Peripheral Neuropathy: Types, Causes and Symptoms
You know the feeling. You cross your legs or sit back on your feet too long and they fall asleep. The numbness, tingling and pain you briefly feel are nearly identical to some of the symptoms people with peripheral neuropathy might experience.
Peripheral neuropathy, often referred to as neuropathy or nerve damage, is a catch-all term that encompasses a broad group of medical conditions involving damage or malfunction of one or more peripheral nerves.
What Are the Peripheral Nerves?
Your peripheral nerves are those outside your brain and spinal cord. They exist in nearly all parts of your body and form a complex signaling network that carries messages between your body and brain. Peripheral nerves help your brain manage many types of functions, from movement to breathing.
Peripheral nerves perform three primary functions: sensory, motor and autonomic.
- Sensory Nerves enable you to detect sensations, including pain, heat, cold and touch. For example, sensory nerves tell your brain when a bumble bee has landed on your arm.
- Motor Nerves carry messages to and from your muscles that enable you to move. When you see that bumble bee on your arm, motor nerves carry messages that enable you to move your hand and shoo it away.
- Autonomic Nerves control the automatic functions of your internal organs and body systems, such as digestion, heart rate and blood pressure. The racing of your heart that occurs when you realize it’s a bumble bee on your arm occurs due to messages carried by autonomic nerves.
Peripheral neuropathy can affect one, a few or many nerves. The number of nerves affected determines how widespread your symptom are. While some types of neuropathy cause primarily sensory problems, many types disrupt a combination of sensory, motor and autonomic functions.
Symptoms of Neuropathy
There are more than 100 types of peripheral neuropathy, and the primary functions of the damaged nerves determine what symptoms you experience. Symptoms can develop suddenly and progress quickly or, more commonly, evolve gradually.
Sensory Nerve Damage
- Tingling or prickling sensations, which often develop first;
- Persistent pain or burning sensations; and
- Numbness and reduced sensitivity to touch and temperature.
Motor Nerve Damage
- Muscle weakness, which may occur suddenly or gradually;
- Muscle cramps or twitching;
- Decreased muscle size; and
- Difficulty moving body parts, such as your arms or legs. Getting up from a chair, walking up stairs and carrying groceries may become increasingly challenging.
Autonomic Nerve Damage
- Feeling full long after a meal;
- Diarrhea or constipation;
- Sweating more or less than usual;
- Dizziness when you stand up;
- Cool feet and hands;
- Difficulty emptying your bladder; and
- Erectile dysfunction
The specific symptoms you experience, the timing of them and their location all help your doctor determine the type of peripheral neuropathy you have and possible causes.
Causes of Peripheral Neuropathy
There are many causes of neuropathy, from sports injuries to certain conditions and diseases. Diabetes, alcohol abuse and kidney disease are among the biggest risk factors. Different neuropathy causes are grouped into broad categories.
Nerve compression or injury, such as:
- Carpal tunnel syndrome
- Thoracic outlet syndrome
Infection-related causes, such as:
- Lyme disease
- Hepatitis B and C
- Shingles (herpes zoster)
- Guillain-Barré syndrome
Immune system disorders, such as:
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Celiac disease
Cancerous conditions, such as:
- Multiple myeloma
- Paraneoplastic syndrome
Systemic or metabolic diseases, such as:
- Kidney failure
Inherited disorders, such as:
- Charcot-Marie-Tooth disease
Toxins, such as:
- Inhaled intoxicants (e.g., glue)
- Heavy metals (e.g., lead, arsenic, mercury)
- Organophosphate pesticides
Drugs and medications, such as:
- Some chemotherapy drugs
- Some HIV medications
- Some heart and/or cholesterol medicines
- Some psychiatric medications
- Some antibiotics
Nutritional deficiencies, such as:
- Vitamin B12
- Vitamin B6
Diagnosis and Treatment
Diagnosing the cause of peripheral neuropathy can be challenging. The location of your symptoms is one of the first things your doctor will consider if you’re being evaluated for neuropathy, as this helps determine how many nerves are involved.
Your doctor will begin by taking your medical history including what symptoms you’re experiencing, where and when they began, any ongoing medical conditions you have, and all medications or supplements you take. A thorough physical examination — including testing your reflexes, muscle strength, coordination and sensitivity to touch — is the next step.
To help narrow the list of possible causes, blood tests are often used to check for abnormalities. Your doctor may recommend electrodiagnostic tests, such as a nerve conduction study or an electromyogram (EMG), to determine how well specific nerves are functioning. Other tests, such as imaging studies, may be needed. Your doctor may refer you to a neurologist if the diagnosis is unclear or your symptoms are severe.
Treatment for peripheral neuropathy depends on the cause but often involves strategies to both manage the underlying cause and relieve your symptoms.
If you are feeling any new or persistent nerve-related symptoms, see your doctor, even if the symptoms come and go. Additionally:
- Report all medications, herbs and supplements you take to your doctor. People commonly omit this information, but it is important when determining the cause of peripheral neuropathy.
- Don’t stop taking any prescribed medication without first checking with your doctor, even if you feel the medication might be causing your symptoms.
- Seek immediate medical care if you experience sudden muscle weakness or have any difficulty breathing.
For Family Caregivers
If you suspect a loved one might have neuropathy, be vigilant if or when symptoms arise in your loved one. Be sure to:
- Schedule a doctor’s appointment as soon as you notice symptoms.
- Keep careful notes before and during the medical appointment to help the doctor determine how many nerves (or nerve groups) may be involved.