PERIPHERAL NEUROPATHY.
NOTE!
There is no single disorder called "Peripheral Neuropathy".
The phrase is a general term for disorders affecting the peripheral nerves. The nerves and nerve fibres of the peripheral nervous system transport information to and from the brain and spinal cord to the skin, blood vessels and muscles in other parts of the body. The motor nerves control muscle contraction and may also control some functions of the autonomic (involuntary) system. Any peripheral nerve damage via the latter could result in problems with bowels or bladder, sweat glands and blood pressure. Sensory nerves carry signals mediating sensation from receptors (such as our touch and heat receptors) to the Central Nervous System. Neuropathies may affect a single peripheral nerve (known as a mononeuropathy) or several nerves (a polyneuropathy). If sensory nerves are damaged the sufferer may experience numbness, burning, sensory loss and pain, varying from the mild to searing hand or foot pain. If motor nerves are damaged then weakness or paralysis of muscles controlled by those nerves will be experienced. In some cases both motor and sensory nerves are damaged.
So it is more accurate to say that there are many peripheral neuropathies, differing in over a hundred underlying causes, severity, speed of onset and progression (acute, chronic or subacute) and likely outcome. However the majority of cases are due to a relatively limited number of causes and conditions. Diabetes is the commonest cause in the Western world, whilst leprosy is the prevailing cause worldwide. Typically, a peripheral neuropathy affects the ends (distal portions) of the lower extremities, any of the feet and legs, the hands and lower arms. Usually the lower limbs are affected first.
Patients' symptoms are frequently described by them in terms of disagreeable sensations such as burning/freezing pain, sharp electric pain, tingling, "crawling on my skin", numbness, glove and stocking patterns, "walking on cotton wool", involuntary hand and finger movements, aching, weakness or unsteadiness and even tightness/contraction of muscles. At some times these symptoms may be barely noticeable. At night they may be quite unbearable. For some sufferers they are constant.
Accurate diagnosis.
It would seem to be inadequate to merely record that a patient has a PN if no attempt has been made to accurately diagnose its' underlying cause. Without that knowledge there can be no suitable specific treatment. Diagnosis of the cause is frustrating, difficult, time consuming and expensive, depending on combining the patient's medical history with physical examination and testing. It is also quite possible that the exact underlying cause cannot be resolved. Valid diagnosis depends on clues from physical and neurological examination including:
Acquired neuropathies include:
- Diabetic Neuropathy. This is the most common PN in the Western world. More than 50% of diabetics eventually develop a PN. It is rarely disabling but is often painful when walking and at night.
- Immune mediated neuropathies, in which the immune system turns against the body by a mistaken attack. These include the GBS/CIDP family. Guillain-Barré Syndrome is a disorder with acute onset. CIDP (Chronic Inflammatory Demyelinating Polyneuropathy) is a chronic version similar to GBS. Paraproteinaemic Demyelinating Neuropathy (PDN) is one of these.
- Multifocal Motor Neuropathy.
- Vasculitis, inflamed blood vessels in the peripheral nerves.
- Chronic alcohol abuse, Toxic metal and chemical caused neuropathies,
- Infection caused neuropathies, including HIV infection, hepatitis B and C, leprosy.
- Nutritional imbalance caused neuropathies, vitamin B12 and vitamin E deficiency.
- Painful Axonal Idiopathic Neuropathy (PAIN), possibly a fairly common PN. Usually a slowly progressive PN primarily affecting the feet.
Hereditary neuropathies. Caused by genetic abnormalities. Includes Charcot Marie Tooth Disease, an hereditary motor and sensory neuropathy (HMSN). May be as high as 1in 2500 people affected in some form.
