19: Follow-Up of High-Risk Infants

Whenever an infant requires neonatal intensive care, concerns about survival are followed by concerns about the infant's quality of life. Follow-up clinics are a necessary adjunct to neonatal intensive care because they provide feedback regarding the child's ongoing health and development to families, pediatricians, neonatologists, and obstetricians. For families, neonatal intensive care unit (NICU) follow-up clinics provide the support and advice they need following NICU discharge.

1. Early identification of neurodevelopmental disability. These infants need comprehensive neurodevelopmental evaluations and appropriate community services.

2. Assessment of a child's need for early interventions. Although NICUs refer many infants directly to community early intervention programs, children's needs change with neuromaturation, requiring periodic review.

3. Parent counseling. Reassurance that their child is making good neurodevelopmental progress is always welcome, as this is a time of high anxiety for parents. Parents of children with developmental delay need realistic information about its significance, and advice about needed evaluations and interventions. Parents need to know as soon as possible if their child is demonstrating signs of neurodevelopmental impairment. A comprehensive evaluation can provide them with essential information. Physical and occupational therapists provide valuable suggestions regarding positioning, handling, and feeding infants. Even if their infant does well, parents of high-risk infants should be warned about early signs of school or behavior problems.

4. Identification and treatment of medical complications that were not recognized or anticipated at the time of discharge from the NICU.

5. Referral for comprehensive evaluations and community services as indicated.

6. Feedback for neonatologists, pediatricians, obstetricians, pediatric surgeons, and others regarding neurodevelopmental outcomes, ongoing medical problems, and unusual or unforeseen complications in these infants is essential.

Pediatricians, neurodevelopmental pediatricians, and neonatologists make up the regular staff of the clinic, and many clinics include neuropsychologists and physical, occupational, and/or speech and language therapists. In addition, some infants may need referrals to audiologists, ophthalmologists, neuropsychologists, social workers, respiratory therapists, nutritionists, gastroenterologists, orthopedic surgeons, or other subspecialists.

It is virtually impossible to diagnose developmental disability with certainty in the neonatal period, but a number of perinatal risk factors have been identified for selecting high-risk infants for close follow-up.

1. Preterm birth. The risks of cerebral palsy and intellectual disability increase with decreasing gestational age. Risk of disability, especially cognitive impairments, is highest in survivors born at the limit of viability (at or before 25 weeks' gestation). Children born preterm have higher rates of language disorders, visual perception problems, minor neuromotor dysfunction, attention deficits, executive dysfunction, and learning disabilities than full-term controls. Although most do well, children born at 33–36 weeks' gestation have higher rates of cognitive impairments, cerebral palsy, and school problems than children born full term. Besides gestational age, predictors of neurodevelopmental disability include poor growth (especially head growth), asphyxia, sepsis (especially meningitis), chronic lung disease, and retinopathy of prematurity. Risk is highest in infants with signs of brain injury on neonatal neurodevelopmental examination and neuroimaging studies (see Chapter 16).

2. Intrauterine growth restriction (IUGR). Full-term infants who are small for gestational age (SGA) have a higher risk of motor or cognitive impairments, attention deficits, specific learning disability, and school and behavior problems than appropriate for gestational age (AGA) infants. The etiology and severity of their IUGR, timing of the insult, and subsequent perinatal complications (eg, asphyxia, hypoglycemia, or polycythemia) influence their degree of risk (see Chapter 105). After 30 weeks' gestation, compensatory mechanisms for adverse intrauterine circumstances include accelerated maturation to improve survival if born preterm. Adverse intrauterine circumstances, preterm birth, and accelerated neuromaturation can adversely influence neurodevelopmental, especially cognitive, outcomes in preterm SGA infants.

3. Neonatal encephalopathy (NE). Neonatal encephalopathy is a clinical syndrome characterized by a constellation of findings, including seizures and abnormalities of consciousness, muscle tone, reflexes, respiratory control, and feeding. Etiologies include infection, inflammation, metabolic errors, drug exposures, brain malformations, stroke, hypoxia, ischemia, or any combination of these conditions. Etiology, severity of clinical symptoms, abnormal electroencephalogram (EEG) pattern (especially low voltage or burst-suppression patterns), and patterns of brain injury (eg, injury to the basal ganglia and thalamus) are much stronger predictors of neurodevelopmental disability than signs of fetal distress, cord pH, or Apgar scores. Infants with mild or moderate NE who do not develop major disability are at risk for more subtle disorders, including attention deficit, learning disability, and other school problems. Infants with severe NE have a high mortality rate; many of the survivors have severe, multiple disabilities, including intellectual disability, spastic quadriplegia, microcephaly, seizures, and sensory impairment. Treatment of infants with moderate to severe NE with hypothermia improves neurodevelopmental outcomes.

4. Respiratory failure. Some late preterm and full-term infants develop respiratory failure that can be due to pulmonary hypoplasia, pneumonia, meconium aspiration, or persistent pulmonary hypertension. Outcome studies for randomized controlled trials of treatments for severe respiratory failure (eg, inhaled nitric oxide, ECMO/ECLS) report cognitive impairment in up to one-quarter of survivors, cerebral palsy in up to 15%, and hearing impairment in up to 30%. When followed to school age, many have problems with attention deficit, specific learning disability, minor neuromotor dysfunction, and behavior problems. Health sequelae include poor growth and reactive airway disease. Some survivors have demonstrated progressive hearing loss, so these children need serial hearing assessments.

5. Infection and/or inflammation. Maternal, fetal, and neonatal infection or inflammation has been implicated as etiologies of preterm birth, brain injury (eg, white matter injury), cerebral palsy, and cognitive impairments.

6. Other risk factors

   1. Congenital infections (TORCH— t oxoplasmosis, o ther, r ubella, c ytomegalovirus, and h erpes simplex virus). Infants with congenital cytomegalovirus infection, toxoplasmosis, or rubella who are symptomatic at birth have a high incidence (60–90%) of neurodevelopmental disability. Asymptomatic infants are at risk for sensory impairment and learning disability.

   2. In utero exposures. Maternal drugs reported to influence fetal development include narcotics, cocaine, alcohol, phenytoin, trimethadione, valproate, warfarin, aminopterin, and retinoic acid. There are concerns that environmental toxicants influence preterm birth and fetal development.

Communicating about preterm outcomes entails consistent definitions.

1. Gestational age. Time between mother's first day of the last menstrual cycle to birth.

2. Postmenstrual age (PMA). Infant's gestational age (GA) plus chronological age (from birth).

3. Corrected age. Calculated from the infant's due date, the infant's age corrected for degree of prematurity (ie, chronological age minus number of weeks born preterm).

4. Use PMA for preterm infants in an NICU and corrected age for preterm follow-up.

1. Growth (height, weight, head circumference, weight for height). Should be assessed at each follow-up visit. Poor head growth is associated with lower cognitive scores. Most preterm infants “catch up” in growth, but some infants with IUGR, extremely preterm birth, chronic lung disease, or short gut syndrome remain smaller than their peers.

2. Blood pressure. High blood pressure (BP) is a serious NICU sequelae; monitor BP.

3. Breathing disorders

   1. Apnea. For infants discharged home on monitors, there is often uncertainty as to when to discontinue the monitor.

   2. Chronic lung disease. Infants with chronic lung disease have higher rates of respiratory infections, reactive airway disease, rehospitalization, and neurodevelopmental disability. Those on supplemental oxygen, monitors, diuretics, and other medications need subspecialty follow-up and protection from secondhand smoke. Anticipatory guidance against ever smoking themselves is essential.

4. Hearing. Hearing is essential for language acquisition, so it should be identified as early as possible. Before hospital discharge, all neonates should have their hearing screened (eg, brainstem auditory evoked potentials, transient evoked otoacoustic emissions) and referred for a comprehensive audiologic evaluation if there are concerns. Hearing aids, cochlear implants, and other treatment strategies have had a profound effect on language acquisition. Infants who had congenital perinatal (eg, TORCH) infection, congenital malformations of the head or neck, persistent pulmonary hypertension, chronic otitis, a family history of hearing impairment, or a language delay warrant serial hearing assessments.

5. Vision. Retinopathy of prematurity (ROP) is a disease of the developing retina in preterm infants (see Chapter 126). Infants at risk for ROP need serial eye examinations until their retinas are fully vascularized. Ophthalmological examinations are also indicated in infants with congenital infection, congenital anomalies, and neonatal encephalopathy. All high-risk infants should have their visual acuity when 1–5 years old.

6. Neuromaturation (the functional development of the central nervous system [CNS]). A dynamic process; what is typical at one age is often abnormal at another age. Extremely preterm infants are hypotonic at birth and typically develop flexor tone, first in the legs then in the arms (eg, caudocephalad direction) as they approach term. Typical preterm infants at term and full-term infants have strong flexor tone (ie, flexor hypertonia), as well as a number of primitive (eg, Moro) and pathological (eg, Babinski) reflexes. In the months following term, emergence of higher cortical control suppresses flexor tone and pathological and primitive reflexes. Examiners must know typical infant development and the significance of deviations from the norm.

7. Neurodevelopmental examination. Includes an assessment of posture, extremity and axial (neck and trunk) muscle tone, deep tendon reflexes, primitive reflexes, pathologic reflexes, postural reactions (eg, automatic movements needed to keep the body upright), and motor function.

8. Neuromotor abnormalities. Common in many high-risk infants during the first year, but they often resolve or become less prominent by 1–2 years. They persist and are accompanied by motor delay in infants who develop cerebral palsy. These infants should have a comprehensive multidisciplinary evaluation, as infants with cerebral palsy may have debilitating associated deficits. Infants with neuromotor abnormalities and mild or no motor delay have minor neuromotor dysfunction, which signifies increased risks of balance and coordination difficulties, learning disability, attention deficit, and behavior problems.

   1. Hypotonia (generalized or axial hypotonia) is common in preterm infants and infants with chronic lung disease.

   2. Hypertonia is most common at the ankles and hips. Persistent hypertonia (especially extensor) and hyperreflexia indicate spasticity. In preterm children, spastic diplegia (ie, of both lower extremities) is the most common type of cerebral palsy. Avoid standing activities until infants can pull up on furniture themselves.

   3. Asymmetry of function, tone, posture, or reflexes. Encourage parents to position infants in their crib so they will turn their head to each side. Some NICU infants develop such a strong head preference that they develop torticollis and plagiocephaly. Spastic hemiplegia is spasticity of an arm and ipsilateral leg.

   4. Neck, trunk, and lower extremity extensor hypertonia and shoulder retraction (ie, excessive arching, shoulders back) can interfere with head control, hand use, rolling, sitting, and getting in and out of a sitting position. Encourage families to hold and position infants with their head and shoulders in line with their body and to avoid standing activities until their children pull themselves up to stand against furniture.

   5. Fine motor dysfunction is difficulty using the hands for manipulating objects.

   6. Feeding problems. Tube-fed infants need oromotor stimulation programs to prevent oral aversion (eg, not tolerating anything in their mouth).

9. Cognitive development. Language and visual attention are early signs of cognitive development. Refer infants with language delay for a follow-up audiologic evaluation. Encourage families to talk and read to their infant, reinforce vocalizations, and, by 9–10 months, identify objects by name. Accuracy of cognitive assessments improves with age.

10. Developmental assessment. A number of standardized tests are available for developmental screening or assessment. Many of them are easy to learn and administer.

    1. Infant developmental milestones. History and observation of language, motor, and adaptive milestone attainment provides a quick overview of developmental progress.

    2. Standardized screening and assessment tests. A number of standardized tests are available, some for developmental screening, as well as comprehensive tests for developmental assessment.

Most agree that one should correct for degree of prematurity in preterm infants, but correcting beyond 2–3 years is controversial. The older a child, the less important correction is: by 5 years, arithmetically 3 months' difference (eg, 60 vs 57 months) matters little. Motor milestone attainment up to independent walking proceeds according to age corrected for degree of prematurity, but some data suggest correction influences cognitive scores in children born extremely preterm well beyond age 3.

Recognizing delay or disability is an indication for comprehensive evaluation of all areas of function. Brain damage is seldom focal and often diffuse. A comprehensive multidisciplinary evaluation recognizes areas of strength and helps develop strategies for intervention, provide realistic data for parent counseling, and identify community programs and resources.