Newborn Neurologic Examination
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RESIDENT AND FELLOW PAGE Teaching Newborn neurologic examination Michele Yang, MD his is the first article in a se- sion of the neurologic examination, weeks gestation, the newborn ries describing the essentials two important aspects of the gen- states of wakefulness and sleep are Tof the pediatric neurologic ex- eral physical examination should be difficult to distinguish. As the new- amination. The series will address noted. Keeping in mind that the born matures, however, there is in- the neurologic examination at dif- neurologic system is derived from creasing duration, frequency, and ferent developmental stages from ectoderm, one should pay particular quality of alertness. Again, it is im- the neonate to the teenage years. attention to the examination of the portant to keep in mind that these The goals of the article are to 1) skin. Outgrowths such as encepha- states will depend on the patient’s describe the newborn examination loceles, cutaneous lesions such as last feed and activity (such as place- and 2) briefly describe the most port-wine stains, and the presence ment of an IV). An irritable infant is common neurologic problems seen of sacral dimples or sinuses should one who is agitated and cries with in the newborn population. be sought as clues to underlying minimal stimulation and is unable to One of the most dreaded calls neurologic dysfunction. Addition- be soothed. Lethargic infants cannot for the adult neurology resident is ally, head circumference should be maintain an alert state. the consult from the neonatal in- measured with a tape measure. The Cranial nerves tensive care unit (ICU). Faced with normal term infant’s head circum- Cranial nerves (CN) II and III the morass of tubes and monitors ference is 35 cm Ϯ 2 cm and is a can be tested by the pupillary re- underneath which lies a tiny infant, reflection of the underlying intra- flex, which appears consistently at the resident is often paralyzed by cranial volume. Thus, it is a good 32 to 35 weeks gestation. A 28- the daunting task of trying to per- way to monitor for intracranial week infant will blink to light form an examination. As one resi- masses and increased intracranial shone into the eyes, testing CN II dent put it, “I could tell he was pressure. Additionally, macroceph- and VII. Beginning at 34 weeks of moving all fours, but that was it.” aly and microcephaly can be indica- gestation, an infant will be able to With keen observation and a sys- tions of underlying metabolic, fix and follow on an object, thus tematic approach, one can obtain a genetic, or infectious processes. testing CN II, III, IV, and VI. Spon- detailed examination of the new- taneous roving eye movements are born. The intent of this article is Neurologic examination common at 32 weeks gestation, as not to be comprehensive, but to pro- Mental status are dysconjugate eye movements in vide a simple approach to the ex- One of the best times to exam- the term infant when not fixing on amination and evaluation of the ine a baby is between feeds. If in- an object. Another maneuver to test newborn. A summary of the neuro- terrupted during a feed, the baby eye movements is the following: logical examination is provided in may cry excessively, limiting the hold the baby underneath the axilla the figure. Further details can be examination, and if examined im- and spin the baby from side to side found in the reference articles mediately after a feed, the baby to test the oculovestibular reflex. listed below.1,2 may be too sleepy to obtain an opti- Not only does this test acuity in the By being organized and having mal examination. Observation of duration of the postrotational nys- the right tools, one can perform as the newborn’s spontaneous eye tagmus, but this also tests the in- comprehensive an examination as opening, movements of the face and tegrity of the vestibular system. in an adult. Tools for examination extremities, and response to stimu- Facial sensation (CN V) is tested of the newborn are as follows: 1) lation are essential for the mental with pinprick and by observing fa- bell, 2) ophthalmoscope, 3) reflex status examination. Arousal is de- cial grimace or change in sucking. hammer, 4) cotton-tipped applica- fined by the duration of eye opening Facial symmetry and movement tion, 5) measuring tape. and spontaneous movement of the should be observed in both the Before proceeding to a discus- face and extremities. Before 28 quiet state and during active move- From the Children’s Hospital of Pittsburgh, PA. Address correspondence and reprint requests to Dr. Michele Yang, 3705 5th Avenue, Children’s Hospital of Pittsburgh, Pittsburgh, PA 15213-2524; e-mail: [email protected] Copyright © 2004 by AAN Enterprises, Inc. E15 Figure. Summary of the neurologic examination with respect to gestational age. ATNR ϭ asymmetric tonic neck reflex. ment (such as crying). Hearing (CN maturity of the passive tone. It is with jerky movements is abnormal VIII) can be tested with a bell, important to keep the head midline and drug withdrawal should be sus- keeping in mind that a ringing bell to avoid asymmetries in tone re- pected. Conversely, a term infant within an isolette can be quite loud lated to the asymmetric tonic neck with choreoathetoid movements and generate 90 dB. The newborn reflex. Flexor tone tends to develop should be evaluated for a number of may have a very subtle response to first in the lower extremities and potential structural or metabolic auditory stimulus and respond with proceed cephalad. A 28-week infant abnormalities. only a blink. To test CN V, VII, and will lie with minimally flexed limbs Sensory examination XII, the newborn can be observed and have minimal resistance to In the newborn, the examina- sucking on a pacifier. This can also passive movement of all extremi- tion is limited to touch and pin- be used to evaluate CN IX and X, ties. In contrast, at 32 weeks, the prick. Particular emphasis should which are tested when the baby newborn develops flexor tone at the be placed on dermatomal evalua- swallows. The 28-week infant can hips and knees, with some resis- tion of the lower extremities, espe- suck and swallow but the syn- tance to manipulation of the lower cially in the sacral region in a child chrony of breathing and feeding is extremities. This progression corre- with a neural tube defect. Assess- not well developed. As the brain- lates with increasing myelination of ment of sensation can be made by stem matures, coordination im- the subcortical motor pathways using the sharp end of a cotton ap- proves by the 32nd to 34th week. Palpation of the sternocleidomas- originating in the brainstem. By 36 plicator on the face and observing toid (CN XI) may be difficult in the weeks, the infant develops flexion the facial grimace or change in newborn, but may be facilitated by at the elbows, and by term, the in- state of the infant. extending the head on the side of fant is flexed in all extremities. The Reflexes the bed with the infant in a supine quality of the infant’s movements Reflexes can be easily elicited position. Now the bulk of the mus- develops as well. For example, the in the biceps, brachioradialis, cle can be palpated as the head is 28-week infant will have writhing knees, and ankles. Cross adductor turned to the side. movements of the extremities, but responses and unsustained clonus Motor examination by term the movements are best de- are not uncommon in the newborn. Observation of the resting pos- scribed as large amplitude “swat- Many child neurologists agree that ture can reveal the symmetry and ting” movements. A 28-week infant the plantar response is not helpful, E16 NEUROLOGY 62 April (1 of 2) 2004 as many factors may elicit flexor or exhibit hypotonia of the upper ex- Neuromuscular junction and extensor responses inadvertently. tremities, with weakness particu- muscle Primitive reflexes larly in the shoulders, in addition In myasthenia gravis and infan- Of the primitive reflexes that to lower extremity weakness. tile botulism, diffuse hypotonia and can be elicited in the newborn, the Periventricular leukomalacia weakness are present, often in con- following are the most important to and paraventricular/intraventric- junction with CN involvement. In perform. ular hemorrhage congenital myopathies, proximal ex- A full Moro reflex consists of bi- The germinal matrix is a tremity weakness is prominent and lateral hand opening with upper ex- vascular-rich zone containing pluri- can be marked by limb deformities if tremity extension and abduction, potential cells from which the cortex the onset occurred in utero. followed by anterior flexion of the develops. It is susceptible to bleeding Seizures vs jitteriness upper extremities, then an audible in the preterm infant. With abnor- A common consult from the cry. This is best elicited by drop- malities in cerebral perfusion, these neonatal ICU is for seizures. In a ping the head in relation to the areas hemorrhage and often develop newborn, many movements such as body, into the examiner’s hands. infarction in the deep white matter of sucking may be mistaken for sei- The asymmetric tonic neck re- the hemispheres. As a result, these zure; on the other hand, subtle flex is elicited by rotating the head babies can develop initial weakness movements such as bicycling of the to one side, with subsequent elbow in their lower extremities, although legs may be overlooked as a mani- extension to the side the head is often they may have relatively nor- festation of seizure.