CHAPTER IX NERVOUS DISEASES (Part 1)

CHAPTER IX NERVOUS DISEASES ANATOMY OF THE NERVOUS SYSTEM The central nervous system is composed of the brain, the spinal cord, and their coverings. The brain is contained within the cavity of the skull. It is the center of thought, of the perception of the five senses, and of the voluntary motor activities of the body. Fig. 47. — Functional areas of the cerebral cortex, left hemisphere (A. A. Stevens). The brain or cerebrum is divided into the right and left hemispheres by the median fissure. The two hemis- pheres are united by fibers running through the corpus callosum. 168 NE'R I 'O US DISEASES i6g The lower portion is divided into the cerebellum, the crura, the pons, and the medulla. The brain is composed of gray and white matter, the gray matter be'ng external and about a half inch in thickness; it is called the cortex. The rest of the brain is made up principally of white matter and consists of nerve fibers running in various directions. The cortex presents upon its surface deep grooves, which are called fissures or sulci. These fissures are numerous and divide the brain into convolutions. This arrangement gives the greatest area of cortex in the smallest amount of space. The more de- veloped the convolutions, the greater the intellect of the individual. The fissures also divide the brain into different lobes, such as the frontal, temporal, and parietal lobes. The fissure of Sylvius is a large sulcus on the external lateral sur- face of the brain, and it receives a portion of the wing of the sphe- noid bone. The fissure oj Rolando runs from Jfefc^fcufi Bourgery ; Schwalbe). the center of the vault of the skull, downward and forward toward the car. Around I/O DISEASES OF CHILDREN FOR NURSES this fissure are located the motor centers of the body; that is, the nerve cells which form the nervous im- pulses, making voluntary motion possible. The arrangement of the motor centers is "upside down"; that is, the center for the legs is uppermost; then, in order, the center for the trunk, the arms, the face, and head, the last-named being the lowest in location. (See Fig. 47.) The nerve fibers run from the centers around the fissure of Rolando, through the internal capsule (a pathway in the substance of the brain), to the crura. A hemor- rhage within the internal capsule is the cause of hemi- plegia. The blood-clot, by exerting pressure, prevents any passage of nervous impulses, producing paralysis of the muscles supplied. The crura are two extensions of the brain, one from each hemisphere, which carry motor and sensory fibers. They unite and carry the fibers from both hemispheres as far as the pons. The pons is a bridge of nervous tissues. It not only contains the motor and sensory fibers from the cortex — carrying them from the crura to the medulla, the next portion of the nervous system below — but it also contains fibers rimning between the two hemispheres of the cere- bellum. The medulla or bulb is the lowest portion of the brain, and at the foramen magnum it becomes the spinal cord. The motor and sensory fibers decussate or cross from one side to the other in the medulla. On account of this crossing of fibers an injury to the left side of the brain produces a paralysis of the right side of the body (hemi- plegia). The medulla contains the center of the involun- tary movements, as respirations, etc. NERVOUS DISEASES 171 The motor 'fibers run through the anterior and lateral columns of the spinal cord and the sensory fibers through the posterior columns. At the level of the muscle to be supplied the motor fiber leaves the cord by one of the spinal nerves and runs through the branch of this nerve to the muscle. The sensory fibers run from the skin surface and return to the cord through the spinal nerve and enter the posterior columns of the cord. In the cerebellum is located the center 0] co-ordination. These centers keep all portions of the body working together in unison. The basal ganglia are isolated areas of gray matter within the white matter of the brain, and are associated with the special senses. The ventricles of the brain are cavities within its sub- stance. There are four in number, all connected and containing cerebrospinal fluid. The spinal cord is contained within the spinal column and is a continuation of the medulla. The pathways of the motor and sensory fibers are external, the gray matter being located in the center in the form of an H. The cord is divided into columns. The posterior column receives the sensory filaments through which they run on their way to the brain. The lateral columns and the anterior columns are com- posed of motor filaments running from the brain to the muscle. The central area of gray matter contains trophic cells in addition to motor fibers. Trophic cells supply the tissues with proper nervous tone; when they are injured bed-sores develop and atrophy of the muscles occurs. 1/2 DISEASES OF CHILDREN FOR NURSES The spinal cord contains most of the centers of reflex action. Since the posterior columns carry only sensory fibers, injury or disease of this part of the cord will cause a loss of sensation below the lesion {locomotor ataxia). Since the anterior and lateral columns carry only motor fibers, injury or disease of this part of the cord will cause paralysis below the lesion (myelitis and lateral sclerosis). Fig. 40. — Lumbar section of spinal cord showing main tracts of white substance and location of principal groups of nerve-cells in gray matter: a, Anterior median fissure; b, posterior median fissure; c, anterior horn of gray matter; d, posterior horn of gray matter; c, central canal; /, anterior white commissure; g, posterior white commissure; /;, i, anterior and posterior gray commissures; /, anterior median column; A', lateral column; L, posterior column; m, column of Clarke; >i, inner group of nerve cells; o, anterior group; p, anterolateral group; q, posterolateral group; r, lateral horn (Leroy'). The Meninges. — The brain and spinal cord are cov- ered by three membranes: the dura, the arachnoid, and the pia. The dura is a thick, fibrous structure lining the cavities of the skull and spinal canal, dipping into the median fissure and separating the cerebellum from the cerebrum. It also forms the venous sinuses of the brain and surrounds NERVOUS DISEASES 1 73 the cranial nerves. The function of the dura is to act as a protection to the structure enclosed. The arachnoid is a serous membrane and is very similar to the pleura and the pericardium. It surrounds the brain and cord, and is reflected so that there are two surfaces between which there is a closed sack, con- taining the cerebrospinal fluid. The sack is continuous with the ventricles of the brain. This arrangement not only lubricates the slight movements of the cord and the brain, but permits the central nervous system to rest on a cushion of water, which annuls many shocks. The pia is a thin meshwork of blood-vessels. It closely surrounds the brain and the spinal cord, dipping into the fissures and ventricles, and is the main blood-supply of the cortex and cord. The cranial nerves are twelve in number: (i) olfac- tory, (2) optic, (3) motor oculi, (4) pathetic, (5) trifacial, (6) abducens, (7) facial, (8) auditory, (9) glossopharyn- geal, (10) pneumogastric, (n) spinal accessory, (12) hypoglossal. They supply the organs of the special senses, the structures of the face, the head and the neck, and, through the pneumogastric, the lungs, the heart, and the stomach. The spinal nerves consist of thirty-one pairs. They leave the spinal cord at various levels and carry motor fibers to, and sensory fibers from, the trunk and the upper and lower extremities. The nerves supplying the various structures of the above parts of the body are branches of the spinal nerves. The sympathetic nerves control involuntary actions and keep the different parts of the body working smoothly together (co-ordination). 174 DISEASES OE CHILDREN EOR NURSES TERMINOLOGY The disturbances of motion are paralysis, convulsions, choreiform movements, and tremors. Paralysis may involve one member only, and it is then termed monoplegia; a lateral half of the body, when it is termed hemiplegia; or it may involve the body from the waist down, when it is called paraplegia. A convulsion is a condition in which there are excessive muscular contractions, continued or intermittent, depen- dent upon the involuntary discharge of the motor impulses from the nerve centers. Intermittent contractions are termed clonic; continued contractions, tonic. Convulsions may be general or local. The term spasm is sometimes applied to the latter. Varieties of convulsions: Epileptiform, tetanic, and hysteroidal. Epileptiform convulsions are characterized by uncon- ciousness, and for the most part the movements are clonic. They are preceded by an aura, and the patients bite their tongues. Tetanic Convulsions.— In this form the discharges emanate from the spinal cord and the convulsive move- ments are continuous and not associated with uncon- ciousness. Hysteroidal convulsions are manifestations of hysteria, and in them consciousness is only partially or apparently lost. They are not preceded by an aura, but sometimes by a sensation as of a ball in the throat. The eyes are partially closed, the face expresses some emotion, the tongue is not bitten, the movements are tonic, or, if clonic, NERVOUS DISEASES lf$ appear wilful. The paroxysm is of long duration and the patient frequently weeps or laughs. There are various local spasms, such as hiccough, croup, and laryngismus stridulus, etc. Choreiform movements are coarse, jerky, irregular, involuntary movements, which more or less simulate purposeful movements. Athetosis is the term applied to certain movements of the hands and feet in which there is a slow, twisting, interwinding, separation and extension of the fingers and toes. It is frequently observed in the cerebral palsies of children. Tremors are fine, vibratory movements due to the alternate contraction and relaxation of antagonistic groups of muscles. The knee-jerk is obtained by tapping the quadriceps tendon between its insertion and the patella while the legs are crossed. The value of the knee-jerk depends upon the mechanism of its production. This is called the reflex arc. It consists of the sensory nerve running from the patella tendon to the spinal cord, where it enters the reflex center. From this center the motor nerve runs to the muscle, causing it to contract. If the arc is broken by disease or injury to any one of its parts the knee-jerk is lost. When there is any irritating lesion of the cord the reflexes are increased. When there is any destructive lesion of the cord the arc is broken and the knee-jerks are absent. They are, therefore, a very important diagnostic symptom. Ankle clonus consists in a vibratory movement obtained by supporting the tendo Achillis with one hand while the foot is strongly flexed. 176 DISEASES OF CHILDREN FOR NURSES Babinski's reflex is obtained by tickling the sole of the foot; if there is an injury or disease of the central nervous system the great toe will move upward instead of downward, as it does normally. Sensation. — Anesthesia means loss of sensation. Hyperesthesia means exaggerated sensation. Parestliesia is used to indicate certain disagreeable sensations, such as numbness, tingling, itching, creeping, and feeling of "pins and needles." Arthropathies are degenerative changes of the joints. Coma is a condition of unconsciousness from which the patient cannot be aroused. Temporary unconsciousness due to anemia of the brain is termed syncope. Catalepsy is characterized by a peculiar stiffness of the muscles, and when this is overcome by force, the limbs can be placed in unnatural positions, which they retain for a long time. There may or may not be a loss of consciousness and sensation. PECULIARITIES OF DISEASE OF THE NERVOUS SYSTEM IN CHILDREN Owing to the immature development of the central nervous system, and to the great irritability of the per- ipheral or terminal sensory nerves, much more serious nervous symptoms are shown by children from trivial causes than are seen in adult life. Hence, conditions such as convulsions, tetany, St. Vitus' dance, and enuresis are common. The greatest factors in the cause of such conditions are stimulants, such as tea and coffee, and the fact that chil- dren live among exciting surroundings. Plenty of sleep NERVOUS DISEASES 1 77 and quiet are essential to the proper development of the nervous system. The effects of such conditions as infantile paralysis and birth palsies last through life. Hemorrhage of the brain is usually cortical, on the outside of the hemisphere, and not within its substance. Fig. 50. — Spina bifida (Eisendrath). Malformations. — Meningocele is a protrusion of the covering of the brain (meninges) through some abnormal opening in the skull or spinal canal. It contains cerebro- spinal fluid. When they are spinal in origin they are spoken of as spina bifida. Encephalocele is a protrusion of a portion of the meningus containing brain substance. Hydro-encephalocele contains both brain substance and fluid. Microcephalics is a name given to a small head due to under-development. I78 DISEASES OF CHILDREN FOR NURSES Hydrocephalus is an enlargement of the skull due to a large amount of cerebrospinal fluid within the ventricles. Other deformities are noted, such as absence of a whole or a part of the brain. Diseases of the Meninges MENINGITIS This is an acute or chronic inflammation of the mem- brane covering the brain and spinal cord. It is similar to tubercular meningitis, but not caused by the tubercle bacillus. These membranes, serous in character, surround the cranial and spinal nerves as they leave the brain and spinal cord; therefore, an inflammation of these mem- branes causes symptoms of irritation characterized by intense pain, together with the symptoms of inflammation, including fever. In cerebral meningitis there is involvement of the nerves of the special senses. This causes intolerance of sound and light. The same condition exists in meningitis, as in the course of inflammation of a serous membrane anywhere else in the body. An exudate develops, followed by pressure symptoms, and instead of irritation there is paralysis of those parts supplied by the nerves subject to the pressure of the exudate. Tubercular meningitis (cerebral) is an acute inflam- mation of the cerebral meninges excited by the tubercle bacillus. In children the disease may be primary or secondary to a focus of tuberculosis in some other part of the body. The majority of cases are seen between the second and fifth year. NERVOUS DISEASES 1 79 The basilar meninges covering the lower part of the brain are especially involved. The pons, crura, and medulla are covered with lymph which mats together in a common mass the adjacent nerves and blood-vessels. The fluid within the ventricles of the brain is increased. Symptoms. — The disease usually begins insidiously with dulness and irritability on the part of the child. Sleep is disturbed. The child twitches, grinds its teeth, and starts up with a cry of alarm. When the disease is Fig. 51. — Kernig's sign. The thigh is held at right angles to the body. When an attempt is made to extend the leg, bringing it into a line with the thigh, there is either marked resistance or an inability to extend the leg, if meningitis is present (Kerr). fully developed headache is intense and causes a shrill scream, known as the hydrocephalic cry. The special senses are extremely acute, bright lights and noises cannot be tolerated; the child becomes irritable when touched. The temperature ranges between 102 ° F. and 103 ° F. The pulse is rapid at first, but later is slow and irregular. The walls of the abdomen are flat. The child lies on its side with the limbs drawn up, the head is bent far back, I So DISEASES OF CHILDREN FOR NURSES the lingers are clenched over the thumbs which are turned into the palm of the hand. This is called opisthotonos. Convulsions are common and may be local or general. Toward the close of the stage the child becomes delirious. When the exudate is of sufficient amount to exert pressure, paralysis develops, especially in the muscles of the face. Coma follows the delirium, the eyes are rolled up, and blindness and deafness result. If the finger is drawn across the body a bright red line develops and remains Fig. 52. — Method of introducing needle in lumbar puncture: Child in lying posture (Boston). for some moments; this is called a tachc. In the last stage the pulse becomes weak, rapid, and irregular; respirations assume the Cheyne-Stokes characteristics, and the tem- perature falls. The duration is from one to three weeks. Kernig's Sign. — The inability to straighten out the leg when the thigh is bent upon the abdomen. It is present in cases of cerebral meningitis. Lumbar Puncture. — A tapping of the spinal canal to relieve tension or to obtain fluid for diagnostic purposes. The place selected is in the lower lumbar region. A long NERVOUS DISEASES l8l hypodermic needle is inserted between the vertebrae and through the membrane. As soon as it passes through the membrane the cerebrospinal fluid runs out of the needle. Injury to the cord is avoided by careful insertion, the distention of the spinal canal by the fluid lessening the danger. Antiseptic precautions must be absolute. Diseases of the Brain In diseases of the brain the centers for the various functions, such as motion, sensation, speech, hearing, seeing, smelling, and hearing, are interfered with. The pathways leading from the centers may be involved as they traverse the brain on their way to the spinal cord. Diseases of the brain are usually diagnosed by what are termed pressure symptoms, produced by clots, tumors, abscesses, cysts, etc. The minute anatomy of the brain is almost as well known as that of the spinal cord. The brain centers are definitely located