Diabetic Neuropathy
Diabetic neuropathy is a form of peripheral nerve damage caused by long-standing and inadequately controlled diabetes mellitus. The condition leads to a gradual loss of nerve-fiber function and is one of the most common late complications of both type 1 and type 2 diabetes. Studies indicate that up to 51% of people with diabetes develop neuropathic changes to varying degrees.²,³,⁴ Clinical manifestations vary considerably, ranging from asymptomatic sensory impairment to marked neuropathic pain, burning sensations and numbness. Diabetic neuropathy is strongly associated with serious complications such as foot ulcers, amputations and increased mortality.⁵,⁶
Anatomy and Pattern of Involvement
The peripheral nervous system includes all neural structures outside the central nervous system, including cranial and spinal nerves. Peripheral nerves contain both sensory and motor fibers that supply muscles, skin and organs. In diabetic neuropathy, nerve fibers undergo distal, symmetrical degeneration, particularly in the lower limbs. The process typically begins in the feet and gradually progresses proximally, producing the characteristic 'stocking-and-glove' distribution of sensory symptoms.⁸
Pathophysiological Mechanisms
The exact cause of diabetic neuropathy is not fully understood and is considered multifactorial. Chronic hyperglycemia, together with lipid abnormalities and microangiopathy, contributes to oxidative stress, mitochondrial dysfunction, neural inflammation and cell death.⁶,⁹ This pathological cascade reduces nerve conduction and contributes to a gradual loss of both sensory and motor function. Blood flow to peripheral nerves is also impaired, adding an ischemic component to nerve injury.
Risk Factors
The development and progression of diabetic neuropathy are influenced by several modifiable and non-modifiable factors:
Poor glycemic control
Hypertension
Smoking
Long duration of diabetes
High alcohol consumption
Increasing age
Greater body height (longer peripheral nerves may be more vulnerable)¹⁰,¹¹
Clinical Presentation
More than half of patients with diabetic neuropathy present with distal symmetrical polyneuropathy, the most common subtype.¹² Sensory symptoms occur bilaterally and begin distally in the extremities. Other variants include focal neuropathies such as carpal tunnel syndrome, reported in approximately 14–30%, as well as plexopathies, radiculopathies and selected cranial neuropathies.¹³,¹⁴
Common symptoms include:¹⁵
Numbness or reduced sensation in the feet and hands
Paresthesia ('tingling' or 'burning')
Neuropathic pain, often described as burning, stabbing or shooting
Dry, cracked skin and callus formation, particularly on the feet
Motor impairment, such as foot drop or tripping during walking
Increased risk of ulceration, particularly when reduced pain sensation allows pressure injuries to go unnoticed
The condition may develop insidiously and remain asymptomatic in its early stages, highlighting the importance of routine screening and neurological examination in people with diabetes.
Diagnosis and Treatment of Diabetic Neuropathy
Diagnosis is based on a combination of medical history, clinical examination and, when indicated, neurophysiological testing. A thorough subjective history should include symptoms, previous foot ulcers, skin changes and any history of trauma to the feet.¹⁶ Objective assessment should systematically examine skin condition, foot anatomy and peripheral circulation because these factors influence wound healing and the risk of complications.
Light touch and pain responses can be tested with simple tools such as a monofilament, cotton wool or a pinprick. Vibration sense is commonly assessed with a 128-Hz tuning fork placed over the base of the great-toe nail.⁸,¹⁷ Deep tendon reflexes, particularly the Achilles reflex, are often reduced or absent and may be an early sign of peripheral sensory neuropathy.¹⁸ When more extensive or atypical involvement is suspected, nerve-conduction studies or electromyography (EMG) can be used to assess the severity and distribution of neural injury.¹⁹
Classification and Stages
Diabetic neuropathy can be divided into four main types:²⁰
Peripheral neuropathy (distal symmetrical polyneuropathy): The most common form, with sensory involvement in a stocking-and-glove pattern.
Proximal neuropathy (diabetic amyotrophy): Typically affects the hip and thigh and is often asymmetric and painful.
Autonomic neuropathy: Affects autonomic functions such as heart rate, blood pressure and digestion.
Focal or multifocal neuropathy: Includes mononeuropathies such as carpal tunnel syndrome and cranial nerve palsies.
Severity can be graded from N0 to N3:²¹
N0: No signs or symptoms
N1a: Clinical findings without subjective symptoms
N2a: Mild symptoms, with the patient still able to walk on the heels
N2b: More severe symptoms with reduced ability to heel-walk
N3: Disabling neuropathy with substantial functional loss
Medical Management
The first step in medical management is optimization of glycemic control, which is especially important in type 1 diabetes.²² Lifestyle interventions such as physical activity and weight management are also part of standard care and can benefit both glucose control and neuropathic symptoms.
Painful neuropathy is often treated with medications such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors such as duloxetine, and anticonvulsants such as pregabalin or gabapentin.²³ There is currently no curative pharmacological treatment that reliably reverses established neuropathy, although this remains an active area of research.²⁴ Multidisciplinary follow-up is essential for preventing and managing foot complications and may involve physicians, podiatrists, diabetes nurses and physiotherapists.⁶
Physiotherapy and Exercise
Physiotherapy plays an important role in the management of diabetic neuropathy. Through targeted exercise and individualized interventions, physiotherapists can address reduced muscle strength, impaired balance, neuropathic pain and increased fall risk. Several studies suggest that structured exercise, particularly resistance and aerobic training, can improve physical function and may positively affect neuropathic symptoms, glucose control and quality of life.²⁵,²⁶
To make exercise safe and effective, appropriate precautions are required. These include monitoring blood glucose before, during and after activity when clinically relevant and having rapid-acting carbohydrates available when needed to prevent or treat hypoglycemia.²⁷ Footwear and foot status should also be assessed carefully because reduced sensation and an increased risk of ulceration require safe, well-adapted loading conditions.
A comprehensive exercise program should be individualized and may include the following components:
Flexibility and Range of Motion
Progressive stretching can help maintain range of motion in major joints, which may become restricted because of neuropathy, inactivity or associated musculoskeletal changes. Particular attention may be given to the ankles, hips and shoulders. Examples include:
Seated hamstring stretch: Hold for 30–60 seconds, 2–3 repetitions per leg.
Soleus stretch against a wall: Stand with the knee slightly bent and the heel on the floor to target the deeper calf musculature.
Plantar fascia and great-toe stretch: May be useful in patients with altered foot mechanics.
Strength Training
Neuropathy can lead to distal muscle weakness, particularly in the ankle dorsiflexors and intrinsic foot muscles. This may contribute to foot drop, reduced push-off and altered gait. Strengthening can use body weight, resistance bands, machines or free weights and may incorporate isometric, concentric and eccentric loading as tolerated. Examples include:
Standing calf raises (gastrocnemius and soleus): 3 sets of 10–15 repetitions, with load increased gradually when appropriate.
Resisted dorsiflexion with a band (tibialis anterior): 3 sets of 15 repetitions.
Seated knee extension with ankle weight (quadriceps): 2–3 sets of 12 repetitions.
Single-leg glute bridge: Useful for gluteal strength and pelvic control when appropriate for the patient's ability.
Aerobic Exercise
Aerobic exercise can improve cardiovascular fitness and glycemic regulation. It may also support peripheral circulation and general function. Exercise is commonly prescribed at moderate intensity, approximately 40–70% of VO₂ max, 3–5 times per week, adjusted for comorbidities, fitness and foot status. Examples include:
Brisk walking on a treadmill or outdoors: Begin with 10–15 minutes and increase gradually.
Cycling (stationary or conventional bicycle): Provides cardiovascular training with relatively low joint impact.
Aquatic exercise or swimming: Reduces loading on the feet and joints while allowing effective aerobic exercise.
Balance and Postural Control
Reduced sensory input from the feet can impair balance and increase fall risk. This is particularly relevant in older adults with diabetic neuropathy. Training that challenges balance and body awareness can therefore be an important component of rehabilitation. Examples include:
Single-leg stance with support: 3 × 30 seconds. Progression may include reducing hand support, closing the eyes only when safe, or using a more challenging surface under supervision.
Tandem stance and line walking: Focus on foot placement and controlled weight transfer.
Balance board or BOSU exercises: Use in a controlled environment with appropriate support.
Mini-squats on an uneven surface: Increase demands on proprioception and lower-limb strength.
Gait and Proprioceptive Training
People with neuropathy often develop altered gait patterns because of reduced sensation, weakness and pain. Changes may include shorter steps, reduced push-off, a wider base of support and reduced arm swing. The goal is to improve functional walking and reduce unnecessary energy expenditure. Examples include:
Video gait analysis: Used to identify deviations and guide individualized interventions.
Gait drills focusing on step length and rhythm: A metronome or rhythmic verbal cues may be used when helpful.
Walking practice with visual or auditory feedback: For example, floor markers can provide external cues for foot placement.
Proprioceptive training emphasizing foot contact and controlled weight transfer: Examples include lateral weight shifts and stepping over obstacles.
Other Interventions
Orthoses and assistive devices: An ankle-foot orthosis (AFO) may be used for foot drop to improve toe clearance and reduce the risk of tripping. Wrist orthoses may be useful when carpal tunnel syndrome coexists, helping reduce mechanical stress on the median nerve.
Foot-care education and pressure off-loading: Patients should be educated about ulcer prevention, including appropriate footwear, daily inspection of the feet and warning signs of skin breakdown or infection.
Follow-up and Progression
All interventions should be reviewed regularly. The physiotherapist should adjust exercise load according to the patient's response and progress the program when appropriate. The plan must also be realistic and sustainable. Many people with diabetic neuropathy have comorbidities such as osteoarthritis, obesity or cardiovascular limitations that need to be considered when selecting and progressing exercise.
Further exercise programming can be individualized according to symptom severity, functional level, comorbidities and treatment goals.
Physiotherapy Management of Pain in Diabetic Neuropathy
Physiotherapy can contribute to pain management and functional improvement in diabetic neuropathy. Treatment aims to reduce neuropathic pain, support circulation and preserve nerve-related function while restoring movement strategies and physical capacity. Several non-pharmacological modalities have been studied for painful diabetic neuropathy, particularly as adjuncts to structured exercise and multidisciplinary care.
Interventions that have been investigated include:
Transcutaneous electrical nerve stimulation (TENS): Low-frequency electrical stimulation applied through the skin has shown short-term analgesic effects in some patients with peripheral neuropathy. Proposed mechanisms include modulation of nociceptive signaling through gate-control mechanisms and activation of endogenous inhibitory systems.³⁵
Massage: Gentle to moderate massage of the lower limbs may improve comfort and temporarily reduce muscle tension, and some studies report subjective pain relief in people with neuropathic pain.³⁶
Static magnetic field therapy: Some studies have reported reductions in pain, but the mechanism remains uncertain and the evidence is inconsistent; it should therefore not replace established treatment strategies.³⁷
Low-level laser therapy: Low-level laser therapy has been investigated for its potential effects on pain and tissue biology. Clinical findings are mixed, and its role should be considered adjunctive rather than definitive.³⁸
Monochromatic infrared light: This technique uses near-infrared light, often around 890 nm, with the aim of affecting local circulation and sensory function. Some studies have reported reduced pain or numbness, but systematic reviews have found variable results.³⁹
Acupuncture: Acupuncture has been studied as an adjunct for peripheral neuropathic pain and may influence peripheral and central pain modulation. Evidence is heterogeneous, and treatment should be individualized.⁴⁰
These approaches should be considered individually according to the patient's presentation, tolerance, preferences and the quality of available evidence. They are best used as supplements to established medical, exercise-based and preventive management rather than as substitutes for them.
Differential Diagnoses
When evaluating peripheral neuropathy, alternative causes should be considered because several disorders can produce tingling, numbness, burning pain and reduced sensation in the extremities.⁴¹
Autoimmune disorders: Examples include Guillain–Barré syndrome, systemic lupus erythematosus (SLE) and rheumatoid arthritis.
Hereditary neuropathies: For example, Charcot–Marie–Tooth disease.
Infections: Examples include varicella-zoster infection, HIV, hepatitis C and Lyme disease.
Chronic alcohol use: Neuropathy may result from direct toxic effects, nutritional deficiency or both.
Vitamin deficiencies: Particularly deficiencies of vitamins B1 (thiamine), B6 (pyridoxine), B12 (cobalamin), vitamin E and niacin.
Trauma: Peripheral nerve injury may occur after surgery, fractures or other accidents.
Toxin exposure: Examples include heavy metals such as lead or mercury and certain industrial chemicals.
Medications: Certain antibiotics and chemotherapeutic agents can be neurotoxic.
Hypothyroidism: Reduced thyroid function can cause or contribute to neuropathic symptoms.
Vascular disorders: Examples include vasculitis and impaired circulation associated with peripheral arterial disease.
A thorough history, assessment of risk factors and targeted clinical examination are necessary to establish the correct diagnosis and develop an appropriate treatment plan.
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