Chapter 92 Clinical Manifestations of Diseases in the Newborn Period

The wide varieties of disorders that affect the newborn originate in utero, during birth, or in the immediate postnatal period. These disorders may be due to prematurity, genetic mutations, chromosomal aberrations, or acquired diseases and injuries. Recognizing disease in newborn infants depends on knowledge of the disorder and evaluation of a limited number of relatively nonspecific clinical signs and symptoms.

Central cyanosis has respiratory, cardiac, central nervous system (CNS), hematologic, and metabolic causes (Table 92-1). Respiratory insufficiency may be due to pulmonary conditions or may be secondary to CNS depression from drugs, intracranial hemorrhage, or anoxia. If respiratory insufficiency is caused by pulmonary conditions, respirations tend to be rapid and may be accompanied by retraction of the thoracic cage. If it is due to the CNS depression, respirations tend to be irregular and weak and are often slow. Cyanosis unaccompanied by obvious signs of respiratory difficulty suggests cyanotic congenital heart disease or methemoglobinemia. Cyanosis resulting from congenital heart disease may, however, be difficult to distinguish clinically from cyanosis caused by respiratory disease. Episodes of cyanosis may also be the initial sign of hypoglycemia, bacteremia, meningitis, shock, or pulmonary hypertension. Peripheral acrocyanosis is common in neonates and does not usually warrant concern unless poor perfusion is suspected.

Pallor, in addition to anemia or acute hemorrhage, should suggest hypoxia, asphyxia, hypoglycemia, sepsis, shock, or adrenal failure.

Hypotension in term infants suggests shock from hypovolemia (hemorrhage, dehydration), the systemic inflammatory response syndrome (bacterial sepsis, intrauterine infection, necrotizing enterocolitis), cardiac dysfunction (left heart obstructive lesions—hypoplastic left heart syndrome, myocarditis, asphyxia-induced myocardial stunning, anomalous coronary artery), pneumothorax, pneumopericardium, pericardial effusion, or metabolic disorders (hypoglycemia, adrenal insufficiency–salt-losing adrenogenital syndrome). Hypotension is a common problem in sick preterm infants and may also be due to any of the problems noted in a term infant. Hypotension may develop in preterm infants with severe respiratory distress syndrome. Strategies used to support blood pressure include volume expansion (normal saline is equally as effective as 5% albumin), pressors (dopamine, dobutamine, epinephrine), and corticosteroids. Hypotension in some infants weighing <1,000 g does not respond to fluids or inotropic agents but may respond to therapy with intravenous hydrocortisone. Sudden onset of hypotension in a very low birthweight (VLBW) infant suggests pneumothorax, intraventricular hemorrhage, or subcapsular hepatic hematoma.

Convulsions (Chapter 586.7) usually point to a disorder of the CNS and suggest hypoxic-ischemic encephalopathy, intracranial hemorrhage, cerebral anomaly, subdural effusion, meningitis, hypocalcemia, hypoglycemia, cerebral infarction, benign familial seizures, or, rarely, pyridoxine dependence, hyponatremia, hypernatremia, inborn errors of metabolism, or drug withdrawal. Seizures beginning in the delivery room or shortly thereafter may be due to the unintentional injection of maternal local anesthetic into the fetus. Convulsions may also result from hyponatremia and water intoxication in the infant after the administration of large amounts of hypotonic fluid to the mother shortly before and during delivery.

Convulsions should be distinguished from the jitteriness that may be present in normal newborns, in infants of diabetic mothers, in those who experienced birth asphyxia or drug withdrawal, and in polycythemic neonates. An examiner may stop the jitteriness resembling simple tremors by holding the infant’s extremity; this jitteriness often depends on sensory stimuli and occurs when the infant is active, and it is not associated with abnormal eye movements. Tremors are often more rapid with a smaller amplitude than those of tonic-clonic seizures. Seizures in premature infants are often subtle and associated with abnormal eye (fluttering, deviation, stare) or facial (chewing, tongue thrusting) movements; the motor component is often that of tonic extension of the limbs, neck, and trunk. Term infants may have focal or multifocal, clonic or myoclonic movements, but they may also have more subtle seizure activity. Apnea may be the 1st manifestation of seizure activity, particularly in a premature infant. Seizures may adversely affect the subsequent neurodevelopmental outcome and may even predispose an infant to non-neonatal seizures. Seizures should be treated aggressively.

After severe birth asphyxia, infants may have motor automatisms characterized by oral-buccal-lingual movements, rotary limb activities (rowing, pedaling, swimming), tonic posturing, or myoclonus. These motor activities are not usually accompanied by time-synchronized electroencephalographic discharges, may not signify cortical epileptic activity, respond poorly to anticonvulsant therapy, and are associated with a poor prognosis. Such automatisms may represent cortical depression that produces a brainstem release phenomenon or subcortical seizures.

Lethargy may be a manifestation of infection, asphyxia, hypoglycemia, hypercapnia, sedation from maternal analgesia or anesthesia, a cerebral defect, or, indeed, almost any severe disease, including an inborn error of metabolism. Lethargy appearing after the 2nd day should, in particular, suggest infection. Lethargy with emesis suggests increased intracranial pressure or an inborn error of metabolism.

Irritability may be a sign of discomfort accompanying intra-abdominal conditions, meningeal irritation, drug withdrawal, infections, congenital glaucoma, or any condition producing pain. As in later infancy, the eardrums should always be examined as a possible source of pain. Hyperactivity, especially in a premature infant, may be a sign of hypoxia, pneumothorax, emphysema, hypoglycemia, hypocalcemia, CNS damage, drug withdrawal, neonatal thyrotoxicosis, bronchospasm, esophageal reflux, or discomfort from a cold environment.

Failure to feed well is seen in most sick newborn infants and should lead a careful search for infection, a central or peripheral nervous system disorder, intestinal obstruction, and other abnormal conditions.

Fever may be the result of too high an environmental temperature because of weather, overheated nurseries or incubators/radiant warmers, or too many clothes. It is also noted in “dehydration fever” of newborn infants. If these causes of fever can be eliminated, serious infection (pneumonia, bacteremia, meningitis, and viral infections, particularly herpes simplex or enteroviruses) must be considered, although such infections often occur without provoking a febrile response in newborn infants (Chapters 169 and 170). Unexplained hypothermia may accompany infection or other serious disturbances of the circulation or CNS. A sudden servocontrolled increase in incubator ambient temperature to maintain body temperature is a sign of temperature instability and may be associated with sepsis or any of the conditions already mentioned.

Periods of apnea, particularly in premature infants, may be associated with various disturbances (Chapter 95.2). When apnea recurs or when the intervals are longer than 20 sec or are associated with cyanosis or bradycardia, an immediate diagnostic evaluation is needed.

Jaundice during the 1st 24 hr of life warrants diagnostic evaluation and should be considered to be due to hemolysis until proven otherwise. Septicemia and intrauterine infections such as syphilis, cytomegalovirus, and toxoplasmosis should also be considered, especially in infants with an increase in direct bilirubin value.

Jaundice after the 1st 24 hr may be “physiologic” or may be due to septicemia, hemolytic anemia, galactosemia, hepatitis, congenital atresia of the bile ducts, inspissated bile syndrome after erythroblastosis fetalis, syphilis, herpes simplex, other congenital infections, or other conditions (Chapter 96.3).

Vomiting during the 1st day of life suggests obstruction in the upper digestive tract or increased intracranial pressure. Roentgenographic studies are indicated when obstruction is suspected. Vomiting may also be a nonspecific symptom of an illness such as septicemia. It is a common manifestation of overfeeding, inexperienced feeding technique, or normal reflux and is rarely due to pyloric stenosis, milk allergy, duodenal ulcer, stress ulcer, an inborn error of metabolism (hyperammonemia, metabolic acidosis), or adrenal insufficiency. Vomitus containing dark blood is usually a sign of a serious illness; the benign possibility of swallowed maternal blood should also be considered. Bile-stained vomitus strongly suggests obstruction below the ampulla of Vater and warrants contrast-enhanced radiography in many cases.

Diarrhea may be a symptom of overfeeding (especially high–caloric density formula), acute gastroenteritis, or malabsorption, or it may be a nonspecific symptom of infection. Diarrhea may occur in conditions accompanied by compromised circulation of part of the intestinal or genital tract, such as mesenteric thrombosis, necrotizing enterocolitis, strangulated hernia, intussusception, and torsion of the ovary or testis.

Abdominal distention, usually a sign of intestinal obstruction or an intra-abdominal mass, may also be seen in infants with enteritis, necrotizing enterocolitis, isolated intestinal perforation, ileus accompanying sepsis, respiratory distress, ascites, or hypokalemia.

Failure to move an extremity (pseudoparalysis) suggests fracture, dislocation, or nerve injury. It is also seen in osteomyelitis and other infections that cause pain on movement of the affected part.

Pain in neonates may be unrecognized and/or undertreated. The intensive care of neonates may involve a number of painful procedures, including blood sampling (heelstick, venous or arterial puncture), endotracheal intubation and suctioning, mechanical ventilation, and insertion of chest tubes and intravascular catheters. Pain in neonates results in obvious distress and acute physiologic stress responses, which may have developmental implications for pain in later life. Moreover, the knowledge that infants may experience pain contributes to the stress of parents of sick newborns.

Pain and discomfort are potentially avoidable problems during the treatment of sick infants. Preemptive relief from painful stimuli should be provided before pain or anxiety develops. The most frequently used drugs are intermittent or continuous doses of opioids (morphine, fentanyl) and benzodiazepines (midazolam, lorazepam). Although the long-term effects of opioids and sedatives are not well established, the 1st concern should be the treatment and/or prevention of acute pain. Continuous opiate infusions should be used with caution. Some minor but painful procedures performed in well neonates can be managed with oral sucrose solutions (Table 92-2).

Table 92-2 PAIN IN THE NEONATE: GENERAL CONSIDERATIONS

Adapted from Prevention and management of pain and stress in the neonate: American Academy of Pediatrics. Committee on Fetus and Newborn. Committee on Drugs. Section on Anesthesiology. Section on Surgery. Canadian Paediatric Society. Fetus and Newborn Committee, Pediatrics 105:454–461, 2000; and Anand KJS; International Evidence-Based Group for Neonatal Pain: Consensus statement for the prevention and management of pain in the newborn, Arch Pediatr Adolesc Med 155:173–180, 2001.

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