Which physical findings are most concerning in an infant with respiratory distress?

Contour, proportions, and postures

The body of a normal newborn is essentially cylindrical; head circumference slightly exceeds that of the chest. For a term baby, the average circumference of the head is 33–35 cm (13–14 inches), and the average circumference of the chest is 30–33 cm (12–13 inches).5 The infant's sitting height, measured from crown to rump, is approximately equal to the head circumference. These values may vary somewhat, but their relation to each other is normally constant. Values should be plotted on an appropriate preterm or term growth chart to evaluate the neonate's head for the presence of microcephaly or hydrocephaly.

During the first few days of life, the infant's posture is largely the result of its position in utero. The normal infant who was delivered from a vertex presentation tends to assume a relaxed fetal position. During the first days of life, it is the “position of comfort” for the infant. Crying episodes can often be ended by taking the infant from the crib and gently curling him or her into the fetal position.

Other postures are associated with more unusual infant positions. After a footling breech presentation, the thighs are abducted in the “frog-leg” position. Infants born in the frank breech position tend to keep their knees in the jackknife posture. After a brow or face delivery, the head is extended and the neck appears elongated, but posture of the spinal column is normal. Normal postures depend on normal muscle tone, which may be visibly diminished in hypoxic infants, who do not maintain intrauterine postures but remain in almost any position imposed on them.

Skin and subcutaneous tissue

At birth, the skin is extensively covered with vernix caseosa. If it is not removed at birth, it dries and disappears within 24 hours. The skin is blush red and smooth at birth and progressively becomes dry, flaky, and pink by the second or third day.

Physiologic jaundice is visible during the second or third day of life in approximately half of all normal newborns disappearing between the fifth and seventh days. Jaundice in the first 24 hours is abnormal and requires an extensive diagnostic evaluation.6 Icteric skin may be difficult to detect when redness is prominent, but blanching readily demonstrates the underlying yellow discoloration. Early jaundice is more easily detected on the infant's face.

The subcutaneous tissue may be moderately edematous for several days. Edema is most noticeable about the eyes, legs, and dorsal aspects of the hands and feet. Peripheral cyanosis (acrocyanosis) involves the hands, feet, and circumoral area. It is evident in most infants at birth and for a short time thereafter. If limited to the extremities in an otherwise normal infant, it is due to venous stasis and is innocuous. Localized cyanosis may occur in presenting parts, particularly in association with abnormal presentations. In breech presentations the buttocks or the feet and legs are edematous and blue as a result of venous stasis; in a transverse lie, a prolapsed arm may be similarly discolored and swollen because of obstructed venous return. Occasionally, a circular area of edema and cyanosis in the scalp is present at the top of the head as a result of pressure against a dilated cervix (caput succedaneum). Occasionally, the forehead and scalp (or even the entire head above the neck) are cyanotic.

Pallor usually accompanies other signs of distress except in anemic infants in whom there has been a fetomaternal hemorrhage across the placenta over a protracted period of time (chronic abruption). Such infants are in no obvious distress even though their pallor may be extreme. Pallor is more commonly a sign of acute blood loss, hypoxia, or poor peripheral perfusion due to hypotension. Subcutaneous edema may mimic pallor.

Ecchymoses are most frequently due to trauma during difficult labor or to brisk handling of the infant during or after delivery. They may also indicate a bleeding diathesis with or without serious infection. High infant serum bilirubin concentrations often follow the breakdown of a large amount of extravasated blood.

Petechiae occur in a number of disease states involving thrombocytopenia and should always prompt an investigation including a sepsis workup and evaluation of the infant for TORCH infections. Occasionally in normal infants, scattered petechiae are observed over the upper trunk or the face as a result of increased intravascular pressure following delivery of the fetal head. They usually fade within 24 to 48 hours, and new lesions do not appear.

Mongolian spots are irregular areas of blue-gray pigmentation over the sacrum and buttocks, but they may be so extensive as to cover the back and sometimes the exterior surfaces of all the extremities as well. They are common in black infants and in infants of Asian and southern European lineage. Mongolian spots usually disappear by 4 years of age, or earlier.

Hemangiomas may appear as an isolated lesions in otherwise normal infants, or they may be a component of several serious generalized disorders. Microscopically, hemangiomas of the skin are capillary or cavernous. Capillary hemangiomas are comprised of a mass of dilated capillaries in the superficial skin. Port-wine nevi (nevus flammeus) are dense concentrations of such dilated capillaries, which may be small and single or multiple and sparse; they may also involve large areas, and occupy as much as half the body surface area. Their color varies from pink to deep purple, and they are sharply demarcated. The skin surface is not disrupted. These lesions are usually permanent, but some pale lesions may virtually disappear. Port wine nevi over the face in a trigeminal distribution suggest Sturge-Weber syndrome (cerebral calcification and glaucoma on the same side as the lesions and hemiparesis on the opposite side) and several other serious disorders are also sometimes associated with nevus flammeus. Telangiectatic nevi (stork bites) are flat, red, localized areas of capillaries that are considerably less dense than those seen in port-wine nevi. Easily blanched, they are commonly situated on the back of the neck, the lower occiput, the upper eyelids, and the nasal bridge. They disappear by 2 years of age, but in many children they reappear evanescently during crying episodes. Strawberry hemangiomas are not seen in normal term infants during the nursery stay because they first appear during the second or third week of life. As a result, they are seen in hospitalized premature infants or in term infants after discharge. They are first evident as bright red, flat spots which are 1–3 mm in diameter and blanch easily. Subsequently, they grow in all directions, protruding prominently from the skin surface. They may not reach their full size for 1–3 months. The temptation to remove these lesions should be resisted because they resolve spontaneously several weeks or months after reaching peak growth. The cosmetic effect is best when they are allowed to resolve. Resolution is heralded by one or more pale purple or gray spots on the surface of the lesion, indicating spontaneous vascular sclerosis and obliteration. In contrast, cavernous hemangiomas are in the subepidermal layer. They are more diffuse and less sharply demarcated than capillary hemangiomas. The color of the overlying skin may be normal or blue as a result of color transmission from subjacent blood. Cavernous hemangiomas are spongy, but on occasion they are tight cystic masses. Generally, these localized lesions have no other significance. They grow at first (like strawberry hemangiomas) and then often resolve spontaneously in a few months to 1–2 years. Growth of the lesion may occasionally impair function of an adjacent organ (trachea, esophagus, or eye). Large cavernous hemangiomas are often associated with serious thrombocytopenia (Kasabach-Merritt syndrome). Mixed hemangiomas are common and are comprised of a superficial strawberry lesion that is continuous with a deeper cavernous one.

Harlequin color change is a rare, peculiar discrepancy in color between the longitudinal halves of the body, extending from the forehead to the symphysis pubis. A curiosity of no known pathologic significance, the phenomenon is elicited by placing the infant on his side for several minutes. The dependent half of the body turns deep pink, while the upper half is pale. The colors are reversed when the infant is turned onto the opposite side. The color change often spontaneously occurs in the supine position.

Lanugo is fine hair, which is barely visible and characteristic of the newborn period. It is more obvious in premature and postmature infants and most easily seen over the shoulder, back, forehead, and cheeks.

Milia are minute, white papules on the chin, nose, cheeks, and forehead. They are distended sebaceous glands that disappear spontaneously in several days or weeks. Sudamina are tiny vesicles over the face and neck that are formed by distention of sweat glands.

Erythema toxicum is a pink papular rash on which vesicles are often superimposed. The vesicles may appear purulent and are thus confused with staphylococcal pyoderma. They appear anywhere over the body within 24–48 hours after birth and resolve spontaneously after several days. The vesicles contain eosinophils that are demonstrable on a smear prepared with Wright's stain. The rash is innocuous and its etiology is unknown.

Sclerema is hardening of the skin and subcutaneous tissue associated with life-threatening disorders (septicemia, shock, severe cold stress). As a rule, the cheeks and buttocks are first involved, then the calves and thighs, and eventually even the entire body. Involved areas are not well demarcated. Sclerema should not be confused with subcutaneous fat necrosis, which is confined to small, sharply delineated areas in infants who are otherwise well.

Café-au-lait spots are irregular oval lesions of varying size and distribution that are not elevated above the skin surface. If six or more of them are present, neurofibromatosis must be suspected.

Puncture wounds or marks can result from attachment of fetal monitor electrodes. Rarely, electrodes are inadvertently applied to eyelids and other parts of the face. Puncture wounds may become infected, and merit observation for signs/symptoms of infection by the health care provider.

Head

After vaginal deliveries from the vertex position, molding of the head is apparent to some degree in virtually all neonates. The change in shape is more pronounced in first-born infants and infants whose heads have been engaged for prolonged periods. Pressure during the usual vertex delivery causes flattening of the forehead with a gradual rise to an apex posteriorly and an abrupt drop at the occiput. In brow presentations, the forehead is unusually prominent, rather than flattened as in vertex deliveries. When forces of the birth process are not exerted on the cranium, its spherical contour is undisturbed. The infant's head is spherical in breech deliveries and elective cesarean section. Molding has largely disappears by the end of the second day of life.

At birth and for 1 or 2 days afterward, as a result of molding, the edges of the cranial bones may overlap obliterating the sutures. The lines of overlap seem to be ridges when palpated and the fontanels are small. Later, as the shape of the cranium changes, the bones separate, suture lines are palpable, and the anterior fontanel expands. Overlapping bones are clearly visible in premature infants. In malnourished infants because of impaired growth of the cranial bones, the sutures may be wide at birth, even over 1 cm. The anterior fontanel is also large in malnourished infants for the same reason, but it is also flat and soft. Inordinately large, flat anterior fontanels and extensive suture separation suggest hypothyroidism, osteogenesis imperfecta, and cleidocranial dysostosis. Small anterior fontanels are characteristically noted in premature infants, in infants with microcephaly of any etiology, and in craniosynostosis. The anterior fontanel may be firm and bulging as a result of high intracranial pressure, suggesting hydrocephalus, meningitis, subdural hematoma, cerebral edema, or intraventricular hemorrhage. If there is doubt concerning the firmness and fullness of the anterior fontanel, the infant should be taken from the crib and held erect in one arm while the fontanel is palpated. A pathologically bulging fontanel does not soften or flatten.

Eyes

Eyelids are frequently edematous during the first 2 days after delivery. Separation of lids must be accomplished gently because forceful traction easily everts them, precluding an adequate view of the eyes.

Purulent conjunctival exudate is most often caused by gonorrhea, chlamydia, and staphylococcal infection, and by a variety of infections caused by Gram negative rods. The application of erythromycin or silver nitrate to prevent neonatal conjunctivitis may also cause inflammation of the lids.

Subconjunctival hemorrhages occur frequently. They result from pressure on the fetal head during delivery, with resultant impairment of venous return and rupture of capillaries in the sclera. They can be seen in the sclera and are of no pathologic significance, even when the entire sclera is reddened by extravasated blood. Retinal hemorrhages are produced by the same mechanism and they may occur in as many as 10% of normal neonates. They are flame shaped or round and are thought to be harmless.7 Extensive hemorrhage, however, over a large segment of the retina may indicate the presence of a subdural hematoma.

Cataracts, if present, should be identified at the time of the first nursery examination. Cataracts vary in size from pinpoint to involvement of the entire lens. Occasionally they can develop several days or weeks after birth. If the entire lens is affected, cataracts are easily seen by shining a light tangentially into the eye by the light source being held to one side. If the opacity is small, it can be identified only with an ophthalmoscope. White pupils may also be seen in the presence of lesions deeper in the eye, such as retinoblastoma. Cataracts are usually bilateral. They are a major manifestation of intrauterine rubella infection and are occasionally seen in cytomegalovirus infection. They may be transmitted as a dominant trait from an affected parent. In congenital galactosemia, cataracts sometimes appear several weeks after birth.

Corneal opacities are also discerned by directing light to the eyes. They occur after trauma, in association with congenital glaucoma, and as a result of infections such as herpes virus and congenital rubella.

Iris coloboma is one of the most common congenital malformations of the eye. The defect varies from a small notch at the inner iris margin to a segmental absence, usually in the inferior portion. It is generally limited to the iris and thus not associated with visual difficulty. Infrequently, the defect involves deeper eye structures such as the retina, macula, and optic nerve, thus impairing normal vision. Rarely, colobomas are associated with serious generalized malformation syndromes.

Nose

Neonates are obligate nose breathers and cannot ordinarily breath through their mouth. Any obstruction to the nasal passages causes some degree of respiratory distress. Partial or complete occlusion may be caused by mucus secretion that has not been removed or by choanal atresia or stenosis, which can be life threatening. An oral airway and close observation is indicated if nasal obstruction cannot be immediately alleviated.

Mouth and throat

Complete visualization of the mouth and pharynx is difficult without tongue depression. Attempts to depress the tongue are usually met with strong reflex protrusions of the depressed tongue. An excellent way to view the mouth is by stimulating a cry before gently depressing the tongue. Examination of the mouth is important for the identification of a cleft palate, which often occurs in the absence of a cleft lip. A cleft palate may involve either the hard or the soft palate, or both. Occasionally, only the uvula is cleft.

Precocious or natal teeth occur infrequently and are most often the lower central incisors. When covered with membranous tissue, they are pink rather than white. If detachment is imminent, they should be removed to prevent aspiration.

Epstein's pearls are small, white papular structures that occur on each side of the midline of the hard palate. They are insignificant and usually disappear within a few weeks after birth.

Neck

The neonate's neck is characteristically short and abnormalities are infrequent. A webbed neck is seen in Turner's syndrome. The webbing is characterized by a redundancy of skin that extends bilaterally from the posterolateral aspect of the neck down to the medial portions of the shoulders along the superior margins of the underlying trapezius muscles. Branchial cleft cysts can be evident on the lateral aspects of the neck and along the anterior margin of the sternomastoid muscle. They are generally firm 1 cm or less in diameter, and are covered by normal skin. More commonly dimples are evident in these areas. These are branchial cleft sinuses, which are autosomal dominant traits. Branchial cleft cysts or sinuses are rarely of clinical significance unless they become infected. Thyroglossal cysts are superficially evident as subcutaneous structures in the midline of the anterior neck at the level of the larynx or above it. They indicate the presence of a thyroglossal duct, which is an abnormal remnant of thyroid gland formation. The duct extends deeply into the neck, often opening at its deep end, onto the surface of the posterior tongue. The duct can contain thyroid tissue. Surgical excision is generally indicated. Goiters are usually visible and easily palpated in the midline of the anterior neck. Goiters are generally the result of thyroid medication used in treatment of maternal thyroid disorders. Goiters are commonly not functional; rarely, however, they are associated with neonatal hyperthyroidism.

Thorax

The ribs are flexible and slight sternal retractions can sometimes be evident during normal respiration. The xiphoid cartilage, which is at the lower end of the sternum, can curve anteriorly to produce a prominent pointed protrusion beneath the skin that disappears in several weeks.

Supernumerary nipples are occasionally noted inferior and medial to the normal ones along the “milk ridge”; less often, they can occur superior and lateral to the normal nipples. These are harmless pink or pigmented spots that vary from a few millimeters in diameter to the size of normal nipples, but they do not contain glandular tissue.

Breast enlargement in the neonate appears on the third day after birth, and toward the end of the first week a milk-like substance (“witch's milk”) may be evident. Massaging the breasts with various preparations is a common lay practice that often produces breast abscess characterized by asymmetrical swelling around the areola and severe erythema of the skin. Yellow or blood tinged, purulent material can exude from the nipple or through inflamed skin. Breast abscesses are presumed to be due to Staphylococcus aureus until proved otherwise and are treated accordingly.

Lungs

Radiologic and blood gas studies should be performed if the examiner is suspicious of a respiratory disorder. The respiratory pattern should be observed before the infant is disturbed. Normal neonates breathe at rates which vary between 40 and 60 respirations per minute. Rapid rates are likely to be present for the first few hours after birth. Respiratory rates fluctuate and for this reason several assessments may be necessary before an abnormality becomes apparent. Periodic breathing, a frequent finding in premature infants that requires no therapy, is characterized by sporadic episodes in which respirations cease for up to 10 seconds. Periodic breathing is not associated with cyanosis or bradycardia and is rare during the first 24 hours of life. It should not be confused with apneic episodes, which are of longer duration, often cause cyanosis and bradycardia, and may appear at any time.

In the normal neonate, respiratory movements are predominantly diaphragmatic. The thoracic cage remains relatively immobile while the abdomen rises and falls with inspiration and expiration.

Respiratory difficulties can be identified by simply observing the infant. A number of abnormal signs are clearly indicative of distress, generalized cyanosis being the most obvious and serious. A sustained rate in excess of 60 respirations per minute after 3 or 4 hours of age is abnormal. Irregular respirations associated with repeated apneic episodes are often the result of depressed central nervous system function. Retractions indicate an obstruction to airflow at any level of the respiratory tract from the nose to the alveoli. They are visible with each inspiration and are characterized by indrawing of the thoracic wall at the sternum, between the ribs, above the clavicles, and below the inferior costal margins. The respiratory grunt is an unequivocal sign of difficulty. It is a fascinating compensatory mechanism by which an infant attempts to maintain a higher end-expiratory pressure and thus increase arterial PO2 by prolonging alveolar distention. An audible sign during each expiration is a variant of the respiratory grunt. Auscultatory sign in the lungs is of less value in the neonate than in any other pediatric age group. The chest is so small that localization of findings is often impossible. The diminutive lung effectively transmits breath sounds from one region to another, and the absence of breath sounds in one part of the lung may not be appreciated because the sounds from the unaffected areas are transmitted from a distance. With experience, diminution of air exchange can be confidently detected, particularly when there is a discrepancy between the two lungs. Diminished breath sounds occur in hyaline membrane disease, atelectasis, emphysema, and pneumothorax, and as a function of shallow respirations from any cause. Rales are heard in some infants with hyaline membrane disease, pneumonia, and pulmonary edema, and occasionally in normal infants immediately after birth. They are sometimes audible only after deep inspiration, which must be induced by stimulating crying. Rhonchi are most frequently present after aspiration of oral secretions or feedings.

Heart

Inspection occasionally reveals a small localized area of pulsation on the chest wall at the fifth intercostal space in the midclavicular line and toward the lateral half of the left hemithorax. The pulsations are more evident in small infants with thin chest walls. If pulsations are prominent in the epigastrium, the heart may be enlarged.

By palpation, the normal apical impulse can be identified at the fifth intercostal space. Ascertainment of cardiac position is particularly important in dyspneic infants. Detection of a shift to either side is an important initial step in suspecting pneumothorax or diaphragmatic hernia. In the rare occurrence of bilateral pneumothorax, cardiac impulse is displaced downward toward the epigastrium and the heart is barely audible in the thorax itself.

Auscultation is the most informative component of the physical examination of the heart. The first and second heart sounds are normally clear and well defined. The second sound is somewhat higher in pitch and sharper than the first. Heart rates normally fluctuate between 120 and 160 beats per minute. In agitated states, a rate of 200 beats per minute may occur transiently. The heart rate of premature infants is usually between 130 and 170 beats per minute, and during occasional episodes of bradycardia it may slow to 70 beats per minute or less. Murmurs are not necessarily indicative of congenital cardiac malformations.8 Greater than 90% of murmurs detected during the neonatal period are transient and not associated with anomalies. Conversely, murmurs are sometimes absent in seriously malformed hearts. Systolic murmurs are the most common and usually extend beyond the second sound into diastole. The appearance of a murmur at any time requires evaluation of several additional physical findings, such as peripheral pulses, blood pressure, size and consistency of the liver, and size and contour of the heart on a chest film.

Routine physical exam fails to detect more than 50% of ductal dependent heart disease. Early detection, prior to ductal closure, is important as delayed diagnosis can lead to cardiac failure, cardiovascular collapse, and death. Postductal pulse oximetry screening in the first few days of life is an effective means for detecting cyanotic congenital heart disease in otherwise healthy newborns. Multiple studies have shown that infants with ductal dependent or cyanotic heart disease have oxygen saturation levels below 95%. A increased sensitivity can be achieved by adding the criteria of saturation of less than 95% in both hand and foot or a difference of greater than 3% between hand and foot. 9, 10

The state of the peripheral pulses is important. Brachial, radial, and femoral pulses are the most easily evaluated. Normal pulses are readily discernible, but the examiner's capacity to assess abnormal weakness and fullness depends on experienced observations of normal neonates. Weakness of all pulses is indicative of a diminished cardiac output. This occurs in “hypoplastic left heart syndrome,” asphyxia with hypoxic myocardium, cardiac failure from other causes, and in septic or hemorrhagic shock. Bounding pulses generally appear several days after birth in premature infants who have developed a large left-to-right shunt from the aorta to the pulmonary artery through a patent ductus arteriosus. The presence of a murmur requires assessment of liver size and consistency. In infants with right-sided congestive heart failure, the liver is enlarged and firm with its inferior edge 5–6 cm below the right costal margin. A chest film is indispensable for initial assessment of cardiac size and contour. Blood pressure is simply and accurately measured with a Doppler apparatus and an ordinary blood pressure cuff. Blood pressure readings are more easily obtained at the popliteal space with the cuff around the thigh. A loose cuff may result in spuriously high readings and an excessively tight cuff may yield falsely low readings.

Abdomen

INSPECTION

The abdomen is ordinarily cylindrical, sometimes protruding slightly in normal term infants. Several gross abnormalities are often apparent on inspection. Distention in its most severe form is characterized by tightly drawn skin through which engorged subcutaneous vessels can be seen. Localized bulging at one or both flanks suggests enlarged kidneys, which is usually a result of hydronephrosis. A severe abnormality of contour characterizes the rare malformation known as congenital absence of abdominal musculature (“prune-belly” syndrome) in which renal and gastrointestinal anomalies are present. The anterior aspect of the abdomen is sunken, or perhaps slightly protuberant, whereas the intestines, which are covered only by skin and a thin layer of subcutaneous tissue, bulge pendulously from the flanks.

PALPATION

With rare exceptions, the edge of the liver is normally palpable below and often as far as 3 cm inferior to the right costal margin. The tip of the spleen can sometimes be felt in normal infants. Examination of the abdomen should include palpation of each kidney, and this is most easily accomplished immediately after birth, when the intestines are not yet distended with air. With the infant supine, a finger is place at the costovertebral angle to maintain upward pressure while the other hand presses downward toward the posteriorly placed finger. The kidney can be felt between the fingers. The lower poles of each kidney are normally situated approximately 1 or 2 cm above the level of the umbilicus. If enlargement is present, they extend below this level. By simple palpation, the astute examiner can identify the majority of gross renal anomalies. If the bladder is distended, a firm globular lower abdominal mass is palpable. If it persists to any degree after voiding, the bladder is incompletely emptied, and an outlet obstruction may be present. Masses perceptible elsewhere in the abdomen are usually intestinal.

Diastasis recti is an inconsequential longitudinal gap in the abdominal midline between the two rectus muscles. It can be palpated from the epigastrium to the umbilicus as a linear absence of abdominal wall musculature approximately 1 cm in width. When the infant cries, a bulge is sometimes visible through the linear gap in musculature. Diastasis recti disappears within a few weeks.

The normal umbilical cord sloughs from its attachment at approximately 7–10 days of age. A single umbilical artery requires search for congenital malformations. In some reports, a significant number of these infants have major congenital anomalies, particularly renal and gastrointestinal malformations. Other reports assert that the incidence of anomalies is no higher in such infants.

Patency of the anus can be ascertained by inserting the tip of a thermometer or a plastic feeding tube for a distance not in excess of 1 cm, or observing the infant for passage of meconium prior to discharge.

Inguinal hernias occur most frequently in males, particularly in low birth weight infants. They are usually unilateral, but can occasionally be bilateral. The swelling can extend into the scrotum. Sometimes, the hernia is not perceptible until the infant cries. The hernias contain intestine, but in females the ovary and fallopian tubes may herniate as well.

Male genitalia

The prepuce covers the entire glans penis so that the external meatus is not visible. The prepuce is not retractable in normal neonates and sometimes cannot be completely displaced until 4–6 months of age to as late as 3 years. It should not be forcibly retracted. This condition is not phimosis and it is not an indication for circumcision. However, the trauma of forceful retraction can cause phimosis. If the ventral surface of the glans is not covered by preputial tissue, hypospadias is present. According to a statement by the American Academy of Pediatrics, “there is no absolute medical indication for routine circumcision of the newborn.”11 It is not an essential component of adequate health care. Good penile hygiene accomplishes as much as a routine circumcision.

In term infants, the testes are in the scrotum. In premature infants, the testes are in the inguinal canal or may not be palpable. The scrotum varies in size according to the maturity of the neonate. In premature infants, the scrotum is small and close to the perineum. In term infants, the scrotum is large, hanging loosely at a greater distance from the perineum. The term infant's scrotum is rugated over its entire surface back to the perineal attachment. The scrotum of the premature infant is less extensively rugated, becoming smoother toward the perineal attachment. Scrotal rugation is one of several external signs used for the assessment of gestational age.

Hydroceles are unilateral, with the affected side of the scrotum appearing larger and cystic. Transillumination of a hydrocele reveals a striking translucency and confirms the diagnosis. In inguinal hernias, the scrotal contents are comprised of intestine or fluid (or both). It is opaque to transillumination, or considerably less translucent than the hydrocele. A hydrocele usually disappears spontaneously in a few days or weeks.

Female genitalia

The labia minora are usually more prominent than the labia majora in preterm infants, whereas in term infants the reverse is true. The clitoris varies in size.

The hymenal tag is a normal redundant segment of the hymen that protrudes from the floor of the vagina and disappears in several weeks. During the first week of life, a milk-white mucoid discharge, which is sometimes blood tinged, may be evident in the vagina. This is a physiologic manifestation of maternal hormonal influences and disappears within 2 weeks.

Extremities

Malformations most frequently involve the fingers. Polydactyly, in its most common form, consists of a rudimentary digit (digitus postminimus) attached to the lateral aspect of the little finger by a thin pedicle. It can be eliminated by firmly tying a silk suture around the pedicle close to the surface of the normal finger. Less commonly, an extra fully formed digit is present that requires surgical removal. Syndactyly most often involves the toes.

Fractures of the clavicle, humerus, and femur are occasionally encountered in the newborn. Fractures should be suspected in any infant who fails to move one extremity as extensively as the others. Malposition and a visible local deformity at the fracture site are helpful signs.

Clavicles must be palpated to ascertain their presence as well as to detect fractures. Absence of the clavicles, either total or segmental, is characteristic of cleidocranial dysotosis, an inherited disorder of membranous bone formation in the skull, the clavicles, and occasionally the pubic bone. Absence of the clavicles permits innocuous anterior displacement of the shoulders so that they almost meet in the midline.

Neurologic evaluation

Abnormal neurologic signs are often transient, but can be persistent. They may disappear by the time the infant is discharged from the nursery, or they may be present throughout the nursery stay. Predictions of later brain dysfunction cannot be made with consistent accuracy on the basis of neurologic abnormalities during the newborn period.12

Observations should be made with as little disturbance to the infant as possible. Reflexes that require the greatest degree of disturbance should be elicited at the end of the examination. Spontaneous movements should be studied first. Infants who are generally depressed will move very little or not at all and can be hypotonic. Drugs administered to the mother are frequent causes of depression. These drugs include analgesics (Demerol), hypnotics (barbiturates, magnesium sulfate, alcohol), and local anesthetics (lidocaine). Central nervous system infections, bacterial or nonbacterial, and metabolic disturbances (hypoglycemia, hypermagnesemia, hypothyroidism) also cause depression. Trauma to the central nervous system, (cerebral contusion, subdural hematoma) also causes diminished or absent spontaneous activity.

Hyperirritability and exaggerated responses to ordinary tactile or acoustic stimuli are abnormal. These responses may range from agitation or jitteriness to frank convulsions. They may thus be manifested as localized twitches, gross rhythmic repetitive jerks of one or more muscle groups (myoclonus), or generalized clonic convulsions. There is little to be gained in attempting to localize central nervous system lesions based on focal convulsive phenomena, in the neonate, because of the lack of correlation. There is also little use in attempting to differentiate between a severely agitated state characterized by ceaseless movement and a frank convulsion. Usually they are of equal significance. These irritative phenomena are most commonly observed during recovery from an asphyxia event after a period of depression. They also occur in infants of narcotic-addicted mothers (heroin or morphine withdrawal) and among infants of mothers who are habituated on barbiturates (phenobarbital withdrawal). Hypocalcemia, hypomagnesemia, and hypoglycemia may cause irritative phenomena. Maternal administration of high doses of local anesthetics such as lidocaine may initially produce depression which is followed by convulsions. Intracranial hemorrhage and occasionally central nervous system infection may produce irritative responses early in their courses.

Asymmetry in movement of the extremities indicates weakness, paralysis, or bone fracture. In brachial plexus palsy, for example, the affected upper extremity is hypoactive or immobile. Failure to move the lower extremities suggests a spinal cord injury. Asymmetry of movement or tone in any extremity is always abnormal.

Muscle tone is extremely important in neurologic evaluation. The normal infant maintains some degree of flexion in all the extremities, and extension by the examiner is followed by at least a partial return to the previous position of flexion. Flexion posture is less pronounced in premature infants. Poor head control (described later) is additional evidence of abnormally diminished muscle tone.

The evaluation of certain reflex responses is essential for assessment of the infant's neurologic status. The grasp reflex is normally strong in term infants. It is elicited by placing a finger across the palm at the base of the fingers. In response, the examiner's finger may be grasped so firmly that using both hands, the infant can often be raised from the surface of the crib. This response is considerably more feeble in premature or depressed infants. It is absent or weak on the affected side in Klumpke-type brachial plexus palsy.

The rooting reflex is activated by lightly stroking the angle of the lips. The baby turns his head to the stroked side. Recently fed infants and those who are lethargic or depressed merely purse the lips or do not respond at all. Vigorous infants turn the head briskly and instantly, pursuing the finger as long as contact with the lips is maintained.

The suck is evaluated by inserting a sterile nipple into the mouth. In normal infants, particularly those who are hungry, the response is immediate, coordinated, and forceful. Recently fed infants, premature babies, and those who are depressed respond with varying degrees of feebleness.

The knee jerk is normally brisk. It is weak in depressed infants, exaggerated to the point of clonus in irritated ones, and asymmetrical in infants who have spinal cord lesions, fractures of the femur, or bone and joint infection of the examined extremity.

Ankle clonus is elicited by placing two fingers against the anterior sole of the foot and abruptly dorsiflexing it with a short brisk movement. The response will usually consist of several repetitive jerks (beats) of the foot or none at all. If more than eight to ten beats occur, the infant is probably in an irritated state.

Head control in the normal neonate is more effective than is generally realized. With the infant supine, the examiner takes the wrists and lifts him slowly to a sitting position. The normal term infant reinforces the maneuver by contracting the shoulder and arm muscles followed by flexion of the neck. As the upright sitting position is reached, the infant controls his head by action of neck muscles and prevents its head from falling forward onto the chest. In many infants, the head falls forward but is soon righted to the erect position. Hypotonic infants, such as those with Down's syndrome, have little or no head control, and they do not respond to traction by activating the muscles of the arms and shoulders. The neck is extremely lax, and the head bobs in any direction. There is no attempt to assume an erect posture once the head has fallen to either side or onto the chest.

The Moro reflex is demonstrable in all normal neonates. It is often erroneously elicited by slapping the bassinet or jerking it. Some examiners abruptly pull a blanket from under the baby. Others lift the infant slightly off the crib surface by the wrists and allow him to fall back. The most consistent responses are obtained by holding the baby in a supine position with both hands, one palm beneath the sacrum and buttocks and the other moving the hand down from the occiput and upper back. By suddenly moving the hand down from the occiput onto the back, the head is allowed to fall through an angle of approximately 30 degrees, thus activating the Moro reflex. The normal response is characterized by straightening the arms and elbows away from the body and by extending the wrists and fingers. This is followed by return of the upper extremities onto the chest in a position of passive flexion. A cry often accompanies the baby's startled response. A rapid single movement of the hips and knees occurs quickly and is of short duration. If an extremity does not respond fully, a localized neurologic defect or fracture should be suspected. Suboptimal vigor of the overall response occurs in depressed infants, whereas in premature infants the response is disorganized and incomplete to varying degrees.

The final impression of the infant's neurologic status is formed with caution. The neonate's relative neurologic immaturity makes it difficult to localize a disorder or, in many instances, to be certain there is any disorder at all. The incidence of spurious signs is high. Furthermore, repeated observations are indispensable because abnormal signs are often transient, disappearing in a matter of hours. Extremes are seldom a puzzle; the gross abnormalities and the unequivocal normal state cause little difficulty. The in-between phenomena are notoriously troublesome in the physical examination generally and in the neurologic evaluation particularly.

What are four common signs of respiratory distress in infants?

What does respiratory distress look like in babies?

What are abnormal findings of respiratory assessment?

Which of the following assessment findings would indicate that the neonate may be in respiratory distress immediately after birth?