PRINCIPLES OF NEUROLOGY - PART 4 pdf

159 Trauma Signs of cranial and CT and MRI show brain Unstable blood pressure, facial injury contusions and other associated systemic injuries (see Chap. 34) injuries Brain abscess Neurologic signs CT scan and MRI ϩ Systemic infection or depending on location neurosurgical procedure, fever Hypertensive Blood pressure CT Ϯ; CSF Acute or subacute encephalopathy; Ͼ 210/110, (lower in pressure elevated evolution, use of eclampsia eclampsia and in aminophylline or children) headache, catecholamine seizures, hypertensive medications retinal changes Coma without focal or Meningitis and Stiff neck, Kernig sign, CT scan Ϯ; pleocytosis, Subacute or acute onset lateralizing signs, with encephalitis fever, headache increased protein, low signs of meningeal glucose in CSF irritation Subarachnoid Stertorous breathing, CT scan may show Sudden onset with hemorrhage hypertension, stiff neck, blood and aneurysm; severe headache Kernig sign bloody or xanthochromic CSF under increased pressure (continued) 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 159 160 TABLE 17-2 Important Points in the Differential Diagnosis of the Common Causes of Coma (continued) Important clinical Important laboratory General group Specific disorder findings findings Remarks Coma without focal Alcohol Hypothermia, Elevated blood alcohol May be combined with neurologic signs or intoxication hypotension, flushed head injury, infection, or meningeal irritation; CT skin, alcohol breath hepatic failure scan and CSF normal Sedative Hypothermia, Drug in urine and History of intake of drug; intoxication hypotension blood; EEG often shows suicide attempt fast activity Opioid intoxication Slow respiration, Administration of cyanosis, constricted naloxone causes pupils awakening and withdrawal signs Carbon monoxide Cherry-red skin Carboxyhemoglobin intoxication Anoxia Rigidity, decerebrate CSF normal; EEG may Abrupt onset following postures, fever, seizures, be isoelectric or show cardiopulmonary arrest; myoclonus high-voltage delta damage permanent if anoxia exceeds 3–5 min Hypoglycemia Same as in anoxia Low blood and CSF Characteristic slow glucose evolution through stages of nervousness, hunger, sweating, flushed face; then pallor, shallow respirations and seizures 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 160 161 Diabetic coma Signs of extracellular Glycosuria, History of polyuria, fluid deficit, hyperglycemia, acidosis; polydipsia, weight loss, hyperventilation with reduced serum bicarbonate; or diabetes Kussmaul respiration, ketonemia and ketonuria, “fruity” breath or hyperosmolarity Uremia Hypertension; sallow, dry Protein and casts in Progressive apathy, skin, uriniferous breath, urine; elevated BUN and confusion, and asterixis twitch-convulsive serum creatinine; precede coma syndrome anemia, acidosis, hypocalcemia Hepatic coma Jaundice, ascites, and Elevated blood NH 3 Onset over a few days or other signs of portal levels; CSF yellow after paracentesis or hypertension; asterixis (bilirubin) with normal hemorrhage from or slightly elevated varices; confusion, protein stupor, asterixis, and characteristic EEG changes precede coma Hypercapnia Papilledema, diffuse Increased CSF pressure; Advanced pulmonary myoclonus, asterixis P CO 2 may exceed disease; profound coma 75 mmHg; EEG theta and brain damage and delta activity uncommon Severe infections Extreme hyperthermia, Vary according to cause Evidence of a specific (septic shock); rapid respiration infection or exposure to heat stroke extreme heat Seizures Episodic disturbance of Characteristic EEG History of previous behavior or convulsive changes attacks movements 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 161 and electrolyte imbalance, and other complications to which the in- sensate patient is subject (e.g., pneumonia, urinary tract infections, phlebothrombosis) can be found in Harrison’s Principles of Internal Medicine. 1. The management of shock, if present, takes precedence over all other diagnostic and therapeutic measures. 2. Shallow and irregular respirations, stertorous breathing (indicating partial obstruction to inspiration), and cyanosis require the estab- lishment of a clear airway and delivery of oxygen. If the cerebral disease is not complicated by a fracture-dislocation of the cervical spine, the patient should initially be placed in a lateral position so that secretions and vomitus do not enter the tracheobronchial tree. Usually the pharyngeal reflexes are suppressed, so an endotracheal tube can be inserted without difficulty. Secretions should be removed by suctioning as soon as they accumulate; otherwise, they will lead to atelectasis and bronchopneumonia. Oxygen can be administered by mask or endotracheal tube, guided by the arterial oxygen saturation and other arterial blood gas measurements. Res- piratory insufficiency and intracranial hypertension dictate the use of endotracheal intubation and a positive pressure respirator. 3. Concomitantly, an IV line is established, an ECG is obtained, and blood samples are drawn for measurement of glucose, toxins, and electrolytes and for tests of liver and kidney function. Dextrose 50% and thiamine 100 mg should be administered if hypoglycemia is possible. Naloxone, 0.5 to 2 mg, should be given cautiously IV if a narcotic overdose is a diagnostic possiblity. In the heroin addict, arrhythmias and seizures may result. Flumazenil is useful in cases of overdose with diazepines. 4. If a mass lesion is evident on the CT scan, the control of raised intracranial pressure becomes paramount. Mannitol, 50 g in a 20% solution, should be given IV over 10 to 20 min. Repeated CT scans allow the physician to follow the size of the lesion and degree of localized edema and to detect displacements of cerebral tissue. 5. An LP should be performed if meningitis (fever, leukocytosis, stiff neck) or subarachnoid hemorrhage (sudden coma preceded by headache) is suspected, although one must keep in mind the risks of this procedure and the means of dealing with them (Chap. 2). A CT scan may have disclosed a subarachnoid hemorrhage, in which case an LP is not necessary. 6. Convulsions should be controlled by measures outlined in Chap. 16. 7. Gastric aspiration and lavage with normal saline may be useful in some instances of coma due to drug ingestion. Salicylates, opiates, and anticholineric drugs (tricyclic antidepressants, phenothiazines, scopolamine), all of which induce gastric atony, may be recovered 162 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 162 many hours after ingestion. Patients in whom the ingested drug is unidentified are treated with activated charcoal, 50 to 100 gm by nasogastric tube, after the airway has been secured. Induction of emesis by ipecac or apomorphine should be reserved for alert patients. 8. The temperature-regulating mechanisms may be disturbed, and extreme hypothermia, hyperthermia, or poikilothermia may occur. In hyperthermia, the use of evaporative cooling with sprayed water and a fan is the most efficient. A cooling mattress may be used as well. 9. The bladder should not be permitted to become distended; if the patient does not void, a catheter should be inserted. The patient should not be permitted to lie in a wet or soiled bed. 10. Diseases of the central nervous system may upset the control of water, glucose, and sodium. The unconscious patient can no longer adjust the intake of food and fluids by hunger and thirst. Both salt- losing and salt-retaining syndromes have been seen with brain disease. Water intoxication and severe hyponatremia may of them- selves prove fatal. If coma is prolonged, the insertion of a gastric tube will ease the problems of feeding the patient and maintaining fluid and electrolyte balance. 11. Aspiration pneumonia is avoided by intubation, prevention of vom- iting (gastric tube), proper positioning of the patient, and restriction of oral fluids. The legs should be examined each day for signs of venous thrombosis; if that is found, it should be treated with anti- coagulants or surgical measures. Deep vein thrombosis, which is a common occurrence in comatose and hemiplegic patients, often does not manifest itself by clinical signs. If the bedridden state is prolonged, the legs should be fitted with intermittent pneumatic compression boots. Thrombosis can also be prevented by the administration of subcutaneous heparin, 5000 units q 12 h. 12. If the patient is capable of moving, suitable restraints should be used to prevent falling out of bed. Sedation for this purpose should be avoided in all but the most overactive patients. Prognosis Deep coma that lasts for 48 to 72 h carries a grave prognosis; many such patients fall into the category of brain death, usually with fatal outcome in a few days. A small number emerge into the category of persistent vegetative state, for which the prognosis is equally grave. A few patients survive in a persistent vegetative state for years, but in most cases survival is measured in weeks or months. The absence of pupillary and corneal reflexes and ocular movements after 1 to 3 days of coma is predictive to a high degree of a fatal outcome or a vegetative state. Low scores on the Glasgow Coma Scale, reproduced CHAPTER 17 / COMA AND RELATED DISORDERS OF CONSCIOUSNESS 163 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 163 in Table 17-3, may be of help in predicting the outcome, particularly in cases due to cerebral trauma. Few patients with scores below 8 emerge from traumatic coma and regain meaningful function. For a more detailed discussion of this topic, see Adams, Victor, and Ropper: Principles of Neurology, 6th ed, pp 344–366. ADDITIONAL READING Beecher HK, Adams RD, Sweet WH: A definition of irreversible coma. Report of the Committe of Harvard Medical School to examine the definition of brain death. JAMA 205:85, 1968. Fisher CM: The neurological examination of the comatose patient. Acta Neurol Scand Suppl 45 (Suppl 36):1, 1969. Guidelines for the detection of brain death in children. Ann Neurol 21:616, 1987. Jennett B, Plum F: Persistent vegetative state after brain damage. Lancet 1:734, 1972. Levy DE, Caronna JJ, Singer BH, et al: Predicting outcome from hypoxic- ischemic coma. JAMA 253:1420, 1985. Plum F, Posner JB: Diagnosis of Stupor and Coma, 3rd ed. Philadelphia, Davis, 1980. Ropper AH: Lateral displacement of the brain and level of consciousness in patients with an acute hemispheral mass. New Engl J Med 314:953, 1986. Ropper AH (ed): Neurological and Neurosurgical Intensive Care, 3rd ed. New York, Raven, 1993. 164 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE TABLE 17-3 Glasgow Coma Scale (Sum of Three Categories) Eyes Open Never 1 To pain 2 To verbal stimuli 3 Spontaneously 4 Best verbal response No response 1 Incomprehensible sounds 2 Inappropriate words 3 Disoriented and converses 4 Oriented and converses 5 Best motor response No response 1 Extension (decerebrate rigidity) 2 Flexion abnormal (decorticate rigidity) 3 Flexion withdrawal 4 Localizes pain 5 Obeys 6 3–15 4777 Victor Ch 17 p154-164 6/11/01 2:02 PM Page 164 18 Faintness and Syncope Syncope is synonymous with the common faint. In most cases, it is a transitory, spontaneously reversible state. A lesser form, a feeling as though one is about to faint, is referred to as faintness, or presyncope. Most otherwise healthy persons have experienced the latter, and many have at some time fainted. CLINICAL FEATURES In the common (vasovagal) type of faint, the person is assailed by a sense of weakness, as though all energy has been drained from the body. He feels uneasy and queasy and has a sense of giddiness and swaying. Headache, dimness of vision, and ringing in the ears are com- mon accompaniments, and the subject may have difficulty in thinking clearly. Color drains from the face; a cold sweat breaks out. Pallor of the face coincides with pallor of the brain, which is the mechanism common to all types of faint. Signs of autonomic overactivity—saliva- tion, nausea, and sometimes vomiting and sweating—are prominent and represent the body’s attempts to counteract the fall in blood pres- sure. The victim, who is usually standing or sitting, looks for a place to lie down. If unable to lie down promptly, he loses consciousness and falls to the ground. Breathing and pulse are imperceptible or almost so. For a brief period, the appearance is one of death. Once horizontal for a few seconds or minutes, the patient stirs, opens his eyes, and quickly takes in the situation. Strength and color soon return as well. Bystanders are relieved by the rapid recovery. The pulse is often slowed during recovery, suggesting vagal overac- tivity (hence the name vasovagal ). But the loss of vasoconstrictive tone and reduced cardiac output are more important factors than bradycardia in the genesis of the faint (vasodepressor effect). Such an episode has at some time been witnessed or experienced by most people, but there are variations that may cause uncertainty. If unconsciousness persists for 15 to 20 s or the patient, for some reason, is maintained upright as the faint comes on, the limbs and trunk may jerk several times or stiffen, as in a convulsive seizure. Or the patient may not lose consciousness completely; he can hear voices of those around him but his responses betray confusion (“grayout”). Syncope of cardiac origin may be so abrupt that the fall results in injury, even a 165 4777 Victor Ch 18 p165-169 6/11/01 2:03 PM Page 165 Copyright 1998 The McGraw-Hill Companies, Inc. Click Here for Terms of Use. concussion. In general, however, the loss of strength and conscious- ness, though of sudden onset, provides sufficient warning for a hurtful fall to be averted. Sphincteric incontinence is also exceptional. With these characteristics in mind, the distinction between a faint and a seizure should rarely occasion difficulty. Only the akinetic (astatic) seizure resembles a faint, but usually the former comes without warn- ing or facial pallor. The seizure-like clonic jerking or tonic spasm of limbs and trunk that sometimes complicates a protracted faint is usually attended by the other manifestations of hypotension. Serum CK is not elevated after syncope, as it is following a convulsive seizure, unless there has been severe muscle trauma. CAUSES OF SYNCOPE AND FAINTNESS In Table 18-1 are listed the many types of syncope and faintness on the basis of their established or presumed physiologic mechanisms. In prac- tice, only a small proportion of the conditions listed in the table are encountered with any degree of frequency. Moreover, the fundamental mechanism in all of them is the same—an inadequacy of blood flow to the brain, which in turn may be due to (1) a loss of peripheral vascular resistance with fall in blood pressure, as in vasodepressor, or vasova- gal, syncope (strong emotion, painful injury, prolonged standing still, orthostatic hypotension); (2) diminished cardiac output, as in heart block (Stokes-Adams attack) or cardiac arrhythmia or as a result of diminished venous return to the heart (Valsalva phenomenon); or (3) an altered state of the blood itself (e.g., blood loss), in which insufficient oxygen or glucose is delivered to the brain. Details of the clinical features and mechanisms of the various types of syncope will be found in the Principles. 166 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE TABLE 18-1 Types of Syncope and Faintness I. Neurogenic vasodepressor and vasovagal reactions A. Elicited by extrinsic signals to the medulla from baroreceptors 1. Vasodepressor (vasovagal) 2. Neurocardiogenic 3. Carotid sinus hypersensitivity 4. Vagoglossopharyngeal B. Coupled with diminished venous return to the heart 1. Micturitional 2. Tussive 3. Valsalva, straining, weightlifting 4. Postprandial C. Intrinsic psychic stimuli 1. Fear, anxiety (presyncope more common) 2. Sight of blood 3. Hysterical fainting (continued) 4777 Victor Ch 18 p165-169 6/11/01 2:03 PM Page 166 CHAPTER 18 / FAINTNESS AND SYNCOPE 167 TABLE 18-1 Types of Syncope and Faintness (continued) II. Sympathetic nervous system failure (postural-orthostatic hypotension) A. Autonomic neuropathy 1. Diabetes 2. Pandysautonomia 3. Guillain-Barré syndrome 4. Amyloid 5. Surgical sympathectomy 6. Antihypertensive medications and other blockers of vascular innervation B. Central autonomic failure 1. Primary autonomic failure 2. Parkinsonian syndromes 3. Tabes dorsalis 4. Syringomyelia 5. Spinal cord transection 6. Centrally acting antihypertensive medications III. Reduced cardiac output or inadequate intravascular volume (hypovolemia) A. Reduced cardiac output 1. Obstruction to left ventricular outflow: aortic stenosis; hyper- trophic subaortic stenosis 2. Obstruction to pulmonary flow: pulmonic stenosis, tetralogy of Fallot, primary pulmonary hypertension, pulmonary embolism 3. Myocardial: infarction or severe congestive heart failure 4. Pericardial tamponade 5. Cardiac arrhythmias (with reduced cranial circulation) Bradyarrhythmias a. AV block (second and third degrees) with Stokes-Adams attacks b. Ventricular asystole c. Sinus bradycardia, sinoatrial block, sinus arrest, sick- sinus syndrome Tachyarrhythmias a. Episodic ventricular fibrillation b. Ventricular tachycardia c. Supraventricular tachycardia without AV block (infrequently causes syncope) B. Inadequate intravascular volume IV. Other causes of episodic faintness and syncope A. Hypoxia B. Anemia C. Diminished CO 2 due to hyperventilation (faintness common, syn- cope rare) D. Hypoglycemia (faintness frequent, syncope rare) 4777 Victor Ch 18 p165-169 6/11/01 2:03 PM Page 167 CLINICAL APPROACH TO SYNCOPE If on the scene of a common vasovagal faint, one need only ensure that the patient remains recumbent until the vasodepressor inadequacy has corrected itself. For the patient who reports one or more faints and is normal when seen, one must ascertain, from the descriptions of the episode, that it was a faint and not a seizure or an attack of anxiety, tran- sient ischemia, or hypoglycemia. Having satisfied oneself on this point, one attempts to determine the mechanism of the faint and the likelihood of its recurrence. Some types of syncope, such as those of cardiac and orthostatic origin, must be taken seriously; others are obviously benign. An otherwise healthy adolescent or young adult who faints at the scene of an accident or when sitting or standing still in an overheated atmo- sphere needs no further study—only an explanation of the nature of vasovagal syncope and the admonition to avoid situations that are known to induce fainting. In fainting of orthostatic type, one must not fail to consider the possible hypotension-producing effects of certain drugs—the common ones being antihypertensive agents, diuretics, phe- nothiazines, benzodiazepines, tricyclic antidepressants, and L -dopa. A person convalescing from illness or one with an inadequate peripheral vasoconstrictor mechanism (orthostatic hypotension, dia- betic neuropathy, Parkinson disease, striatonigral degeneration, and Shy-Drager syndrome) requires investigation of the underlying disease and the institution of certain corrective measures to help avoid future attacks. The latter include elevating the head of the bed by 8 to 12 in., arising slowly for a recumbent position, the use of a snug elastic abdominal binder and stockings, increasing salt intake to expand blood volume, and the administration of fludrocortisone acetate (Florinef ), 0.01 to 0.02 mg/day in divided doses. The ␣-1 sympathetic agonist Midodrine may also be used to elevate standing blood pressure. It is given in doses of 10 mg every 4 h, with care taken to monitor supine blood pressure for an excessive rise. In patients with cardiac syncope, it may be necessary to monitor car- diac rhythm for several days or weeks or even longer. The drug treat- ment of the various arrhythmias that induce syncope and the need for a pacemaker require consultation with a cardiologist. The treatment of carotid sinus syncope can be difficult. Atropine or ephedrine should be tried in patients whose attacks are associated with bradycardia or hypotension, respectively. If these medications fail and the attacks are incapacitating, surgical denervation of the carotid sinus or the place- ment of a demand pacemaker in the right ventricle needs to be consid- ered. Tussive syncope, micturition syncope, and “weight-lifter’s syncope” simply require the use of antitussive medicines and treatment of tra- cheobronchitis, instruction to urinate while sitting, and interdiction of straining and heavy lifting, as the case may be. In patients who faint because of hypovolemia or the effects of antihypertensive drugs, it may 168 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE 4777 Victor Ch 18 p165-169 6/11/01 2:03 PM Page 168 [...]... Figs 2 2-1 , 2 2-2 , and 2 2-3 192 Copyright 1998 The McGraw-Hill Companies, Inc Click Here for Terms of Use 47 77 Victor Ch 22 p19 2-2 03 6/11/01 2:05 PM Photograph of the lateral surface of the human brain (From MB Carpenter and J Sutin, Human Neuroanatomy, 8th ed, Baltimore, Williams & Wilkins, 1982, with permission.) Page 193 193 FIG 2 2-1 47 77 Victor Ch 22 p19 2-2 03 1 94 6/11/01 2:05 PM Page 1 94 PART II... this topic, see Adams, Victor, and Ropper: Principles of Neurology, 6th ed, pp 40 3 41 6 ADDITIONAL READING Medina JL, Rubino FA, Ross A: Agitated delirium caused by infarction of the hippocampal formation, fusiform and lingual gyri Neurology 24: 1181, 19 74 Mesulam M-M: Attention, confusional states, and neglect, in Mesulam M-M (ed), Principles of Behavioral Neurology, Philadelphia, Davis, 1985, pp 125–168... discussion of this topic, see Adams, Victor, and Ropper: Principles of Neurology, 6th ed, pp 41 7 43 4 47 77 Victor Ch 21 p18 1-1 91 6/11/01 2: 04 PM Page 191 CHAPTER 21 / DEMENTIA AND THE AMNESIC SYNDROME 191 ADDITIONAL READING Deutsch JA (ed): The Physiological Basis of Memory, 2nd ed New York, Academic, 1983, pp 199–268 Fisher CM, Adams RD: Transient global amnesia Acta Neurol Scand 40 (Suppl 9):1, 19 64 Folstein... Marchiafava-Bignami disease (often with apraxia and other frontal lobe signs) 8 Angiitis of the brain III Diseases in which dementia is the only evidence of neurologic or medical disease A Alzheimer disease B Pick disease C Some cases of AIDS D Lewy body disease E Degenerative disease of unspecified type 47 77 Victor Ch 21 p18 1-1 91 1 84 6/11/01 2: 04 PM Page 1 84 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC... insight in the Principles of Neurology or some other textbook of neurology and psychiatry It is necessary then to become skilled in the bedside examination of mental disorders of all types (A simplified mental status examination can be found at the end of this chapter.) NEUROLOGY OF THE DEMENTIAS Table 2 1-1 lists the dementing diseases, which are subdivided into three categories on the basis of their associated... signs of medical disease 181 Copyright 1998 The McGraw-Hill Companies, Inc Click Here for Terms of Use 47 77 Victor Ch 21 p18 1-1 91 182 6/11/01 2: 04 PM Page 182 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE The special clinical and pathologic features of the dementing diseases will be discussed in subsequent chapters, but several general points should be made here An inspection of Table 2 1-1 ... treatment of both “restless legs” and periodic nocturnal leg movements: L-dopa, bromocriptine, propoxyphene, and baclofen The management of primary insomnia is difficult In general, the long-term use of sedative-hypnotic drugs is not the answer to the problem Barbiturates, short or long acting, should not be used because of the danger of addiction and of rebound insomnia (i.e., an intense worsening of the... already noted, an endogenous late-life depression may simulate a type of progressive dementia The patient’s lack of interest and unwillingness to participate in tests of mental status make clinical evaluation difficult Complaints by the patient of loss of memory, the presence of a sad facial expression, crying, talk of dying, discrepancies in memory tests coupled with intactness of language function and capacity... individual who functions adequately on 4 to 5 h of sleep, the primary insomniac complains of the effects of sleep deprivation Moreover, sleep-laboratory recordings verify the inadequacy of his sleep Secondary (situational) insomnia is most often related to worry and anxiety (difficulty in falling asleep), depression (early-morning awakening), and the abuse of alcohol or drugs Of course, breathing difficulty... the hippocampus: A clinical-pathologic study J Cog Neurosci 2: 246 , 1990 Wade JPH, Mirsen TR, Hachinski VC, et al: The clinical diagnosis of Alzheimer’s disease Arch Neurol 44 : 24, 1987 Warrington EK, McCarthy RA: Disorder of memory, in Asbury AK, McKhann GM, McDonald WI (eds): Diseases of the Nervous System, 2nd ed Philadelphia, Saunders, 1992, pp 718–728 47 77 Victor Ch 22 p19 2-2 03 22 6/11/01 2:05 PM . 17 / COMA AND RELATED DISORDERS OF CONSCIOUSNESS 163 47 77 Victor Ch 17 p15 4- 1 64 6/11/01 2:02 PM Page 163 in Table 1 7-3 , may be of help in predicting the outcome, particularly in cases due to cerebral. discussion of this topic, see Adams, Victor, and Ropper: Principles of Neurology, 6th ed, pp 344 –366. ADDITIONAL READING Beecher HK, Adams RD, Sweet WH: A definition of irreversible coma. Report of the. brain. Details of the clinical features and mechanisms of the various types of syncope will be found in the Principles. 166 PART II / CARDINAL MANIFESTATIONS OF NEUROLOGIC DISEASE TABLE 1 8-1 Types of Syncope