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STUDENT DIGITAL NEWSLETTER ALAGAPPA INSTITUTIONS |
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Christopher V. Chien, MD
With excessive worry spasms in lower abdomen order 60 ml rumalaya liniment visa, the ability to think with accustomed efficiency is reduced; the patient complains that his mind is not functioning properly and he is forgetful and unable to concentrate spasms hamstring discount rumalaya liniment 60ml fast delivery. If the patient is naturally of suspicious nature spasms vs seizures cheap rumalaya liniment 60 ml online, paranoid tendencies may assert themselves muscle relaxant liver disease buy discount rumalaya liniment 60 ml on-line. Indeed, most cases formerly diagnosed as hypochondriasis are now regarded as depression. Pain from whatever cause- a stiff joint, a toothache, fleeting chest or abdominal pains, muscle cramps, or other disturbances such as constipation, frequency of urination, insomnia, pruritus, burning tongue, weight loss- may lead to obsessive complaints. The patient passes from doctor to doctor seeking relief from symptoms that would not trouble the normal person, and no amount of reassurance relieves his state of mind. The anxiety and depressed mood of these persons may be obscured by their preoccupation with visceral functions. When the patient is examined, his facial expression is often plaintive, troubled, pained, or anguished. In other words, the affect, which is the outward expression of feeling, is consistent with the depressed mood. During the interview the patient may sigh frequently or be tearful and may cry openly. In some, there is a kind of immobility of the face that mimics parkinsonism, though others are restless and agitated (pacing, wringing their hands, etc. Occasionally the patient will smile, but the smile impresses one as more a social gesture than a genuine expression of feeling. The retardation extends to all topics of conversation and affects movement of the limbs as well (anergic depression). The most extreme forms of decreased motor activity, rarely seen in the office or clinic, border on muteness and stupor ("anergic depression"). Conversation is replete with pessimistic thoughts, fears, and expressions of unworthiness, inadequacy, inferiority, hopelessness, and sometimes guilt. In severe depressions, bizarre ideas and bodily delusions ("blood drying up," "bowels are blocked with cement," "I am half dead") may be expressed. Three theories have emerged concerning the cause of the pathologic depressive state: (1) that the endogenous form is hereditary, (2) that a biochemical abnormality results in a periodic depletion in the brain of serotonin and norepinephrine, and (3) that a basic fault in character development exists. Part of the trouble is with the word itself, which implies being unhappy about something. Endogenous depression should be suspected in all states of chronic ill health, hypochondriasis, disability that exceeds the manifest signs of a medical disease, neurasthenia and ongoing fatigue, chronic pain syndromes- all of which may be termed "masked depressions. Depressive illnesses and theories of their causation and management are considered further in Chap. Careful examination of clinical material discloses that a diversity of phenomena are being so classified: anxiety states, cycles of depression and mania, reactions to distressing life situations, so-called psychosomatic diseases, and illnesses of obscure nature. Obviously great license is being taken with the term emotional, the result no doubt of its indiscriminate nonmedical usage. Nevertheless, in certain clinical states, patients appear to be excessively apathetic or elated under conditions that are not normally conducive to such displays of emotion. If the emotion is intense, there may ensue a disturbance of intellectual functions- that is, a disorganization of rational thought and a tendency toward a more automatic behavior of unmodulated, stereotyped character. In its most easily recognized human form, emotion is initiated by a stimulus (real or imagined), the perception of which involves recognition, memory, and specific associations. Subdivided, the components of emotion appear to consist of (1) the perception of a stimulus, which may be internal (an idea) or external, (2) the feeling, (3) the autonomic-visceral changes, (4) the outward display of affect, and (5) the impulse to a certain type of activity. In many cases of neurologic disease, however, it is not possible to separate these components from one another, and to emphasize one of them does no more than indicate the particular bias of the examiner. Anatomic Relationships the occurrence of abnormal emotional reactions in the course of disease is associated with lesions that preferentially involve certain parts of the nervous system. These structures have been grouped under the term limbic and are among the most complex and least understood parts of the nervous system. Actually, Thomas Willis had pictured this 442 region of the brain and referred to it as the limbus in 1664. Broca preferred his term, le grand lobe limbique, to rhinencephalon, which was the term then in vogue and referred more specifically to structures having an olfactory function. Neuroanatomists who followed Broca affirmed his position and have extended the boundaries of the limbic lobe to include not only the cingulate and parahippocampal gyri but also the underlying hippocampal formation, the subcallosal gyrus, and the paraolfactory area. The terms visceral brain and limbic system, introduced by MacLean, have an even wider designation and more completely describe the structures involved in emotion and its expression; in addition to all parts of the limbic lobe, they include a number of associated subcortical nuclei such as those of the amygdaloid complex, septal region, preoptic area, hypothalamus, anterior thalamus, habenula, and central midbrain tegmentum, including the raphe nuclei and interpeduncular nucleus. The major structures comprised by the limbic system and their relationships are illustrated in. The cytoarchitectonic arrangements of the limbic cortex clearly distinguish it from the surrounding neocortex (isocortex). In contrast, the inner part of the limbic cortex (hippocampus) is composed of irregularly arranged aggregates of nerve cells that tend to be in a trilaminate configuration (archi- or allocortex). The cortex of the cingulate gyrus, which forms the outer ring of the limbic lobe, is transitional between neocortex and allocortex- hence it is known as the mesocortex, or juxtallocortex. The amygdaloid complex, a subcortical nuclear component of the limbic system, also has a unique composition, consisting of several separable nuclei, each with special connections to other limbic structures. The connections between the orbitofrontal neocortex and limbic lobes, between the individual components of the limbic lobes, and between the limbic lobes and the hypothalamus and midbrain reflect their many functional relationships in regard to emotion. At the core of this system lies the medial forebrain bundle, a complex set of ascending and descending fibers that connect the orbitomesiofrontal cortex, septal nuclei, amygdala, and hippocampus rostrally and certain nuclei in the midbrain and pons caudally. This system, of which the hypothalamus is the central part, was designated by Nauta as the septohypothalamomesencephalic continuum. There are many other interrelationships between various parts of the limbic system, only a few of which can be indicated here. It leads from the hippocampus, via the fornix, to the mammillary body and septal and preoptic regions. Also, the cingulum receives fibers from the inferior parietal lobule and temporal lobe, which are multimodal suprasensory centers for the integration of visual, auditory, and tactile perceptions. A Fornix Cingulate gyrus Occipital lobe Frontal lobe Physiology of the Limbic System the functional properties of the limbic structures Hippocampus first became known during the third and fourth Temporal lobe decades of the twentieth century. From ablation and stimulation studies, Cannon, Bard, and others established the fact that the hypothalamus contains B Anterior thalamic nuclei Cingulum the suprasegmental integrations of the autonomic Medial dorsal nervous system, both the sympathetic and paranucleus of thalamus sympathetic parts. Soon after, anatomists found efStria terminalis ferent pathways from the hypothalamus to the neural structures subserving parasympathetic and sympathetic reflexes. Dorsal tract Following Cannon, Bard localized the central longitudinal Anterior fasciculus commissure regulatory apparatus for respiration, wakefulness, and sexual activity incorrectly, in the hypothalaMedial mus. Later, the hypothalamus was also found to forebrain Olfactory bulb bundle contain neurosecretory cells, which control the secretion of the pituitary hormones; within it also are Ventral amygdalofugal special sensory receptors for the regulation of hunpathway ger, thirst, body temperature, and levels of circuAmygdala lating electrolytes. Gradually the idea emerged of a hypothalamic-pituitary-autonomic system that is Hippocampus Mammillary essential to both the basic homeostatic and emerbody gency ("fight-or-flight") reactions of the organism. Top: surface topography of the limbic the functional anatomy of these autonomic and neuroendocrine systems is discussed in Chaps. Bottom: connections of the limbic structures and their relation to the thalamus, hypothalamus, and midbrain tegmentum. In subsequent studies, Bard and Mountcastle found that lacy of this theory became evident when it was demonstrated by only if the ablations included the amygdaloid nuclei on both sides Cannon that the capacity to manifest emotional changes remained would sham rage be produced; removal of all the neocortex but sparafter all visceral afferent fibers had been interrupted. Interestingly, in the Although the natural stimuli for emotion involve the same nemacaque monkey, a normally aggressive and recalcitrant animal, reocortical perceptive-cognitive mechanisms as does nonemotional moval of the amygdaloid nuclei bilaterally greatly reduced the resensory experience, there are important differences, which relate to actions of fear and anger (see further on). The role of the hypothalthe prominent visceral effects and particular behavioral reactions amus and amygdala in the production of both directed and undirected evoked by emotion. Clearly, specific parts of the nervous system anger and displays of rage has turned out to be far more complex. Bard, in 1928, first produced "sham rage" in cats In any case, Papez, on the basis of these and his own anatomic by removing the cerebral hemispheres and leaving the hypothalamus observations, postulated that the limbic parts of the brain elaborate and brainstem intact. Of unknown significance is the fact that the zinc content of the limbic system is the highest of any part of the nervous system. All of this having been said, it would be a mistake to assume that the many structures listed above and their connections constitute a unified functional system.
Syndromes
In familial dysautonomia 3m muscle relaxant cheap rumalaya liniment 60ml fast delivery, the flare response to histamine and to scratch is absent muscle relaxant elderly cheap 60ml rumalaya liniment mastercard. It may also be absent in peripheral neuropathies that involve sympathetic nerves muscle relaxant gi tract discount rumalaya liniment 60ml with amex. A different mechanism must be invoked for the blood pressure response induced by angiotensin; perhaps it is due to defective baroreceptor function spasms on left side of abdomen cheap rumalaya liniment 60 ml visa. The integrity of autonomic innervation of the heart can be evaluated by the intramuscular injection of atropine, ephedrine, or neostigmine while the heart rate is monitored. In patients with central and peripheral autonomic failure, there is little or no elevation on standing or with exercise. The dopamine -hydroxylase enzyme is deficient in patients with a rare form of sympathetic dysautonomia. In summary, the noninvasive tests listed in Table 26-1 and described above are quite adequate for the clinical testing of autonomic function. Low has emphasized that the most informative tests are those that are quantitative and have been standardized and validated in patients with both mild and severe autonomic disturbances. At the bedside, the most convenient ones are measurement of orthostatic pulse and blood pressure changes, blood pressure response to the Valsalva maneuver, estimation of pulse changes with deep breathing, pupillary responses to light and dark, and a rough estimate of sweating of the palms and soles. The results of these tests and the clinical situation will determine whether further testing is needed. Over a period of a week or a few weeks, the patient develops some combination of anhidrosis, orthostatic hypotension, paralysis of pupillary reflexes, loss of lacrimation and salivation, impotence, impaired bladder and bowel function (urinary retention, postprandial bloating, and ileus or constipation), and loss of certain pilomotor and vasomotor responses in the skin (flushing and heat intolerance). Severe fatigue is a prominent complaint in most patients, and abdominal pain and vomiting in others. Clinical and laboratory findings indicate that both the sympathetic and parasympathetic parts of the autonomic nervous system are affected, mainly at the postganglionic level. Somatosensory and motor nerve fibers appear to be spared or are affected to only a slight extent, although many patients complain of paresthesias, and tendon reflexes are frequently lost. In one of the patients described by Low and colleagues, there was physiologic and morphologic (sural biopsy) evidence of loss of small myelinated and unmyelinated somatic fibers and foci of epineurial mononuclear cells; in other cases, sural nerve fiber counts have been normal; and in an autopsied case, in which there had also been sensory loss, there was lymphocytic infiltration in sensory and autonomic nerves (Fagius et al). The original patient described by Young and colleagues and most of the other patients reported with pure dysautonomia are said to have recovered completely or almost so within several months, but some of our patients have been left with disordered gastrointestinal and sexual functions. In addition to this idiopathic form of autonomic paralysis, some cases are postinfectious, and there is a similar but rare paraneoplastic form (page 586). Antibodies against ganglionic acetylcholine receptors have been found in half of idiopathic cases and one-quarter of paraneoplastic cases (Vernino et al). Some of the children with this disease and a few adults have had a predominantly cholinergic dysautonomia with pain and dysesthesias (Kirby et al). There is little or no postural hypotension, and the course has been more chronic than that in the complete dysautonomia described above. An acquired form of orthostatic intolerance, referred to as sympathotonic orthostatic hypotension (Polinsky et al), may represent another variant or partial form of autonomic paralysis. In this syndrome, unlike the common forms of orthostatic hypotension (see below), the fall in blood pressure is accompanied by tachycardia. Its relationship to the similarly indistinct entity of postural orthostatic tachycardia syndrome and to the orthostatic intolerance associated with the chronic fatigue syndrome is uncertain, but asthenia is a feature common to all of them. We are inclined to view those so-called orthostatic intolerance syndromes as part of the asthenia-anxiety disorders. The autonomic changes may represent sympathetic overactivity in susceptible individuals. Lambert-Eaton Myasthenic Syndrome One of the characteristic features of the fully developed Lambert-Eaton myasthenic syndrome, which is discussed more fully on page 1259, is a dysautonomia, characterized by dryness of the mouth, impotence, difficulty in starting the urinary stream, and constipation. Presumably, circulating antibodies interfere with the release of acetylcholine (Ach) at both muscarinic and nicotinic sites. One is a degenerative disease of middle and late adult life, first described by Bradbury and Eggleston in 1925 and designated by them as idiopathic orthostatic hypotension. This term is not entirely apt, since it emphasizes only one feature of the autonomic failure and neglects the disturbances of sweating and of bladder and sexual functions, which are usually associated. In the second more common disorder, described by Shy and Drager, the preganglionic lateral horn neurons of the thoracic spinal segments degenerate; these changes are responsible for the orthostatic hypotension. Later, signs of basal ganglionic or cerebellar disease or both are usually added, in which case the disorder is called multiple system atrophy (an unfortunate descriptive term in our view, as expressed below and in Chaps. In both types of orthostatic hypotension, anhidrosis, impotence, and atonicity of the bladder may be conjoined, but orthostatic fainting is the main problem. The distinction between the postganglionic and the central preganglionic types of disease is also based on pharmacologic and neurophysiologic evidence, but it must be emphasized that the results of these tests do not always conform to clinical experience. Nonetheless, Cohen and associates, who studied the postganglionic sudomotor and vasomotor functions of 62 patients with idiopathic orthostatic hypotension, found that the signs of postganglionic denervation were uncommon in patients classified as having the central type. The use of these neurochemical tests in clinical practice is difficult and the data in the literature are inconsistent. Pathologic studies have disclosed the central type of autonomic failure to be somewhat heterogeneous. Oppenheimer, who collected all the reported central cases with complete autopsies, found that they fell into two groups: (1) that which was designated by Adams as striatonigral degeneration or, later, Shy-Drager syndrome, where autonomic failure was associated with a parkinsonian syndrome and often with the presence of cytoplasmic inclusions in sympathetic neurons, and (2) another with involvement of the striatum, cerebellum, pons, and medulla but without inclusions, formerly designated olivopontocerebellar degeneration (there are now reported to be glial and neuronal cytoplasmic inclusions in all these cases). Both conditions are now loosely referred to as multiple system atrophy, as discussed in Chap. In both groups, the autonomic failure is attributable to degeneration of lateral horn cells of the thoracic cord. There is also a degeneration of nerve cells in the vagal nuclei as well as nuclei of the tractus solitarius, locus ceruleus, and sacral autonomic nuclei, accounting for laryngeal abductor weakness (laryngeal paralysis and stridor are features in some cases), incontinence, and impotence. The sympathetic ganglia have been normal, an exception being the case of Rajput and Rozdilsky, in which most of the ganglion cells had degenerated. Peripheral Neuropathy with Secondary Orthostatic Hypotension Impairment of autonomic function, of which orthostatic hypotension is the most serious feature, may occur as part of the more common acute or chronic peripheral neuropathies. Disease of the peripheral nervous system may affect the circulation in two ways: the nerves from baroreceptors may be affected, interrupting normal homeostatic reflexes on the afferent side, or postganglionic efferent sympathetic fibers may be involved in the spinal nerves. The severity of the autonomic failure need not parallel the degree of motor weakness. These same stretch baroreceptors are implicated in the intermittent hypertension that sometimes complicates these acute neuropathies. Of particular importance is the autonomic disorder that accompanies diabetic neuropathy. It presents as impotence, constipation, or diarrhea (especially at night), hypotonia of the bladder, gastroparesis, and orthostatic hypotension, in some combination. There are invariably signs of a sensory polyneuropathy, consisting of a distal loss of vibratory and thermal-pain sensation and reduced or lost ankle reflexes; but again, the severity of affection of the two systems of nerve fibers may not be parallel. The pupils are often small and the amplitude of constriction to light is reduced (ArgyllRobertson pupils); this has been attributed to involvement of the ciliary ganglia. The pathologic basis of the other features has been difficult to assess because of the frequency of artifact in the sympathetic ganglia in autopsy material. Duchen and coworkers attributed the autonomic disorder to vacuolization of sympathetic ganglionic neurons, cell necrosis and inflammation, loss of myelinated fibers in the vagi and white rami communicantes, and loss of lateral horn cells in the spinal cord. Another polyneuropathy with unusually prominent dysautonomia is that due to amyloidosis. Extensive loss of pain and thermal sensation is usually present; other forms of sensation may also be reduced to a lesser degree. Iridoplegia (pupillary paralysis) and disturbances of other smooth muscle and glandular functions are variable. Both the primary and secondary types of orthostatic hypotension are also discussed in connection with syncope in Chap. Autonomic Failure in the Elderly Orthostatic hypotension is prevalent in the elderly, so much so that norms of blood pressure and pulse changes have been difficult to establish. Caird and coworkers reported that among individuals who were more than 65 years of age and living at home, 24 percent had a fall of systolic blood pressure on standing of 20 mmHg; 9 percent had a fall of 30 mmHg; and 5 percent, a fall of 40 mmHg. An increased frequency of thermoregulatory impairment has been documented as well. The elderly are also more liable to develop hypothermia and, when exposed to high ambient temperature, to hyperthermia.
Exceptionally back spasms 20 weeks pregnant 60 ml rumalaya liniment free shipping, the patient with meningomyelocele muscle relaxant reversals discount 60 ml rumalaya liniment, and most of those with lumbar meningocele muscle relaxant renal failure discount 60 ml rumalaya liniment with amex, are mentally normal spasms vulva purchase 60 ml rumalaya liniment mastercard. Other Developmental Spinal Defects and Delayed Effects of Failure of Midline Fusion, Including Tethered Cord the problems of meningomyelocele and its complications are so strictly pediatric and surgical that the neurologist seldom becomes involved- except perhaps in the initial evaluation of the patient- in the treatment of meningeal infection, or in the case of shunt failure with decompensation of hydrocephalus. Of greater interest to the neurologist are a series of closely related abnormalities that produce symptoms for the first time in late childhood, adolescence, or even adult life. These include sinus tracts with recurrent meningeal infections, lumbosacral lipomas with low tethering of the spinal cord ("tethered cord"), and a delayed radicular or spinal cord syndrome; diastematomyelia, cysts, or tumors with spina bifida and a progressive myeloradiculopathy; and a Chiari malformation and syringomyelia that first present in adolescence or adult life. Another class of disorders involves an occult lumbosacral dysraphism that is not inherited but is due to faulty development of the cell mass that lies caudal to the posterior neuropore (normally this undergoes closure by the 28th day of embryonic life). Occult spinal dysraphism of this type is also associated with meningoceles, lipomas, and sacrococcygeal teratomas. Another well-recognized anomaly is agenesis of the sacrum and sometimes the lower lumbar vertebrae (caudal regression syndrome). Interestingly, in 15 percent of such cases, the mother is diabetic (Lyon and Evrard). Here there is flaccid paralysis of legs, often with arthrogrypotic contractures and urinary incontinence. Sensory loss is less prominent, mental function develops normally, and there is no hydrocephalus. Sinus tracts in the lumbosacral or occipital regions are of importance, for they may be a source of bacterial meningitis at any age. They are often betrayed by a small dimple in the skin or by a tuft of hair along the posterior surface of the body in the midline. Cloacal defects (no abdominal wall and no partition between bladder and rectum) may be combined with anterior meningoceles. Evidence of sinus tracts should be sought in every instance of unexplained meningitis, especially when there has been recurrent infection or the cultured organism is of nosocomial dermal origin. There are, in addition, other congenital cysts and tumors, particularly lipoma and dermoid, that arise in the filum terminale and attach (tether) the cord to the sacrum; progressive symptoms and signs are produced as the spine elongates during development, stretching the caudally fixed cord. Others deteriorate neurologically at a later age (generally between 2 and 16 years, sometimes later- see below). According to Chapman and Davis, it is not the myelolipoma but the tethering of the cord that gives rise to symptoms; removal of the tumor is of little benefit unless the cord is untethered (detached from the sacrum) at the same time. This may be difficult, for the lipoma may be fused with the dorsal surface of the spinal cord. Diastematomyelia is another unusual abnormality of the spinal cord often associated with spina bifida. Progressive spastic weakness in some of the weak muscles of the legs in a patient known to have had a meningocele or meningomyelocele. Presumably the spinal cord, which is securely attached to the lumbar vertebrae, is stretched during the period of rapid lengthening of the vertebral column. The implicated sensory and motor roots are believed to be injured by sudden or repeated stretching. This is a developmental cavity within the cervical cord, extending a variable distance caudally or rostrally, associated with an Arnold-Chiari malformation (see below). Also, there are a variety of neurologic problems associated with spinal abnormalities in the high cervical region [fusion of atlas and occiput or of cervical vertebrae (Klippel-Feil syndrome), congenital dislocation of the odontoid process and atlas, platybasia and basilar impression]. Chiari Malformation Encompassed by this term are a number of congenital anomalies at the base of the brain, the most consistent of which are (1) extension of a tongue of cerebellar tissue, posterior to the medulla and spinal cord, into the cervical canal and (2) displacement of the medulla into the cervical canal, along with the inferior part of the fourth ventricle. These and associated anomalies were first clearly described by Chiari (1891, 1896). Use of the double eponym Arnold-Chiari malformation is so entrenched that a dispute over its propriety will not alter its usage. It should be emphasized that a proportion of normal individuals have a small tongue of the posterior cerebellum protruding below the opening of the foramen magnum by a few millimeters; this is usually of no significance and does not justify inclusion as a Chiari malformation. The displaced tissue (medulla and cerebellum) occludes the foramen magnum; the remainder of the cerebellum, which is small, is also displaced so as to obliterate the cisterna magna. The foramina of Luschka and Magendie open into the cervical canal, and the arachnoidal tissue around the herniated brainstem and cerebellum is fibrotic. All these factors are probably operative in the production of hydrocephalus, which is always associated. Just below the herniated tail of cerebellar tissue there is a kink or spur in the spinal cord, pushed posteriorly by the lower end of the fourth ventricle. The main features were a flaccid bladder, asymmetrical weakness and atrophy of the forelegs, and a degree of spasticity in the legs. Or the division of the cord may be complete, each half with its own dural sac and complete set of nerve roots. This longitudinal fissuring and doubling of the cord are spoken of as diplomyelia. With body growth, it leads to a traction myelopathy, presenting with pain and progressive sensory, motor, and bladder symptoms, sometimes as late as adult life. Removal of the fibrous-bony spicule and untethering of the spinal cord have been beneficial in some cases. Several clinical syndromes of delayed progressive disease (in adolescents or adults), due mainly to a tethered cord, have been delineated: 1. In our experience this has been the most common presentation of the tethered cord syndrome, with or without a lipoma or dermoid. Complex disturbances of bladder function that produce urgency and incontinence beginning in the second or third decade may be the only manifestation, or the bladder symptoms may be combined with impotence (in the male) and numbness of the feet and legs or foot drop (Pang and Wilberger). Developmental abnormalities of the cerebrum (particularly polymicrogyria) may coexist, and the lower end of the spinal cord. The posterior fossa is small; the foramen magnum is enlarged and grooved posteriorly. Nishikawa et al have suggested that smallness of the posterior fossa, with overcrowding, is the primary abnormality leading to the brain malformation. Often the base of the skull is flattened or infolded by the cervical spine (basilar impression). However, lower cranial nerve abnormalities- laryngeal stridor, fasciculations of the tongue, sternomastoid paralysis (causing head lag when the child is pulled from lying to sitting), facial weakness, deafness, bilateral abducens palsies- may be present in varying combinations. If the patient survives to later childhood or adolescence, one of the syndromes that occurs with the type I malformation may become manifest. In the more common type I Chiari malformation (without meningocele or other signs of dysraphism), neurologic symptoms may not develop until adolescence or adult life. The symptoms may be those of (1) increased intracranial pressure, mainly headache, (2) progressive cerebellar ataxia, (3) progressive spastic quadriparesis, (4) downbeating nystagmus, or (5) cervical syringomyelia (segmental amyotrophy and sensory loss, with or without pain). Or the patient may show a combination of disorders of the lower cranial nerves, cerebellum, medulla, and spinal cord (sensory and motor tract disorders), usually in conjunction with headache that is mainly occipital. This combination of symptoms is often mistaken for multiple sclerosis or a foramen magnum tumor. The symptoms may have an acute onset after sustained extension of the neck, as, for example, after a long session of dental work, hairdressing in women, or chiropractic manipulation. The physical habitus of such patients may be normal, but about 25 percent have signs of an arrested hydrocephalus or a short "bull neck. Treatment the treatment of Chiari malformation (and basilar impression) is far from satisfactory. If clinical progression is slight or uncertain, it is probably best to do nothing. If progression is certain and disability is increasing, upper cervical laminectomy and enlargement of the foramen magnum are indicated. The outcome, in our experience, has been less satisfactory when decompression was performed mainly for intractable headache. Opening of the dura and extensive manipulation of the malformation or excision of herniated cerebellum may aggravate the symptoms or even cause death. The treatment of an associated syringomyelia and other developmental abnormalities in this region is discussed further on page 1082. We are unable to comment on the use by a limited number of neurosurgeons of posterior fossa decompression for the treatment of chronic fatigue syndrome except to say that it is illogical, even when a Chiari malformation is detected. Jacobs and Lejeune almost simultaneously were the first to note a triplication of the 21st chromosome in the Down syndrome, and there followed the discovery of a number of other trisomies as well as deletions or translocations of other autosomal chromosomes and a lack or excess of one of the sex chromosomes.
Meningiomas also elaborate a variety of soluble proteins muscle relaxant benzo cheap 60 ml rumalaya liniment with amex, some of which (vascular endothelial growth factor) are angiogenic and relate to both the highly vascularized nature of these tumors and their prominent surrounding edema (see Lamszus for further details) muscle relaxer x buy rumalaya liniment 60 ml lowest price. The implications of these findings are not yet clear but may relate to the increased incidence of the tumor in women muscle relaxant zanaflex rumalaya liniment 60ml overnight delivery, its tendency to enlarge during pregnancy muscle relaxant in india 60 ml rumalaya liniment overnight delivery, and an association with breast cancer. According to Rubinstein, they may arise from dural fibroblasts, but in our opinion, they are more clearly derived from arachnoidal (meningothelial) cells, in particular from those forming the arachnoid villi. Grossly, the tumor is firm, gray, and sharply circumscribed, taking the shape of the space in which it grows; thus, some tumors are flat and plaque-like, others round and lobulated. They may indent the brain and acquire a pia-arachnoid covering as part of their capsule, but they are clearly demarcated from the brain tissue (extra-axial) except in the unusual circumstance of a malignant invasive meningioma. Rarely, they arise from arachnoidal cells within the choroid plexus, forming an intraventricular meningioma. Microscopically, the cells are relatively uniform, with round or elongated nuclei, visible cytoplasmic membrane, and a characteristic tendency to encircle one another, forming whorls and psammoma bodies (laminated calcific concretions). A notable electron microscopic characteristic is the formation of very complex interdigitations between cells and the presence of desmosomes (Kepes). Cushing and Eisenhardt and, more recently, the World Health Organization (Lopes et al) have divided meningiomas into many subtypes depending on their mesenchymal variations, the character of the stroma, and their relative vascularity, but the value of such classifications is debatable. Currently neuropathologists recognize a meningothelial (syncytial) form as being the most common. It is readily distinguished from other similar but non-meningothelial tumors such as hemangiopericytomas, fibroblastomas, and chondrosarcomas. The usual sites of meningioma are the sylvian region, superior parasagittal surface of the frontal and parietal lobes, olfactory groove, lesser wing of the sphenoid bone, tuberculum sellae, superior surface of the cerebellum, cerebellopontine angle, and spinal canal. Some meningiomas- such as those of the olfactory groove, sphenoid wing, and tuberculum sellae- express themselves by highly distinctive syndromes that are diagnostic in themselves; these are described further on in this chapter. Inasmuch as they extend from the dural surface, they often invade and erode the cranial bones or excite an osteoblastic reaction, even giving rise to an exostosis on the external surface of the skull. The following remarks apply to meningiomas of the parasagittal, sylvian, and other surface areas of the cerebrum. The size that must be reached before symptoms appear varies with the size of the space in which the tumor grows and the surrounding anatomic arrangements. The parasagittal frontoparietal meningioma may cause a slowly progressive spastic weakness or numbness of one leg and later of both legs, and incontinence in the late stages. The sylvian tumors are manifest by a variety of motor, sensory, and aphasic disturbances in accord with their location, and by seizures. In the past, before brain imaging techniques became available, the meningioma often gave rise to neurologic signs for many years before the diagnosis was established, attesting to its slow rate of growth. Even now some tumors reach enormous size, to the point of causing papilledema, before the patient comes to medical attention. Increased intracranial pressure eventually occurs, but it is less frequent with meningiomas than with gliomas. However, it is also occurring with increased frequency in immunocompetent persons- a finding without evident explanation (although theories abound). For many years, the cell of origin of this tumor was thought to be the reticulum cell and the tumor was regarded as a reticulum cell sarcoma. The meningeal histiocyte and microgliacytes are the equivalent cells in the brain to the reticulum cell of the germinal centers of lymph nodes. Later, the intracerebral lymphocytes and lymphoblasts, also prominent components of the tumor, led to its reclassification as a lymphoma (large-cell histiocytic type). It is appreciated, on the basis of immunocytochemical studies, that the tumor cells are B lymphocytes. There is a fine reticulum reaction between the reticulum cells derived from fibroblasts and microglia or histiocytes. As matters now stand, most pathologists believe that the B lymphocyte or lymphoblast is the tumor cell, whereas the fine reticulum and "microgliacytes" are secondary interstitial reactions. We tend to believe that both cell types are present and have not entirely abandoned the notion of an origin in a reticulum cell. Since the brain is devoid of lymphatic tissue, it is uncertain how this tumor arises; one theory holds that it represents a systemic lymphoma with a particular proclivity to metastasize to the nervous system. This seems unlikely to the authors; systemic lymphomas of the usual kind rarely metastasize, as discussed further on, under "Involvement of the Nervous System in Systemic Lymphoma. Vitreous, uveal, and retinal (ocular) involvement occurs in 10 to 20 percent of cases; here vitreous biopsy may be diagnostic, but it is not often performed. Most such cases of what has been termed neurolymphomatosis present with painful, predominantly motor polyradiculopathies. Whether this indicates a widespread or multifocal origin of brain lymphoma is not clear. The primary large-cell lymphoma forms a pinkish gray, soft, ill-defined, infiltrative mass in the brain, difficult at times to distinguish from a malignant glioma. Meningiomas characteristically take the form of smoothly contoured masses, sometimes lobulated, with one edge abutting the inner surface of the skull or the falcial or tentorial dura. Treatment Surgical excision should afford permanent cure in all symptomatic and accessible surface tumors. Recurrence is likely if removal is incomplete, as is often the case, but for some the growth rate is so slow that there may be a latency of many years. Tumors that lie beneath the hypothalamus, along the medial part of the sphenoid bone and parasellar region, or anterior to the brainstem are the most difficult to remove surgically. Carefully planned radiation therapy including gamma-knife or proton beam treatment is beneficial in cases that are inoperable and when the tumor is incompletely removed or shows malignant characteristics (Kornblith et al). Smaller tumors at the base of the skull can be obliterated or greatly reduced in size by focused radiation, probably with less risk than surgery would pose (Chang and Alder). Conventional chemotherapy is probably ineffective; hormonal therapy with the antiprogestin agents has been used with variable results but is still under study (McCutcheon). The nuclei are oval or bean-shaped with scant cytoplasm, and mitotic figures are numerous. B-cell markers applied to fixed tissue define the lymphoblastic cell population as monoclonal and identify the tumor cell type. Primary lymphoma involving the cerebral hemispheres pursues a clinical course somewhat similar to that of the glioblastoma but with a vastly different response to treatment. The interval between the first symptom and operation has been approximately 3 months. Behavioral and personality changes, confusion, dizziness, and focal cerebral signs predominate over headache and other signs of increased intracranial pressure as presenting manifestations. Seizures may occur but are less common in our experience than they are as the introductory feature of gliomas. Most cases occur in adult life, but some have been observed in children, in whom the tumor may simulate the cerebellar symptomatology of medulloblastoma. However, nodular, ring-like enhancement also occurs, and any part of the brain may be involved. Characteristic is the radiographic disappearance of the lesions or complete but transient resolution of contrast enhancement in response to corticosteroids. Sometimes this tumor appears as a complication of an obscure medical condition such as salivary and lacrimal gland enlargement (Mikulicz syndrome). Stereotactic needle biopsy is the preferred method of establishing the histologic diagnosis in sporadic cases. Reduction in the size of the lesion(s) with antimicrobial drugs makes biopsy unnecessary. Treatment Because the tumors are deep and often multicentric, surgical resection is ineffective except in rare instances. Treatment with cranial irradiation and corticosteroids often produces a partial or, rarely, complete response, as remarked above, but the tumor recurs in more than 90 percent of patients. Until recently the median survival of patients treated in this way has been 10 to 18 months, Figure 31-9. Right: Another typical appearance of a smaller ring-enhancing periventricular mass with subtle infiltration of the subependymal regions. In immunocompetent patients, the addition of intrathecal methotrexate and intravenous cytosine arabinoside increases median survival to more than 3 years (DeAngelis), and apparent cure is not unknown.
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