Dysesthesia

Among the various neurological symptoms and signs of sensory disorders, dysesthesia stands out, defined as a change in sensations with the emergence of a feeling of pain and increased tactile response, the obvious connection of which with damaging factors may be absent.

This condition is considered a type of neuropathic (neurogenic) pain in various diseases; the ICD-10 code for dysesthesia (in the section on symptoms, signs and abnormalities) is R20.8. [ 1 ]

Epidemiology

As clinical statistics note, with diabetic neuropathy, changes in sensitivity with the occurrence of pain are observed in 25% of patients.

In multiple sclerosis, burning, tingling or aching pain – as a manifestation of dysesthesia – is observed in 15-28% of patients.

The prevalence of this symptom after a stroke is estimated at 7.5-8.6%.

Causes dysesthesias

The main causes of dysesthesia are disturbances in nerve conduction, leading to sensory-type peripheral neuropathy.

Diabetic neuropathy, which is observed in almost half of patients with hyperglycemia, is of metabolic origin, and along with dysesthesia, it is accompanied by skin itching, tingling and numbness (paresthesia), and muscle weakness.

Most often, dysesthesia is clinically manifested by:

• in patients suffering from multiple sclerosis;
• as one of the symptoms of post-stroke condition;
• in Guillain-Barré syndrome;
• for fibromyalgia;
• in cancer patients - with the development of progressive polyneuropathy after chemotherapy
• in cases of alcoholic polyneuropathy in chronic alcoholism.

Risk factors

Experts, calling dysesthesia neuropathic or neurogenic pain, include all of the above diseases and conditions as factors that increase the likelihood of developing this symptom.

There is an increased risk of somatosensory nervous system disorders with any nerve damage associated with various injuries and problems with the cervical spine; endocrine, autoimmune and oncological diseases; herpes virus and HIV; deficiency of calcium, magnesium, vitamins D and group B. [ 2 ]

In addition, risk factors include psychogenic conditions such as anxiety and obsessive-compulsive disorder, hypochondria and depression, as well as somatoform disorder with psychogenic pain.

For more information on the relationship between depression and abnormal pain syndrome, see the publication Chronic pain and comorbid conditions.

Pathogenesis

The pathogenesis of dysesthesia is explained by nerve damage, disruption of the transmission of nerve impulses along the spinothalamic tract (transmitting somatosensory information about pain and itching) and spontaneous inappropriate excitation of nociceptors (pain receptors).

Disruption of receptor excitation causes a response from the corresponding areas of the cerebral cortex in the form of altered sensations - from mild tingling to pain of varying intensity.

In the case of multiple sclerosis, the mechanism of development of dysesthesia is caused by autoimmune destruction of myelin, the protective sheath of nerve fibers, which leads to disruption of the transmission of afferent nerve impulses.

Damage to the peripheral or central somatosensory nervous system, as well as complete or partial interruption of the transmission of afferent nerve signals (transmitting sensory information to the CNS), results in so-called deafferent pain, which is usually accompanied by abnormal manifestations such as dysesthesia. [ 3 ]

More information in the articles:

• Anatomy of the nociceptive system
• Sensory neuropathies

Symptoms dysesthesias

As a rule, symptoms of dysesthesia associated with alteration of peripheral or central sensory pathways appear locally - with varying degrees of intensity depending on the diagnosis.

Common first signs include a painful burning sensation (a stinging sensation under the skin), tingling, or aching pain.[ 4 ]

This is how dysesthesia of the extremities manifests itself – in the legs (especially in the feet), as well as dysesthesia of the hands (most often, the hands and forearms). The sensations of pain can be sharp – stabbing in nature or similar to an electric shock – or long-lasting, with an increase in the ambient temperature, after physical exertion or when falling asleep. For more information, see – Sensory neuropathy of the upper and lower extremities

Nocturnal dysesthesias – when neuropathic pain intensifies at night – are characteristic not only of multiple sclerosis and diabetes, since their appearance after falling asleep is associated with a decrease in body temperature and a slowdown in blood flow during sleep. [ 5 ]

Generalized cutaneous dysesthesia, affecting most or all of the skin, may be characterized by a painful burning sensation that is aggravated by changes in temperature, heat, or clothing. Localized cutaneous dysesthesia is characterized by a painful subcutaneous burning sensation or intense itching of the scalp.

Patients with multiple sclerosis sometimes experience a feeling of compression (general tension) in the chest and ribs. [ 6 ]

Oral dysesthesia causes discomfort in the mouth in the form of: a burning sensation, the presence of a foreign body, increased or decreased salivation, a sensation of sour or metallic taste. Pain affecting the tongue, lips, jaws, mucous membrane of the cheeks and the bottom of the mouth is also possible. Discomfort when biting without any apparent cause is defined as occlusive dysesthesia. Some experts associate the occurrence of these sensations with neuropathy of the branches of the trigeminal nerve, which can be damaged by trauma or during dental procedures.

Complications and consequences

Persistent dysesthesia may have negative consequences and complications. For example, the burning and itching sensation of scalp dysesthesia may lead to scratching with damage to hair follicles and hair loss. Dermatological complications associated with itching include skin inflammation, hyperpigmentation, and/or lichenification. [ 7 ]

In addition, dysesthesia at night due to sleep disturbance leads to chronic daytime fatigue, irritability and depression. [ 8 ]

In any case, this symptom reduces the quality of life of patients.

Diagnostics dysesthesias

When dysesthesia develops against the background of obvious neurological damage, its diagnosis is made on the basis of anamnesis, physical examination of the patient and recording of his complaints and accompanying symptoms.

However, there are many diagnostic problems that can be solved by blood tests (for HIV, C-reactive protein, glycosylated hemoglobin, antinuclear and antineutrophil antibodies, iron, folic acid and cobalamin); analysis of cerebrospinal fluid; skin biopsy. [ 9 ]

Instrumental diagnostics include: nerve conduction studies (electroneuromyography), ultrasound of the nerves, magnetic resonance imaging (MRI) of the brain and cervical spine. [ 10 ]

If there is a suspicion of a connection between dysesthesia and a somatoform disorder, a study of the neuropsychiatric sphere with the involvement of a psychotherapist is necessary.

Differential diagnosis

Differential diagnosis is also necessary to distinguish dysesthesia from paresthesia (painless tingling and numbness, a “pins and needles” sensation on the skin), hyperalgesia (increased sensitivity to painful stimuli), and allodynia (pain that is caused by a stimulus that is usually painless).

Treatment dysesthesias

In mild dysesthesia, treatment may not be required. In other cases, antidepressants are prescribed, and most often these are Maprotiline (Maprotibene), Depres (Fluoxetine), Venlafaxine (Venlaxor, Velaxin ), Zolomax, Duloxetine, Citalopram.

It is also possible to use anticonvulsants such as Pregabalin, Gabapentin (Gabalept, Gabantin, Neuralgin), Carbamazepine.

Dysesthesia in patients with diabetes can be relieved with topical creams containing capsaicin or lidocaine. [ 11 ]

Also read:

• Treatment of sensory neuropathy
• Treatment of neuropathic pain

Prevention

There are currently no comprehensive measures that could prevent the occurrence of this symptom. [ 12 ]

Forecast

For life expectancy, the symptom of dysesthesia has a good prognosis. However, in many cases it occurs due to progressive diseases and conditions, so the condition of patients may worsen over time.