In the most common forms of polyneuropathy, the nerve fibers most distant from the brain and the spinal cord malfunction first. Pain and other symptoms often appear symmetrically, for example, in both feet followed by a gradual progression up both legs. Next, the fingers, hands, and arms may become affected, and symptoms can progress into the central part of the body. Many people with diabetic neuropathy experience this pattern of nerve damage.
In acute neuropathies, such as Guillain-Barré syndrome, symptoms appear suddenly, progress rapidly and resolve slowly as damaged nerves heal. In chronic forms, symptoms begin subtly and progress slowly. Some people may have periods of relief followed by relapse. Others may reach a plateau stage where symptoms stay the same for many months or years. Some chronic neuropathies worsen over time, but very few forms prove fatal unless complicated by other diseases. Occasionally, the neuropathy is a symptom of another disorder.
Because every peripheral nerve has a highly specialized function in a specific part of the body, an array of symptoms can occur when nerves are damaged. Symptoms may include:
- Temporary numbness, tingling and pricking sensations
- Sensitivity to touch
- Muscle weakness
- Painful cramps
- Burning pain, especially at night
- Muscle loss
- Bone degeneration
- Changes in skin, hair and nails
- Loss of pain sensation
- Organ or gland dysfunction
- Inability to digest food easily
- Inability to maintain safe blood pressure levels
- Difficulty breathing
- Diarrhea, constipation or incontinence
Neuropathic pain is often worse at night, seriously disrupting sleep and adding to the emotional burden of the disorder.