Chapter 114: Neonatal Emergencies and Common Neonatal Problems

Neonates are infants ≤1 month old, or preterm infants within 30 days of their term due date. Symptoms that precipitate ED visits in neonates are often vague and nonspecific. Signs are usually subtle and may not point to a specific diagnosis. For example, respiratory distress can be caused by pulmonary or cardiac disease, generalized sepsis, abdominal pathology, or metabolic disorders. Many visits occur because of caregiver concerns about normal variants of newborn vegetative functions. Such concerns must be distinguished from potentially life-threatening congenital and acquired conditions that can present in the first month of life. This chapter reviews normal neonatal vegetative patterns, life-threatening neonatal emergencies, and common neonatal problems.

FEEDING PATTERNS

In the first few weeks of life, expect variation in times between feedings, but by the end of the first month, the vast majority of newborns establish a regular feeding schedule. Most healthy, bottle-fed infants eat 2 to 4 ounces every 2 to 4 hours (six to nine feedings in 24 hours) by the end of the first week of life; breastfed infants prefer shorter intervals—feeding every 1 to 3 hours. Intake is adequate if the neonate gains weight appropriately and appears content between feedings. Feedings are progressing well if the infant is no longer losing weight by 5 to 7 days of age and is gaining weight by 12 to 14 days of age.

WEIGHT GAIN

Weigh neonates completely undressed. Normal newborns may lose up to 12% of their birth weight during the first 3 to 7 days of life, with earlier and slightly more accentuated weight loss in exclusively breastfed newborns. A weight loss of up to 10% is accepTable if the infant's examination, stooling, and voiding frequency and behavior are normal. On average, infants gain between 20 and 30 grams per day in the first 3 months of life and between 15 and 20 grams per day for the next several months.

STOOL PATTERNS

The number, color, and consistency of bowel movements can vary greatly in the same infant and between infants, regardless of diet or environment (Table 114-1).

An excessive intake of human milk or maternal use of laxatives increases the water content of the infant's stool. Overfeeding or use of formula that is too concentrated or too high in sugar content also can produce loose stools.

Stool color has no significance unless it is acholic or bloody. The first stool, which consists of meconium, is usually passed within the first 24 hours after birth and is thick, sticky, and black. Transitional stools, which are greenish brown, appear after initiation of milk feeding and are replaced by typical yellow, seedy milk stools 3 to 4 days later. Infrequent bowel movements do not necessarily mean constipation, because breastfed infants may occasionally go 5 to 7 days without a bowel movement. Failure to pass meconium in the first 48 hours of life may suggest Hirschsprung's disease or cystic fibrosis.

BREATHING PATTERNS

The normal respiratory rate in neonates is 30 to 60 breaths/min. Newborn breathing is almost entirely diaphragmatic, and the soft front of the thorax is usually drawn inward during inspiration while the abdomen protrudes. Count the respiratory rate for a full minute with the infant resting or preferably asleep. Neonates increase minute ventilation almost entirely through an increase in respiratory rate rather than inspiratory volume; a neonate with a resting respiratory rate of >60 breaths/min during periods of regular, quiet breathing requires evaluation for the causes of tachypnea. Observe respirations to determine if breathing is thoracic or abdominal. Thoracic breathing or tachypnea usually signifies intrathoracic or intra-abdominal pathology. Check the nares and upper airway, as neonates are obligate nose breathers, and nasal congestion, or choanal stenosis or atresia, can cause respiratory distress.

Newborn infants, especially those born prematurely, may exhibit periodic breathing that is characterized by alternating periods of a normal or fast rate and periods of a markedly slow rate of respiration, with pauses of 3 to 10 seconds between breaths. Irregular respiratory patterns are seen in many premature babies during sleep, but are less common in term infants. Periods of apnea >20 seconds or apnea accompanied by bradycardia, cyanosis, or a change in muscle tone is abnormal and requires evaluation (see chapter 115, Sudden Infant Death Syndrome and Apparent Life-Threatening Event).

SLEEPING AND FEEDING PATTERNS

Infants are not born with the ability to sleep through the night. Instead, they awaken every 20 minutes to 6 hours, and sleep periods are spread evenly across the day and night. By 3 months of age, most sleep occurs at night, and by 6 months, most infants are sleeping through the night. Night waking is defined as waking and crying once or more between midnight and 5 A.M. for ≥4 nights per week, for ≥4 consecutive weeks. Night waking occurs in about 25% of bottle-fed infants and about 50% of breastfed infants <12 months old. When the child cries during the night, parents should make sure that there is no physical reason for crying. If there is no physical problem, parents may ignore the crying so that the child learns to fall asleep on his or her own. If parents usually feed the child at that time and the child is about ≥6 months old, the volume of the night feedings should be progressively tapered and then discontinued, so all nourishment is given during the daytime.

CRYING

The symptom complex of crying or irritability is fairly common yet difficult to treat, even in the presence of an identifiable cause. Most neonates exhibit varying degrees and periods of crying during a 24-hour period. Total crying time increases after birth, peaking at 3 to 5 months of age. Infants who present with an episode of acute, inconsolable crying, however, require careful evaluation for an underlying cause (Table 114-2).

Principles of basic life support, pediatric advanced life support, and the Neonatal Resuscitation Program are reviewed in chapter 108, Resuscitation of Neonates. A brief discussion of critical neonatal illness is presented here (Table 114-3), with further discussion of specific complaint-based differential diagnosis and management to follow.

For the neonate with respiratory and/or cardiovascular distress, pay primary attention to adequacy of the airway and breathing. There are more stresses and fewer compensatory responses available to the neonate. The neonate has a compliant chest wall and cannot increase inspiratory force; the neonatal airway is small; neonatal metabolism is characterized by high oxygen consumption; and abdominal distention can further impair ventilation. Consider the early use of positive-pressure ventilation or endotracheal intubation for respiratory insufficiency and nasogastric tube placement for gastric distention. Bradycardia in the neonate is almost always due to respiratory failure and hypoxia and usually corrects with restoration of adequate airway and breathing.

Tachypnea can be caused by minor problems, such as gaseous abdominal distention, or life-threatening illnesses, such as sepsis. True tachypnea (respiratory rate >60 breaths/min) or grunting is an emergency; admit for further investigations, monitoring, and therapy in all but the mildest cases.

Cardiorespiratory symptoms in neonates are nonspecific and may be due to cardiovascular or respiratory failure or to systemic diseases. Search for pathologic conditions in all organ systems. For example, sepsis, meningitis, gastroenteritis, and metabolic acidosis may cause respiratory distress as the predominant symptom. Regardless of the cause, assess and stabilize the cardiac and respiratory systems before, or simultaneously with, further diagnostic evaluation.

When a specific cause cannot be identified, initiate a full sepsis evaluation (see chapter 116, Fever and Serious Bacterial Illness in Infants and Children) and begin broad-spectrum antibiotics, and add IV acyclovir if there are any findings consistent with or suggestive of exposure to herpes simplex virus.

Conditions discussed in the following sections include common and uncommon symptom complexes in the critically ill neonate: neonatal sepsis; congenital heart disease; pneumonia; bronchiolitis; anatomic airway lesions; inborn errors of metabolism; congenital adrenal hyperplasia; neuromuscular disorders; intracranial hemorrhage; and abdominal catastrophe.

NEONATAL SEPSIS

Overwhelming neonatal sepsis is the most common cause of neonatal cardiorespiratory distress. Fever or hypothermia signals serious infection in the neonate. Fever in the first month of life is a rectal temperature ≥38°C (100.4°F), and hypothermia is a rectal temperature <36.5°C (97.7°F). Neonates have about twice the risk of serious bacterial infection as do infants 4 to 8 weeks of age. Neonatal sepsis tends to appear as an "early-onset" or a "late-onset" syndrome, with some overlap. Early-onset disease is seen in the first few days of life, tends to be fulminant, and is usually associated with maternal or perinatal risk factors, such as maternal fever, prolonged rupture of membranes, and fetal distress. Late-onset disease usually occurs after 1 week of age, tends to develop more gradually, and is less likely to be associated with risk factors. Septic shock and neutropenia are more common with early-onset syndrome, and meningitis is more common in late-onset disease.

Clinical signs of early- or late-onset sepsis are not specific. Septic infants may exhibit any of a variety of symptoms as described in Table 114-4. Tachypnea and respiratory distress may be a sign of sepsis, meningitis, or urinary tract infection. Localizing signs may be absent—for instance, nuchal rigidity and Kernig and Brudzinski signs are present in a small minority of neonates with meningitis.

Bacterial causes of neonatal sepsis reflect organisms that colonize the female genital tract and nasal mucosa of caregivers. In general, the two groups of pathogens most frequently encountered are gram-positive cocci, such as β-hemolytic streptococci, and enteric organisms, such as Escherichia coli and Klebsiella species, and Haemophilus influenzae. Listeria monocytogenes also causes sepsis and meningitis in neonates. Viral infections are another cause of fever and are most likely due to enteroviruses (coxsackievirus and echovirus) acquired at the time of delivery or respiratory syncytial virus and influenza A virus acquired postnatally. The height of the temperature does not distinguish a viral versus bacterial cause in neonates.

The clinical investigation for neonatal sepsis is similar to that of an older infant except that the threshold for a full sepsis workup, including cerebrospinal fluid analyses, is lower. Admit all neonates to the hospital and initiate treatment with empiric IV antibiotics. Initial treatment of a neonate with suspected bacterial septicemia or meningitis usually includes ampicillin (50 milligrams/kg to cover group B Streptococcus and Listeria) and an aminoglycoside (gentamicin, 2.5 milligrams/kg) to cover E. coli and other gram-negative organisms and possible gram-negative meningitis. Avoid ceftriaxone in neonates as it can cause kernicterus. When gram-negative meningitis is strongly suspected, replace gentamicin with cefotaxime or ceftazidime (50 milligrams/kg), which have better CNS penetration. Add IV acyclovir for neonates with a maternal history of herpes or suspicious cerebrospinal fluid findings (predominance of lymphocytes and erythrocytes in a nontraumatic lumbar puncture) and all neonates who are ill appearing.³ For further detailed discussion, see chapter 116.

CONGENITAL HEART DISEASE

Suspect congenital heart disease in a well-developed neonate who presents with unexplained cardiorespiratory collapse, cyanosis, and or tachypnea, especially without chest retractions or use of accessory muscles for breathing (see chapter 126, Congenital and Acquired Pediatric Heart Disease). Undiagnosed congenital heart disease may be first identified after discharge from the newborn nursery and typically becomes symptomatic at one of two distinct time frames: in the first week of life or after the second week of life (see also chapter 126, Congenital and Acquired Pediatric Heart Disease). In the first week of life, lesions dependent on pulmonary or systemic blood flow through the ductus arteriosus (e.g., hypoplastic left heart syndrome, critical coarctation of the aorta) present with shock and acidosis as the duct begins to close. Lesions that involve left-to-right shunting of blood (ventricular and atrial septal defects) typically present after the second week of life with congestive heart failure as pulmonary vascular resistance falls, allowing pulmonary overcirculation and the onset of congestive heart failure.

PNEUMONIA

The lungs are the most common site of infection in neonates. Neonatal pneumonia contributes to significant mortality in developing countries, whereas the incidence of neonatal pneumonia in full-term infants in developed countries is lower. Table 114-5 displays the various causes, the associated clinical picture, and suggested management of neonatal pneumonia.⁴ Chapter 125, Pneumonia in Infants and Children, further addresses pneumonia after the neonatal period.

BRONCHIOLITIS

A detailed discussion of bronchiolitis can be found in chapter 124, Wheezing in Infants and Children. Neonates are at particularly high risk for serious complications from bronchiolitis, because of obligate nose breathing and respiratory mechanics. Factors that predispose to complications of bronchiolitis include prematurity, underlying pulmonary or congenital heart disease, initial oxygen saturation <92%, and bronchiolitis caused by respiratory syncytial virus.

Acute bronchiolitis is a clinical diagnosis, and neonates present with nasal discharge and sneezing followed by diminished appetite, difficulty with feeds, cough, dyspnea, irritability, and, occasionally, periods of apnea. Respiratory symptoms include hypoxia, wheezing, retractions, and possibly palpable liver and spleen due to pulmonary hyperinflation. Bronchiolitis caused by respiratory syncytial virus is associated with apnea, especially in neonates and preterm infants delivered at <34 weeks of gestational age. While apnea usually presents within the first 3 days of illness, it may develop even if the neonate displays only minimal respiratory distress, and there are no reliable predictors for the development of apnea.

Perform a nasal wash for rapid respiratory syncytial virus testing in all neonates and admit those who test positive. Obtain a chest radiograph in critically ill neonates and in those in whom the diagnosis is not clear, although bacterial pulmonary infection is not likely in confirmed viral bronchiolitis. Obtain a urinalysis in febrile neonates (temperature >38.0°C [100.4°F]), as up to 4% of febrile infants with bronchiolitis have concomitant urinary tract infection.^5,6 The risk of bacteremia and meningitis associated with bronchiolitis is quite low, and full sepsis evaluation is not needed unless the neonate appears ill.^5,6

Administer a trial of nebulized racemic epinephrine for treatment of wheezing and evaluate response with respiratory rate and oxygen saturation. Continue racemic epinephrine treatment only if the neonate shows improvement with the first dose. Inhaled β-adrenergic bronchodilators provide no clinical benefits. There is conflicting evidence surrounding the use of corticosteroids. There is no role for antibiotics.

ANATOMIC AIRWAY LESIONS

The anatomically correcTable causes of respiratory distress in newborns are less common and include anomalies of the upper respiratory tract (e.g., choanal atresia, laryngomalacia, tracheomalacia, micrognathia, macroglossia, tracheoesophageal fistula, vascular slings) or lower respiratory tract (e.g., congenital lobar emphysema, sequestration, cystic adenomatous malformation, congenital diaphragmatic hernia). Most of these anomalies are identified in the newborn nursery, but in the ED, these diagnoses should be considered in any infant with respiratory distress. Admission is needed for diagnosis.

NEUROMUSCULAR DISORDERS

Any form of muscle weakness may be associated with shallow breathing and a compensatory increase in respiratory rate. Infantile botulism is one possible acquired cause and is usually preceded by constipation, followed by a weak cry and feeding difficulties. Ocular palsies, apnea, weakness or hypotonia, and lethargy are late symptoms of botulism. Other causes of hypotonia that may cause respiratory symptoms include Down's syndrome; hypoxic-ischemic encephalopathy; spinal cord lesions, such as myelomeningocele; spinal muscular atrophy; myasthenia gravis; metabolic disorders; and myotonic dystrophy.

INBORN ERRORS OF METABOLISM

Inborn errors of metabolism may manifest as lethargy or respiratory and/or cardiovascular collapse in the neonate. Although the differential diagnosis of inborn errors of metabolism is extensive, the ED evaluation necessitates only a few tests, including bedside glucose, electrolytes, blood gas analysis, serum ammonia, and urine for ketones. More specific testing can wait until after resuscitation. Administer dextrose-containing IV fluids for suspected metabolic disease until specialty consultation can be obtained. For further discussion, see chapter 144, Metabolic Emergencies in Infants and Children.

CONGENITAL ADRENAL HYPERPLASIA

Congenital adrenal hyperplasia is one of the few acute life-threatening endocrine emergencies that present in the neonatal period (see chapter 144, Metabolic Emergencies in Infants and Children). Although many state newborn screens test for this disorder, infants may present in shock before screening results are known, typically in the first or second week of life. On examination, look for virilization, ambiguous genitalia, and hyperpigmentation. Hyponatremia and hyperkalemia occur in the salt-wasting form of congenital adrenal hyperplasia. Administer hydrocortisone (12.5 to 25.0 milligrams IV/IM/IO) promptly, while undertaking other resuscitative measures. Treat hyperkalemia with standard measurements only if associated with electrocardiogram changes.

INTRACRANIAL HEMORRHAGE

Intracranial hemorrhage, either as a result of birth trauma or nonaccidental trauma, is another consideration in the critically ill neonate. Risk factors include home delivery without administration of vitamin K (associated with hemorrhagic disease of the newborn) or traumatic vaginal delivery. Consider head CT after initial resuscitation if a diagnosis is not apparent or intracranial pathology is suspected.

ABDOMINAL CATASTROPHE

Consider abdominal catastrophe in the critically ill neonate with abdominal symptoms. Congenital malrotation can lead to midgut volvulus and intestinal infarction, with bilious vomiting, a distended rigid abdomen, sepsis, and circulatory collapse. Necrotizing enterocolitis, while typically a disease of premature infants, can present in the term neonate with poor feeding; abdominal distension, tenderness, and discoloration; lethargy or irritability; vomiting or diarrhea; temperature instability; apnea; and circulatory collapse. These and other abdominal considerations are discussed in chapter 130, Acute Abdominal Pain in Children, and are reviewed briefly later (see "GI Symptoms").

Common symptom-based neonatal problems that may result in ED visits include irritability, colic, upper airway complaints, apnea and periodic breathing, GI symptoms, eye complaints, and abnormal movements.

IRRITABILITY

Normal crying was discussed earlier (see "Normal Neonatal Vegetative Functions"), and Table 114-2 lists the important causes of irritability in the neonate. Obtain a thorough history focusing on symptoms other than crying, such as changes in feeding, temperature instability, and vomiting, and perform a systematic head-to-toe examination. Palpate the fontanelles for signs of dehydration (sunken) or infection or intracranial hemorrhage (bulging). If corneal abrasion is possible, examine the eyes with fluorescein staining.⁷ Inspect the mouth for oral thrush and check diaper area and groin for rashes, hair tourniquets (also check fingers and toes), and hernias or testicular torsion. Auscultate the heart to appreciate dysrhythmias or murmurs, and observe respiratory effort that may point to a pulmonary or metabolic cause of irritability. Obtain a bedside glucose in all neonates with altered mental status, vomiting, or a history of poor oral intake. Examine the abdomen for tenderness, distension, or discoloration suggestive of intra-abdominal pathology and the extremities for signs of trauma.

If a careful history and complete physical examination reveal no source for the crying and the infant quiets during the ED visit, further testing is unnecessary and parents can be reassured and advised to follow up with their primary care physician.

INTESTINAL COLIC

Colic is a symptom complex consisting of the sudden onset of paroxysmal crying, a flushed face, circumoral pallor, tense abdomen, drawn up legs, cold feet, and clenched fists. The cause is not known. Colic is defined as a paroxysm of crying for ≥3 hours per day for ≥3 days per week over a 3-week period. It may begin as early as the first week of life but seldom lasts beyond 3 to 4 months of age. Infant colic is a diagnosis of exclusion. Physical examination is normal, and laboratory tests are not required. However, when the diagnosis is unclear, a careful history, physical examination, and appropriate laboratory investigations are necessary to rule out conditions listed in Table 114-2.

There is no specific treatment for colic. Overfeeding without adequate burping during feedings may result in an irritable, crying infant. Improved feeding practices may decrease symptoms.

Administration of drugs or sedatives is contraindicated. A 1-week trial of hypoallergenic formula (non–cow's milk protein) may help. Infant colic can create significant caregiver stress and fatigue and is a risk factor for nonaccidental neonatal trauma. Carefully assess the caretaker's mental health and explore strategies to provide respite if needed.

UPPER AIRWAY COMPLAINTS

Cough and Nasal Congestion

Cough associated with sneezing and nasal congestion is usually due to viral upper respiratory infection. Neonates with underlying pulmonary or heart disease such as bronchopulmonary dysplasia or hypoplastic left heart may develop respiratory failure with even mild upper respiratory infections. Inquire about sick siblings and perinatal infectious risk factors. Pay attention to the relation between respiratory symptoms and feeding that might suggest reflux and aspiration, or even congenital tracheoesophageal fistula, as a cause. Respiratory difficulty when quiet and improvement during crying suggest choanal atresia. Treat the underlying condition: cough is the infant's primary protective reflex; do not give cough suppressants to neonates. Over-the-counter cold medications are not effective, may be dangerous in infants, and are contraindicated for children <24 months old. Treat nasal congestion with instillation of saline drops and bulb suctioning.

Noisy Breathing and Stridor

Noisy breathing is a common presenting complaint in neonates and is usually benign, but consider serious underlying pathology. Distinguish between inspiratory and expiratory sounds through careful listening in order to distinguish stertor, stridor, and wheezing. Stertor is an inspiratory sound like snoring or snorting that localizes to the nose or nasopharynx and is usually benign, but can be a symptom of choanal stenosis. Inability to pass a small nasogastric tube through the affected nostril is diagnostic of this condition. Stridor is a sign of upper airway obstruction and may be evident on both inspiration and expiration. The most common cause of stridor in neonates is laryngomalacia, which is characterized by noisy, crowing, inspiratory sounds, usually present from birth, that usually decrease during the first year of life. Nasal pharyngoscopy by an otolaryngologist confirms the diagnosis.

Stridor may also be a symptom of congenital anomalies causing a fixed obstruction anywhere from the nose to the trachea and bronchi, such as webs, cysts, atresia, stenosis, clefts, and hemangiomas. Stridor from fixed lesions is often biphasic, although it may be predominant in either inspiration or expiration. Stridor worsening with cry or increased activity suggests laryngomalacia, tracheomalacia, or subglottic hemangioma (which often become symptomatic after the first few weeks of life). Stridor accompanied by feeding difficulties suggests a vascular ring, laryngeal cleft, or tracheoesophageal fistula. Occasionally an H-type tracheoesophageal fistula may present in the first month of life or later with recurrent pneumonia, respiratory distress after feedings, and problems clearing mucus. Tracheal stenosis may present initially with noisy breathing or a high-pitched cry and disproportionate respiratory distress with mild upper respiratory infections. Stridor with hoarseness or weak cry suggests vocal cord paralysis, which is typically present at birth. Infants who were intubated in the neonatal period may develop subglottic stenosis causing stridor. Infection (e.g., croup, epiglottitis, and abscess) as a cause of stridor in neonates is rare and is associated with fever. When the diagnosis is in doubt, admit the neonate for further evaluation, which may include pharyngoscopy, bronchoscopy, radiographs, or even ultrasonography.

APNEA AND PERIODIC BREATHING

Periodic breathing, which occurs in normal neonates, must be differentiated from apnea; however, periodic breathing may precede apnea, and both may occur in the same patient. Periodic breathing is alternating periods of a normal or fast respiratory rate with periods of a slow rate of respiration, with pauses of 3 to 10 seconds between breaths. Apnea is cessation of breathing for ≥20 seconds, or cessation of breathing for a period <20 seconds accompanied by bradycardia, cyanosis, or a change in muscle tone. It signifies critical illness and warrants investigation and admission for monitoring and therapy. Apnea may be precipitated by any of the disease conditions listed in Table 114-4 and usually indicates respiratory muscle fatigue and impending respiratory arrest. Provide airway and ventilatory support, and search for the cause. If no obvious cause is found, presume sepsis, obtain cultures, and initiate broad-spectrum antibiotics and acyclovir if there is concern for herpes simplex virus. Chapter 115, Sudden Infant Death Syndrome and Apparent Life-Threatening Event, covers conditions associated with apnea in detail.

GI SYMPTOMS

Common GI symptoms that bring neonates to the ED include feeding difficulties, gastroesophageal reflux, vomiting, blood in the diaper, diarrhea and dehydration, abdominal distension, and constipation.

Feeding Difficulties

Most visits for feeding difficulties occur because parents perceive that the infant's food intake is inadequate; normal feeding and benign feeding problems are discussed earlier (see "Normal Neonatal Vegetative Functions"). Rarely, anatomic abnormalities may cause difficulty in feeding and swallowing. A careful history usually pinpoints such difficulties as having started at birth, and these infants appear malnourished and dehydrated. Potential causes include upper GI abnormalities (e.g., stenoses, strictures, laryngeal clefts, or cleft palate) and compression of the esophagus or trachea by a double aortic arch. Infants with a recent decrease in intake usually have acute illness, most often infectious, and should be evaluated urgently.

Regurgitation and Gastroesophageal Reflux

Regurgitation of small amounts of milk or formula is common in neonates due to reduced lower esophageal sphincter pressure and relatively increased intragastric pressure. Regurgitation is independent of effort or muscular contraction and likely represents the ultimate degree of GI reflux. Parents may confuse regurgitation with vomiting. As long as the neonate is gaining weight, parents can be reassured that regurgitation is of no clinical significance and will decrease as the infant grows. Strategies to reduce reflux include thickening of feeds and upright feeding positioning. Infants who are not thriving or have respiratory symptoms related to feeding should be investigated for anatomic causes of regurgitation or chronic aspiration.

Regurgitation rarely results from pathologic processes, such as intrinsic compression of the esophagus or, occasionally, compression of the trachea, in which case it is usually accompanied by stridor and cough. Dysphagia, irritability, feeding aversion, anemia, and malnutrition are sequelae of chronic regurgitation with esophagitis, but this condition is rare. Investigations such as pH monitoring, endoscopy, and biopsy confirm the diagnosis of reflux esophagitis.

Vomiting

Vomiting results from forceful contraction of the diaphragm and abdominal muscles. A detailed discussion of vomiting in childhood is provided in chapter 128, Vomiting, Diarrhea, and Dehydration in Children, while surgical conditions that present with vomiting are discussed in chapter 130, Acute Abdominal Pain in Children; those specific to the neonatal period are briefly discussed here.

Vomiting beginning at birth is most likely due to an anatomic abnormality, such as tracheoesophageal fistula (with esophageal atresia), upper GI obstruction (e.g., duodenal atresia, which has a higher incidence among Down's infants), or midgut malrotation. Vomiting may be a symptom unrelated to the GI tract, such as increased intracranial pressure, metabolic disorders, or infections (e.g., sepsis, urinary tract infections, and gastroenteritis).

Pyloric Stenosis

Projectile vomiting is usually seen in infants with pyloric stenosis and may assume its characteristic pattern, projectile vomiting at the end of feeding or shortly thereafter, after the second and third weeks of life. Pyloric stenosis classically presents between 6 weeks and 6 months of age and is the most common surgically correctible cause of vomiting in newborns. The vomitus does not contain bile or blood, and typically the infant appears well with an increased appetite. Perform an abdominal examination with the infant relaxed and the stomach empty. Observe for prominent gastric waves progressing from left to right. Palpate for a firm olive-shaped mass under the liver edge. Observe the neonate feeding to confirm projectile vomiting and distinguish this from regurgitation. Definitive diagnosis is most commonly made with ultrasound examination of the pyloric length and diameter, although barium studies may also make the diagnosis.⁸

The well-appearing infant without dehydration, malnutrition, or electrolyte abnormalities can be discharged with a plan for outpatient surgical correction. Admit ill-appearing or dehydrated infants.

Other Surgical Causes of GI Complaints

Emergent surgical causes of vomiting in the neonate include malrotation with volvulus, intussusception, necrotizing enterocolitis, and incarcerated hernia, all of which are discussed in chapter 130.⁸

Blood in the Diaper

Parents may come to the ED complaining of blood in the neonate's diaper. Several important distinctions must be made: first, confirm that the discoloration is blood by testing with a guaiac card if possible; it is not uncommon in the neonatal period to find urinary crystals that may cause an orange or red discoloration in the diaper that can be mistaken for blood. If blood is confirmed, the next important distinction is whether the origin is the GI tract or, in girls, the vagina. Bloody or mucous discharge is common and normal in female neonates due to withdrawal from placental estrogen. Physical examination may reveal a small anal fissure as the source of bleeding. In the first 2 to 3 days of life, blood in the diaper is most commonly due to maternal blood that is swallowed during delivery. This possibility may be confirmed by the Kleihauer-Betke or Apt-Downey test, performed on a stool sample or scraped from the diaper if possible, which differentiates fetal from maternal hemoglobin in the stool. After the first few days of life, most causes of blood in the diaper are idiopathic, but consider coagulopathies, necrotizing enterocolitis, allergic or infectious colitis, and congenital defects. Cow's milk allergy is an immunoglobulin E–mediated disorder, but most infants have cow's milk protein intolerance rather than true allergy. Both conditions cause changes in the bowel mucosa that result in gassy, bloody, and mucous bowel movements; painful feeds; and worsened reflux. Eosinophils may be present in the stool, and the diagnosis may be confirmed by resolution of the problem after cow's milk is removed from the diet. For unresponsive or severe cases, endoscopy and biopsy may be needed for diagnosis. A newborn with a single event of hematochezia and no concerning findings may be observed as an outpatient. Persistent symptoms or concerning exam findings should be further evaluated, and depending on the infant's condition (hydration status and weight gain), admission with appropriate subspecialty care may be necessary (see chapter 131, Gastrointestinal Bleeding in Infants and Children).

Diarrhea and Dehydration

Diarrhea and dehydration are discussed in detail in chapter 128, and fluid and electrolyte therapy in chapter 129, Fluid and Electrolyte Therapy in Infants and Children. Diarrhea is abnormally frequent and liquid stools (Table 114-1). The modifier abnormal is critical because stools can normally be frequent and liquid in young children. Consider infection in addition to feeding-related causes, although infectious diarrhea is predominantly seen in older infants in the United States. Neonates are particularly susceptible to dehydration and electrolyte abnormalities associated with severe diarrhea. In an infant, the normal extracellular fluid volume is 25% of body weight; therefore, a loss of 8% of body weight as extracellular fluid results in severe dehydration.

Weigh all neonates with diarrhea unclothed to allow comparison with previous weights and to provide a baseline for monitoring subsequent weights during the course of the disease. Start the physical examination with a general assessment of mental status and hydration (see Table 129-2).⁹ Document rectal temperature, pulse, and blood pressure, which provide additional information concerning the degree of illness. Consider rectal examination to look for anal fissures as a potential source of blood, and obtain a stool sample for detection of occult blood, culture, examination for leukocytes, measurement of pH, and detection of reducing substances.

Obtain serum electrolytes, particularly sodium and glucose, in all neonates with diarrhea and dehydration. Markedly elevated serum urea nitrogen with a relatively normal creatinine may indicate recent or rapid dehydration. Serum creatinine values tend to be low in infants and young children, and a creatinine value of 1 milligram/dL may represent a doubling in the normal value. In addition to stool testing as above, obtain a urine sample in the setting of fever to evaluate for urinary tract infection.

Admit most newborns with ongoing GI losses to the hospital for rehydration, since the loss of even seemingly small volumes of stool may cause severe dehydration in the neonate. Diarrhea, particularly when bloody or containing mucus, may be a symptom of a more severe surgical abdominal process, such as volvulus, intussusception, or necrotizing enterocolitis, although all three of these conditions typically present with vomiting as well.

Abdominal Distention

Abdominal distention may be normal in neonates and is usually due to lax abdominal musculature, relatively large intra-abdominal organs, and distension from swallowed air. If the infant is comforTable and feeding well and the abdomen is soft, there is no need for concern. Abdominal distention may also occur in association with bowel obstruction, constipation, necrotizing enterocolitis, or ileus due to sepsis or gastroenteritis. Congenital organomegaly (e.g., hepatomegaly, splenomegaly, or renal enlargement) undetected in the perinatal period also may cause abdominal distention.

Constipation

Infrequent bowel movements in neonates do not necessarily mean that the infant is constipated. Infants occasionally may go without a bowel movement for 5 to 7 days and then pass a normal stool. However, if the neonate has never passed stools, especially if there has not been a stool in the first 48 hours of life, consider intestinal stenosis, Hirschsprung's disease, or meconium ileus associated with cystic fibrosis. Constipation occurring after birth but within the first month of life suggests Hirschsprung's disease, hypothyroidism, anal stenosis, or an anteriorly displaced anus. Correct anatomic positioning of the anus is determined by measuring the distance between the gluteal cleft and the posterior fourchette in girls or the median raphe in boys. The anus should be no more anterior than two thirds of this distance. Neonates with constipation should have a careful evaluation of the lumbosacral spine for evidence of occult dysraphism, which may be associated with neurogenic bowel or bladder. The diagnosis of Hirschsprung's disease is supported by absence of feces on rectal examination, a tonic or tight sphincter tone, and an abrupt change in bowel luminal size on barium enema, and is confirmed by a rectal biopsy demonstrating absence of ganglion cells. Infants with hypothyroidism present with constipation, feeding problems, a weak or hoarse cry, a large anterior fontanelle, hypothermia, hypotonia, and peripheral edema. Thyroid testing as part of the routine newborn metabolic screen varies from state to state in the United States.

JAUNDICE (HYPERBILIRUBINEMIA)

Jaundice signifies hyperbilirubinemia and can represent normal newborn physiology or a pathologic process. Bilirubin is a breakdown product of hemoglobin that is conjugated in the liver by glucuronyl transferase before it is excreted with bile into the GI tract. Once bilirubin reaches the intestinal lumen, brush border enzymes deconjugate some of the bilirubin, which is then reabsorbed through enterohepatic circulation. The remainder of the bilirubin is either oxidized by intestinal bacteria to urobilinogen (which is excreted in the urine) or passed in the feces, creating the normal yellow color of neonatal stool. Physiologic jaundice is characterized by a slow rise in bilirubin (<5 milligrams/dL per 24 hours), with a peak of 5 to 6 milligrams/dL during the second to the fourth days of life and a decrease to <2 milligrams/dL by 5 to 7 days. Decreased neonatal hepatic glucuronyl transferase activity, a shortened life span of neonatal red blood cells and relative polycythemia, and decreased intestinal bacterial colonization all lead to an increase in enterohepatic circulation that produces the normal rise in bilirubin seen in physiologic jaundice. Other processes, both benign and pathologic, often cause bilirubin levels that are significantly higher than 6 milligrams/dL, and excessive hyperbilirubinemia can lead to permanent brain injury—kernicterus. Practice parameters for the evaluation and treatment of neonatal jaundice are summarized in Table 114-6.¹⁰

Distinguishing between physiologic and pathologic neonatal jaundice is important, and the timing of the onset of jaundice in the newborn provides useful clues. Table 114-7 lists various causes of hyperbilirubinemia in the neonate and their timing.

The evaluation of the jaundiced neonate begins with a thorough history, including maternal infections during pregnancy; maternal blood type and RhoGAM^® administration; estimated gestational age (i.e., term or preterm); feeding patterns, including formula or breast milk, frequency, duration, and whether maternal milk supply is adequate and latching successful; stool history, including timing of first stool and transitional stools, color (yellow, acholic), and frequency; regurgitation or vomiting; urine output; and documented fever. A family history of hemolytic anemia or prior neonatal jaundice might indicate an inherited disorder. Review maternal and fetal medications. When possible, obtain results of the infant's blood type and maternal antibody screen.

On physical examination, note the degree of jaundice, which progresses in a cephalocaudal direction, although the level of jaundice does not reproducibly correlate with serum bilirubin levels. Scleral icterus is typically noted with serum bilirubin >5 milligrams/dL. Examine the head for cephalohematoma and assess the fontanelles for signs of dehydration or possible infection. Palpate the abdomen for organomegaly that might signify congenital infection or liver disease.

It is important to distinguish unconjugated hyperbilirubinemia from conjugated hyperbilirubinemia. Unconjugated hyperbilirubinemia is much more common, presents earlier in the neonatal period, and is related to the normal or abnormal breakdown of hemoglobin, although inherited enzyme deficiencies or infection may be pathologic causes. Conjugated hyperbilirubinemia results from the inability to excrete bilirubin into the bile and intestines and is usually the result of primary hepatic or biliary disease such as biliary atresia or hepatitis. Conjugated hyperbilirubinemia is always pathologic and often presents later in the neonatal period with jaundice, acholic stools, and dark urine.

At a minimum, laboratory studies for the jaundiced neonate should include a direct and indirect bilirubin. Transcutaneous bilirubin measurement correlates fairly well with total serum levels but does not distinguish conjugated and unconjugated bilirubin. Transcutaneous measurement is thus limited to very low-risk neonates with a normal physical examination.^11,12 When other pathologic conditions are suspected, the evaluation should be determined by the differential diagnosis and may include a CBC for anemia and red cell indices, a blood smear for hemolysis, reticulocyte count, and liver function tests. When infection is a concern, obtain appropriate cultures and Gram stains (urine, cerebrospinal fluid).

Septic infants with hyperbilirubinemia may have an increase in bilirubin by greater than the accepTable 5 milligrams/dL per 24-hour period and have other features of sepsis, such as vomiting, abdominal distention, respiratory distress, and poor feeding. Breast milk jaundice is thought to be due to the presence of substances that inhibit glucuronyl transferase in the breast milk; it may start as early as the third to fourth day and reaches a peak of 10 to 27 milligrams/dL by the third week of life. Although cessation of breastfeeding will result in a rapid decline of bilirubin over 2 to 3 days, it is not routinely recommended. Breast milk jaundice is unlikely to cause kernicterus and usually can be treated with phototherapy, when necessary. This should be distinguished from breastfeeding jaundice, or starvation jaundice, which can occur when a newborn is exclusively breastfed and the mother's milk supply is still inadequate. Poor oral intake resulting in reduced bowel movement and bilirubin excretion through the GI tract, coupled with relative dehydration, may accentuate physiologic jaundice. Optimizing the neonate's feeding pattern with controlled supplementation, whether with expressed breast milk, donated breast milk, or formula, usually resolves the problem, but severe hyperbilirubinemia may require treatment.

The treatment of hyperbilirubinemia depends on the cause, but for most cases of unconjugated hyperbilirubinemia, phototherapy is sufficient. Phototherapy causes a configurational change in the bilirubin structure that allows it to be excreted in the urine. There is no additional benefit to IV fluids coupled with phototherapy, so enteral feeding should always be encouraged, although the dehydrated infant may require fluid resuscitation. Extreme levels of hyperbilirubinemia are treated emergently with exchange transfusion and require admission to hospital.

Risk factors include hemolysis risks (e.g., isoimmune hemolytic disease, glucose-6-phosphate dehydrogenase deficiency, ABO incompatibility), sepsis (lethargy, temperature instability, irritability), asphyxia, hypoalbuminemia, and acidosis. In the first 24 hours of life, response to phototherapy is less predictable, and specific exchange transfusion indications are less certain during this period.

EYE COMPLAINTS

Watery Eyes

Clear eye discharge, and occasionally crusting over of the eyelashes without associated conjunctival redness or irritation, is commonly seen in neonates and infants and results from narrow or obstructed nasolacrimal ducts. This condition usually resolves spontaneously and requires antibiotics only when complicated by conjunctival erythema and inflammation (conjunctivitis or dacryocystitis). Ophthalmologic consultation for nasolacrimal duct probing is appropriate if this problem persists past 12 months of age or earlier if complicated by recurrent infection.

Red Eye and Irritation

Corneal irritation or abrasion can result from an eyelash or scratch from a fingernail. Perform fluorescein staining and evaluate with a Wood's lamp or a hand-held slit lamp to identify corneal abrasions. Acute glaucoma, although rare, also presents as a red, teary eye. The cornea is cloudy, the anterior chamber is shallow, and the intraocular pressure may be increased. Promptly consult pediatric ophthalmology for all suspected cases of glaucoma.

Red Eye and Discharge

Conjunctivitis is described in detail in chapter 119, Eye Emergencies in Infants and Children. The most common causes of neonatal conjunctivitis are chemical irritation, bacterial or chlamydial infection, and herpes simplex infection. Chemical conjunctivitis due to ocular prophylaxis usually occurs on the first day of life and requires no treatment.

Gonococcal conjunctivitis generally has its peak time of onset between 3 and 5 days after birth. Despite antibiotic prophylaxis at delivery, the failure rate of prophylaxis is about 1%. Neisseria gonorrhoeae invades superficial layers of the conjunctiva and, if untreated, causes corneal ulceration and can result in permanent loss of vision. For diagnosis, obtain a Gram stain and culture for N. gonorrhoeae. Treat gonococcal conjunctivitis with cefotaxime (50 milligrams/kg IV or IM). Cefotaxime is recommended for neonates, as ceftriaxone can displace bound bilirubin and precipitate kernicterus. Perform septic workup including lumbar puncture. Disseminated disease should be suspected until CSF cultures are negative. Supportive care includes ocular irrigation with normal saline as soon as diagnosis is suspected, with frequent irrigation until the discharge is eliminated. Admit the neonate and obtain ophthalmology consultation. Topical antibiotic treatment alone is inadequate and unnecessary when systemic antibiotic treatment is given.

Chlamydial conjunctivitis becomes evident by the end of the first week throughout the first month after birth. The disorder varies in severity, from mild to severe hyperemia with a thick, profuse mucopurulent discharge and pseudomembrane formation. There often is severe edema of both lids. Because isolation of Chlamydia trachomatis requires specialized tissue cultures, assure proper technique in collecting culture specimens (e.g., Dacron swabs) and specimens for antigen detection.

Treat chlamydial conjunctivitis and pneumonia in neonates with oral erythromycin (50 milligrams/kg PO per day in four divided doses, for 14 days). Oral sulfonamides may be used after the immediate neonatal period for infants who do not tolerate erythromycin. Topical treatment is unnecessary. Because the efficacy of erythromycin therapy is approximately 80%, a second course is sometimes required. A specific diagnosis of C. trachomatis infection in an infant should prompt the treatment of the mother and her sexual partners.

The finding of vesicles anywhere on the skin or mucous membranes in association with neonatal conjunctivitis suggests herpes simplex infection and warrants a full sepsis evaluation with cerebrospinal fluid evaluation for herpes simplex virus and treatment with acyclovir, 20 milligrams/kg/dose three times a day.

ABNORMAL MOVEMENTS AND SEIZURES

Seizures are covered in detail in chapter 135, Seizures in Infants and Children. It is important to distinguish benign sleep myoclonus in infancy and the normal startle reflex from actual seizures. Sleep myoclonus consists of rhythmic myoclonic jerks observed when the infant is drowsy or in quiet sleep and can be suppressed upon touching and/or waking the infant; the startle reflex is a single myoclonic jerk with extension of the arms and legs triggered by noise or tactile stimulation. Tetany due to hypocalcemia is associated with congenital syndromes, such as DiGeorge's syndrome, and must also be distinguished from seizure activity. Recognition of seizures in the newborn period is important, because seizure management and outcome are different than at any other age. Neonatal seizures are likely to present with subtle manifestations, such as eye deviation, tongue thrusting, eyelid fluttering, apnea, pedaling movements, or arching, rather than generalized activity. Neonatal seizures usually indicate a severe underlying structural or metabolic problem and are rarely idiopathic.

Acknowledgment: The authors gratefully acknowledge the contributions of Tonia J. Brousseau, the lead author of this chapter in the previous edition.