velocity (NCV) test, which measures how long it takes nerves to transmit signals, and electromyography (EMG) tests, which help assess how well muscles are responding to the signals from nerves. These tests are performed by a physiatrist (a doctor trained in physical medicine and rehabilitation). 

Diabetic Neuropathy Medications

Diabetic nerve pain impacts 25% of all diabetics who are treated in the hospital, and an estimated 30%–40% of all people with diabetes. Unfortunately, many people with this condition do not report symptoms or do not seek care in a hospital setting. Therefore, these figures are likely huge underestimations.

Diabetic neuropathy poses a great threat to the quality of life experienced by those with diabetes. Several drugs within various drug classes have been shown to reduce diabetic nerve pain and increase one’s quality of life.

Currently, the anticonvulsant Lyrica (pregabalin), the antidepressant Cymbalta (duloxetine), the opioid Nucynta (tapentadol), and the topical Qutenza (capsaicin) are the only drugs approved by the Food and Drug Administration (FDA) for the treatment of diabetic neuropathy. Other drugs may help to manage symptoms of diabetic neuropathy, although they are not specifically approved to treat the condition.

Anti-Seizure Drugs

• Lyrica (pregabalin): Lyrica is a first-line treatment of diabetic neuropathy. Lyrica inhibits the neurotransmitter gamma-aminobutyric acid (GABA), which is involved in nerve pain, but its exact mechanism of action is not yet completely clear.
  
• Trileptal (oxcarbazepine): While Trileptal has been used in the treatment of diabetic neuropathy, there is little evidence of its effectiveness.
  
• Topamax (topiramate): Topamax works by blocking sodium channels that open and close in response to specific levels of charged chemicals and promote nerve pain. It is a good alternative to nerve-pain medications if you are experiencing side effects or cannot tolerate them.
  

Antidepressants

• Cymbalta (duloxetine): Cymbalta is a first-line treatment of diabetic neuropathy that reestablishes the chemical balance between serotonin and norepinephrine—two important chemicals in physiology and perception of pain.  
• Effexor (venlafaxine): Effexor is a reasonably well-tolerated antidepressant that has been found to reduce the symptoms of neuropathic pain.  
• Tricyclic antidepressants (TCA): Clinical trials have shown that TCAs such as Pamelor (nortriptyline) and Norpramin (desipramine) are effective in decreasing pain perception in those with severe diabetic neuropathy.

Other Nerve Pain Medication

• Ultram (tramadol): There is only low-quality evidence supporting the beneficial effects of Ultram, a muscle relaxer, on moderate or severe neuropathic pain.
  
• Nucynta (tapentadol): Nucynta extended-release is currently the only FDA-approved opioid for neuropathic pain associated with diabetic peripheral nerve pain.
• Neurontin (gabapentin): Neurontin is a commonly prescribed medication in the treatment of diabetic neuropathy, but research has shown that the drug is not more effective than placebo (dummy pills used in studies) for the treatment of diabetic peripheral neuropathic pain.
  

Other Treatment Options

• Botox (botulinum toxin): Currently there is only weak evidence for its effectiveness.
• ProAmatine (midodrine): Diabetic neuropathy in your nerves that control blood pressure can cause dizziness when you stand up, known as orthostatic hypotension. ProAmatine may be used to increase blood pressure in those with diabetes who have orthostatic hypotension. 
  
• Reglan (metoclopramide): Currently, Reglan is the only US FDA-approved medication for the treatment of gastroparesis (delayed stomach emptying). However, the FDA has placed a black box warning (alerting users to its serious safety risks) due to the risk of related side effects, such as tardive dyskinesia (a neurological condition characterized by repetitive involuntary movements, usually involving the tongue or face).
  
• Erectile dysfunction (ED) drugs: Viagra (sildenafil), a phosphodiesterase-5 (PDE5) inhibitor, is an erectile dysfunction drug that works by widening blood vessels and improving blood flow to the penis during sexual arousal, has been shown to promote recovery of peripheral nerve damage in mice, but human trials are needed to show its effectiveness in people. 
  
• Alpha-lipoic acid (ALA): This antioxidant has been shown to reduce inflammation and improve blood flow. In one study, more than 50% of patients with diabetic neuropathy who were treated with 600 milligrams of alpha-lipoic acid over 40 days reported significant improvement in their symptoms and quality of life. ALA is available as an over-the-counter (OTC) supplement, and can be used to complement medical treatments, but consult your healthcare provider before trying.

Topicals

• Qutenza and Zostrix (capsaicin): Qutenza is a prescription patch approved by the FDA for treating diabetic neuropathic pain in the feet. Study results suggest that a high concentration of topical capsaicin, like Qutenza (8%), is safe and effective in treating painful diabetic neuropathy. A lower concentration capsaicin cream, Zostrix (0.1%), is sold over the counter for the express use of decreasing nerve pain symptoms.
  
• Lidoderm (lidocaine) skin patch: The reports on the efficacy of 5% lidocaine skin patches vary. Some report the use of these patches in mild to moderate diabetic neuropathy while other reports claim that there is no credible evidence to support the use of a 5% lidocaine skin patch for pain relief of diabetic neuropathy. 
  
• Cuvposa (glycopyrrolate): Cuvposa blocks cholinergic muscarinic receptors that are involved in diabetic gustatory sweating (sweating from the face while or after eating).

Drugs to Be Avoided

Opioids generally have not been found to help with neuropathic pain. Even more, some medicines have shown that they can worsen peripheral neuropathy. The following antibiotics were included in a safety warning issued by the FDA:

• Cipro (ciprofloxacin)
• Factive (gemifloxacin)
• Levaquin (levofloxacin)
• Avelox (moxifloxacin)
• Noroxin (norfloxacin)
• Floxin (ofloxacin)

Managing Diabetic Neuropathy

Lifestyle Changes

Nerve damage can reduce blood flow throughout the body and disrupt nerve signals, impacting sensation and motor function of the arms, legs, and major organs of the body resulting in a host of symptoms that may range from mild discomfort to severely debilitating. 

The following lifestyle changes can help decrease your symptoms of diabetic neuropathy:

• Manage your diabetes: Maintaining a healthy blood sugar level and practicing proper foot care can reduce neuropathy symptoms and even encourage nerve regeneration. 
• Eat a healthy diet: Eating a low-carbohydrate diet that is rich in fish, nuts, whole grains, and fresh produce helps you to maintain a healthy weight and correct nutritional deficiencies—an important component of diabetes management. A healthy diet may also reduce the effects of peripheral neuropathy and may improve gastrointestinal symptoms such as diarrhea, constipation, or incontinence.
• Avoid excess alcohol: Alcohol worsens peripheral neuropathy so men and women with diabetes should limit their alcohol intake to no more than one drink per day, especially after the age of 65.
• Get regular exercise: Staying on a routine exercise regimen may improve muscle strength, help control blood sugar levels, and prevent muscle loss.
  

Prevention

The following steps may help you prevent diabetic neuropathy:

• Keep your blood glucose levels within a healthy range: Managing your carbohydrate intake and taking your medication and insulin as prescribed are key to keeping your blood glucose levels within a healthy range, which will help prevent nerve damage from developing. 
• Check your blood sugar levels: Use a blood glucose meter and schedule a hemoglobin A1C test (a lab test that measures your average blood sugar levels for the past two or three months) to make sure you can quickly get back on track if you fall off. 
• Protect your feet: Use lotion when your skin is dry, and wear warm socks and shoes whenever possible. 
  

Outlook

While diabetic neuropathy cannot be reversed, you can slow down its progression and improve your symptoms over time. Your general outlook ultimately depends on how well you control your diabetes.

Summary

Diabetic neuropathy is a late manifestation of uncontrolled or long-standing diabetes. Its main symptom is nerve pain. the anticonvulsant Lyrica, the antidepressant Cymbalta, and the opioid Nucynta are the only FDA-approved drugs in the treatment of diabetic neuropathy. However, other nerve pain medications, such as Neurontin, have been shown to reduce nerve pain symptoms and increase quality of life.

A Word From Verywell 

Diabetic neuropathy is a highly treatable condition with oral medications, helping to relieve pain and restore function. However, the best way to limit symptoms and slow the progression of your condition is through strict management of your diabetes.