What are paresthesias and how do they occur?
Sensory nerve fibers transmit signals from the skin to the spinal cord and brain. If a nerve is compressed, poorly supplied with blood, damaged by toxins or metabolic disorders, it begins to send distorted signals - tingling, burning, and numbness occur. The nature and distribution of sensations help the doctor understand the level of damage. Numbness of individual fingers is more often associated with one nerve, symmetrical numbness of the feet and hands of the “socks and gloves” type is associated with polyneuropathy, and numbness of half the body is associated with brain damage.
- Transient - from compression in an uncomfortable position, disappears in minutes
- Mononeuropathies - tunnel syndromes, damage to one nerve
- Polyneuropathy - symmetrical numbness of the feet and hands
- Radiculopathy - numbness along the root due to disc herniation
- Central - for stroke, multiple sclerosis, brain tumors
Possible reasons
Numbness in the fingers at night is most often caused by carpal tunnel syndrome, in which the median nerve is compressed at the level of the wrist. Numbness in the little and ring fingers is characteristic of compression of the ulnar nerve. Numbness radiating from the neck to the arm or from the lower back to the leg indicates a root lesion. Symmetrical paresthesias in the feet, gradually rising upward, are typical for diabetic and alcoholic polyneuropathy, vitamin B12 deficiency. Hypothyroidism, kidney disease, certain medications, and chemotherapy may also be causes. Tingling around the mouth and fingers with frequent deep breathing occurs with anxiety and hyperventilation.
- Carpal tunnel syndrome
- Cervical and lumbar radiculopathy
- Diabetes mellitus
- Vitamin B12 deficiency
- Alcoholic polyneuropathy
- Hypothyroidism, chronic kidney disease
- Multiple sclerosis, stroke
- Hyperventilation for anxiety and panic attacks
Associated symptoms
The doctor is interested not only in the numbness itself, but also in what accompanies it. Weakness in the hand, awkwardness when fastening buttons, and thinning of the muscles at the base of the thumb indicate long-term compression of the nerve. Burning pain in the feet at night, instability in the dark, and invisible wounds on the legs are characteristic of polyneuropathy. Pain in the neck or lower back that worsens with movement indicates a radicular cause. Paleness, shortness of breath, tongue inflammation and forgetfulness may accompany vitamin B12 deficiency. Previous episodes of visual impairment are suggestive of multiple sclerosis.
- Weakness and awkwardness in the hand
- Burning pain in the feet, worse at night
- Unsteadiness when walking, especially in the dark
- Neck or back pain
- Muscle cramps
- Dry skin and non-healing wounds on the feet
- Pallor, fatigue, sore tongue
What examinations are needed
The neurologist checks sensitivity, muscle strength, reflexes, and conducts provocative tests for tunnel syndromes. Basic tests help identify metabolic causes: glucose and glycated hemoglobin, vitamin B12, TSH, complete blood count, creatinine. Electroneuromyography shows which nerve is affected, at what level and how severely, and also distinguishes polyneuropathy from radiculopathy. If root compression is suspected, an MRI of the corresponding part of the spine is prescribed; if there are signs of damage to the brain or spinal cord, an MRI of the brain is prescribed. Nerve ultrasound is sometimes used for carpal tunnel syndromes.
- Neurological examination
- Blood glucose, glycated hemoglobin
- Vitamin B12, complete blood count
- TSH, creatinine
- Electroneuromyography
- MRI of the cervical or lumbar spine
- MRI of the brain - according to indications
What to do and how to treat it
Treatment depends on the cause found. For diabetes mellitus, the main thing is stable glucose control; for vitamin B12 deficiency, its replenishment according to the regimen prescribed by the doctor; for alcoholic polyneuropathy, complete abstinence from alcohol. Carpal tunnel syndrome can be treated with a night splint for the wrist, restriction of repetitive movements, injections, and if the compression is severe, simple surgery. For radiculopathy, exercise therapy, anti-inflammatory drugs, and blockades are used. To reduce burning neuropathic pain, the doctor may prescribe special medications. Self-administration of vitamins “just in case” does not replace examination.
- Don't ignore numbness that lasts longer than a few days
- Control sugar levels in diabetes
- Give up alcohol
- Use a wrist splint for carpal tunnel syndrome
- Take breaks when working at the computer
- Inspect your feet daily for polyneuropathy