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ЗмістIntrauterine development of nervous system
The age peculiarities of nervous system
Neurologic evaluation in children
Stance and Locomotion
Independent work of the students
Bukovinian State Medical University
Department of Developmental Pediatrics
to the practical class for medical students of 3-rd years
Modul 1: Child’s development
Subject: THE AGE ANATOMICAL AND PHYSIOLOGICAL PECULIARITIES OF THE NERVOUS SYSTEM IN CHILDREN. NEUROLOGIC EVALUATION IN CHILDREN. CONGENITAL ANOMALIES OF THE NERVOUS SYSTEM.
It is completed by:
MD, MSc, PhD Strynadko Maryna
Chernivtsy – 2007
The evaluation of the infant or child with a suspected or certain neurological disorder requires both a carefully elicited history and an accurate assessment and interpretation of physical signs. Also necessary is a working knowledge of the expected rate of growth and development of the child and the accepted range of deviation from the norm. It is essential that the history include adequate information regarding the child's prior health, acquisition or loss of developmental milestones, family history, and social as well as physical environment. Such considerations may modify the child's response to illness or provide clues to inciting factors.
Nervous system develops from ectoderm on the end of the 2nd week. During the 3d week the primary neural plate forms. Later it divides into neural tube, which later gives rise to the spinal cord and the brain, and neural crest cells, which form the peripheral nervous system, meninges, melanocytes, and adrenal medulla. The most intensive dividing of nervous cells takes place during the period from 10th till 18th weeks of gestation that is the critical period of formatting of central nervous system. Any insult (e.g., infectious, metabolic, toxic, or vascular disorders) sustained during this period is likely to impair brain growth.
The brain is the most morphologically developed organ at birth, but its functional abilities are immature. The brain weight consists 1/9 of body weight in newborns. It doubles by the end of 1 year and is elual 1 /11-1/12 of body weignt, at the age of 5 years - 1/13-1/14 and in adult - 1 /40 of body weight.
The brain tissue is characterized by rich vascularization, but the back-flow of blood is weak that courses easy development of brain edema and collecting of toxin substances.
The neurocyte needs as much as in 22 times more oxygen than any somatic cell. That is why lots of diseases in infancy lead to development of hypoxic encephalopathy.
The amount of cerebrospinal fluid in newborn is equal 30-40 ml, in 12 month - 40-60 ml, and it enlarges to 150 ml by reaching adolescence.
Lumbar Cerebrospinal Fluid
The adult person has got 16 billion of neurocytes. At birth the quantity of mature neurocytes is 25% of the amount of all undifferentiated cells situated in the rain. By the end of the 6th month they reach 66 %, and at the age of 1 year - 90-95%. At 18 months all 100 % of neurocytes are similar to those of adult. That is why the proper nutntion, development, caring of the child and absence of diseases are so important during this period.
It is instructive to report the presenting symptom in the words of the child or, when this is not possible, the parent or caretaker. Citing the problem in its simplest terms emphasizes the importance of the child's own perception of his or her illness and also encourages an approach that considers all relevant disease mechanisms rather than focusing prematurely on a specific diagnosis. For example, a child who is "not walking right" may be experiencing symptoms of rapid ventricular enlargement; drug intoxication; midline cerebella dysfunction; spinal cord compression; peripheral neuropathy; primary muscle disease; or traumatic or inflammatory disease of bones, joint or soft tissue of the lower limb.
When eliciting an historical account of the child's presepresent illness the examiner must attempt to define the disease process with respect to both time course and localization within the nervous system. Before focusing on a specific diagnosis, answers to each of the following questions should be found: (1) is the disease acute or chronic? (2) Is the disease static or progressive? (3) Is the disease focal or diffuse?
The history of the present illness should incorporate information provided by child and parents as well as observations of other individuals such as teachers, baby sitters, referring physicians or other health care providers. Information that the child fails to acnieve expected milestones; a progressive disease in which previously acquired skills are lost; or a recurrent illness in which, despite dramatic symptoms or signs, the child returns to his or her baseline level of junction should be reported. Warning or premonitory symptoms are particularly relevant when evaluating paroxysmal or intermittent illnesses such as migraine or epilepsy. Exacerbating or ameliorating factors should also be sought. Inquiry should be made into associated systemic complaints such as nausea, weight loss, fever, pallor and visceral enlargement. Results of previous diagnostic studies should be obtained to avoid untimely delays or repetition of costly or invasive procedures.
If not already elicited in the history of the present illness, the past history should include details of the mother's pregnancy, length of gestation, exposure to drug or substance abuse, and complications of labor and delivery. A chronologic account of growth and development will often provide critical information regarding the onset and tempo of neurological impairment. Specific details regarding acquisition of language, cognitive and social skills, and motor milestones may help distinguish a global or pervasive syndrome from one that affects a more restricted area of function. Changes in school performance and level of activity or personality may be illuminating. Inquiry also should be made regarding common infectious diseases, transfusions, immunizations, trauma, and exposure to environmental toxins, and unusual dietary habits.
Health status of immediate family members should be elicited. History of unusual birthmarks or tumors may provide clues regarding a possible neurocutaneous syndrome. Specific inquiry should be made into family history of seizures, migraine, neuromuscular disease, learning disability, or early infant demise. When positive for one or more of the above, a sketch of the family pedigree may help delineate the pattern of inheritance.
Height, weight, and head circumference should be measured and recorded on appropriate standardised grids preferably with previously obtained values. In the case of the child in whom a large head size is of concern, serial measurements are of particular interest in order to distinguish a bening process from the consequences of increased intracranial pressure. Enlargement of anterior and posterior fontanels or diastasis of cranial sutures are other signs that may occur in the absence of symptoms of intracranial hypertension. A careful funduscopic examination should be attempted in every child being evaluated for a neurological disorder, noting the presence or absence of optic disc elevation, atrophy, vascular engorgement, hemorrhage, or abnormal retinal pigmentation. It should be remembered, however, that the optic discs might appear entirely normal early in the course of acute, life-threatening elevation of intracranial pressure. The spine should be examined for the presence of head tilt, neck stiffnes, resistance to flexion of the hips with the knees extended ( "straight leg praising", Kernig sign), tenderness or spasm of the paraspinal muscles, unusual dimples, skin tags, or palpable defects of the vertebral column Scoliosis and limb asymmetry should also be noted. Cardiac auscultation should be performed especially in the setting of possible cerebrovascular disease or brain abscess. Visceral enlargement toted on examination of the abdomen may provide critical information in the child with acute loss of neurological function resulting from a systemic malignancy or with developmental delay from an inborn error of metabolism. Examination of the skin for areas of abnormal pigmentation is best accomplished with the child completely disrobed. Axillary and other intertrigenous regions should not be overlooked because "freckles" in these areas may help identify the child with neurofibromatosis. Illumination of the skin with ultraviolet light may accentuate depigmented "ash leaf spots" associated with tuberous sclerosis. Although 50% or more of children with these neurocutaneous syndromes may represent new mutations, examination of the parents may yield important data for purpose of genetic counseling or clarification of an otherwise uncertain diagnosis.
With the exception of emergent situations such as status epilepticus or coma, the neurological examination shold be enjoyable for both child and examiner. Every effort shold be made to put the child and parents at ease.
The initial phase and often most revealing aspect of the neurological examination consists of observation. The child should be observed at play, interacting with parents, moving about the room and exploring the surroundings while the history is being taken. Deliberate attention should be directed to social skills, attention span, and quantity of motor activity. Observing their reactions to the child in the examining room can also make a preliminary assessment of the parents' expectations and coping skills.
The neurological examination, while recorded in a stereotyped orderly fashion, must be performed in a manner that is flexible and adapted to accommodate each child at his or her own level of function and development. Tasks requiring the greatest level of attention are best done early in the session, whereas potentially uncomfortable tests such as eliciting a Babinski sign are deferred until the end of the examination. By following these basic guidelines, even subtle deficits may be detected by the careful examiner.
The mental status examination includes assessment of level of alertness; orientation with respect to awareness of self, place, and time; mood; affect; expressive and receptive language; abnormal thought content (i.e., hallucinations or delusions); memory; problem solving; and abstract reasoning and insight. More than other aspects of the neurological examination, mental status must be evaluated in the context of what is expected for age and level of development. When indicated, more detailed evaluation of cognitive function and academic achievement should be assessed by a trained individual using standardised test instruments.
Whether the task is maintaining an upright sitting position on the floor or toddling down the corridor, the ability of a child to maintain his posture against gravity and to move about should be noted. The presence of trunk and proximal hip girdle weakness may be revealed by a "waddling" gait or by "climbing up the; thighs" when arising from the floor (Gower maneuver). Loss of proprioception or awareness of joint position can be demonstrated as loss of balance provoked by eye closure (Romberg sign). Peripheral neuropathy may be manifested by impairment of dorsiflexion of the feet at the ankles, leading to either a "slapping" gait or inability to "walk on the heels". Dystonic postures of the upper limb, toe walking or torsion of the foot are frequently seen with a hemiparetic gait because of corticospinal tract involvement or with torsion dystonia.
Examination of the motor system includes assessment of muscle power, tone, and bulk, often the earliest signs of weakness are those detected by simply noting persistent asymmetries in the child's spontaneous activities. Thus, disuse or paucity of movement of one arm in an infant may be an early sign of significant hemi paresis. Games in which the child is asked to hold his or her arms out like "Superman" or as if to "catch some raindrops" while closing the eyes may elicit drift or pronation of the weaker limb. Muscle tone is estimated by the amount of resistance or recoil encountered while gently moving the limbs through their expected ranges of motion. Although increased muscle tone is considered a hallmark of lesions of the upper motor neuron (i.e., motor cortex and corticospinal tract), injury to the brain or spinal cord often produces decreased muscle tone acutely with increased tone or "spasticity". Palpation enables the examiner to better appreciate the presence of muscle pseudohypertrophy as in Duchenne muscular dystrophy, loss of muscle bulk as in spinal muscular atrophy.
Assessment of sensory function should be attempted even when cooperation is limited by young age. Observation of withdrawal to lignt touch or grimacing in response to noxious stimuli will provide a gross estimate of sensory level in an infant. In children older than 2 or 3 years patience will permit testing of perception of light touch, temperature, vibration, and join position. Pain perception can be evaluated using the sharp edge of a brouken sterile cotton swab. Care should be exerted to avoid breaking the skin or otherwise alarming the child. Safety pins or other sharp objects should be used only if sterility of the test object can be assured.
Myotactic or muscle stretch reflexes, inaccurately referred to as deep tendon reflexes, can be elicited at virtually all ages. Although absent or difficult to elicit in certain otherwise normal individuals, loss of muscle stretch reflexes is an early and frequently persistent sign of acquired neuropathies such as Guillain-Barre syndrome or vincristine toxicity. In contrast, muscle stretch reflexes are usually preserved late into the course of most primary muscle disorders. Muscle stretch reflexes are considered to be pathologic when asymmetric, clearly exaggerated, or accompanied by reduplication of the muscle contraction referred to as clonus. Other pathologic reflexes not mediated through the myotactic arc include the Babinski sign. Persistence of certain primitive reflexes such as the Moro, grasp, rooting and sucking well beyond the ages at which they are normally extinguished may be a sign of diffuse cerebral dysfunction.
Performance of certain maneuvers such as touching finger-to-nose and heel-to-knee-to-shin requires smooth regulation of the force and velocity of contraction of agonist and antagonist muscle groups while maintaining stable posture of the remainder of the body during the course of the task. Decomposition of such coordinated activities leads to typical signs of cerebella impairment.
Neurological evaluation of infants and children requires a detailed history, careful observation of the patient, and accurate interpretation of symptoms and physical signs. Ultimately, the data derived in this process should provide a tentative localization of the site of dysfunction within the nervous system and also a chronologic profile of disease progression. While laboratory and imaging studies are often necessary to establish a diagnosis, an accurate history and physical examination are mandatory in order to determine what studies are appropriate and how a definitive diagnosis may be made in the safest, least invasive, and most efficient manner.
Make a general conclusion on a theme of a class №1 and conducted practical work.
1. Nursing care of Infants and Children / editor Lucille F. Whaley and I. Wong. Donna L. - 2nd ed. - The C.V. Mosby Company. - 1983. - 1680 p.
2. Nykytyuk S.O. et al. Manual of Propaedeutic Pediatrics. – Ternopil: TSMU, 2005. – P. 6-22.
3. Pediatric Nurse Practitioner Certification Review Guide / editor, Virgina layng Milloing: contributing authors, Ellen Rudy Clore and all. - 2nd ed. - Health Leadership Associates,Inc.,1994. - 628 p.
4. Nelson Textbook of Pediatrics / edited by Richard E. Behrman, Robert M. Kliegman, Ann M. Arvin; senior editor, Waldo E. Nelson - 15th ed. - W.B.Saunders Company, 1996. - 2200 p.
5. Whaley L.F., Wong D.L.: Nursing care of infants and children, St. Louis, Toronto, London, 1983.
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