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Head and brain injury after birth may be the result of accidental trauma or nonaccidental trauma. Impact injuries can be divided into those in which the head is struck by an object, as with a blow, or the head hits a surface, as with a fall. In the former circumstance, the head may be struck by a hand, fist, elbow, or foot or by a held or falling object. When the blow is by a "blunt" instrument, it usually leaves no identifying mark. [ABSTRACT FROM AUTHOR]

Minamata disease (methylmercury poisoning) can affect all ages. In adults all the organs contain increased mercury, but lesions occur mainly in the nervous system, particularly the brain. The neurons, especially nonpyramidal cells in the cerebral and cerebellar cortices, are destroyed. In the cerebrum, there is selective involvement of the calcarine and precentral regions involving neurons in the second and upper third layer and predominantly in the depth of the sulci. In the cerebellum, the granular cells are most susceptible and are lost in the deeper regions of the folia of both hemispheres. In nonfetal infantile Minamata disease there is hypoplasia of various organs, including the brain. There is widespread disintegration of cortical neurons and secondary degeneration of myelin sheaths. [ABSTRACT FROM AUTHOR]

The viruses known to be responsible for significant intrauterine infections include rubella virus, measles virus, mumps virus, enteroviruses (coxsackie virus, echovirus, hepatitis A, poliovirus), lymphocytic choriomeningitis virus, human immunodeficiency virus (HIV), herpes viruses (cytomegalovirus, varicella, herpes simplex), Epstein-Barr virus, and arboviruses. [ABSTRACT FROM AUTHOR]

The primary diseases of the peripheral nervous system are clinically classified as sensorimotor neuropathies and motor or sensory neuropathies. They present with some of the following signs and symptoms: weakness, sensory loss, muscle atrophy, autonomic dysfunction. The disorders may present as symmetrical polyneuropathies (usually hereditary disorders) or as focal and multifocal neuropathies (usually diabetes, arteritis, trauma). In children and adolescents, the hereditary disorders are the commonest causes of peripheral nerve disease. In some cases the peripheral neuropathy is a part of a multisystem disorder, involving other parts of the nervous system and/or body, whereas with other disorders the peripheral nerve is the main site of the disease. [ABSTRACT FROM AUTHOR]

Brain tumors are the commonest solid tumors of childhood. They range from hamartomas to pleomorphic, highly aggressive, undifferentiated neoplasms, many of which are unique to childhood. Their behavior depends on several factors: cell type, location in the brain, and age of the child. Despite scientific and technical advances, their treatment remains a challenge. Exceptional outcomes challenge molecular biologists, geneticists, oncologists, and surgeons to better understand and treat these common lesions. [ABSTRACT FROM AUTHOR]

Epilepsy is more common during childhood than in adulthood, suggesting that the developing brain is more prone to seizure activity than the mature brain. Epilepsy has been defined as an episodic disorder of the central nervous system (CNS) characterized by paroxysmal abnormal brain electrical activity and recurrent behavioral seizures [1]. The pathological substrates of epilepsy include malformations, metabolic errors, neoplasia, hypoxic-ischemic and traumatic lesions, and infection and are discussed elsewhere in this present volume. In this chapter the lesions that are observed during surgical resection for intractable epilepsy are illustrated. [ABSTRACT FROM AUTHOR]

Skeletal muscle begins to develop in the mesodermic somites at 2-3 weeks' gestation. At 4-5 gestational weeks (GW), the myotomes develop as a syncytium of nuclei and cytoplasm. At 7-9 GW, the syncytium elongates, and cells fuse and form the primitive myotubes. These are multinucleated cells with nuclei situated centrally in a hollow tube of thin cytoplasm. This process continues, with the newest myotubes being the smallest. Actin and myosin filaments develop and form myofibrils in the myotubes. At 10 GW, the embryonic muscle is well formed into myotubes. The muscle fibers are larger, and striations are evident. At 12 GW, motor end plates and muscle spindles are developing. At 13 GW, the myofibrils become thicker in the older fibers, and new smaller myotubes continue to develop. At 15 GW, two populations of muscle fibers are present: (1) large, more mature fibers with peripheral nuclei and filled-in cytoplasm and (2) smaller, more immature myotubes. After 16 GW, all of the muscle fibers continue to increase in size, and the myotubes gradually disappear. However, the pattern of large and small muscle fibers persists into the postnatal period and into the second year of life. The [ABSTRACT FROM AUTHOR]

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disease that affects all ages, except children less than 2 years. It occurs during the course of various infections, particularly the acute exanthematous diseases of childhood (measles, rubella, chickenpox, and smallpox immunization), other common viral infections (i.e., Epstein-Barr virus, adenovirus, cytomegalovirus, influenza, rhinoviruses, coronaviruses), and following vaccination against smallpox, measles, and rabies. The clinical features are the same regardless of the inciting event. The symptoms develop days to weeks after the onset of the predisposing cause. The symptoms and signs of acute disseminated encephalomyelitis are related to the portion of the central nervous system (CNS) that is most severely damaged. Death occurs in 20%-30%. There are neurological deficits in survivors. [ABSTRACT FROM AUTHOR]

Wernicke's encephalopathy is a serious neurological disorder caused by vitamin B1 or thiamine deficiency, chiefly in chronic alcoholics and rarely in children. It may be associated with starvation, prolonged intravenous treatment without vitamin supplementation, hemodialysis, and gastric stapling. The classic triad of clinical symptoms described by Wernicke (gait ataxia, ophthalmoplegia, confusion) are found in only one-third of patients during the initial examination. [ABSTRACT FROM AUTHOR]

Dentato-rubro-pallido-luysian atrophy (DRPLA) is a rare familial disorder comprising degeneration of the cerebellar efferent system and of the pallido-luysian tracts. Ataxic choreoathetoid, pseudo-Huntington, and myoclonic epilepsy forms of this syndrome have been described. The disorder begins between 7 and 20 years of age. [ABSTRACT FROM AUTHOR]

Wilson's disease is an autosomal recessive disorder in which excessive amounts of copper accumulate in body tissues, particularly in the liver, kidneys, cornea, and brain. It presents initially at ages 8-12 with hepatic, neurological, or psychiatric disturbances including movement disorders (dysarthria, rigidity, tremor) and psychotic behavior. There are characteristic Kayser-Fleischer rings caused by copper in the limbus of the cornea. Serum ceruloplasmin and copper levels are low, and urinary copper is increased. [ABSTRACT FROM AUTHOR]

GM1 gangliosides accumulate in lysosomes secondary to a deficiency of acid β-galactosidase. The increased GM1 gangliosides in cell membranes cause abnormal neuronal growth and synaptic dysfunction. There is a severe infantile type (with bony and visceral involvement) and milder juvenile and adult types. [ABSTRACT FROM AUTHOR]

Vanishing leukoencephalopathy is a vacuolating leukoencephalopathy with subcortical cysts. Symptoms develop at 18 months to 5 years of age with slowly progressive cerebellar ataxia, spasticity, variable optic atrophy, late development of bulbar symptoms, and preserved mental capacities. There are adult cases. [ABSTRACT FROM AUTHOR]

Infantile neuroaxonal dystrophy is an autosomal recessive neurodegenerative disorder characterized by dystrophic changes involving mainly the terminal axons. The dystrophic axons result from a defective retrograde axonal transport, but the underlying metabolic defect is unknown. A disorder with similar axonal pathology called schindler's disease is caused by N-acetylgalactosaminidase deficiency. It has been reported in two siblings with clinical and neuropathological features of infantile neuroaxonal dystrophy [1]. The both disorder present during the first 2 years of life with psychomotor deterioration, hypotonia, pendular nystagmus, and symmetrical pyramidal tract signs. [ABSTRACT FROM AUTHOR]

Zellweger's syndrome is an X-linked autosomal recessive disorder of peroxisomal biogenesis with an absence of the peroxisome. There is a wide range of characteristic dysmorphic features and cerebrohepatorenal involvement. Laboratory studies characteristic of Zellweger's syndrome include (1) elevated levels of pipecolic acid in plasma, cerebrospinal fluid (CSF) and urine; (2) elevated levels of saturated (C26) and monosaturated (C26 : 1) VLCFA in plasma, body fluids, and tissues with an elevated C26 : 0/C22 : 0 ratio; (3) decreased (<10% of normal) tissue level of phosphatidyl ethanolamine plasmalogen, a phospholipid constituent of myelin and platelet-activating factor; and (4) deficient activity of dehydroxyacetone phosphate acyltransferase, the key enzyme in the pathway for plasmalogen synthesis (located in the peroxisomal membrane). [ABSTRACT FROM AUTHOR]

Several genetic abnormalities can produce excessive excretion of urinary homocystine. Cystathion β-synthase deficiency (CBS) is the most common. Others include 5,10-methylene tetrahydrofolate reductase deficiency, defects in cobalamine and folate metabolism, and nutritional deficiencies of vitamin B12 and folate. [ABSTRACT FROM AUTHOR]

Galactosialidosis (α-neuraminidase deficiency + galactosidase deficiency with defective protective protein) has congenital (severe resembling sialidosis type 2), infantile (mild), and juvenile-adult forms. There are dysmorphic features, hepatosplenomegaly, psychomotor retardation, macular cherry-red spots, and myoclonus. There is cytoplasmic vacuolization of many cell types. Rare brain reports suggest atrophy and neuronal loss in optic nerves, thalamus, globus pallidus, brain stem, and cerebellum with neuronal storage in Betz cells, basal forebrain, cranial nerve nuclei, anterior horns, and ganglia. Electron microscopy (EM) shows variable shapes of storage material. The disorder is caused by a defective "protective protein" encoded on chromosome 20q13.1 and a resulting deficiency of β-galactosidase and α-neuraminidase [1]. [ABSTRACT FROM AUTHOR]

In the urea cycle, six enzymes are required to convert ammonia to urea: N-acetylglutamate synthetase (NAGS), carbamoylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (ASS), argininosuccinate lyase, and arginase. Deficiency of any of these enzymes may cause disease. Such infants are asymptomatic for 1-5 days but then feed poorly, vomit, and become lethargic. They may be irritable, rigid, and convulse. They exhibit hyperpnea and respiratory alkalosis, hepatomegaly, and jaundice; and they may have brain edema with bulging fontanels. Death ensues without treatment. [ABSTRACT FROM AUTHOR]

Tuberous sclerosis (TS) is a dominantly inherited disorder that affects multiple organ systems [1]-[3]. The current diagnostic criteria require TS complex-associated lesions of two or more organ systems or two dissimilar lesions of the same organ system. TS is sporadic in 60%-70% of cases. Two genes have been identified: TSC1 (hamartin) located at 9q34 and TSC2 (tuberin) located at 16p13.3 [4]. The genes have tumor-suppressing activity, but the pathogenesis of TS is not fully understood. [ABSTRACT FROM AUTHOR]

Cerebral edema, alterations in the amount or the site of brain water, is caused by brain injuries, infection, intoxication, and metabolic encephalopathies. It has been classified as being vascular/interstitial or toxic/cytoplasmic. Excessive brain edema produces increased intracranial pressure, which may cause brain herniation, with displacement of tonsilar, uncal, or cingulate brain tissues into the foramen magnum, posterior fossa, or below the falx, respectively. The herniated brain tissues can compress and interfere with regions of vital brain function (i.e., the brain stem). The gross deformations of brain herniations are not obvious in the brain of an infant with nonfused skull sutures, but the detrimental pressure effects of excessive brain edema may still operate [1]. [ABSTRACT FROM AUTHOR]

Vascular malformations are classified into four categories: (1) arteriovenous malformation (AVM); (2) cavernous hemangioma; (3) venous angioma and varix; and (4) capillary telangiectasis or telangiectasia. Symptoms of a vascular malformation may be secondary to rupture of the lesion, the vascular steal phenomenon (diversion of blood flow by the arteriovenous shunt from normal surrounding areas, which subsequently become ischemic), or to a mass effect. [ABSTRACT FROM AUTHOR]

The cerebral surface develops gradually from the fetal flat (lissencephalic) brain to the adult gyral pattern, increasing the cortical surface area until the second year of life. The sylvian fissure is apparent at approximately 14 weeks' gestation (GW). The primary sulci, such as rolandic, calcarine, superior temporal, and precentral sulci, appear after 20 GW, the secondary sulci appear from 28 GW, and the tertiary sulci from 36 GW. The gestational age of a brain can be estimated by counting the number of convolutions (gyri) crossed by a line drawn from the frontal to the occipital pole above the insula and adding 21 to the gyral count [1]. Gestational age can also be estimated by counting gyri and sulci in neuroimages [ultrasonography and magnetic resonance imaging (MRI)]. [ABSTRACT FROM AUTHOR]

Perinatal brain damage includes all brain injuries that occur during the perinatal period in infants of all gestational ages, whereas injury from birth trauma per se occurs more frequently in full-term neonates. Important advances in perinatal care have decreased the incidence of birth trauma. Birth trauma of the nervous system may result in the following. [ABSTRACT FROM AUTHOR]

Down syndrome (DS), caused by trisomy 21, is characterized clinically by somatic abnormalities, intellectual disabilities in children, and Alzheimer-type dementia in adults. The phenotype may vary, with minor brain anomalies such as hypoplasia of the superior temporal gyrus, brain stem, and cerebellum, decreased brain weight and rounded occipital poles [1]. Basal ganglia calcification is more frequently found in the region of the globus pallidus and putamen, and its incidence increases with age [2]. Dendrites gradually show abnormal arborization and decreased spines after 4 months of age [3,4]. Alzheimer-type dementia with neuritic plaques and neurofibrillary tangles develops in young adults. Senile plaques and cerebrovascular amyloidosis involve β-amyloid protein (Aβ). In Alzheimer-type dementia, Aβ42, which aggregates more rapidly than Aβ40, is a major component of diffuse (early) plaques, whereas Aβ43 demonstrates early axonal damage in diffuse plaques [5]. [ABSTRACT FROM AUTHOR]

The brain and upper spinal cord form from the neural plate during primary neurulation beginning at 22 days' gestation; the sacral spinal cord forms from the tail bud during secondary neurulation [1]. The various classifications of neural tube defects (NTDs) is complex and somewhat contradictory [2]. Practically, they can be considered as "open" (e.g., anencephaly, craniorachischisis, myelomeningocele) or "closed" (e.g., encephaloceles, meningoceles, split spinal cord). There are several pathoetiologies [3]. Folic acid supplementation before and during early pregnancy prevents most NTDs [3,4]. A mutant mouse model for NTD, Splotch, is being used to define the mechanism of teratogenesis by folate insufficiency [5]. A second mutant, curly tail, has an NTD that responds to myoinositol [6]. [ABSTRACT FROM AUTHOR]

The most common childhood forms of spinal muscular atrophy (SMA) are early-onset severe type 1 SMA (Werdnig-Hoffmann disease), chronic intermediate type 2 SMA, and chronic mild type 3 SMA (Kugelberg-Welander disease). Werdnig-Hoffmann disease (WHD) is an autosomal recessive, early-infantile form of spinal and bulbar muscular atrophy, sparing only the extraocular muscles. In late-infantile forms of SMA, the onset is between 3 and 24 months of age. The juvenile form of SMA (Kugelberg-Welander syndrome) has its onset between 2 and 10 years, or adolescence. [ABSTRACT FROM AUTHOR]

Pompe's disease, the infantile form of generalized glycogenesis (infantile type II glycogenesis), is an autosomal recessive lysosomal glycogen storage disease. It presents with early onset of cardiomegaly, hypotonia, cerebral dysfunction, failure to thrive, and early death. Lysosomal glycogen storage affects practically all the tissues in the body and results from a defect of acid α-1,4-glucosidase (or acid maltase). The acid α-glucosidase locus has been localized on chromosome 17. [ABSTRACT FROM AUTHOR]