Polyneuropathy: A Common and Heterogeneous Disease

Peripheral nerves are the nerves that exit the brain and spinal cord and carry the motor message from the Central Nervous System to the peripheral organs, but also the sensory message in the opposite direction from the periphery to the center. Polyneuropathy is therefore the damage to multiple nerves resulting in symptoms such as numbness, weakness, difficulty in coordinating movements.

Nerves consist of their outer sheath, myelin, and the axon which is centrally located. Therefore, polyneuropathies, depending on the part of the nerve that is affected, are divided into demyelinating type, axonal and mixed type. In case of sensory nerve damage, we speak of sensory polyneuropathy, motor nerve damage, while there is often a combination of both. Furthermore, depending on the time of attack and appearance of symptoms, they are divided into acute, subacute and chronic. This distinction is important because it helps in investigating the underlying cause.

Polyneuropathy Causes

There are many possible causes of polyneuropathy, with one of the most common being Diabetes Mellitus , as it appears that 1/5 of patients with diabetes will develop diabetic polyneuropathy. Alcohol abuse is also a common cause of polyneuropathy both due to its direct toxic effect on the nerves and due to the vitamin deficiency it causes. Other causes are autoimmune diseases such as Systemic Lupus Erythematosus, Rheumatoid Arthritis, Sjogren's syndrome, Guillain Barre syndrome. Hematological diseases , exposure to toxins such as chemicals, drugs , hypothyroidism , liver and kidney diseases , infections , poor nutrition and hereditary diseases are other causes of polyneuropathy.

Symptoms

The symptoms of polyneuropathy are varied and depend on the nerves affected. The most common are numbness (numbness) usually distributed like a sock-glove, burning pain, pain, hypoesthesia for superficial sensation, pain and temperature, but very often there are also motor symptoms, i.e. weakness and disturbance in walking and more rarely in swallowing. In case the nerves of the autonomic nervous system are also involved, i.e. the nerves that regulate visceral functions, the patient may present disorders in blood pressure, incontinence, sweating and intolerance to heat.

Diagnosis

The diagnosis of polyneuropathy is initially based on the patient's history and clinical examination to establish the suspicion of the disease. This is followed by an electromyogram and an electroneurogram, a non-invasive examination that is crucial for confirming the disease and its type. To investigate the underlying etiology, additional blood tests will be needed, possibly CT or MRI scans, nerve or muscle biopsy.

Treatment

Treatment depends on the underlying pathology, for example, regulation of diabetes mellitus, cessation of alcohol abuse, regulation of thyroid function, removal of toxic agents , while specific treatments may also be needed depending on the disease. Symptomatic treatment is often needed to treat pain and numbness, and of course, physiotherapy plays an important role in restoring functionality.

In case persistent symptoms suggestive of polyneuropathy are observed, it is important to be evaluated by a neurologist so that a diagnosis can be made immediately and treatment can begin.