Peripheral Neuropathy (PN)

For a simple pictorial overview of the peripheral nervous system:

Peripheral nervous system 101

Peripheral neuropathy (PN) results from damage to peripheral nerves that connect the central nervous system (CNS /Brain and Spinal cord) to the rest of the body for two-way communication.    Peripheral nerves branch out of the spinal cord to all parts of the body, providing a communication link between the brain and the muscles, skin, internal organs, and blood vessels. Damage to this communication network can cause the equivalent of static on a phone line:

PN -Neuron

-   Damage occurs to axons or myelin surrounding peripheral nerves.   The axon is the “fiber-optic cable”of a neuron for transmitting messages from neuron body (soma) to make contact with other cells - usually neighboring neurons but sometimes muscle or gland cells.

-   PN damage can affect any or all of the nerves in:

(1) Somatic Nervous System (Used for voluntary control)

•  Sensory (afferent) nerves from body.   Receive and transmit sensations from the parts of the body to the brain, E.g. heat, pain or touch.

Damaged sensory nerves may:

▪ Stop relaying signals.   Resulting in numbness and pain (most often in hands and feet)

▪ Send incorrect signals.   Transmittingsensations of pain, burning or tingling sensations (sometimes described as “pins and needles”)

•   Motor (efferent) nerves to muscles.   Send messages from the brain to the muscles to control movement.

Damaged motor nerves may:

▪ Impair movement and can lead to muscle weakness / wasting or even paralysis

(2) Autonomic Nervous System (Used for involuntary control)

•  Sensory and motor nerves.   Control involuntary functions. E.g. blood pressure, heart rate, digestion and bladder function;

Damaged autonomic nerves may:

▪ Impair any involuntary function - depending on location of damage.

-   PN commonly starts in the longest nerves.    i.e. those going to your toes;

-   PN may affect one to several nerves:

•   Mononeuropathy.   1 nerve;

•   Multiple mononeuropathy.   2 or more nerves in different areas;

•   Polyneuropathy.   Many nerves.

-   If known, PN is classified according to cause or location.    For example:

•  Diabetic neuropathy

•  Nutritional neuropathy

•  Radiculopathy.   Neuropathy resulting from pressure on/injury to a spinal nerve root (Radix) affecting nerve function. Radicular pain and other symptoms (weakness, numbness, pins and needles, lack of muscle control) may manifest as “referred”pain/symptoms in an extremity. E.g. Impingement in the lower back can result in pain/symptoms in the foot. Radiculopathy may be experienced in such as herniated disk, spinal stenosis (narrowing of spinal canal), sciatica and degenerative disk disease;

•   Entrapment neuropathy.    Occurs when inflammation of connective tissue puts pressure on a nerve passing through it;

•   Idiopathic neuropathy.   When a cause cannot be identified;