The Gale Encyclopedia of Neurological Disorders vol 2 - part 6 pot

GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS 755 Seizures ❙ Seizures Definition A seizure is a sudden change in behavior characterized by changes in sensory perception (sense of feeling) or motor activity (movement) due to an abnormal firing of nerve cells in the brain. Epilepsy is a condition characterized by recurrent seizures that may include repetitive muscle jerking called convulsions. Description Seizure disorders and their classification date back to the earliest medical literature accounts in history. In 1964, the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) devised the first official classification of seizures, which was revised again in 1981. This classification is accepted worldwide and is based on electroencephalographic (EEG) studies. Based on this system, seizures can be classified as either focal or generalized. Each of these categories can also be further subdivided. Focal seizures A focal (partial) seizure develops when a limited, con- fined population of nerve cells fire their impulses abnormally on one hemisphere of the brain. (The brain has two portions or cerebral hemispheres—the right and left hemispheres.) Focal seizures are divided into simple or complex based on the level of consciousness (wakefulness) during an attack. Simple partial seizures occur in patients who are conscious, whereas complex partial seizures demonstrate impaired levels of consciousness. Generalized seizures A generalized seizure results from initial abnormal firing of brain nerve cells throughout both left and right hemispheres. Generalized seizures can be classified as follows: • Tonic-clonic seizures: This is the most common type among all age groups and is categorized into several phases beginning with vague symptoms hours or days before an attack. These seizures are sometimes called grand mal seizures. • Tonic seizures: These are typically characterized by a sustained nonvibratory contraction of muscles in the legs and arms. Consciousness is also impaired during these episodes. • Atonic seizures (also called “drop attacks”): These are characterized by sudden, limp posture and a brief period of unconsciousness and last for one to two seconds. • Clonic seizures: These are characterized by a rapid loss of consciousness with loss of muscle tone, tonic spasm, and jerks. The muscles become rigid for about 30 seconds during the tonic phase of the seizure and alternately contract and relax during the clonic phase, which lasts 30–60 seconds. • Absence seizures: These are subdivided into typical and atypical forms based on duration of attack and level of consciousness. Absence (petit mal) seizures generally begin at about the age of four and stop by the time the child becomes an adolescent. They usually begin with a brief loss of consciousness and last between one and 10 seconds. People having a petit mal seizure become very quiet and may blink, stare blankly, roll their eyes, or move their lips. A petit mal seizure lasts 15–20 seconds. When it ends, the individual resumes whatever he or she was doing before the seizure began, will not remember the seizure, and may not realize that anything unusual happened. Untreated, petit mal seizures can recur as many as 100 times a day and may progress to grand mal seizures. • Myoclonic seizures: These are characterized by rapid muscular contractions accompanied with jerks in facial and pelvic muscles. Subcategories are commonly diagnosed based on EEG results. Terminology for classification in infants and newborns is still controversial. Causes and symptoms Simple partial seizures can be caused by congenital abnormalities (abnormalities present at birth), tumor growths, head trauma, stroke, and infections in the brain or nearby structures. Generalized tonic-clonic seizures are associated with drug and alcohol abuse, and low levels of blood glucose (blood sugar) and sodium. Certain psychi- atric medications, antihistamines, and even antibiotics can precipitate tonic-clonic seizures. Absence seizures are im- plicated with an abnormal imbalance of certain chemicals in the brain that modulate nerve cell activity (one of these neurotransmitters is called GABA, which functions as an inhibitor). Myoclonic seizures are commonly diagnosed in newborns and children. Symptoms for the different types of seizures are specific. Partial seizures SIMPLE PARTIAL SEIZURES Multiple signs and symptoms may be present during a single simple partial seizure. These symptoms include specific muscles tensing and then alternately contracting and relaxing, speech arrest, vocalizations, and involuntary turning of the eyes or head. There could be changes in vision, hearing, balance, taste, and smell. Additionally, patients with simple partial seizures may have a sensation in the abdomen, sweating, LetterS.qxd 10/1/04 11:08 AM Page 755 756 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Seizures Key Terms Electroencephalograph (EEG) An instrument that measures the electrical activity of the brain. The EEG traces the electrical activity in the form of wave pattens onto recording paper. Wave patterns that have sudden spikes or sharp waves strongly suggest seizures. An EEG with a seizure-type wave pattern is called an epileptiform EEG. Hallucination False sensory perceptions. A person experiencing a hallucination may “hear” sounds or “see” people or objects that are not really present. Hallucinations can also affect the senses of smell, touch, and taste. Illusion A misperception or misinterpretation in the presence of a real external stimulus. paleness, flushing, hair follicles standing up (piloerection), and dilated pupils (the dark center in the eye enlarges). Seizures with psychological symptoms include thinking disturbances and hallucinations, or illusions of memory, sound, sight, time, and self-image. COMPLEX PARTIAL SEIZURES Complex partial seizures often begin with a motionless stare or arrest of activity; this is followed by a series of involuntary movements, speech disturbances, and eye movements. Generalized seizures Generalized seizures have a more complex set of signs and symptoms. TONIC-CLONIC SEIZURES Tonic-clonic seizures usually have vague prodromal (pre-attack) symptoms that can start hours or days before a seizure. These symptoms include anxiety, mood changes, irritability, weakness, dizzi- ness, lightheadedness, and changes in appetite. The tonic phases may be preceded with brief (lasting only a few seconds in duration) muscle contractions on both sides of affected muscle groups. The tonic phase typically begins with a brief flexing of trunk muscles, upward movement of the eyes, and pupil dilation. Patients usually emit a characteristic vocalization. This sound is caused by contraction of trunk muscles that forces air from the lungs across spasmodic (abnormally tensed) throat muscles. This is followed by a very short period (10–15 seconds) of general muscle relaxation. The clonic phase consists of muscular contractions with alternating periods of no movements (muscle atonia) of gradually increasing duration until abnormal muscular contractions stop. Tonic- clonic seizures end in a final generalized spasm. The affected person can lose consciousness during tonic and clonic phases of seizure. Tonic-clonic seizures can also produce chemical changes in the body. Patients commonly experience low- ered carbon dioxide (hypocarbia) due to breathing alter- ations, increased blood glucose (blood sugar), and elevated level of a hormone called prolactin. Once the affected person regains consciousness, he or she is usually weak, and has a headache and muscle pain. Tonic-clonic seizures can cause serious medical problems such as trauma to the head and mouth, fractures in the spinal col- umn, pulmonary edema (water in the lungs), aspiration pneumonia (a pneumonia caused by a foreign body being lodged in the lungs), and sudden death. Attacks are generally one minute in duration. TONIC SEIZURES Tonic and atonic seizures have dis- tinct differences but are often present in the same patient. Tonic seizures are characterized by nonvibratory muscle contractions, usually involving flexing of arms and relaxing or flexing of legs. The seizure usually lasts less than 10 seconds but may be as long as one minute. Tonic seizures are usually abrupt and patients lose consciousness. Tonic seizures commonly occur during non-rapid eye movement (non-REM) sleep and drowsiness. Tonic seizures that occur during wakeful states commonly produce physical injuries due to abrupt, unexpected falls. ATONIC SEIZURES Atonic seizures, also called “drop attacks,” are abrupt, with loss of muscle tone lasting one to two seconds, but with rapid recovery. Consciousness is usually impaired. The rapid loss of muscular tone could be limited to head and neck muscles, resulting in head drop, or it may be more extensive, involving muscles for balance and causing unexpected falls with physical injury. CLONIC SEIZURES Generalized clonic seizures are rare and seen typically in children with elevated fever. These seizures are characterized by a rapid loss of consciousness, decreased muscle tone, and generalized spasm that is followed by jerky movements. ABSENCE SEIZURES Absence seizures are classified as either typical or atypical. The typical absence seizure is characterized by unresponsiveness and behavioral arrest, abnormal muscular movements of the face and eyelids, and lasts less than 10 seconds. In atypical absence seizures, the affected person is generally more conscious, the seizures begin and end more gradually, and do not ex- ceed 10 seconds in duration. MYOCLONIC SEIZURES Myoclonic seizures commonly exhibit rapid muscular contractions. Myoclonic seizures are seen in newborns and children who have either symptomatic or idiopathic (cause is unknown) epilepsy. Demographics Approximately 1.5 million persons in the United States suffer from a type of seizure disorder. The annual incidence (number of new cases) for all types of seizures LetterS.qxd 10/1/04 11:08 AM Page 756 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS 757 Seizures is 1.2 per 1,000 and, for recurrent seizures, is 0.54 per 1,000. Isolated seizures may occur in up to 10% of the general population. Approximately 10–20% of all patients have intractable epilepsy (epilepsy that is difficult to man- age or treat). It is estimated that 45 million people in the world are affected by seizures. Seizures affect males and females equally and can occur among all age groups. There seems to be a strong genetic correlation, since seizures are three times more prevalent among close rela- tives than they are in the general population. Children delivered in the breech position have increased prevalence (3.8%) of seizures when compared to infants delivered in the normal delivery position (2.2%). Seizures caused by fever have a recurrence rate of 51% if the attack occurred in the first year of life, whereas recurrence rate is decreased to 25% if the seizure took place during the second year. Approximately 88% of children who experience seizures caused by fever in the first two years experience recurrence. Approximately 45 million people worldwide are affected by epilepsy. The incidence is highest among young children and the elderly. High-risk groups include persons with a previous history of brain injury or lesions. Diagnosis Patients seeking help for seizures should first undergo an EEG that records brain-wave patterns emitted between nerve cells. Electrodes are placed on the head, sometimes for 24 hours, to monitor brain-wave activity and detect both normal and abnormal impulses. Imaging studies such as magnetic resonance imaging (MRI) and computed axial tomography (CT)—that take still “pictures”—are useful in detecting abnormalities in the temporal lobes (parts of the brain associated with hearing) or for helping diagnose tonic-clonic seizures. A complete blood count (CBC) can be helpful in determining whether a seizure is caused by a neurological infection, which is typically accompanied by high fever. If drugs or toxins in the blood are suspected to be the cause of the seizure(s), blood and urine screening tests for these compounds may be necessary. Antiseizure medication can be altered by many commonly used medications such as sulfa drugs, erythromy- cin, warfarin, and cimetidine. Pregnancy may also decrease serum concentration of antiseizure medications; therefore, frequent monitoring and dose adjustments are vital to maintain appropriate blood concentrations of the antiseizure medication—known as the therapeutic blood concentration. Diagnosis requires a detailed and accurate history, and a physical examination is important since this may help identify neurological or systemic causes. In cases in which a central nervous system (CNS) infection (i.e., meningitis or encephalitis) is suspected, a lumbar puncture (or spinal tap) can help detect an increase in immune cells (white blood cells) that develop to fight the specific infection. Treatments Treatment is targeted primarily to: • assist the patient in adjusting psychologically to the diagnosis and in maintaining as normal a lifestyle as possible • reduce or eliminate seizure occurrence • avoid side effects of long-term drug treatment Simple and complex partial seizures respond to drugs such as carbamazepine, valproic acid (valproate), phenytoin, gabapentin, tiagabine, lamotrigine,and topiramate. Tonic-clonic seizures tend to respond to valproate, carbamazepine, phenytoin, and lamotrigine. Ab- sence seizures seem to be sensitive to ethosuximide, valproate, and lamotrigine. Myoclonic seizures can be treated with valproate and clonazepam. Tonic seizures seem to respond favorably to valproate, felbamate, and clonazepam. People treated with a class of medications called bar- biturates (Mysoline, Mebral, phenobarbital) have ad- verse cognitive (thinking) effects. These cognitive effects can include decreased general intelligence, attention, memory, problem solving, motor speed, and visual motor functions. The drug phenytoin (Dilantin) can adversely affect speed of response, memory, and attention. Other medications used for treatment of seizures do not have substantial cognitive impairment. Surgical treatment may be considered when medications fail. Advances in medical sciences and techniques have improved methods of identifying the parts of the brain that generate abnormal discharge of nerve impulses. Surgical treatment now accounts for about 5,000 procedures annually. The most common type of surgery is the focal cortical resection. In this procedure, a small part of the brain responsible for causing the seizures is removed. Surgical intervention may be considered a feasible treatment option if: • the site of seizures is identifiable and localized • surgery can remove the seizure-generating (epilepto- genic) area • surgical procedure will not cause damage to nearby areas Prognosis About 30% of patients with severe seizures (starting in early childhood), continue to have attacks and usually never achieve a remission state. In the United States, the prevalence of treatment-resistant seizures is about one to LetterS.qxd 10/1/04 11:08 AM Page 757 758 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Septo-optic dysplasia two per 1,000 persons. About 60–70% of persons achieve a five-year remission within 10 years of initial diagnosis. Approximately half of these patients become seizure-free. Usually the prognosis is better if seizures can be controlled by one medication, the frequency of seizures decreases, and there is a normal EEG and neurological examination prior to medication cessation. People affected by seizure have increased death rates compared with the general population. Patients who have seizures of unknown cause have an increased chance of dying due to accidents (primarily drowning). Other causes of seizure-associated death include abnormal heart rhythms, water in the lungs, or heart attack. Prevention There are no gold standard recommendations for prevention, since seizures can be caused by genetic factors, blood abnormalities, many medications, illicit drugs, infection, neurologic conditions, and other systemic diseases. If a person has had a previous attack or has a genetic propensity, care is advised when receiving medical treatment or if diagnosed with an illness correlated with possible seizure development. Resources BOOKS Goetz, Christopher G . Textbook of Clinical Neurology. 1st edition. Philadelphia: W. B. Saunders Company, 1999. Goldman, Lee, and others. Cecil Textbook of Medicine. 21st edition. Philadelphia: W. B. Saunders Company, 2000. Goroll, Allan H. Primary Care Medicine. 4th edition. Philadelphia: Lippincott Williams and Wilkins, 2000. PERIODICALS Dodrill, C. R., C. G. Matthew. “The role of Neuropsychology in the Assessment and Treatment of Persons with Epilepsy.” American Psychologist (September 1992). ORGANIZATIONS Epilepsy Foundation. 4351 Garden City Drive, Landover, MD 20785-7223. (800) 332-1000. <http://www.efa.org>. Laith Farid Gulli, MD Alfredo Mori, MD, FACEM ❙ Septo-optic dysplasia Definition Septo-optic dysplasia (SOD) is a rare, congenital disorder. Findings include optic nerve hypoplasia with a thin or absent septum pellucidum and/or corpus callosum and pituitary dysfunction. Optic nerve hypoplasia is manda- tory for the diagnosis of SOD. Description SOD also known as DeMorsier’s syndrome is a combination of optic nerve underdevelopment (hypoplasia) with abnormalities of a part of the brain called the septum pellucidum and/or corpus callosum. Endocrine disorders such as dwarfism, decreased thyroid gland function (hypothyroidism), dehydration, delayed or precocious puberty and reduced blood sugar may occur from dysfunction of the pituitary gland of the brain. SOD has also been associated with congenital architectural brain anomalies. Causes and symptoms The cause of SOD is thought to be related to in- trauterine viral infections or diabetes during pregnancy. Antiseizure medications, alcohol and illicit drugs have also been linked to SOD. In addition vascular abnormalities and uncommonly genetics are thought to play a role. Patients afflicted with SOD can present at any age depending on the severity of the symptoms. Signs and symptoms such as failure to thrive, prolonged jaundice, body temperature dysregulation, decreased blood sugar, small genitalia or muscular flaccidity can herald the diagnosis of SOD in newborns. Older children may complain of visual difficulties and be found to have strabismus (crossed eyes), nystagmus (involuntary, jerky eye movements) or inability to fixate on an object. In addition pupillary and color vision abnormalities may be noted. The optic nerves will appear small and grey or pale in color and can be surrounded by a yel- lowed halo signifying hypoplasia or atrophy. A large percentage of SOD patients will have endocrine disorders. By far growth hormone deficiencies are the most common in patients with optic nerve hypoplasia. Growth hormone deficiency can lead to reduced blood sugar, while abnormal levels of reproductive hormones can result unusual pubertal development. Reduced levels of thyroid-stimulating hormone will cause suboptimal thyroid gland functioning (hypothyroidism). Other endocrine problems include increased urination, dehydration and death. In some instances patients will have behavioral and cognitive problems resulting from brain maldevelopment or endocrinologic disorders. Diagnosis Suspicion for the diagnosis of SOD is based on clinical findings described above. In addition magnetic resonance imaging (MRI) of the brain focusing on the visual LetterS.qxd 10/1/04 11:08 AM Page 758 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS 759 Shaken baby syndrome Key Terms Corpus callosum The largest commissure con- necting the right and left hemispheres of the brain. Septum pellucidum Two-layered thin wall sepa- rating the right and the left anterior horn of lateral ventricle. pathways, hypothalamus-pituitary region and other midline structures and septum pellucidum is invaluable for so- lidifying the diagnosis. Treatment team Pediatricians, endocrinologists, optometrists, ophthalmologists, neuro-ophthalmologists and neurologists can all contribute to patient care. Treatment SOD is treated symptomatically. Hormone deficiencies are managed with hormone replacement therapy while the best possible visual acuity is achieved with cor- rective spectacle lenses. Recovery and rehabilitation Patients with extremely poor vision may benefit from a low vision specialist. He or she may be able to prescribe a visual apparatus to maximally improve visual function. Special concerns Patients with severe visual depression may have dif- ficulty obtaining a driver’s license or gainful employment. Resources BOOKS Liu, Grant T., Nicholas J. Volpe, and Steven L. Galetta. Neuro- Ophthalmology Diagnosis and Management, 1st ed. Philadelphia, PA: W. B. Saunders Company, 2001. PERIODICALS Campbell, Carrie. “Septo-optic dysplasia: a literature review.” Optometry 72, no. 7 (July 2003): 417-426. ORGANIZATIONS National Organization for Rare Disorders. PO Box 1968, Danbury, CT 06813-1968. 202-744-1000 or 800-999- NORD; Fax: 203-798-2291. orphan@rarediseases.org. <http://www.rarediseases.org>. National Eye Institute. National Institute of Health, Bldg. 31, Rm. 6A32, Bethesda, MD 20892-2510. 301-496-5248. 2020@b31.nei.nih.gov. <http://www.nei.nih.gov>. Adam J. Cohen, MD ❙ Shaken baby syndrome Definition Shaken baby syndrome is a severe form of head injury caused by the forcible shaking of a child. The force is sufficient to cause the brain to bounce against the baby’s skull, causing injury or damage to the brain. Description Shaking an infant forcibly transfers a great deal of energy to the infant. When the shaking occurs as the infant is being held, much of the force is transferred to the neck and the head. The force can be so great that the brain can move within the skull, rebounding back and forth from one side of the skull to the other. The bashing can be very destruc- tive to the brain, causing bruising, swelling, or bleeding. Bleeding of the brain is also called intracerebral hemor- rhage. The force of shaking can also damage the neck. As its name implies, shaken baby syndrome can often be a result of deliberate abuse. The brain damage can also be the result of an accident. The force and length of the force necessary to cause shaken baby syndrome is debat- able. What is clear is that not much time is needed, since most shaking events likely tend to last only 20 seconds or less. It is the explosive violence of the shaking that exacts the damage. Demographics Reliable statistics on the prevalence of shaken baby syndrome do not exist. Estimates in the United States approach 50,000 cases each year. Nearly 25% of infants with shaken baby syndrome die from the brain injuries sustained. The victims of this syndrome range in age from just a few days to five years, with an average age of six to eight months. Statistics point to men as the usual perpetrators, typically young men (i.e., early 20s). Females who shake babies tend to be caregivers. As reliable statistics emerge, it would not be unexpected to find the actual number of cases greatly exceeds these crude estimates. Abuse of children is a hidden event, so many cases of abuse, including shaken baby syndrome, are not reported or are presented in some other form (such as a fall or an accident). LetterS.qxd 10/1/04 11:08 AM Page 759 760 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Shaken baby syndrome Key Terms Increased intracranial pressure Increased overall pressure inside the skull. Subdural hematoma A collection of blood or a clot trapped under the dura matter, the outermost membrane surrounding the brain and spinal cord, often causing neurological damage due to pressure on the brain. Causes and symptoms The cause of the brain, neck, and spine damage that can result from shaken baby syndrome is brute force. The violent shaking of a baby by a much stronger adult con- veys a tremendous amount of energy to the infant. Part of the reason for the damage is because an infant’s head is much larger than the rest of the body, in relation to an older child or an adult. This, combined with neck muscles that are still developing and are incapable of adequately supporting the head, can make shaking an explosively de- structive event. The amount of brain damage depends on how hard the shaking is and how long an infant is shaken. If accidental, the force and length of the head trauma sim- ilarly determines the extent of injury. The normal tossing and light “horse play” that can occur between an adult and an infant is not sufficient to cause shaken baby syndrome. The damage to the brain can have dire consequences that include permanent and severe brain damage or death. Other symptoms that can develop include behavioral changes, lack of energy or motivation, irritable behavior, loss of consciousness, paling of the skin color or development of a bluish tinge to the skin, vomiting, and convulsions. These symptoms are the result of the destruction of brain cells that occurs directly due to the trauma of the blow against the skull, and secondarily as a result of oxygen deprivation and swelling of the brain. The banging of the brain against the sides of the skull causes the inflammation and swelling as well as internal bleeding. Increased intracranial pressure can be damaging to the structure and function of the brain. Additionally, because the neck and head can absorb a tremendous amount of energy due to the shaking force of the adult, bones in the neck and spine can be broken and muscles can be torn or pulled. The eyes can also be dam- aged by the explosive energy of shaking. Retinal damage occur in 50–80% of cases. The damage can be so severe as to permanently blind an infant. Shaken baby syndrome is also known as abusive head trauma, shaken brain trauma, pediatric traumatic brain injury, whiplash shaken infant syndrome, and shaken im- pact syndrome. Diagnosis Diagnosis depends on the detection of a blood clot below the inner layer of the dura (a membrane that sur- rounds the brain), but external to the brain. The clot is also known as a subdural hematoma. Two other critical features of shaken baby syndrome that are used in diagnosis are brain swelling and hemorrhaging in the eyes. An infant may also have external bruising on parts of the body that were used to grip him or her during shaking. Bone or rib fractures can also be apparent. However, these external features may not always be present. Diagnosis can also involve the nondestructive imaging of the brain using the techniques of computed tomography (CT), skull x ray, or magnetic resonance imaging (MRI). Typically, these procedures are done after an infant has been stabi- lized and survival is assured. Treatment team Treatment in an emergency setting typically involves nurses and emergency room physicians. A neurosurgeon is usually consulted when shaken baby syndrome is suspected. Depending on the extent of injury, neurosurgeons can become involved if surgery for brain repair is needed. Police officers and social workers also become involved in cases of shaken baby syndrome, who work to ensure that the child is placed in a safe environment. Treatment Initially, treatment is provided on an emergency basis. Life-saving measures can include stopping internal bleeding in the brain and relieving pressure that can build up in the brain because of bleeding and swelling of the brain. Recovery and rehabilitation If the infant survives the initial injury from shaken baby syndrome, rehabilitation focuses on recovering as much function as possible. Physical and occupational therapies can offer exercises for caregivers to provide the child, as well as any supportive or positional devices required. The full effects of the brain injury sustained in infants who survive shaken baby syndrome may not become apparent until delays in developmental milestones such as sitting alone, walking, or acquiring speech are noticed. Clinical trials As of May 2004, there are no clinical trials on shaken baby syndrome underway or recruiting participants in the United States. However, agencies such as the Na- tional Institute of Neurological Disorders and Stroke fund LetterS.qxd 10/1/04 11:08 AM Page 760 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS 761 Shingles studies that seek to better understand the basis of the damage. Other agencies attempt to lessen the occurrence of the syndrome through counseling, anger management, and in- terventions in abusive situations. Prognosis The prognosis for children with shaken baby syndrome is usually poor. Twenty percent of cases result in death within the first few days. If an infant survives, he or she will most often be left with intellectual and developmental disabilities such as mental retardation or cerebral palsy. Damage to the eyes can cause partial or total loss of vision. A survivor will likely require specialized care for the remainder of his or her life. Resources BOOKS Lazoritz, Stephen, and Vincent J. Palusci, eds. Shaken Baby Syndrome: A Multidisciplinary Approach. Binghamton, NY: Haworth Press, 2002. PERIODICALS Geddes, J. F., and J. Plunkett. “The Evidence Base for Shaken Baby Syndrome.” British Medical Journal (March 2004): 719–720. Harding, B., R. A. Risdon, and H. F. Krous. “Shaken Baby Syndrome.” British Medical Journal (March 2004): 720–721. OTHER “NINDS Shaken Baby Syndrome Information Page.” National Institute of Neurological Disorders and Stroke. May 13, 2004 (May 27, 2004). http:// www.ninds.nih.gov/health_and_medical/disorders/ shakenbaby.htm>. ORGANIZATIONS National Institute for Neurological Diseases and Stroke. P.O. Box 5801, Bethesda, MD 20824. (301) 496-5751 or (800) 352-9424. <http://www.ninds/nih.gov>. The National Center on Shaken Baby Syndrome. 2955 Harrison Blvd., #102, Ogden, UT 84403. (801) 627-3399 or (888) 273-0071; Fax: (801) 627-3321. dontshake@ mindspring.com. <http://www.dontshake.com>. National Institute of Child Health and Human Development. 31 Center Drive, Rm. 2A32 MSC 2425, Bethesda, MD 20892-2425. (301) 496-5133; Fax: (301) 496-7101. <http://www.nichd.nih.gov>. The Arc of the United States. 1010 Wayne Avenue, Suite 650, Silver Spring, MD 20910. (301) 565-3842; Fax: (301) 565-3843. info@thearc.org. <http://www.thearc.org>. Think First Foundation [National Injury Prevention Program]. 5550 Meadowbrook Drive, Suite 110, Rolling Meadows, IL 60008. (847) 290-8600 or (800) 844-6556; Fax: (847) 290-9005. thinkfirst@thinkfirst.org. <http://www.think first.org>. Brian Douglas Hoyle, PhD ❙ Shingles Definition Shingles is infection by the varicella-zoster virus of the dorsal root ganglia of the spine. Equivalent terms for shingles are herpes zoster, zoster, zona, or acute posterior ganglionitis. Description Shingles is an infection of the central nervous system, in particular, the dorsal root ganglia of the spine, which migrates through sensory nerves to the skin. There it manifests (usually on the upper trunk) as painful, bumpy, fluid-filled eruptions or vesicles. Shingles may also cause nerve pain (neuralgia). The affected areas of skin are those supplied by sensory nerves radiating from the infected dorsal root ganglia. Sensory nerves from these ganglia serve non-overlapping, sharply bounded strips or areas of the skin called dermatomes. Because the left and right sides of the body are divided into separate sets of dermatomes, shingles lesions do not cross the midline of the body. Demographics The virus that causes shingles is usually contracted in childhood. It is the same virus that causes chicken pox, which is primarily a disease of childhood because it is highly contagious; that is, few individuals live to adulthood without contracting chicken pox. (This statement applies to the temperate zones of the world. For unknown reasons, chicken pox and shingles are less prevalent in tropical re- gions.) The virus that causes both chicken pox and shingles can, however, be contracted by an individual for the first time in adulthood. First infection, at whatever age it occurs, is called primary infection. Primary infection does not cause shingles; shingles arises from reactivation of virus introduced to the body by an earlier, primary infection. Shingles arises in individuals who have already had chicken pox, and especially in people with weakened immune systems, such as the elderly or people receiving chemotherapy or bone marrow transplantation. Persons with AIDS are also vulnerable to shingles. Shingles incidence increases steadily with age. Among 10–19 year olds, the rate per 1,000 persons per year is only 1.38. In the 30–49 age range, it rises to 2.29 cases of shingles per 1,000 persons per year. By age 60–79, almost seven cases occur per 1,000 people per year, and this increases to 10 in the 80–89 age group. Causes and symptoms Shingles is caused by the varicella-zoster virus (VZV), also known as HHV-3. VZV is genetically similar to the herpes simplex viruses, the type of viruses that LetterS.qxd 10/1/04 11:08 AM Page 761 762 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Shingles Key Terms Ganglion A mass of nerve cells usually found out- side the central nervous system, from which axons arrive from the periphery and proceed to the spinal cord or brain; plural form: ganglia . Herpes simplex An infection caused by the herpes simples virus, affecting the skin and nervous system and producing small, temporary, often- painful blisters on the skin and mucous mem- branes. Hemiparesis Muscle weakness of one side of the body. Neuralgia Pain along a nerve pathway. Vesicle A small, raised lesion filled with clear fluid. causes cold sores and genital herpes. Herpes simplex virus also takes up permanent residence in sensory nerve ganglia, but not in the dorsal root ganglia of the spine, as does VZV. In chicken pox, the virus is inhaled and begins repli- cating in the upper respiratory tract before spreading to the liver and other body systems. Following primary infection, VZV remains as a symptomless infection in the dorsal root ganglia of the spinal cord. It may or may not become active again, that is, begin reproducing, later in life. Reactivation occurs more often in older people, probably as a result of decreased immune response with age. Reactivation may be symptomless, but usually causes shingles. Repeat episodes of shingles are rare (occurring in less than 4% of patients) because the immune system’s response to VZV is boosted by a first shingles episode. Chills, fever, malaise, gastrointestinal problems, and pain in the affected skin areas may precede appearance of skin eruptions by several days. Viral particles travel away from the spinal cord along the sensory nerves toward the skin, causing inflammation of those nerves, which may be painful. On the fourth or fifth day, skin vesicles begin to appear. The affected area is usually hypersensitive, and disabling pain (described as sharp, stabbing, or burning) may occur in the affected area. About the fifth day after appearing, the vesicles begin to crust or scab and the disease resolves within the next two weeks. There may be no visible aftereffects, although slight scarring from the vesicles may occur. Especially in elderly patients, pain may persist for months or years after shingles has otherwise resolved. This pain, postherpetic neuralgia, is caused by damage to the dorsal root ganglia that renders them either spontaneously active (perceived as chronic pain) or hypersensitive to slight stimuli such as light touch. VZV can become active in the cranial nerves as well as in the spinal ganglia. Involvement of branches of the trigeminal nerve (fifth cranial nerve) is most common. When the ophthalmic branch of the trigeminal nerve is involved, this condition is called herpes zoster ophthalmi- cus. It can cause swelling of the eyelid, pain, and other complications involving the eye. Herpes zoster oph- thalmicus can also lead to weakness or partial paralysis (hemiparesis) on the opposite side of the body from the nerve affected, possibly by inducing irritation of the blood vessels in the brain. Infection of cranial nerves by reactivated VZV can also affect the hearing. When this occurs, it is usually associated with facial palsy and is known as Ramsay-Hunt syndrome. Large amounts of free virus (i.e., virus not held inside cells) is present in the fluid-filled vesicles or bumps that erupt on the skin during shingles. Thus, people who are not resistant to VZV are easily infected by contact with persons having an outbreak of shingles. A particular strain of VZV can remain latent for decades and then reappear as a new epidemic. Diagnosis Diagnosis is based on history and symptoms. The person must have initially had chicken pox in order to have shingles. Definite diagnosis is difficult before eruption of the characteristic vesicles or bumps on the skin. Often persons with early shingles mistake the reddened, painful area as an accidental burn. Once vesicles appear, however, they are hard to mistake because of their dermatome-bounded distribution on the body. In children, shingles (VZV reactivation) must be differentiated from chicken pox (primary VZV infection). This is normally not difficult, as chicken pox vesicles occur widespread on the body and shingles lesions are usually limited to one area on the person’s mid- section. Herpes simplex virus can also produce vesicle eruptions similar to those of shingles. If there is doubt about which virus is present, virus from the patient can be cultured. Treatment team Unless there are complications such as in a person with AIDS, or a child with leukemia, a primary physician can usually treat shingles. Treatment Treatment for shingles is primarily with antiviral drugs, traditionally acyclovir but, more recently, famcy- clovir and valacyclovir. Additionally, a live attenuated- virus vaccine for chicken pox has been licensed since LetterS.qxd 10/1/04 11:08 AM Page 762 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS 763 Shingles 1995. The vaccine was developed to immunize children undergoing cancer treatment because chicken pox can cause severe complications in such children. The pain associated with shingles, and with the postherpetic neuralgia that may linger (especially in older patients, after the condition has otherwise resolved), is best treated using combination therapy based on antivirals, an- tidepressants, corticosteroids, opioids (morphine), and topical agents (applied directly to the skin). The inexpen- sive amino acid lysine has also been reported to ease the symptoms of both herpes simplex infections and shingles. Recovery and rehabilitation Recovery from shingles for the otherwise healthy patient is straightforward and generally requires no special rehabilitation aid or therapy. Clinical trials As of mid 2004, several clinical trials related to shingles are recruiting patients. One is sponsored by the Na- tional Center for Research Resources, University of Texas, and titled “Randomized Study of Two Doses of Oral Vala- cyclovir in Immunocompromised Patients with Uncom- plicated Herpes Zoster.” The study seeks to investigate the efficacy of higher-than-standard doses of valacyclovir by assessing quality of life, pain level, and utilization of medical resources of patients treated with a higher-than-standard dose of valacylovir as compared to a control group treated with the standard dose. Contact information is Uni- versity of Texas Medical Branch, Galveston, Texas, 77555-0209; Stephen K. Tyring is the recruiter, telephone: (281) 333-2288. Another trial recruiting patients as of 2004 is sponsored by the Baylor College of Medicine, Texas Children’s Hospital, and titled “Valacyclovir in Immunocompromised Children.” The study seeks to learn how the body handles valacyclovir, its efficacy in treating immunocompromised children with shingles, and the side effects of such treatment. The recruiting inquiries in Pennsylvania is Children’s Hospital of Philadelphia, Pennsylvania, 19104; Donna Sylvester, RN, phone: (215) 590-3284. The recruiting inquiries in Texas is Texas Children’s Hospital, Houston, Texas, 77030; Susan Blaney, MD, phone: (832) 822-4215, e-mail: sblaney@bcm.tmc.edu , or Lisa R Bomgaars, MD, phone: (832) 824-4688, e-mail: lbomgaars@bcm.tmc.edu. A third study ongoing in 2004 is sponsored by the drug maker NeurogesX and titled “Controlled Study of NGX-4010 for the Treatment of Postherpetic Neuralgia.” NGX-4010 consists of a capsaicin dermal (skin) patch. Capsaicin is the active substance in chili peppers, and is used, paradoxically, both as an irritant and for pain relief. The purpose of this clinical trial is to evaluate the efficacy of a capsaicin patch for relief of postherpetic neuralgia. Contact information varies by state but can viewed at the National Institutes of Health Web site at <http://www.clinicaltrials.gov/ct/show/NCT00068081? order=3>. Prognosis Generally, the prognosis for persons with shingles is good. Shingles is almost never a life-threatening disease in otherwise healthy patients, and usually resolves without treatment in a few weeks. However, postherpetic neuralgia, which occurs more often in elderly patients, can be disabling and difficult to treat. Persons who have an impaired immune system , such as those deficient in cytotoxic T lymphocytes, persons undergoing immune suppression (e.g., for organ transplant), and persons who have AIDS or leukemia may suffer more serious effects from shingles, as the reactivated virus sometimes disseminates from the dorsal root ganglia to other parts of the body. In these cases, complications can resemble those for primary infection of adults with VZV, namely, viral pneumonia, male sterility, acute liver failure, and (in pregnant women) birth defects. Resources BOOKS Glaser, Ronald, and James F. Jones, (eds). Herpes Virus Infections. New York: Marcel Dekker, Inc., 1994. Strauss, James H., and Ellen G. Strauss. Viruses and Human Disease. New York: Academic Press, Elsevier Science, 2002. PERIODICALS Ho, Charles C., “Use of Combination Therapy for Pin Relief in Acute and Chronic Herpes Zoster.” Geriatrics (Dec. 1, 2001). Johns Hopkins Medical Institutions. “Opioid Medications a Good Bet for Shingles-Related Pain.” Ascribe Higher Education News Service (Oct. 7, 2002). Madison, Linda K. “Shingles Update: Common Questions in Caring for a Patient with Shingles.” Orthopaedic Nursing (Jan. 1, 2000). “New Therapies Reduce Morbidity from Herpes Zoster.” Ophthalmology Times (Jan. 1, 1999). Sheff, Barbara, “Microbe of the Month: Varicella-Zoster Virus.” Nursing (Nov. 1, 2000). Smith, Angela D. “Lysine for Herpes Simplex Infections.” Medical Update (Nov. 1, 2001). OTHER “NINDS Shingles Information Page.” National Institute of Neurological Disorders and Stroke. April 28, 2004 (May 27, 2004). <http://www.ninds.nih. gov/health_and_medical/disorders/shingles_ doc.htm>. Larry Gilman, PhD LetterS.qxd 10/1/04 11:08 AM Page 763 764 GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Single Proton Emission Computed Tomography Key Terms Half-life The time required for half of the atoms in a radioactive substance to decay. Radioisotope One of two or more atoms with the same number of protons but a different number of neutrons with a nuclear composition. In nuclear scanning, radioactive isotopes are used as a diagnostic agent. Seizure A sudden attack, spasm, or convulsion. Shy-Drager syndrome see Multiple system atrophy ❙ Single Proton Emission Computed Tomography Definition Single proton (or photon) emission computed tomography (SPECT) allows a physician to see three-dimensional images of a person’s particular organ or body system. SPECT detects the course of a radioactive substance that is injected, ingested, or inhaled. In neurology, a SPECT scan is often used to visualize the brain’s cerebral blood flow and thereby, indicate metabolic activity patterns in the brain. Purpose SPECT can locate the site of origin of a seizure, can confirm the type of seizure that has occurred, and can provide information that is useful in the determination of therapy. Other uses for SPECT include locating tumors, monitoring the metabolism of oxygen and glucose, and determining the concentration of neurologically relevant compounds such as dopamine. Currently, a clinical trial is underway in the United States to evaluate the potential of SPECT to study brain re- ceptors for the neurotransmitter acetylcholine. The study will help to determine the usefulness of the technique in charting the progress of the brain deterioration associated with Parkinson’s disease. Precautions The exposure to radiation, particularly to the thyroid gland, is minimized as described below in the sections on preparation and aftercare. Description Since its development in the 1970s, single proton emission computed tomography has become a critical and routine facet of a clinician’s diagnostic routine. A SPECT scan is now a typical part of the diagnosis of coronary artery disease, cancer, stroke, liver disease, bone and spinal abnormalities, and lung maladies. SPECT produces two-dimensional and three-dimensional images of a target region in the body by detecting the presence and location of a radioactive compound given prior to the test. The photon emissions of the radioactive compound can be detected in a manner that is similar to the detection of x rays in computed tomography (CT). The image produced is a compilation of data collected over time following introduction of the tracer. The radioactive compound that is introduced typically loses its radioactive potency rapidly (this is expressed as the half-life of a compound). For example, gamma-emit- ting compounds can have a half-life of just a few hours. This is beneficial for the patients, as it limits the contact time with the potentially damaging radioisotope. The emitted radiation is collected by a gamma-cam- era through thousands of round or hexagonal channels that are arranged in parallel in a part of the machine called the collimator. Only gamma rays can pass through the channels. At the other end of the channel, the radiation contacts a crystal of sodium iodide. The interaction produces a photon of light (hence, the name of the technique). The light is subsequently detected and the time and body location of the light-producing radiation is stored computationally. At the end of the SPECT scan, the stored information can be integrated to produce a composite image. Typically, a patient is stationary. The SPECT scanner can move completely around the patient. Usually the patient will lie on a bed with their head restrained in a holder. Scans are taken for periods up to six hours following the injection of the tracer. Monitoring of the heartbeat (electrocardiogram), res- piration, and blood pressure are accomplished just prior to the start of the scan, five minutes after the introduction of the tracer, and 30–60 minutes after injection. Blood and urine samples are often collected towards the end of the scan. Preparation On the night before a scan, the patient takes an oral dose of potassium iodide. This protects the thyroid gland from the radioactive tracer. If a patient is allergic to potassium iodide, potassium perchlorate can be taken instead. Just prior to a scan, small radioisotope markers that contain the element 99Tc are attached with adhesive to the patient’s LetterS.qxd 10/1/04 11:08 AM Page 764 [...]... from the heart to be delivered by arteries throughout the body Christopher Reeve Paralysis Foundation / Paralysis Resource Center 500 Morris Avenue, Springfield, NJ 07081 973379 -2 6 90 or 800 -2 2 5- 029 2; Fax: 97 3-9 1 2- 9433 info@ crpf.org; research@crpf.org National Spinal Cord Injury Association 67 01 Democracy Blvd #30 0-9 , Bethesda, MD 20 817 301 -2 1 4-4 0 06 or 80 0-9 6 2- 9 62 9 ;... OTHER Apneos Corporation 20 33 Ralston Avenue #41, Belmont, CA 940 02 (65 0) 591 -2 8 95 (March 2, 20 04) ORGANIZATIONS The American Lung Association 61 Broadway, 6th Floor, New York, NY 100 06 (21 2) 31 5-8 700 (March 2, 20 04) The Sleep Apnea Society of Alberta c/o 91 1-7 8 Avenue SW, Calgary, AB T2V0T7 (800) 81 7-5 337 (March 2, 20 04) ... exercise), resulting in the core of a 7 82 The prognosis of spinal cord infarction tends to be very poor There is a high risk of death, either during the acute phase of infarction or over the long term, particularly GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS Key Terms Aneurysm A weakness and ballooning of the wall of an artery, which can burst with potentially catastrophic ramifications Aorta The major artery... Families of Spinal Muscular Atrophy May 5, 20 04 (May 27 , 20 04) ORGANIZATIONS Families of SMA PO Box 1 96, Libertyville, IL 60 04 8-0 1 96 (847) 36 7-7 62 3 or (800) 88 6- 1 7 62 sma@fsma.org Borut Peterlin, MD, PhD S Spina bifida Definition Spina bifida belongs to a group of disorders known as neural tube defects (NTDs) These all involve problems in the. .. Foundation When You Can’t Sleep: The ABCs of ZZZs 20 02 February 22 , 20 04 (March 2, 20 04) Stanford University Medical Center 300 Pasteur Drive, Stanford, CA 94305 (65 0) 723 -4 000 (March 2, 20 04) U.S National Library of Medicine 860 0 Rockville Pike, Bethesda, MD 20 894 (March 2, 20 04) ... However, the injection of the radioactive tracer results in the swift movement of the tracer through the body, and its rapid elimination Normal results The image of the target region of the body is compared to an image of the healthy target region Analysis of the images by a qualified physician determines the result Resources BOOKS Brant, Thomas Neurological Disorders: Course and Treatment, 2nd ed Philadelphia:... wiki/Speech_synthesis> “What is MND?” Motor Neuron Diesease Association March 26 , 20 04 (cited March 26 , 20 04 [June 3, 20 04]) ORGANIZATIONS American Speech-Language-Hearing Association 10801 Rockville Pike, Bethesda, MD 20 8 52 (800) 63 8- 825 5 actioncenter@asha.org Motor Neuron Disease Association P.O Box 24 6, Northampton NN1 2PR, United... roots The peripheral nerve roots enter and exit the spinal cord by passing through the spaces between the stacked vertebrae Each pair of nerves is named for the vertebra from which it exits These are known as: • C 1-8 These nerves enter from the eight cervical or neck vertebrae • T 1- 12 These nerves enter from the thoracic or chest vertebrae • L 1-5 These nerves enter from the lumbar vertebrae of the lower... Box 1133, Washington, DC 20 01 3-1 133 (March 1, 20 04) National Institute of Neurological Disorders and Stroke NIH Neurological Institute PO Box 5801, Bethesda, MD 20 824 (800) 3 5 2- 9 424 (March 2, 20 04) National... by the synthesizer This may cause the user to miss some information on the screen WEBSITES Maxey, H David “Smithsonian Speech Synthesis History Project.” National Museum of Natural History, Smithsonian Institute July 1, 20 02 (cited March 23 , 20 03 [June 3, 20 04]) “Speech Synthesis.” Wikipedia March 23 , 20 04 (cited March 26 , 20 04 [June 3, 20 04]) . Institute of Child Health and Human Development. 31 Center Drive, Rm. 2A 32 MSC 24 25, Bethesda, MD 20 8 9 2- 2 425 . (301) 49 6- 5 133; Fax: (301) 49 6- 7 101. <http://www.nichd.nih.gov>. The Arc of the United. 1 968 , Danbury, CT 068 1 3-1 968 . 20 2-7 4 4-1 000 or 80 0-9 9 9- NORD; Fax: 20 3-7 98 -2 2 91. orphan@rarediseases.org. <http://www.rarediseases.org>. National Eye Institute. National Institute of Health, Bldg CA 940 02. (65 0) 591 -2 8 95. (March 2, 20 04). <http:// www.apneos.com>. ORGANIZATIONS The American Lung Association. 61 Broadway, 6th Floor, New York, NY 100 06. (21 2) 31 5-8 700. (March 2, 20 04). <http://lungusa.org/diseases/sleepapnea.html>. The

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