Paresthesia: causes, treatment and associated phenomena

When a nerve is subjected to physical pressure (as happens when we fall asleep with the head on one arm, for example) it is common to produce abnormal sensations such as tingling or numbness. This phenomenon is known as paresthesia, and sometimes it has a chronic and pathological nature .

In this article we will describe the causes and treatment of chronic paresthesia. We will also describe in a synthetic way other similar sensory alterations, many of them characterized by the appearance of pain, unlike paresthesia.

• Related article: "The 15 most frequent neurological disorders"

What is paresthesia?

Paresthesia is a phenomenon that consists of the appearance of sharp sensations, tingling, itching, numbness or burning in different parts of the body . It is more common to occur in the arms, hands, legs and feet, although not always occurs in these areas. It is usually not associated with pain symptoms.

The term "paresthesia" comes from the Greek words "aisthesia", which means "sensation", and "para", which can be translated as "abnormal". The word began to be used as usual in the nineteenth century, although you can find some precise prior reference in classical Greek literature.

Paresthesia experiences are relatively common in the general population, so they do not always deserve consideration of pathology or alteration. For example, it is common for sensations of this type to appear when a limb is numbed by sustained pressure from a nerve , as it can happen when crossing the legs.

Cases of chronic paresthesia, on the other hand, are considered medical problems. This type of paresthesia occurs as a consequence of disorders that affect the central nervous system, as well as severe injuries of the peripheral nerves; When this happens, it is common for paresthesia to have a painful component.

Causes

Transient and non-pathological paraesthesia occurs when a nerve undergoes pressure and disappears shortly after it is interrupted. In contrast, chronic paresthesia is a sign of lesions in the central or peripheral nervous system.

Transient paresthesia is also related to hyperventilation , including the one that occurs in the context of the crisis of anguish, and with the infection by the herpes virus. However, in most cases these experiences are due to unnatural postures for the body.

Among the alterations that affect the central nervous system and are associated with the appearance of chronic paresthesia are multiple sclerosis, encephalitis, transverse myelitis and ischemic strokes. Tumors that press certain regions of the brain or spinal cord can also cause this type of paresthesia.

Compression syndromes of the peripheral nerves are also common causes of chronic paresthesia accompanied by painful sensations. Among this set of alterations, it is worth mentioning the carpal tunnel syndrome, in which the median nerve is compressed inside the carpal tunnel, a group of bones of the wrist.

Other common causes of paresthesia include diabetes, rheumatoid arthritis, circulatory problems (for example in cases of atherosclerosis), malnutrition, metabolic disorders such as diabetes and hypothyroidism, systemic lupus erythematosus, alcohol abuse and benzodiazepine withdrawal syndrome.

Treatment of this alteration

The treatment of chronic paresthesia is mainly aimed at correcting the ultimate causes of the alteration , which is also usually accompanied by other physical and cognitive symptoms of greater significance when it affects the central nervous system. Cases of transient paresthesia do not require any type of intervention since they are normal phenomena.

Depending on the underlying alteration, one or the other drug will be used. Some of the most commonly used drugs include antiviral drugs, anticonvulsants, corticosteroid prednisone or intravenous injection of gamma globulin.

On the other hand, sometimes topical medications, such as lidocaine, are prescribed to reduce the sensations of paresthesia when they are bothersome or painful in themselves. Of course, this type of treatment only relieves symptoms temporarily, but may be necessary in cases where the cause can not be eliminated.

Associated sensory phenomena

There are different sensory phenomena similar to paresthesia . Dysesthesia, hyperesthesia, hyperalgesia and allodynia, among others, are abnormal sensations that occur as a result of certain types of stimulation.

1. Dysesthesia

The term "dysesthesia" is used to refer to the appearance of abnormal sensations that are unpleasant; in other words, it is a painful or annoying variant of paresthesia.

2. Hyperesthesia

We call hyperesthesia to increase sensitivity to pain, that is, a reduction in pain threshold. This phenomenon includes allodynia and hyperalgesia.

3. Hyperalgesia

Hyperalgesia is the increased perception of pain in the presence of painful stimuli. The source of the sensation and this occur in the same sensory modality (for example, a puncture causes mechanical pain).

4. Allodynia

Allodynia consists of the appearance of pain sensations in response to objectively non-painful stimuli. The sensory modality of the stimulus and the sensation do not have to be equivalent.