Pure sensory syndrome: symptoms, causes and treatment

The pure sensory syndrome occurs after a cerebral infarction in the thalamus, a structure of vital importance for filtering sensory information, and causes, among other symptoms, paralysis and a loss of sensitivity in half of the body.

In this article we explain what pure sensory syndrome consists of, what its main causes are, what symptoms it causes and what treatment to follow.

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What is pure sensory syndrome?

Pure sensory syndrome is one of the classic lacunar syndromes best defined by the physician Charles M. Fisher, one of the first neurologists to study and contribute to the understanding of accidents cerebrovascular disorders, especially those related to carotid artery diseases and heart attacks lacunares.

In clinical practice, lacunar syndrome is understood to be any clinical manifestation in which a lacunar-type cerebral infarction occurs.

This type of heart attack characterized by the presence of tiny lesions (no larger than 15 mm in diameter) caused by the occlusion of small branches of the perforating arteries of the brain.

Pure sensory syndrome constitutes 7% of lacunar infarcts and people who suffer from it manifest persistent or transient sensory symptoms that affect half of the body.

Causes

Little is known about the frequency with which the various forms of the syndrome occur., including: complete hemisensory syndrome (with sensory involvement involving the entire facio-brachio-crural axis, that is, the face, arm, and leg on one side of the body); and incomplete hemisensory syndrome (less specific and with different clinical variants).

The most common cause of pure sensory syndrome includes lacunar infarction in the thalamus, although it can also be secondary to intracerebral hemorrhage or cortical injury, of the internal capsule, parietal, mesencephalic or pontine (related to the pons or bridge, a structure located at the base of the brain).

There is still not much information regarding the different types of lacunar infarcts that can cause the pure sensory syndrome, as well as differences between lacunar-type and non-lacunar-type strokes lacunar.

However, the studies carried out indicate that in 80-90% of cases, the cause of pure sensory syndrome is lacunar infarction; and in the remaining 10% of cases, the causes would be varied, including atherothrombotic infarcts, primary intracerebral hemorrhages, and other types of infarcts of unknown etiology.

• You may be interested in: "Lacunar infarction: causes, symptoms and treatment"

Symptoms

Pure sensory syndrome causes a series of sensory symptoms that usually affect the face, arm and leg on one side of the body (facio-brachio-crural hemi-hypoesthesia).

The most common symptoms include: hypoesthesia (reduced sensitivity) isolated without motor involvement, paralysis on one side of the body or hemiplegia, the dysarthria (difficulty articulating sounds and words), nystagmus (uncontrollable and involuntary movement of the eyes) and defects visual or cognitive (impairments in executive functions, such as semantic fluency or short-term verbal memory term).

This lacunar syndrome also can be associated with neuropathic pain, and the epicritic sensitivity (which allows discriminating both the quality and the localization of a sensory stimulus), protopathic (opposed to epicritic) sensitivity, or both.

Other types of symptoms such as paresthesias (numbness and tingling in the body, mainly the extremities) are usually infrequent, as is isolated proprioceptive loss, which involves the ability to know the relative position of the body and muscles at all times.

Hypoesthesia that occurs in pure sensory syndrome can be faciobrachial, facio-brachio-crural, facio-crural, or trunk and crural, with frequent thalamic topography, and that which occurs in the fingers can be associated with parietal cortical lesions. Other patterns with this same symptom have also been associated with lesions in the Brain stem.

Treatment

One of the maxims when treating pure sensory syndrome and, in general, any type of lacunar infarction, is intervene on time. This means that treatment must be urgent, since the first hours after the stroke are crucial, and a difference in hours can mean that the patient survives or not.

After the heart attack the person should be taken to the nearest hospital as soon as possible to start treatment as soon as possible (within the first 3 hours after the injury), usually by use of anticoagulant drugs that remove the occlusion and allow the blood supply to flow again with normal. Sometimes brain surgery is required, but it is not usual.

After surgery, the patient You must begin a rehabilitation that includes visiting different professionals from various health branches.

Physiotherapy and medical monitoring

The role of the physiotherapist is to help the patient restore motor functions, mainly by performing exercises with the affected joints. The professional must take special care not to generate further complications in the patient's body and extremities, which will be very weak after the heart attack.

For his part, the specialist doctor (the neurologist, in this case) will be in charge of carrying out a follow-up of possible neurological complications and may request any type of test required (a CT scan, MRI, etc.).

neuropsychological rehabilitation

The role of the neuropsychologist in these cases is to rehabilitate higher cognitive functions that have been affected. In lacunar infarctions, for example, the executive functions, which are in charge of planning, the review and evaluation of complex information that helps the individual to adapt to the environment and achieve goals effectively.

The neuropsychologist, through the application of individualized programs and the performance of specific tasks, will help the patient to restore and/or compensate the deficits caused by the injury, so that the person recovers their autonomy and can once again be functional in all areas of their life (family, work and socially).

Occupational and psychological therapy

The main objective of occupational therapy is enable the patient to participate in activities of daily living. The work of the occupational therapist is to facilitate that the individual, after the recovery period, be able to modify his environment so that he can return to participate in social activities and community.

Psychological therapy will serve the patient to improve skills that have been diminished and to recover from damage on an affective level that a disorder of this type causes in the patient and his closest environment. The psychologist must provide the patient with the necessary tools to achieve that psychological well-being and vital balance that every person needs after a process like this.

Bibliographic references:

• Arboix, A., García-Plata, C., García-Eroles, L., Massons, J., Comes, E., Oliveres, M., & Targa, C. (2005). Clinical study of 99 patients with pure sensory stroke. Journal of neurology, 252(2), 156-162.
• Fisher CM (1965) Pure sensory stroke involving face, arm and leg. Neurology 65:76-80.
• Grau-Olivares, M., Arboix, A., Bartrés-Faz, D., & Junqué, C. (2004). Neuropsychological alterations in lacunar type cerebral infarcts. Mapfre Medicine, 15(4), 244 - 250.