Polyneuropathies

What are the different types of polyneuropathies? All the information about their characteristics, symptoms, and treatments.

Symptoms and Causes

Polyneuropathy is a disease of the peripheral nervous system involving the simultaneous damage of multiple peripheral nerves. These injuries affect the trunk of the motor, sensory, and vegetative nerve fibers, and they are typically bilateral and symmetrical.

This dysfunction can be caused by various factors, so polyneuropathy is divided into several types, some of which include:

Axonal Polyneuropathy: Affects the extension of neurons (axons) that transmit impulses. Depending on its duration, it can be acute (begins suddenly), subacute (develops over months), or chronic (persists over time).
Demyelinating Polyneuropathy: Studies suggest it could be due to an autoimmune response of the body that damages the sheath covering the nerves (myelin). This type also manifests in acute, subacute, or chronic forms.
Diabetic Polyneuropathy: When blood glucose levels remain high for prolonged periods, they can damage nerves.
Alcoholic Polyneuropathy: Excessive alcohol consumption impairs nerve function.

The prognosis of polyneuropathies varies, as some patients experience no disabling symptoms while others may have significant motor impairments or potentially life-threatening nerve alterations.

Symptoms

While they may vary depending on the type of polyneuropathy, the most characteristic symptoms of the condition include:

Muscle weakness
Tingling or numbness in the limbs
Loss of sensation
Respiratory insufficiency
Instability while walking
Distal polyneuropathy (a burning sensation in the hands or feet caused by diabetic neuropathy)
Variation in blood pressure
Constipation
Sexual dysfunction
Pallor

Causes

The main causes of polyneuropathy include:

Autoimmune reaction
Bacterial infections that attack the nerves
Exposure to toxins such as triorthocresyl phosphate, often used as a plasticizer, or certain chemotherapy agents
Diabetes, the leading cause of polyneuropathy in the developed world
Alcoholism
Vitamin B12 deficiency, which causes spinal cord degeneration
Hypothyroidism
Multiple myeloma, a type of cancer that damages nerves

Risk Factors

The risk of developing polyneuropathy increases in the following cases, which are related to the causes of the disease:

Family history
Diabetes
Alcoholism
Autoimmune diseases
Infections by agents that attack nerves
Exposure to toxins
Jobs or activities with repetitive movements that damage nerve endings

Complications

Some complications of neuropathies include falls due to lack of stability, infections, or foot damage when sensation is lost. In extreme cases, it can lead to quadriplegia or death from respiratory difficulties, though this is uncommon.

Prevention

While in most cases polyneuropathies cannot be prevented, it is advisable to control blood sugar levels when diabetes is present, avoid alcohol consumption, and lead a healthy lifestyle.

Which Doctor Treats Polyneuropathies?

Polyneuropathies are diagnosed in neurophysiology and neurology consultations. Family doctors or specialists in physical medicine and rehabilitation are also involved in treatment.

Diagnosis

To diagnose polyneuropathy, the following tests are used:

Medical history and evaluation of the patient's overall health
Neurological examination: assesses reflex quality, muscle tone, coordination, and balance
Electromyography: provides information about the functioning of muscles and motor neurons. This involves inserting an electrode with a needle into the muscle to record electrical activity
Nerve conduction studies: measure the time it takes for nerves to send electrical signals to muscles
Blood and urine tests: used to detect the source of the disease once diagnosed
Imaging tests: determine if a tumor, pinched nerve, or hernia is pressing on the nerves
Nerve or muscle biopsy: provides information about the causes of polyneuropathy