Peripheral polyneuropathy of the feet
back to main page
Peripheral polyneuropathy of the feet is damage to multiple peripheral nerves, primarily affecting their distal segments, meaning those furthest from the torso. The disorder may involve sensory, motor, and autonomic fibers, which are responsible, respectively, for receiving stimuli, muscle function, and regulating, among other things, sweating and skin microcirculation. The typical clinical presentation is symmetrical and begins in the toes and soles of the feet, gradually moving upwards. The patient may experience tingling, burning, and pain, while simultaneously losing the ability to perceive pressure, temperature, or injury. Polyneuropathy is a distinct neurological entity from limb ischemia, although both disorders can occur simultaneously and significantly increase the risk of foot damage.
Peripheral polyneuropathy of the feet - where does it come from
Polyneuropathy develops as a result of impaired neuronal metabolism, damage to the axon, or the myelin sheath surrounding the nerve fiber. The most common variant is distal symmetric sensorimotor polyneuropathy. Its causes include:
- diabetes, in which chronic hyperglycemia, oxidative stress, the formation of advanced glycation end-products, and microcirculatory damage lead to progressive degeneration of nerve fibers;
- alcohol abuse, which has a toxic effect and promotes B-vitamin deficiencies;
- deficiency of vitamin B₁₂, folic acid, thiamine, vitamin B₆, vitamin E, or copper;
- chronic kidney disease, liver diseases, and hypothyroidism;
- anticancer treatment, particularly using taxanes, vinca alkaloids, platinum derivatives, bortezomib, or thalidomide;
- autoimmune and inflammatory diseases, including vasculitis, Sjögren's syndrome, and chronic inflammatory demyelinating polyneuropathy;
- monoclonal gammopathies, amyloidosis, and selected neoplastic diseases;
- infections, including HIV, hepatitis viruses, and the bacterium Borrelia burgdorferi;
- toxic substances and medications, including heavy metals, certain antibiotics, antiarrhythmic, and antiepileptic drugs;
- genetically determined neuropathies, such as Charcot-Marie-Tooth disease.
Some cases remain idiopathic, meaning without an identifiable cause despite diagnostic evaluation. In a person with diabetes, the diagnosis of diabetic neuropathy also requires the assessment of other potential sources of nerve damage.
Peripheral polyneuropathy of the feet - how does it manifest
The clinical picture depends on the type and diameter of the damaged fibers. Involvement of thin sensory fibers causes burning, prickling, hyperesthesia, paroxysmal electric shock-like pain, and impaired temperature sensation. Damage to large fibers leads to impaired sensation of vibration, touch, and limb position.
The most common symptoms include:
- numbness of the toes and soles;
- tingling and a sensation of „walking on cotton wool”;
- burning or stabbing pain, usually worsening in the evening and at night;
- hypersensitivity to light touch, including contact with bed linen;
- reduced recognition of heat, cold, pressure, and cuts;
- balance disorders, unsteady gait, and more frequent falls;
- weakness of the small muscles of the foot, over time contributing to toe deformities;
- weakening or loss of ankle reflexes;
- dryness, cracking, and impaired thermoregulation of the skin due to autonomic neuropathy.
The symptoms are usually distributed symmetrically in the area referred to as „socks”. Advanced sensory loss can occur without pain. In this situation, the absence of pain in the presence of a wound, burn, or significant pressure is a symptom of impaired protective nerve function, rather than a sign of a mild injury.
Sudden onset, rapid worsening of symptoms, marked asymmetry, foot drop, muscle weakness, sphincter dysfunction, or systemic symptoms require urgent medical evaluation.
Peripheral polyneuropathy of the feet - why it is dangerous for the feet
Protective sensation warns the body against overload, a foreign body, extreme temperature, and disruption of skin integrity. Its loss means that a pebble in a shoe, overly tight footwear, a hot water bottle, or a minor cut can act for many hours without a clear pain signal.
Damage to motor fibers leads to muscle imbalance, the formation of hammer toes, prominence of the metatarsal heads, and altered pressure distribution. A callus builds up in overloaded areas. The callused tissue increases local pressure, under which a hematoma, necrosis, and ulceration can develop.
Autonomic neuropathy reduces sweat secretion. The skin becomes dry, inelastic, and prone to fissures that serve as a portal of infection. The risk of complications is particularly high in the presence of coexisting peripheral arterial disease, diabetes, renal failure, foot deformity, and a prior amputation or ulceration.
Possible consequences include:
- chronic neuropathic ulceration;
- skin and soft tissue infection;
- osteomyelitis;
- Charcot neuroarthropathy, which is the progressive destruction of the bones and joints of the foot;
- gait disturbances and falls;
- amputation of part of the foot or limb.
A warm, red, and swollen foot, a new wound, blister, necrosis, purulent discharge, fever, or rapidly progressing deformity require urgent medical evaluation.
Peripheral polyneuropathy of the feet - what tests to perform
Diagnosis begins with a medical history covering the duration of symptom development, chronic diseases, diet, medications, alcohol consumption, occupational exposure, oncological treatment, and family history of neuropathy. The neurological examination assesses sensation, muscle strength, reflexes, coordination, and gait.
Foot assessment should include:
- inspection of the skin, interdigital spaces, and nails;
- checking for wounds, fissures, calluses, corns, and deformities;
- testing pressure sensation with a ten-gram monofilament;
- assessment of vibration sensation with a one-hundred-twenty-eight-hertz tuning fork;
- assessment of pain, temperature, and toe position sense;
- examination of ankle reflexes;
- assessment of pulses in the foot arteries, skin temperature, and capillary refill time.
Basic laboratory diagnostics usually include a complete blood count, fasting blood glucose, glycated hemoglobin, vitamin B₁₂ levels, thyrotropin, creatinine, liver parameters, electrolytes, and serum protein electrophoresis with immunofixation. The scope of further investigations depends on the clinical picture and may include an oral glucose tolerance test, determination of vitamin B₁₂ metabolites, as well as immunological, infectious, or toxicological tests.
Electroneurography assesses the velocity and amplitude of impulse conduction, while electromyography analyzes muscle activity. These tests help distinguish axonal from demyelinating damage. When small fiber neuropathy is suspected, a skin biopsy with assessment of intraepidermal nerve fiber density or autonomic function tests are used. Symptoms of ischemia are an indication for measuring the ankle-brachial index, toe pressures, and performing an arterial ultrasound examination.
Peripheral polyneuropathy of the feet - how to care for feet
The foundation of prevention is the daily inspection of the entire surface of the feet, including the soles and interdigital spaces. An unbreakable mirror can be helpful. Every day, it is worth checking for the presence of abrasions, blisters, cracks, redness, discharge, color changes, and swelling.
Safe care principles include:
- washing feet in lukewarm water and checking the temperature with a hand or thermometer;
- thoroughly drying the spaces between the toes;
- regularly applying an emollient to dry skin, avoiding the interdigital spaces;
- trimming nails in a nearly straight line and gently smoothing the edges;
- daily inspection of the inside of footwear;
- wearing breathable, sufficiently wide shoes and non-binding socks;
- gradually breaking in new footwear;
- reducing local pressure using custom-fitted insoles or therapeutic footwear;
- regular blood glucose monitoring and treating the cause of neuropathy according to medical recommendations.
Corns, calluses, and thickenings require specialist treatment. Self-use of blades, highly abrasive foot files, keratolytic plasters, and high-concentration acid preparations increases the risk of deep injury. Sources of intense heat, such as a hot water bottle or electric heating pad, can cause burns when temperature sensation is impaired.
Ambasada Urody's preventive foot care offer includes podiatric consultation, basic and advanced podiatry treatments, therapeutic pedicure, and medical diabetic pedicure. Depending on the assessment results, professional treatment of nails, hyperkeratosis, and calluses, corn removal, cracked heel therapy, debridement of diseased nails, nail plate reconstruction, and wart therapy are available.
For ingrown toenails, trimming and relieving the irritating edge, as well as orthonyxia braces, are available. The selection of the procedure requires an assessment of blood supply, sensation, skin condition, and healing risk. These treatments support tissue protection and local lesion care, but treating the cause of polyneuropathy remains the responsibility of a physician. Active ulceration, infection, necrosis, or suspected Charcot neuroarthropathy require medical care and multidisciplinary treatment instead of a routine cosmetic procedure.
