Peripheral neuropathies refer to disorders of the peripheral nervous systems. Neuropathies are usually characterized by sensory symptoms and weakness in feet and hands, predominantly distally, starting from soles and toe tips. Peripheral nerves have sensory, autonomic, and motor divisions, which are concerned with sensation information to the brain and motor(strength) control; autonomic nerves control functions like sweating.
Sensory symptoms are a common presentation of neuropathy; these can be positive (burning pain, walking on cotton wool, tingling, pins, and needles) and negative symptoms (numbness, loss of sensation) in feet and hands. The most common motor symptom is a distal weakness; patients have difficulty turning keys in locks, unfastening buttons, atrophy of muscles, and longstanding neuropathies develop distal deformities like clawing.
Autonomic symptoms such as postural hypotension, impotence, sphincter disturbance, skin changes, diarrhea, constipation, dryness, or excessive sweating point to the involvement of small unmyelinated nerve fibers. Neuropathies can present symptoms of diseases like Diabetes Mellitus, alcoholic neuropathy, exposure to lead, arsenic, thallium, chemotherapy drugs for cancer, infection like leprosy, HCV HIV, and autoimmune diseases like polyarteritis nodosa, and SLE. Dietary deficiencies of thiamine, vitamin B12.
Hereditary neuropathies present with a chronic history of distal weakness with few sensory complaints, plus there can be evidence of long-standing muscle weakness. Neuropathies can have Acute onset, meaning symptoms develop within a short span, subacute neuropathies develop over a few days to a week, and chronic ones take more than 8 weeks. It is important to note how rapidly they develop; progress can give clues regarding causes. A good clinical examination by a neurologist neurologist will guide the pattern of nerve affection, which blood test to perform to ascertain the cause and treat it.
One particular test done by neurologists to confirm that symptoms are due to nerve damage and also gives confirmation about which type of neuropathy has to develop is NCS(nerve conduction study), In this test, a recording electrode will be attached to the skin, and a mild and brief electrical shock will be supplied through the stimulating electrode to stimulate the nerve. The response of the nerve will be displayed and recorded on a monitor.
This recorded response gives vital information about nerve function. Moreover, it also helps if sensory symptoms are due to spinal cord or brain disorders. Correct and timely confirmation of the type of neuropathy and cause can save further nerve damage.