2 Neonatology
General Techniques of Physical Examination
Assessment of the Newborn
The purposes of the routine newborn assessment are to determine the infant’s gestational age, document normal growth and development for a given gestational age, uncover signs of birth-related trauma or congenital anomalies, and evaluate the overall health and condition of the infant. The assessment begins with the establishment of a historical database. Information may be obtained from antenatal, labor, delivery, and postpartum records and a brief interview with the parents (Fig. 2-1). The aim of this data gathering is to assess the fetal and neonatal responses to pregnancy, labor, and delivery; to estimate the risk for hereditary or congenital diseases; and to identify the potential for future difficulties by reviewing the family’s social history and observing maternal–infant interactions. This background is recorded in the infant’s medical record and serves as a guide to the subsequent physical examination (Table 2-1).
Table 2-1 Newborn Historical Database
Antenatal Record |
Labor and Delivery Record |
Postpartum Record |
Parental Interview |
Observation must be done before the quiet infant is disturbed by the examination. By visual inspection the clinician can assess skin and facies; general tonus and symmetry of movement; respiratory rate, retractions, and color; and abdominal contour. Auscultation of the heart and lungs should be done before more stressful portions of the examination, which are likely to make the infant fussy. Allowing the infant to suck on a gloved finger can help quiet the infant and permit assessment of sucking strength and palate integrity. Lifting the infant under the arms (Fig. 2-2) and gently rocking him or her (such that the head swings toward and away from the examiner) is usually calming. This maneuver also induces a reflexive opening of the eyes, which assists the ophthalmologic examination. Sucking also induces eye opening. Such maneuvers may be necessary to convince the examiner that the patient does not have a congenital cataract or an intraorbital mass (see Chapter 19) requiring prompt intervention.
Assessment of Gestational Age
The Ballard assessment for gestational age determination of newborns uses six morphologic and six neurologic criteria to estimate gestational age on the basis of an examination performed at 12 to 24 hours of life (Fig. 2-4). Individual findings are scored on a scale of 0 to 5, and the total score is compared with the chart shown in Figure 2-4.
Physical Maturity
One of the most striking differences among newborns of various gestational ages is the quality of the skin. The chemical nature of skin changes during intrauterine development, with a gradual decrease in water content and a thickening of the keratin layer. Very premature infants (24 to 28 weeks) have nearly translucent, paper-thin skin (Fig. 2-5) that is easily abraded. A diffuse red hue and a prominent venous pattern are characteristic. At term, the skin no longer appears thin, and the general color is a pale pink. Some superficial peeling and cracking around the ankles and wrists may be visible. Postterm infants (42 to 44 weeks) often have more diffuse peeling and cracking of the skin because the outermost layers are sloughed (Fig. 2-6).
Breast tissue, which is responsive to maternal hormonal influences, shows progressive increase in size as gestational age advances. Infants born at younger than 28 weeks’ gestation have barely perceptible breast tissue (see Fig. 2-5). With advancing age, breast tissue increases in size (see Fig. 2-6) and, occasionally, a term infant has active glandular secretions, which resolve spontaneously. Breast tissue can remain palpable for 2 to 3 months.
Neuromuscular Maturity
Tests for flexion angles assess a combination of muscle tone, ligament and tendon laxity, as well as flexion–extension development. The inexperienced examiner usually assumes that the very premature infant is the most flexible, but observation of flexion angles demonstrates that this is false. The square-window test of the wrist (Fig. 2-12) is performed by gently flexing the hand on the wrist and assessing the resultant angle. The wrists of babies younger than approximately 32 weeks can be flexed only to 45 to 90 degrees, whereas the wrists of term infants undergo full flexion. Sometime between birth and adulthood this flexion ability is lost. Examination of the flexion of the knees reveals a different pattern of development, with decreasing flexibility as gestational age increases. The knee is completely flexed (Fig. 2-13, A) and the thigh is stabilized against the stomach. The leg is extended by raising the foot (Fig. 2-13, B). Gentleness is essential in these evaluations because any result can be achieved if the examiner applies undue force.
Primitive Reflexes
The rooting reflex may be elicited by lightly stimulating the infant’s cheek and observing the reflexive attempts to bring the stimulating object to the mouth. The sucking reflex is activated by placing an object in the infant’s mouth and observing the sucking movements. In the grasp reflex (Figs. 2-16 and 2-17), transverse stimulation of the midpalm (without touching the back of the hand) or midsole leads to flexion of the digits or toes around the examiner’s fingers.

Figure 2-16 Grasp reflex (palm). Transverse stimulation of the midpalm leads to a grasp by the infant.

Figure 2-17 Grasp reflex (sole). Transverse stimulation of the midsole triggers a grasp by the infant.
The Moro reflex (Fig. 2-18, A and B) evaluates vestibular maturation and the relationship between flexor and extensor tone. Elicitation of the reflex involves a short (10 cm), sudden drop of the head when the infant is supine. The full response involves extension of the arms, “fanning” of the fingers, and then upper extremity flexion followed by a cry. An incomplete but identifiable reflex becomes apparent at approximately 32 weeks’ gestation, and by 38 weeks it is essentially complete. Very immature infants demonstrate extension of the arms and fingers but do not show true flexion or make a sustained cry. Marked asymmetry of response may be associated with focal neurologic impairment.
Abnormalities of Growth
The relationship among weight, length, and head circumference can be useful in understanding the etiology of the small size (see Fig. 2-19). By comparing length or head circumference percentiles with the weight percentile at any given gestational age, the clinician can detect growth retardation even if the actual weight still falls within 2 standard deviations of normal. Conditions that affect growth during the third trimester of pregnancy, such as preeclampsia, tend to interfere with the normal acquisition of fatty tissue while sparing brain growth (and thus head circumference) and linear growth. These newborns have an asymmetrical form of growth retardation (Fig. 2-20). Often postmature infants (>42 weeks) have some decrease in weight compared with length or head circumference. Problems beginning earlier than the third trimester tend to produce generalized growth retardation because head circumference, weight, and length are affected to equivalent degrees. Historically, infants with symmetrical IUGR have higher rates of chromosomal disorders, dysmorphic syndromes, and congenital infection and are associated with higher rates of prematurity and neonatal mortality. In very premature infants, global decreases in growth often complicate assessment of gestational age because the tools are rather limited in babies born at 24 to 28 weeks’ gestation. A thorough investigation should be undertaken in any unexplained instance of growth retardation.
Placenta
In multiple-gestation deliveries, a careful placental evaluation is crucial to determine chorion number and to distinguish between monozygotic and dizygotic twins. The major distinction to be made is whether there is a single chorion, or outer layer of the fetal membranes. When twins with a single chorion are present in a single amniotic cavity (Fig. 2-29), monozygosity is ensured. For all practical purposes, a single chorion that bridges two amniotic sacs is also evidence of monozygotic twins. In this instance it is essential to examine the membranes at the site of connection of the two amniotic sacs. When two chorions and two amnions (or a total of four membranes at their interface) are present (Fig. 2-30), twins may be monozygotic or dizygotic. Approximately 36% of monozygotic twins are dichorionic. Monochorionic (MC) twin placentas, developed for a singleton pregnancy, may not adapt to the demands of twin circulations. The majority of MC twin placentas have connecting vessels, which account for the higher rates of complications.
Birth Trauma
Caput Succedaneum
Normal transit of the fetal head through the birth canal induces molding of the skull and scalp edema, especially if labor is prolonged. The edema, which can be massive, is known as a caput succedaneum (Fig. 2-31). Much of this edema is present at birth and tends to overlie the occipital bones and portions of the parietal bones bilaterally. In some cases, bruising of the scalp may also be present (especially if a vacuum extractor was used). The presence of a caput requires no therapy, and spontaneous resolution within a few days is the rule. Distinguishing caput from a subgaleal (subaponeurotic) hematoma, a rare but serious complication of delivery, is important. A subgaleal hematoma is a collection of blood within scalp tissues extending beneath the epicranial aponeurosis. Palpation of a large caput succedaneum reveals firm, nonpitting swelling. In contrast, the cranial swelling of subgaleal bleeding is boggy due to the palpation of clotted blood just beneath the epicranial aponeurosis (Fig. 2-32). The collection of blood in this potential space can be quite large, and these infants must be monitored for signs of hypovolemia. Serial examinations, which can include measurement of head circumference and hematocrit, are important to identify ongoing blood loss.
Cephalhematoma
Often, confusion arises between the diagnosis of a caput and that of a cephalhematoma. The latter is a localized collection of blood beneath the periosteum of one of the calvarial bones; it may be bilateral, but is most often unilateral (Fig. 2-33). It is distinguished from a caput by the fact that its borders are limited by suture lines, usually those surrounding the parietal bones (see Fig. 2-32). However, diagnosis can be difficult in the immediate newborn period, when there may be overlying scalp edema. On palpation, the border may feel elevated and the center depressed. Most patients have an uncomplicated course of slow resolution over one or more months, although calcification may occur. On occasion, these infants may develop jaundice from the breakdown and resorption of the large hematoma. Underlying hairline skull fractures occur with some regularity but are rarely of clinical significance. The exception is the uncommon development of a leptomeningeal cyst. Radiologic investigation for an underlying depressed fracture is indicated in infants whose histories suggest significant trauma and those having depressed levels of consciousness or neurologic abnormalities on examination. Infection is another potentially serious but rare complication, which is more likely when the integrity of the overlying skin is broken.
Nasal Deformities
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