Manuals 2 SENSITIVITY AND ITS DISORDERS PDF

MINISTRY OF HEALTH OF THE REPUBLIC OF BELARUS ESTABLISHMENT OF EDUCATION "GOMEL STATE MEDICAL UNIVERSITY" Department of Neurology and Neurosurgery with courses of Medical Rehabilitation, Psychiatry, FCE and R METH...

MINISTRY OF HEALTH OF THE REPUBLIC OF BELARUS ESTABLISHMENT OF EDUCATION "GOMEL STATE MEDICAL UNIVERSITY" Department of Neurology and Neurosurgery with courses of Medical Rehabilitation, Psychiatry, FCE and R METHODOLOGICAL DEVELOPMENT for 4th year students of the faculty of foreign students in neurology and neurosurgery Topic 2: SENSITIVITY AND ITS DISORDERS Time 6 hours Author: Head of the Department of Neurology and neurosurgery with medical courses rehabilitation, psychiatry, FPKiP N.N. Usova Senior Lecturer, Department of Neurology and neurosurgery with medical courses rehabilitation, psychiatry, FPKiP E.V.Serebrova Gomel, 2022  Scientific and methodological substantiation Reception is one of the most important functions of the body. Sensory disorders accompany most diseases of the nervous system and are an important criterion for topical diagnosis. Knowledge of the symptoms that develop when the structures responsible for sensitivity are affected is necessary for the correct diagnosis and further therapeutic tactics. The performance of voluntary and automated movements is impossible without the normal functioning of the cerebellum, which is responsible for maintaining muscle tone and coordination. Damage to the cerebellum is caused by a variety of disorders, the knowledge of which is necessary in the preparation of students. Differential diagnosis of various types of ataxia is a prerequisite for the formation of a doctor of any profile. Target: Teaching students the basics of topical diagnosis of lesions of the nervous system, accompanied by sensory disturbances and pathology of the cerebellum, the methodology for studying the sensitivity of cerebellar disorders, as well as the differentiation of various forms of ataxia. Tasks: The student must know: anatomical and physiological principles of organization of the human sensitive sphere; methodology for the study of surface sensitivity and deep muscle feeling; symptoms of tension to determine the severity of the pain syndrome; principles of topical diagnosis of lesions of various departments of conduction pathways of deep and superficial sensitivity; structure of the cerebellum, its ascending and descending connections; syndromes of damage to the hemispheres and cerebellar vermis; types of ataxia. The student must be able to: explore different types of surface sensitivity (pain, temperature, tactile); explore deep muscle feeling, vibrational sensitivity; determine the symptoms of tension of the nerve trunks; explore muscle tone; investigate the symptoms of damage to the hemispheres and cerebellar vermis. The student must be proficient in: a method of special questioning and examination of patients with lesions of the sensitive sphere and pathology of the cerebellum. Questions for self-study 1. The concept of reception, sensation, perception. Pathways of superficial sensitivity. 2. Pathways of deep sensitivity. 3. Methodology for the study of deep and superficial sensitivity. 4. Types of sensitivity disorders. 5. Types of sensory disorders (peripheral, spinal, cerebral).  6. Sensitive ataxia. Segmentally dissociated sensory disorder. 7. Brown-Sekara syndrome. 8. Symptoms of tension ( Lasegue , Matskevich, Wasserman ). 9. Cerebellum. Anatomy, functions. Anterior and posterior spinal tracts. 10. Cerebellar ataxia: types, symptoms, research methods. Didactic tools for organizing students' independent work:  Working program in neurology and neurosurgery.  Educational and methodical manual for a practical lesson for students.  Text of lectures on neurology and neurosurgery.  Situational tasks in neurology and neurosurgery.  Test control of the level of knowledge in general and particular neurology and neurosurgery (a teaching aid for a practical lesson for students).  Brain model, models of the skull and spine, models of topical sections of the brain and spinal cord.  Sets of training tables in general neurology.  Devices and kits for the study of neurological status. Answers to the questions of the topic Sensitivity - the ability of the body to perceive irritations emanating from the environment or from its own organs and tissues. In physiology, the entire set of afferent systems is united by the concept of reception. Sensitivity is a special case of reception, when afferent impulses lead to the formation of sensations. Not everything that undergoes reception is felt (for example, the paths of Govers and Flexig ). Irritants of the external environment are perceived by a person with the help of specific functional systems-analyzers. Analyzers are functional combinations of structures of the peripheral and central nervous system ( CNS ), which carry out the perception and analysis of information from the external and internal environment. Structurally, analyzers are divided into three main sections. 1. Receptor formations that perceive and transform specific stimuli (peripheral section). 2. A conductor system with switching neurons that transmit a centripetal impulse ( conductive section). 3. The cortical end of the analyzer, in which the highest analysis and synthesis of the received excitations takes place (cortical section). Receptors (and, in accordance with them, sensitivity) are divided into general and special (associated with the sense organs). The former are subdivided into:  exteroreceptors - pain , temperature ( Krause bulbs, Ruffini bodies ), tactile ( Vater-Pacini bodies, Meissner , Merkel , Golgi-Mazzoni bodies ) - superficial sensitivity;  proprioceptorslocated in muscles , tendons, ligaments, joints - deep sensitivity;  complex forms of sensitivity: a sense of localization, a two-dimensional- spatial sense (writing letters, numbers, signs), etc.;   and interoreceptors located in the internal organs - baro- and chemoreceptors - interoceptive sensitivity, i.e. sensation due to irritation of the receptors of internal organs. Pathways of superficial and deep sensitivity Conductors of pain, temperature and partially tactile sensitivity (spinothalamic pathway) The first pseudounipolar neuron is located in the spinal ganglia. The peripheral process as part of the posterior sensory root, spinal nerve, plexus, peripheral nerve goes to the receptors of the corresponding dermatome , from where pain, temperature and tactile irritations come through the extrareceptors. Axons, entering through the posterior root into the substance of the spinal cord, form a synapse with the second neuron at the base of the posterior horn. The axon of the second neuron goes obliquely and upwards, 1–2 segments higher and in the region of the anterior gray commissure passes to the opposite side, and entering the lateral funiculus of the opposite side, goes up along with similar fibers that entered the lateral funiculus below. A bundle is formed that passes through the entire spinal cord and brain stem. In the pons and midbrain, it adjoins the lemnicus on the dorsal side. medialis and ends in the ventrolateral nucleus of the thalamus. According to the place of beginning and end, this path is called spinothalamic. The axons of the third neuron (thalamic) through the posterior third of the posterior leg of the internal capsule as part of the thalamocortical pathway are sent to the postcentral gyrus and superior parietal lobule. The fibers of the lateral spinothalamic tract are distributed in a certain way: from dermatomeslocated below (for example, legs) , the fibers lie outward, and from those located higher (arms) - inwards. Such a pattern of arrangement of long conductors, or the law of the eccentric arrangement of long conductors (Auerbach - Flattau law ), is important for topical diagnostics. With an extramedullary tumor, the zone of superficial sensitivity disorder begins with the distal legs, and with further growth spreads upwards (ascending type of sensitivity disorders). With an intramedullary tumor, the zone of sensitivity disorders, on the contrary, spreads from top to bottom (descending type). Conductors of deep , vibrational and partially tactile sensitivity (paths of Goll and Burdakh ). The first neuron of this pathway is represented by cells of the spinal ganglion. The axon enters the posterior funiculus of its side, giving off a branch to form an arc of the segmental reflex, then ascends to the medulla oblongata. The totality of these ascending fibers forms thin and wedge-shaped bundles ( Gaull and Burdach bundles ). In the course of the fibers of the posterior cords, there is the following feature - the newly arrived fibers lie outwards. Therefore, in the medially located thin bundle (Gaulle), fibers from the lower limb pass, and in the lateral wedge-shaped ( Burdaha ) - from the trunk and arm, starting at the level of the Th 5 vertebra. The axons of the first neurons at the level of the caudal sections of the medulla oblongata end in the nuclei of the same name. Here are the bodies of the second neurons. Their axons pass to the opposite side and take an upward direction. According to the place of the beginning and end of the second neuron, this path was called bulbo-thalamic. Connecting after the transition on the opposite side with the spinothalamic pathway, it forms a medial loop. The third neuron of this bulbo- thalamic pathway is located in the ventrolateral nucleus of the thalamus; its axon passes through the posterior third of the posterior pedicle of the internal capsule to the postcentral gyrus and superior parietal lobule. Sensory Disorder Syndromes Types of sensitivity disorders:  Anesthesia is the loss of some kind of sensation. There are anesthesia tactile, thermal ( thermoanesthesia ), pain (analgesia);  hypoesthesia - incomplete loss, decrease in sensitivity and / or its individual types;  hyperesthesia - hypersensitivity;  hyperpathy - characterized by an increase in the threshold of perception ;  dysesthesia - a perversion of the perception of irritation: touch is perceived as pain, cold as heat;  polyesthesia - a single irritation is perceived as multiple;  synesthesia - a feeling of irritation not only at the site of its application, but also in some other area;  allocheiria - irritation is localized not where it was applied, but on the opposite side of the body, usually in a symmetrical area. Characteristics of sensitive phenomena that occur without the application of external stimuli - pain and paresthesia Paresthesia - pathological sensations experienced without external irritation can be extremely diverse (crawling, hot or cold, tingling, burning). Pain is a real subjective sensation caused by an applied (too intense) irritation or pathological process in the body. Pain is local, projection, radiating and reflected. Types of Sensory Disorders Peripheral option:  the neural type in case of damage to the trunk of a peripheral nerve is characterized by a violation of all types of sensitivity in the area of \u200b\u200bthe zone of skin innervation of the nerve;  polyneuritic - sensitivity is disturbed in the distal parts of the arms and legs by the type of "gloves and socks";  plexus - there is a disorder of all types of sensitivity in the corresponding territory innervated by the nerves of this plexus;  ganglionic - pain and impaired sensitivity along the spine. Often occurs with herpes zoster or with damage to the ganglion ( spinal, trigeminal );  radicular type - paresthesia, pain, violation of all types of sensitivity in the corresponding dermatomes. Segmentally dissociated type occurs when the posterior horns of the spinal cord are affected (syringomyelia, tumors of the spinal cord) and is characterized by a disorder of superficial sensitivity in the dermatome corresponding to this segment on the side of the lesion. The defeat of the anterior gray commissure causes a sensitivity disorder on both sides of the "jacket" type. Tactile and deep sensitivity remain intact.  The conduction type occurs when the spinal cord is damaged and is characterized by a sensory disorder 1–2 dermatomes below the level of the lesion. The cortical type is characterized by a sensory disorder on the opposite side of the body like monohypesthesia or monoanesthesia , and when the area of the cortex is irritated, it manifests itself in sensory Jacksonian seizures. When half of the diameter of the spinal cord is affected (Brown- Sequard syndrome ), due to a tumor or grass, deep sensitivity is disturbed on the side of the focus and paresis of the extremities occurs, and on the opposite side, a violation of pain and temperature sensitivity according to the conduction type. Tension symptoms: - Lasegue 's symptom - flexion of the straightened leg in the hip joint accompanied by the occurrence of pain in the lower back and on the back surface of the lower leg and thigh ( 1st phase); further bending of the leg in the knee joint leads to a decrease in pain ( 2nd phase). - Matskevich's symptom - in the position of the patient lying on his stomach , flexion of the leg at the knee joint is accompanied by pain along the anterior surface of the thigh and in the inguinal region. Wasserman 's symptom - in the position of the patient lying on his stomach , leg extension in the hip joint is accompanied by pain along the anterior surface of the thigh and in the inguinal region. Disorder of deep muscle ( proprioceptive ) sensitivity manifests itself in the form of sensitive ataxia. At the same time, patients have difficulty and unsteadiness when walking, which are significantly increased in the dark and with their eyes closed, as a result of which patients are forced to walk under visual control. A classic example of diseases accompanied by sensitive ataxia are funicular myelosis with B 12 -deficiency anemia and dorsal tabes - with neurosyphilis. Research methodology To identify sensory disorders with a needle, a test tube with cold and warm water, a brush, pain, temperature and tactile sensitivity are checked. Deep muscle sensation is tested by making passive movements in the joints of the limbs, while the subject with his eyes closed must indicate the location and direction of movement. Vibration sensitivity is examined with a tuning fork C (256 vibrations per minute) for 14–16 s or with a vibration tester MBN VG -01-1. Cerebellum The cerebellum (weight 120–150 g) is located in the posterior cranial fossa ( PCF ). The middle part of the cerebellum is called the vermis. On either side of it lie the hemispheres of the cerebellum - right and left. The cerebellum is divided into convolutions by parallel arcuate grooves. The cerebellum has three pairs of legs: the upper pair connects the cerebellum to the midbrain, the middle pair to the pons , and the lower pair to the medulla oblongata. In the depths of the cerebellum, the gray matter forms nuclei: dentate, corky, spherical, and the nucleus of the tent. The cerebellum performs the function automatic coordination of movements , participates in the regulation of muscle tone and body balance. The cerebellum receives afferent impulses from all receptors that are irritated during movement (from proprioceptors, vestibular, visual, auditory, etc.). Receiving information about the state of the motor apparatus, the cerebellum affects the red nuclei and the reticular formation, which sends impulses to the gamma motor neurons of the spinal cord, which regulate muscle tone. In addition, part of the afferent impulses through the cerebellum enters the motor area of the cerebral cortex. Efferent impulses from the cerebellar nuclei regulate proprioceptive stretch reflexes. The main afferent and efferent connections of the cerebellum: the Flexig path (posterior spinocerebellar), not crossed; gowers path (anterior spinocerebellar), crossing twice; fronto- bridge -cerebellar path; occipital-temporal-cerebellar path. The efferent pathway is descending, from the cerebellum passes through the red nucleus, making two decussations. The first of them is carried out in the upper cerebral sail (Wernicking's cross - supranuclear cross ), after which the axons approach the red nucleus and switch to the next neuron. Its axons form tractus rubrospinalis , making a subnuclear decussation , or Trout decussation , after which they lie in the lateral funiculus of the spinal cord, immediately in front of the tractus corticospinalis lateralis. The last neuron of this pathway is the small γ - motoneuron of the anterior horns of the spinal cord. Thus, the cerebellar hemispheres receive sensitive information from their half of the body and coordinate the movements of the side of the same name. existing intersections of the cerebellar afferent and efferent systems lead to a homolateral connection of one hemisphere of the cerebellum and limbs. Therefore, when the hemisphere of the cerebellum or the lateral columns of the spinal cord are affected, cerebellar disorders are observed in their own half of the body. The hemispheres of the brain are connected to opposite hemispheres of the cerebellum. In this regard, when suffering from the brain or red nuclei, cerebellar disorders are observed on the opposite half of the body. In the cerebellum there is a certain somatotopic. It is believed that the cerebellar vermis is involved in the regulation of the muscles of the body, and the cortex of the hemispheres is involved in the regulation of the distal extremities. As a result, static and dynamic ataxia are distinguished. Damage symptoms Static ataxia is due to the function of the cerebellar vermis. Upset mostly standing and walking. The gait resembles the gait of a drunk. Turning is especially difficult. In the Romberg position , the patient sways or cannot stand at all with the feet shifted. Asynergy appears ( Babinsky 's test, Stuart-Holmes' "reverse push" syndrome). Types of ataxia: sensitive, cerebellar (static and dynamic), vestibular, frontal, hysterical (astasia-abasia). Dynamic ataxia depends mainly on damage to the cerebellar hemispheres. When performing a finger-nose test, overshooting and intentional tremor are observed. With a heel -knee test, the patient does not hit the knee with the heel, the heel slips to the side when held along the lower leg. Observed adiadochokinesis and hypermetry.  With the defeat of the cerebellar systems, other simple and complex acts are also upset: speech ( bradilalia , scanned speech), handwriting ( megalography ), nystagmus. In patients with cerebellar lesions, muscle hypotonia is also observed. Research methodology To identify cerebellar disorders, a walking study is performed, a check of stability in the Romberg position , Babinsky 's test, a Stewart-Holmes test, coordinating finger-nose and calcaneal -knee tests, a test for adiadochokinesis , hypermetry , detection of speech disorders, handwriting, nystagmus, and muscle tone testing. Vestibular ataxia develops when the vestibular apparatus is damaged and has a static character. With vestibular ataxia, the following clinical symptoms are characteristic: dizziness of a systemic nature, increased excitability of the vestibular apparatus to special loads. In the Romberg position , the patient loses his balance and always falls in a certain direction. The disease occurs when the inner ear, vestibular nuclei and pathways are affected in various pathological processes. Sensitive ataxia occurs when there is a loss of receptors or pathways of proprioceptive sensitivity in any area. At the same time, the clarity of movements is upset. An atactic gait is observed: the patient spreads his legs wide, bending and unbending them disproportionately , hitting the floor with his heel (“punching”, “ tabetic ” gait). in switching off of sight sharply increases an ataxy. Sensitive ataxia is observed with polyneuropathy , funicular myelosis , tabes of the spinal cord, Fredreich 's familial ataxia. Astasia - abasia (from the Greek stasis - standing and basis - walking) - the inability to walk, stand due to a sharp violation of coordination of movements. It is observed with damage to the frontal- bridge -cerebellar pathways and in hysterical conditions. Astereognosia is a disorder of recognition of an object when it is felt (touched). True astereognosis is astereognosis in which all types of sensitivity in the hand are preserved. It is caused by the loss of synthetic ability due to damage to the left supramarginal gyrus in right-handers. Secondary astereognosis ( stereoanesthesia ) is caused by loss of musculo- articular and tactile sensitivity.  List of used literature 1. Karpov, S. M. Topical diagnosis of diseases of the nervous system = Топическая диагностика заболеваний нервной системы : учебник на англ. и рус. яз. / С.М. Карпов, И.Н. Долгова. – Москва : ГЭОТАР-Медиа, 2018. – 896 с. 2. Neurology : textbook for students of higher education establishments – med. univ., inst. and acad. / ed. by I. A. Hryhorova, L. I. Sokolova. – 2nd ed. - Kyiv : AUS Medicine Publishing, 2021. – 623 p., col. insert sh. : ill., tab. – Approved by the Min. of education and science of Ukr. – Approved by the Min. of health of Ukr. as a nat. textbook.