A Guide Living With Small Fiber Neuropathy: Is This Condition Fatal? Discover The Causes, Symptoms, and Treatment Options

Peripheral neuropathy can take a turn for the worst if not treated in time. Sadly, most people take this condition very lightly and often fail to see the need to visit a doctor.

For those of you who don’t know, “Peripheral neuropathy is a condition caused by diabetes, which affects the motor, sensory and autonomic nerves. As a result, you feel pain, numbness and tingling in the hands and feet, which indicates nerve damage”.

Neuropathy pain has varying degrees due to its progression. Let’s talk about another disorder that follows the same line: small fiber neuropathy.

What Is Small Fiber Neuropathy?

This neuropathy disorder primarily affects small autonomic fibers or somatic fibers and in some cases both. As a result, a person experiences autonomic dysfunction and sensory changes.

The peripheral nerves are enclosed in a myelin sheath, which protects the transmission of electrical impulses. The pain you feel in neuropathy depends on the size of the nerves, which are as followed:

  • Small Fibers: These fibers innervate involuntary muscles and skin (somatic nerves), including autonomic fibers (smooth muscles) and cardiac. Together, they meditate thermal sensation, pain, and autonomic function.
  • Medium-Sized Fibers: Carry out information to the muscle spindles.
  • Large Nerve Fibers: mediate motor strength along with touch and vibratory sensation.

Causes

There are plenty of causes behind small fiber neuropathy. Following is a list that mentions some of the common disorders that lead to neuropathy:

  • Metabolic disorders
  • Hereditary diseases
  • Immune system disorders
  • Inflammatory bowel disease
  • Guillain-Barre syndrome (an autoimmune disease)
  • Lupus
  • Psoriasis
  • Mixed connective tissue disease
  • Rheumatoid arthritis
  • Vasculitis
  • Hepatitis C
  • Fabry disease (a genetic disease)
  • HIV
  • Infectious diseases
  • Sarcoidosis (an inflammatory disease that affects lungs and lymph glands)

Symptoms

Depending on which nerves are affected, the symptoms can differ from person to person. The usual symptoms include:

  • Loss of sensation
  • Bursts of pain
  • Prickling (paresthesia), burning and tingling

When the somatic nerves are affected, something as simple as touching a bed sheet can cause pain.

On the other hand, when autonomic nerves are affected, the following symptoms attack the body:

  • Constipation
  • Dry eyes
  • Difficulty sweating
  • Dizziness
  • Dry mouth
  • Sexual dysfunction
  • Incontinence
  • Skin discoloration

Living With Small Fiber Neuropathy

According to a neurology specialist Mohammad Khoshnoodi from Johns Hopkins, “If we wait until these patients have large-fiber neuropathy, we’ve needlessly lost time and nerve function. This is one more reason to be aggressive about controlling patients’ glucose levels”.

Khoshnoodi conducted several studies along with his colleagues on peripheral neuropathy and small fiber neuropathy, which lead him to the conclusion that living with this condition is not that easy.

His study, published in the JAMA Neurology, revealed that whether a person is pre-diabetic or diabetic, neuropathy progresses at the same stage.

In fact, as time passes, it becomes severe — turning from small fiber neuropathy to large fiber neuropathy.

Michael Polydefkis, a professor of neurology, also working at Johns Hopkins reached a conclusion through another study that neurological dysfunction symptoms such as difficulty in walking, blood pressure regulation and problems with balance are the top symptoms that push small fiber neuropathy further. This order is often referred to as “stocking-and-glove” distribution because it starts in the feet and progresses to the hands.

Is It Fatal?

Talking about his study, Polydefkis said, “We’ve seen some dramatic improvements over time in these patients’ nerves. It’s an example of a severe form of peripheral neuropathy, a fatal form that appears to be changing before our eyes”.

This answers our question to the point. However, in some cases, the answer teeters between “Yes” and “No”. As small never fiber progresses to large nerve fiber, both motion and sensation become limited.

A study published in the BMJ Journal under Practical Neurology section revealed that there are no treatments that can reverse small fiber neuropathy. Depending on the disorder that has caused neuropathy, the pain can be suppressed but in cases such as the Amyloid disease, it can be fatal.

When it comes to treating this order, Ahmet Hoke, an expert in nerve conduction at Johns Hopkins, says, “Skin biopsies can tell us exactly how much neuropathy you have, but they don’t tell us anything about the cause. The blood work becomes the key”.

There are plenty of clinical trials being conducted on different medicines to find out, which one is effective in treating small fiber neuropathy and stopping its progress. The fact remains that this disorder can never be completely corrected.

According to a study published in the Current Pain and Headache Reports journal, there are various ways to diagnose and treat pain in small fiber neuropathy. However, unless the underlying cause is discovered, there’s no way to treat the pain.

Diagnosis

To diagnose the origin of the pain, neurology specialists begin with asking your medical history. As mentioned in the causes, hereditary might be behind small fiber neuropathy. It gives the doctors an idea that the numbness and tingling in your feet and hands are being caused by neuropathy.

Electromyography or Nerve Conduction Test

To find out if the neuropathy has reached the large fibers, a nerve conduction test of electromyography is done. If the results don’t show any damage, other tests are done to find small fiber damage.

Nerve conduction test on a man's left hand

Electromyography is a procedure which evaluates the condition of nerve cells and muscles.

The motor neurons transmit electrical signals, which cause muscles to relax and contract.

The signals are translated into numbers, which help doctors figure out the nerves that are affecting muscle reflexes.

A nerve conduction test helps the doctors find out never damage. Through this procedure, doctors are able to measure the movement of electrical signals through the peripheral nerves.

The faster the signals are, the healthier the nerves. This helps differentiate whether the myelin sheath is injured or the nerve fibers.

Skin Biopsy

This mildly invasive technique effectively diagnoses small fiber neuropathy. A few skin samples are taken from the sight of the pain, preferably the leg, which are then examined to find out if the nerves are damaged or not.

However, as mentioned earlier, this procedure tells us about the severity of the neuropathy and not the cause. This is why blood work is important. A small sample of the patient’s blood tells the doctor whether the person is diabetic or has any other kind of disease.

Now the treatment can begin, which often involves leading a healthy lifestyle. Easier said than done but sadly, it is the best way to manage neuropathy.

Reflex Testing

Another great way to test the autonomic function is through Quantitative sudomotor axon reflex testing (QSART). Patients are given gentle electrical shocks to find out their sweat response. Low sweat output indicates that the person has fiber neuropathy.

Treatments

Medication

One way to treat small fiber neuropathy is through managing blood glucose levels. As for the pain, a medicinal approach is taken. Vitamin B12 deficiency is one of the biggest causes of neuropathy. It’s also possible the chemotherapy treatment and the medication you are taking for the cancers is causing neuropathy.

The pain caused through small nerve fiber is typically treated by the following medications:

One anticonvulsant that is proving its worth in treating small fiber neuropathy is Gabapentin. Several studies have been conducted that list the medication as the first line of treatment.

And thus we reach the conclusion that living with small fiber neuropathy is quite difficult because it involves many complications. The more delays you make in the treatment, the severe it becomes. Eventually, this disorder leads to fatal consequences.