Paresthesia: Causes, Treatment And Associated Phenomena
When a nerve is subjected to physical pressure (as happens when we fall asleep with our head on an arm, for example) it is common for abnormal sensations such as tingling or numbness to occur. This phenomenon is known as paresthesia, and sometimes it has a chronic and pathological character.
In this article we will describe the causes and treatment of chronic paresthesia. We will also briefly describe other similar sensory alterations, many of them characterized by the appearance of pain, unlike paresthesia.
Paresthesia is a phenomenon that consists of the appearance of stinging, tingling, itching, numbness or burning sensations in different parts of the body. It is more common for it to occur in the arms, hands, legs and feet, although it does not always occur in these areas. It is generally 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 regularly in the 19th century, although some previous specific reference can be found in classical Greek literature.
Experiences of paresthesia are relatively common in the general population, so they do not always merit consideration as pathology or alteration. For example, It is common for sensations of this type to appear when an extremity becomes numb due to sustained pressure on a nerve as can happen when crossing your 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 to the peripheral nerves; When this happens, it is common for the paresthesia to have a painful component.
Causes
Transient and non-pathological paresthesia appears when a nerve is put under pressure and disappears shortly after this pressure 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 that which occurs in the context of panic attacks, and with herpes virus infection. 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, multiple sclerosis, encephalitis, transverse myelitis and ischemic strokes stand out. Tumors that press on certain regions of the brain or spinal cord can also cause this type of paresthesia.
Peripheral nerve compression syndromes are also common causes of chronic paresthesia accompanied by painful sensations. Among this set of alterations, carpal tunnel syndrome stands out, in which the median 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 alteration
The treatment of chronic paresthesia is fundamentally 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 another drug will be used. Some of the most commonly used include antiviral medications, anticonvulsants, the corticosteroid prednisone, or intravenous injection of gamma globulin.
On the other hand, topical medications, such as lidocaine, are sometimes prescribed to reduce sensations of paresthesia when they are uncomfortable or painful in themselves. Of course, this type of treatment only relieves symptoms temporarily, 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 consequence 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 the increased sensitivity to pain, that is, a reduction in the 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 the sensation 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.
