Peripheral neuropathy

Overview 

Peripheral neuropathy occurs when damage affects the peripheral nerves located outside the brain and spinal cord. It can arise due to a variety of factors, resulting in different symptoms. Typically, individuals with peripheral neuropathy experience weakness, numbness, and pain, primarily in their hands and feet. Moreover, it can extend its impact to other bodily functions, such as digestion and urination. 

Several factors contribute to peripheral neuropathy, including traumatic injuries, infections, metabolic issues, inherited factors, and exposure to toxins. Among these factors, diabetes is a common cause of neuropathy. 

Individuals affected by peripheral neuropathy often describe the pain as sharp, burning, or tingling. Fortunately, in some cases, symptoms can improve, especially if the condition’s root cause is treatable. Medications are available to help alleviate the pain associated with peripheral neuropathy, offering relief and improving the quality of life for those affected. 

Peripheral neuropathy can occur in two main types: 

• Demyelinating neuropathy: This occurs when the myelin sheath surrounding the axon deteriorates or forms improperly, disrupting signal transmission within the neuron. 
• Axonal degeneration: This results in the deterioration and death of the axon itself. Longer neurons, such as those connecting to the legs and feet, are more susceptible to this type of damage, making it the most common pattern in peripheral neuropathy. 

Symptoms  

The peripheral nervous system consists of different types of nerves, each with specific functions: 

• Sensory nerves: These nerves receive sensations like temperature, pain, vibration, or touch from your skin. 
• Motor nerves: They control muscle movement. 
• Autonomic nerves: These nerves regulate functions like blood pressure, sweating, heart rate, digestion, and bladder control. 

Symptoms of peripheral neuropathy can vary and depend on the type of nerves affected: 

• • Gradual numbness and tingling: Initially in your feet or hands, which can spread to your legs and arms. 
  • Pain: Sharp, jabbing, throbbing, or burning sensations. 
  • Increased sensitivity: Feeling discomfort even with light touch. 
  • Unexplained pain: Experiencing pain during activities that shouldn’t cause pain, like walking or being under a blanket. 
  • Coordination problems: Difficulty balancing and falling. 
  • Muscle weakness: Reduced strength in muscles. 
  • Strange sensations: Feeling as if you’re wearing gloves or socks when you’re not. 
  • Loss of movement: Inability to move if motor nerves are affected. 

If autonomic nerves are involved, symptoms may include: 

• • Heat intolerance: Struggling with temperature regulation. 
  • Sweating issues: Either excessive sweating or an inability to sweat. 
  • Digestive problems: Including bowel and bladder issues. 
  • Blood pressure drops: Resulting in dizziness or lightheadedness. 

Peripheral neuropathy can affect different numbers of nerves: 

• • Mononeuropathy: When it impacts a single nerve, like in carpal tunnel syndrome. 
  • Multiple mononeuropathy: When two or more nerves are affected in different areas. 
  • Polyneuropathy: When many nerves are involved, which is the most common scenario. 

If you notice unusual tingling, weakness, or pain in your hands or feet, it’s essential to seek medical attention promptly. Early diagnosis and treatment offer the best chance of managing symptoms and preventing further nerve damage. 

Causes 

Peripheral neuropathy is a condition characterized by nerve damage, which can be triggered by various underlying factors. Some health conditions associated with peripheral neuropathy include: 

• Diabetes and metabolic syndrome: The most common cause of peripheral neuropathy is diabetes, with over half of diabetes patients developing some form of neuropathy. Metabolic syndrome is also a contributing factor. 
• Infections: Viral or bacterial infections, including Lyme disease, shingles, hepatitis B and C, leprosy, diphtheria, and HIV, can result in peripheral neuropathy. 
• Autoimmune diseases: Conditions like Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, and vasculitis can lead to nerve damage. Additionally, certain immune system-related cancers may cause a form of autoimmune disorder known as paraneoplastic syndrome. 
• Genetic conditions: Inherited genetic conditions like amyloidosis, Fabry disease, and Charcot-Marie-Tooth disease can lead to peripheral neuropathy. Some of these conditions have available treatments. 
• Tumors: Both cancerous (malignant) and noncancerous (benign) growths can grow on or exert pressure on nerves, causing neuropathy. 
• Bone marrow disorders: Certain blood disorders, such as monoclonal gammopathies, rare forms of myeloma, lymphoma, and amyloidosis, can affect nerves. 
• Other diseases: Metabolic disorders like kidney disease, liver disease, and hypothyroidism (underactive thyroid) are additional contributors to peripheral neuropathy. 

Other potential causes of neuropathies include: 

• Medications: Certain medications, particularly chemotherapy drugs used in cancer treatment, may induce peripheral neuropathy. 
• Exposure to toxins: Nerve damage can result from exposure to industrial chemicals and heavy metals like lead and mercury. 
• Alcohol use disorder: Excessive and prolonged alcohol consumption can damage nerves and lead to vitamin deficiencies that exacerbate neuropathy. 
• Nerve injury or pressure: Physical injuries (e.g., from accidents, falls, or sports), prolonged pressure on nerves (e.g., from casts or crutches), or repetitive motions (e.g., frequent typing) can damage or compress peripheral nerves. 
• Vitamin and nutrient deficiencies: Deficiencies in essential vitamins such as copper, B1, B6, B9, B12, folic acid (B9), and E can lead to nerve damage. Excessive vitamin B6 intake can also contribute to this condition. 

In some instances, the cause of peripheral neuropathy remains unidentified, termed idiopathic peripheral neuropathy. 

Risk factors  

Risk factors for peripheral neuropathy include: 

• Exposure to toxins. 
• Family history of neuropathy. 
• Autoimmune diseases, such as rheumatoid arthritis and lupus, in which the immune system attacks your own tissues. 
• Low levels of vitamins in the body, especially vitamin B-12. 
• Diabetes, especially if your sugar levels are not controlled well. 
• Alcohol misuse. 
• Repetitive motion, such as those performed for certain jobs. 
• Infections, such as Lyme disease, shingles, hepatitis B and C, and HIV. 
• Kidney, liver, or thyroid disorders.