When a nerve is under physical pressure (such as when we have fallen asleep with our head on one arm, for example), it is common for abnormal sensations such as tingling or numbness to occur. This phenomenon is known as paresthesia, and is sometimes chronic and pathological in nature..
In this article, we will describe the causes and treatment of chronic paresthesia. We will also briefly describe other similar sensory alterations, many of which are characterized by the onset of pain, as opposed to paresthesia.
What is paresthesia?
Paresthesia is a phenomenon that consists of the appearance of tingling, tingling, itching, numbness, or burning sensations in different parts of the body. It is most common in the arms, hands, legs and feet, although it does not always occur in these areas. It is usually not associated with pain symptoms.
The term “paresthesia” comes from the Greek words “aisthesia”, which means “sensation” and “for”, which can be translated as “abnormal”. The word began to be used regularly in the 19th century, although some specific references can be found in classical Greek literature.
Paresthesia experiences are relatively common in the general population, so they do not always merit consideration for a pathology or alteration. For example, it is common for such sensations to appear when a limb is numb from sustained pressure from a nerve, As 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 result of disorders affecting the central nervous system, as well as severe damage to the peripheral nerves; when this happens, it is common for the paresthesia to have a painful component.
Transient, non-pathologic paresthesia occurs when a nerve comes under pressure and goes away shortly after it stops. In contrast, chronic paresthesia is a sign of damage to the central or peripheral nervous system.
Transient paresthesia is also linked to hyperventilation, Including what occurs against the background of anxiety attacks and infection with the herpes virus. However, in most cases, these experiences are due to unnatural postures of the body.
Alterations that affect the central nervous system and are associated with the onset of chronic paresthesia include multiple sclerosis, encephalitis, transverse myelitis, and ischemic stroke. Tumors that put pressure on certain areas 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 paresthesias accompanied by painful sensations. Among this set of alterations is carpal tunnel syndrome, in which the middle nerve is compressed inside the carpal tunnel, a group of bones in 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 disorder
The main focus of treatment for chronic paresthesia is to correct the ultimate causes of the disorder.This is also often accompanied by other more important physical and cognitive symptoms when they affect the central nervous system. Cases of transient paresthesia do not require any type of intervention because they are normal phenomena.
Depending on the underlying condition, one or another medication will be used. Some of the more commonly used drugs include antiviral drugs, anticonvulsants, the corticosteroid prednisone, or intravenous injection of gamma globulin.
In contrast, topical medications, such as lidocaine, are sometimes prescribed to reduce feelings of paresthesia when they are both bothersome and painful on their own. Of course, this type of treatment only temporarily relieves symptoms, but may be necessary in cases where the cause cannot 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.
The term “dysesthesia” is used to denote the appearance of abnormal sensations which prove to be unpleasant; in other words, it is a painful or bothersome variant of paresthesia.
An increase in pain sensitivity, that is, a reduction in the pain threshold, is called hyperesthesia. This phenomenon includes allodynia and hyperalgesia.
Hyperalgesia is the increased perception of pain in the presence of painful stimuli. The source of the sensation and the sensation occur in the same sensory modality (for example, a puncture causes mechanical pain).
Allodynia consists of the appearance of pain sensations in response to objectively painless stimuli. The sensory modality of stimulus and sensation need not be equivalent.