What is small fiber neuropathy?

Neuropathy No More By JODI KNAPP Neuropathy No More is an eBook which is a compilation of all the essential information and details about the nervous system and how to keep it active and healthy. With the help of this program, one can get a relief from the symptoms of neuropathy. This eBook not only tells you about the nervous system, but also helps to provide essential information to get relief from the condition of neuropathy. It also provides information about how you can prevent this condition from coming back in the near future.

What is small fiber neuropathy?

Small fiber neuropathy (SFN) is a type of peripheral neuropathy that specifically affects the small nerve fibers responsible for transmitting sensations of pain and temperature, as well as controlling some autonomic functions (such as heart rate, blood pressure, sweating, and digestion). These small nerve fibers are part of the peripheral nervous system, which connects the brain and spinal cord to the rest of the body. SFN can cause various sensory and autonomic symptoms, depending on the nerves affected.

Key Features of Small Fiber Neuropathy

1. Symptoms

Sensory Symptoms:
- Pain: A burning, prickling, or tingling sensation, often described as a “pins and needles” feeling. This pain typically occurs in the feet, legs, hands, or arms, but it can spread to other parts of the body.
- Numbness or Reduced Sensation: Some people experience a loss of sensation or an inability to feel temperature changes, particularly in the hands and feet.
- Allodynia: Pain caused by stimuli that wouldn’t normally be painful, such as a light touch or the pressure of clothing on the skin.
- Hyperalgesia: Increased sensitivity to pain, where normal pain sensations are exaggerated.
Autonomic Symptoms:
- Dysautonomia: Issues with autonomic functions can lead to a variety of symptoms, such as:
  - Irregular heart rate or blood pressure
  - Digestive problems like constipation, diarrhea, or bloating
  - Excessive or reduced sweating (sweating abnormalities)
  - Urinary issues (difficulty urinating or bladder control problems)
  - Dry eyes or mouth
Symptom Pattern: The symptoms of SFN are often worse at night and may begin in the feet and hands (a pattern called “stocking-glove” distribution) but can progress to affect other areas.

2. Causes

Small fiber neuropathy can have a variety of causes, though in some cases, it is idiopathic (meaning no specific cause is identified). Common causes include:

Diabetes: Diabetic neuropathy is a well-known cause of SFN. High blood sugar levels can damage small nerve fibers over time.
Pre-diabetes: Even before full-blown diabetes develops, impaired glucose tolerance can lead to nerve damage.
Autoimmune Diseases: Conditions like lupus, Sjögren’s syndrome, or sarcoidosis can trigger immune system attacks on the nerves.
Genetic Mutations: Some cases of SFN are linked to inherited genetic mutations, including those affecting sodium channels in nerve cells (such as mutations in the SCN9A gene).
Infections: Viral infections like HIV, or bacterial infections such as Lyme disease, can lead to nerve damage.
Toxins: Exposure to certain chemicals or toxins, such as chemotherapy drugs, heavy metals, or alcohol, can damage small nerve fibers.
Vitamin Deficiencies: Deficiencies in vitamins such as B12, B6, or folate, which are crucial for nerve health, can cause SFN.
Medications: Some medications, such as certain chemotherapy drugs, have been associated with nerve damage.
Metabolic Disorders: Conditions like hypothyroidism or metabolic syndrome can affect nerve function.

3. Diagnosis

Diagnosing SFN can be challenging because it does not show up on standard nerve conduction studies, which typically detect damage to larger nerve fibers. Specific diagnostic tools include:

Skin Biopsy: A small skin sample is taken and examined under a microscope to count the number of small nerve fibers in the skin. A reduced number of these fibers can indicate SFN.
Quantitative Sudomotor Axon Reflex Test (QSART): This test evaluates how well the nerves that control sweating are functioning, which can help assess the function of autonomic small fibers.
Autonomic Testing: Tests that evaluate heart rate variability, blood pressure changes, or sweating abnormalities can help determine if the autonomic nervous system is involved.

4. Treatment

Treatment of small fiber neuropathy focuses on managing symptoms and addressing the underlying cause if identified. Common treatment strategies include:

Medications for Pain Relief:
- Antidepressants: Drugs like amitriptyline, duloxetine, or nortriptyline can help manage nerve pain.
- Anticonvulsants: Medications like gabapentin and pregabalin are often prescribed to treat neuropathic pain.
- Topical Treatments: Capsaicin cream or lidocaine patches may provide localized pain relief for certain individuals.
- Opioids: In severe cases, opioid pain relievers may be prescribed, but they are generally used with caution due to the risk of dependence.
Treating the Underlying Cause: If the SFN is due to an underlying condition such as diabetes, autoimmune disease, or a vitamin deficiency, managing that condition can help alleviate symptoms.
- Blood Sugar Control: For diabetic patients, keeping blood sugar levels well-managed can slow the progression of nerve damage.
- Immunosuppressive Therapy: For autoimmune-related SFN, treatments that suppress the immune system (such as corticosteroids or IVIG) may be beneficial.
- Vitamin Supplementation: In cases of deficiency, replenishing vitamins like B12 or B6 can help improve nerve function.
Lifestyle Modifications:
- Exercise: Regular physical activity can improve circulation and nerve function, as well as reduce pain.
- Diet: A balanced diet rich in vitamins and minerals, particularly those important for nerve health (B vitamins), can support nerve regeneration and function.
Alternative Therapies:
- Acupuncture: Some people with SFN find relief from acupuncture, which may help improve nerve function and reduce pain.
- Transcutaneous Electrical Nerve Stimulation (TENS): This non-invasive therapy uses electrical impulses to help relieve nerve pain.

5. Prognosis

The prognosis of small fiber neuropathy varies depending on the cause. In cases where the underlying cause is treatable (such as vitamin deficiency or diabetes), managing the root cause can help slow or halt progression and may even lead to symptom improvement. However, in idiopathic or genetic cases, the condition may be more difficult to treat, and symptom management becomes the primary focus.

Summary

Small fiber neuropathy is a condition that affects the small nerves responsible for pain, temperature, and autonomic functions. It can cause a range of sensory and autonomic symptoms, and the severity varies depending on the cause. Early diagnosis and treatment are important to manage symptoms and prevent further nerve damage.

Jodi Knapp