Disorders of the Nervous System

101 Disorders of the Nervous System



The neonatal period is an important time for development of the nervous system. Interruption of normal development through disease or injury often leads to permanent neurologic sequelae. As our ability to care for critically ill neonates improves, neurologic disorders continue to be a significant cause of morbidity and mortality. It is crucial to identify neonates at risk for neurologic disorders through careful history taking and physical examination so that problems can be prevented or treated early.



Etiology and Pathogenesis





Neonatal Seizures


Neonatal seizures are often a manifestation of underlying neurologic disease or injury (Table 101-1). In each case, the metabolic or structural abnormalities cause disorganized electrical activity that can lead to epileptogenic foci.





Clinical Presentation





Neonatal Seizures


The newborn brain remains immature, particularly with regard to myelination. This immature anatomic organization makes neonatal seizures difficult to recognize and classify and often presents problems in selecting therapy and gauging efficacy. The fact that normal newborn infants often exhibit unusual movements confounds the diagnosis of neonatal seizures. With these difficulties, neonatal seizures often experience a paradoxical combination of overdiagnosis and underdiagnosis.


Neonatal seizures have a variety of manifestations and a variety of normal mimics (Box 101-1). Clonic seizures can occur either focally or multifocally and are repetitive high-amplitude, low-frequency jerking movements. Tonic seizures are constant stiffening of a portion of the body and may be focal or generalized. Myoclonic seizures include sudden extension or flexion of part of the body. Subtle seizures encompass other small abnormal movements that do not fit into the previously listed seizure types, including eye deviation, lip smacking, and tongue thrusting, among others. Subtle seizures and generalized tonic seizures often do not have electroencephalographic (EEG) correlates and are thought to emanate from deeper subcortical brain regions, a theory supported by animal studies.



Several other unusual movements frequently seen in newborns must be considered in the differential diagnosis of seizures. These may occur in normal infants or may suggest other underlying disease. Jitteriness is a hypersensitivity to stimulus and may be suggestive of underlying abnormalities such as drug withdrawal; hypoxic-ischemic injury; or metabolic disease, particularly hypoglycemia. Benign myoclonus is a sudden, brief, jerking movement of the extremities that occurs during sleep in many normal infants. Opisthotonus is a tonic stiffening of the body, often resulting in arching of the back and neck. This is a common finding associated with gastroesophageal reflux (Sandifer’s syndrome). Neonatal apnea may or may not be associated with seizures, but it is frequently an independent clinical event in premature infants.

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Jun 19, 2016 | Posted by in PEDIATRICS | Comments Off on Disorders of the Nervous System

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