Neurology

Chapter 66 Neurology



Adam Hartman



ACQUIRED NEUROLOGIC CONDITIONS



ETIOLOGY



What Acquired Neurologic Conditions Might I See?


Injuries to the brachial plexus occur commonly in newborn infants. Stroke occasionally occurs in childhood. Brain tumors, although relatively infrequent, cause major morbidity and mortality.



What Causes Brachial Nerve Plexus Palsies?


Erb’s palsy and Klumpke’s palsy are the result of brachial plexus injury. The nerve tracts are injured because the neck and arms are sometimes malpositioned in utero or during a difficult delivery. Fractures of the clavicle and ribs can be associated with either. Erb’s palsy involves the upper brachial plexus (C5-C7), which affects shoulder and arm muscles. Diaphragm paralysis occurs if C3-C5 are also injured. Klumpke’s palsy involves the lower brachial plexus (C8-T1), which affects the hand. Klumpke’s palsies tend to be more severe because lower plexus injuries are often caused by avulsion of the spinal roots. Upper plexus injuries more commonly involve stretching injuries of the trunks.



What Causes Strokes in Children?


The incidence of strokes in children outside the neonatal period is about 2.5 to 5 events per 100,000 children per year. Stroke can present as hemiparesis, seizures, irritability, headache, fever, dystonia, vomiting, papilledema, or lethargy. Risk factors associated with strokes in neonates include hypoxic-ischemic injuries, trauma, infections, polycythemia, hypotension, congenital heart disease, clotting abnormalities, and cocaine. In older children, strokes are associated with congenital heart disease, infections (including varicella), prothrombotic and clotting disorders, sickle cell disease, trauma, vasculitis, moyamoya disease, migraines, malignancy, and sequelae of perinatal infections.



How Common Are Brain Tumors in Children?


Brain tumors occur in 2.5 to 4 per 100,000 children per year, making them the second most common form of cancer in children and the most common solid tumor of childhood. Their incidence has been increasing in recent years. Most brain tumors in children older than 1 year arise in the infratentorial compartment of the brain.



TREATMENT



How Are Brachial Plexus Injuries Treated?


Treatment is primarily supportive, including management of associated injuries such as clavicle fracture. If the palsy does not improve within the first 6 months of life, it is likely to persist.



Can Stroke Be Treated?


Treatment is aimed at the underlying disorder and also must support the child during the immediate poststroke period. Rehabilitative services may be needed and generally will involve a multidisciplinary team.



How Are Brain Tumors Treated?


Primary surgical resection and chemotherapy are the primary treatment modalities, depending on the type of tumor. Cranial radiation is used for certain tumors in older children. The long-term sequelae of treatment include learning problems, focal neurologic deficits, and endocrinologic problems, in addition to the sequelae that occur with treatment of other tumors (e.g., immunosuppression, cytopenia, and second tumors). The prognosis depends on the histology of the tumor, age at presentation, and presence of metastases.



CONGENITAL MALFORMATIONS



ETIOLOGY



What Congenital Malformations Affect the Central Nervous System?


Central nervous system (CNS) malformations most commonly occur at the distal and caudal ends of the developing neural tube. Spina bifida occulta and myelomeningocele will be encountered most often. Table 66-1 lists some abnormalities in the formation of the CNS.


Table 66-1 Selected Congenital CNS Malformations*

































Anencephaly
Schizencephaly
Lissencephaly
Heterotopias
Holoprosencephaly
Encephalocele
Agenesis of the corpus callosum
Septo-optic dysplasia
Dandy-Walker cyst
Diastematomyelia
Myelomeningocele
Spina bifida occulta
Lipomeningocele
Teratoma
Tethered cord

* In order of caudal to rostral. CNS, Central nervous system.



What Causes Neural Tube Defects?


The neural tube closes like a zipper during the third and fourth weeks of gestation, starting in the middle and extending to the ends. Failure of distal closure leads to a condition called spinal dysraphism. The defect may be benign, severe such as a sacral dimple or spina bifida occulta, or more meningocele or myelomeningocele (MMC). Failure of caudal closure leads to encephalocele and anencephaly. Maternal folate deficiency causes a significant number of neural tube defects. Supplementation with folate before conception is largely responsible for the recent decreased incidence of neural tube defects.



Why Are Midline Malformations Concerning?


Malformations such as encephaloceles and midline “cysts” may indicate the presence of more complex congenital lesions. In addition, they can communicate with underlying CNS tissue. Decompression or drainage of these malformations should only be done by a neurosurgeon.



What Is a Dandy-Walker Malformation?


It is a malformation of the fourth ventricle characterized by cerebellar vermis hypoplasia or aplasia, a dilated fourth ventricle, and an upwardly displaced tentorium. It is associated commonly with hydrocephalus and other malformations of the CNS, such as cortical dysplasias or agenesis of the corpus callosum. Clinically, it can cause macrocephaly, ataxia, or signs of increased intracranial pressure.



EVALUATION



What Are Clinical Findings of Neural Tube Defects?


The level at which the defect occurs determines the impact on neurologic function and the long-term prognosis. A child with spina bifida occulta may have no visible defect and no physical findings, the diagnosis having been made incidentally with a radiograph. Occasionally, enuresis or encopresis may lead to the diagnosis of “occult” spinal dysraphism. Conversely, infants with severe MMC may have marked neurologic and structural dysfunction (Table 66-2) and may develop life-threatening infection of the nervous system.


Table 66-2 Organ System Dysfunction in Meningomyelocele





















Brain Arnold-Chiari II malformations, hydrocephalus, seizures, learning problems
Endocrinologic Precocious puberty, obesity, short stature
Eyes Strabismus
Kidney/bladder Neurogenic bladder, urinary tract infections, vesicoureteral reflux
Orthopedic Contractures, lower extremity malformations, scoliosis, kyphosis
Skin Decubitus ulcers


TREATMENT



How Are Children with Neural Tube Defects Managed?


Care is best managed where multidisciplinary medical, surgical, and supportive clinical services can be obtained. A general pediatrician has a critical role to coordinate various aspects of care. Because the spinal cord level of the lesion largely dictates the severity of involvement, treatment must be based on an individualized management plan that focuses on the specific lesion and on the many problems that result from that lesion. Children with neural tube defects often develop allergy to latex, so latex-containing materials should be avoided. Services to address social, developmental, and physical therapy needs are crucial to successful management, as is education about the disorder for parents and older children. In addition, coordination with schools will be necessary to develop individualized educational plans for each child. Prenatal surgery is being investigated in this condition.



MOVEMENT DISORDERS



ETIOLOGY



What Movement Disorders Occur in Childhood?


During infancy and early childhood, dyskinetic movements may be appropriate for the stage of development. As the child’s nervous system matures, these developmental dyskinetic movements disappear. Their persistence, or the appearance of new movement disorders, may be a sign of underlying disease. Tics and Tourette syndrome are the movement disorders most often seen by general pediatricians. Sydenham’s chorea is occasionally seen, but its incidence has declined dramatically because rheumatic fever rates have decreased. Torticollis is a form of dystonia usually caused by a hematoma in the sternocleidomastoid muscle, although infection, tumors, and congenital malformations should be considered in the differential diagnosis. Other dystonias include opisthotonic posturing in infants caused by gastroesophageal reflux (Sandifer syndrome) and blepharospasm. Myoclonus and tremors also can be seen in children. Movement disorders may be seen in patients with Wilson disease, lupus, neuroblastoma, and toxic ingestions. Movement disorders associated with multiple neurologic signs require evaluation by an expert.



EVALUATION



How Do I Evaluate Movement Disorders?


Your major diagnostic tools are a careful history and meticulous physical neurologic examinations. Observation of the patient during routine activities will help you describe in detail the movements. Videotapes obtained from parents may allow you to compare current movements with those exhibited before the onset of the disorder. Laboratory tests and imaging will only be needed if a specific disorder is suspected as the cause of the abnormal movement. Psychological assessment can be important for many patients.



What Are Simple Tics?


Simple motor or habit tics, such as blinking and arm jerks, are common. Careful evaluation of neurologic function, behavior, and development is important. Tics not associated with other problems will eventually disappear. If tics persist or cause problems at home or school, a referral should be made to a child neurologist.



How Do I Identify Tourette Syndrome?


Tourette syndrome is a complex disorder that includes both motor and vocal tics, and often has associated behavior problems such as obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD). Evaluation must focus on the spectrum of presenting features. Tourette syndrome has onset before 21 years of age and a variable clinical course with a duration of at least 1 year. It is common for children to be referred for an allergy evaluation of sniffing or vocalizations before the diagnosis of Tourette syndrome is made. Many children with Tourette syndrome are first diagnosed with ADHD and receive medical therapy with stimulants, such as methylphenidate. The syndrome, not psychostimulant medication, is the cause of the tics. Coprolalia is not as common in patients with Tourette syndrome as has been portrayed on television.

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Jun 19, 2016 | Posted by in PEDIATRICS | Comments Off on Neurology

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