Definition and Overview
Peripheral neuropathy is a general term for diseases that cause damage to peripheral nerves excluding the brain and spinal cord (central nervous system). It shows various clinical manifestations depending on the type of damaged nerve (sensory nerve, motor nerve, autonomic nerve), distribution (single, multiple), and cause.
According to European epidemiological studies, the overall prevalence of chronic polyneuropathy is approximately 1-2.5% in the general population, and approximately 8% in people over 70 years of age. Neuropathy occurs in approximately 50% of diabetic patients.
Classification
Classification by type of nerve involved
- Sensory neuropathy: Numbness, burning pain, and paresthesia are the main symptoms.
- Motor neuropathy: Muscle weakness and muscle atrophy occur.
- Autonomic neuropathy: Abnormalities in blood pressure, heart rate, sweating, digestive tract, and bladder function occur.
- Mixed type: A combination of the three above occurs.
Classification according to distribution pattern
- Mononeuropathy: Damage to one nerve. Representative examples include carpal tunnel syndrome and peroneal neuropathy.
- Polyneuropathy: Multiple peripheral nerves are affected simultaneously. It is characterized by a symmetrical distribution, with a typical 'stocking-glove pattern' starting from the toes and fingertips and progressing to the proximal area.
- Mononeuritis multiplex: Multiple non-contiguous nerves are involved. Appears in vasculitis and diabetes.
cause
diabetic neuropathy
It is the most common cause. Neuropathy occurs in approximately 50% of diabetic patients, and the risk of developing it is proportional to the duration of the disease and the degree of blood sugar control. The mechanisms are oxidative stress caused by high blood sugar, accumulation of advanced glycation end products (AGEs), and decreased neuronal blood flow.
Other major causes
- Nutritional deficiencies: Vitamin B1 (thiamine), B6, B12, and folic acid deficiencies. B12 deficiency is common in vegetarians and gastrointestinal malabsorption.
- Alcoholism: A combination of neurotoxicity caused by chronic drinking and B1 deficiency.
- Immune-mediated: Guillain-Barre syndrome (acute), chronic inflammatory demyelinating polyneuropathy (CIDP).
- Drug triggers: chemotherapy (vincristine, paclitaxel, cisplatin), tuberculosis drugs (isoniazid), antivirals.
- Hereditary: Charcot-Marie-Tooth disease, etc.
- Renal failure: uremic neuropathy.
- Hypothyroidism: Myxedema neuropathy.
- Idiopathic: Cause unknown. It accounts for approximately 20-30% of the total.
symptoms
sensory symptoms
- Typically, symmetrical numbness starts from the toes on both sides and moves up to the ankles, calves, and fingertips.
- Neuropathic pain such as burning pain, electric shock sensation, and stabbing pain occurs.
- Balance disorders occur due to decreased vibration and position sense.
- Paradoxically, there are cases where hypoesthesia, a dulling of the senses, occurs and the trauma cannot be recognized.
motor symptoms
- Decreased muscle strength in the toes and ankles, foot drop.
- Foot muscle atrophy can cause foot deformity.
autonomic symptoms
It is prominent in diabetic autonomic neuropathy.
- Orthostatic hypotension: dizziness and fainting when standing up.
- Heart rate fixation (cardiac denervation): Heart rate changes due to exercise or change in position decrease.
- Gastroparesis: Early satiety, nausea, and vomiting.
- Bladder dysfunction: feeling of residual urine, frequent urination, difficulty urinating.
- Sweating abnormalities: anhidrosis of the extremities and compensatory hyperhidrosis of the trunk.
diagnosis
Nerve conduction study (NCS) and electromyography (EMG)
Presence and type of neuropathy (axonal damage vs. It is a key test to evaluate demyelination, extent, and severity. Patterns of slow nerve conduction speed (demyelinating type) or decreased action potential (axonal type) help determine the cause.
blood test
Check fasting blood sugar, glycated hemoglobin, vitamin B12, thyroid function, CBC, CRP, ESR, liver and kidney function, protein electrophoresis, and autoantibodies (ANA, ANCA, etc.).
Autonomic function test
Autonomic nerve fiber damage is assessed through heart rate variability (HRV) analysis, Valsalva maneuver test, deep breathing test, and sweating function test (QSART).
treatment
Cause Treatment
Treatment of the causative disease is key to restoring neurological function and preventing progression.
- Diabetic neuropathy: Tight blood sugar control. Studies have shown that intensive blood sugar control in type 1 diabetes can reduce the incidence of neuropathy by about 60%.
- B12 deficiency: Intramuscular or high-dose oral B12 supplementation.
- CIDP: Intravenous immunoglobulin, plasmapheresis, steroids.
- Drug-induced: Adjust the causative medication.
Neuropathy Pain Treatment
According to a systematic meta-analysis, the following drugs have a significant effect on neuropathic pain:
- Calcium channel ligands (gabapentin, pregabalin): drugs of first choice.
- SNRIs (duloxetine, venlafaxine): Effective for both pain and mood improvement.
- Tricyclic antidepressants (amitriptyline): Effective, but cautious about side effects in elderly people.
- Topical capsaicin, topical lidocaine patches: For adjunctive use in localized pain.
life guide
- Foot care: Check your feet daily for cuts or blisters. Wear well-fitting, comfortable shoes and avoid walking barefoot. Do not soak your feet in hot water.
- Balance training: Because the risk of falling is high, it is recommended to install anti-slip bathroom mats and handles along with balance exercises.
- Abstaining from alcohol: Abstaining from alcohol is essential in alcoholic neuropathy.
- Blood Sugar Management: In diabetic patients, blood sugar control is the most important way to slow the progression of neuropathy.
- Regular low-impact aerobic exercise (swimming, cycling) helps improve nerve blood flow and reduce pain.