In my practice, one of the most common set of symptoms, or a syndrome relate to peripheral neuropathy. Peripheral neuropathy is caused by nerve damage, which may be temporary, stable, progressive, mildly bothersome or disabling: Nerves are comprized of two parts which may be damaged: 1) axons, the body of the nerve and 2) myelin, the sheath around the axons of nerves. Nerves are then divided into sensory neurons ( associated with sensation) and motor neurons( associated with muscle activity). The nerves can come from different pathways: spinal nerve roots, the dorsal ganglia, peripheral nerve trunks and branches, autonomic nerves. Neuropathies can effect sensory nerves, motor nerves or more commonly both.
Differences between axonal and demylinating neuropathy can be seen with a routine exam: large sensory fibers abnormalities may be associated with decreased sensation to pin prick, light touch and vibration. All that is needed is something sharp and a tuning fork. Small, unmylinated sensory fiber abnormalities associated with decreased temperature sensation.
Sensory symptoms of axonal small fiber neuropathy, may for exmple, inclde: burning pain, radiating/lancinating/ electrical like sensations, pins and needles, increased sensation to light touch, numbness and reduced sensation.
Motor symptoms may include: weakness, muscle wasting, cramps, fasiculations, difficulty climbing stairs, decreased hand grip and restless leg syndrome.
Major characteristics of axonal vs demylelinating neurve damage can be seen with the EMG/NCV. Simply put: Axonal problems are seen with needle portion of the test and demyelinating problems are seen with the shocking part of the exam.
Some patients, with clear symptoms and abnormal physical examinations have negative EMGs. There is another test.
Patients may have small-fiber neuropathy not visable on an EMG. This can be diagnosed with a biopsy of 2-3 areas of skin sent to a specialty lab.
The lab reports the "ENFD" - Epidermal Nerve Fiber Density. The test is fairly accurate.( I can perform this simple test in my office).
Most treatments for neuropathy are only symptomatic. The only therapy I have found to be curative is IViG. This therapy is extraordinarily expensive, costing $10,000 per dose given every 3-4 weeks. The FDA has approved IViGfor a limited number of conditions. It may be possible to get insurance coverage for some forms of neuropathy like CIDP which is discussed elswhere.