Contents
Diagnoses and Conditions
Anemia of Prematurity
Characteristics
- Occurs during the normal developmental switch from fetal to adult hemoglobin synthesis.
- Immediately after birth, the increase in blood oxygen content results in the downregulation of erythropoietin.
- Once hemoglobin level decreases enough, tissue oxygen needs are greater than oxygen delivery, and erythropoietin production increases.
- Anemia is more profound and occurs earlier in premature infants due to:
- Blood loss from sampling.
- Short survival time of RBC's (40-60 days compared to adult 120 days, and term infant 60-80 days).
- Suboptimal erythropoietic response.
- Relatively more rapid rate of growth than in term infants.
- Usually reach nadir of 7-10 g/dL at 4-8 weeks of life.
- Normocytic, normochromic, hypoproliferative anemia.
- Premature infants may have lower iron stores despite iron supplementation; consider iron deficiency anemia as an etiology for persistent or progressive anemias.
Monitoring
- May check hematocrit and reticulocyte count periodically, but most babies can be managed by watching for symptoms (tachycardia, tachypnea, apnea and bradycardia, poor weight gain, oxygen requirement, diminished activity, pallor, poor feeding).
Treatment
- Healthy asymptomatic newborns will self correct, provided their iron intake is adequate.
- Transitional formulas and fortified breast milk provide approximately 2 mg/kg/day of iron.
- Iron administration before 10-14 weeks of age does not reduce the nadir, but iron is stored for later use.
- Full-term infants should receive 1 mg/kg/day of iron supplementation from age 4 months to 1 year.
- Premature or low-birthweight infants (<2500g) should receive 2 mg/kg/day from 2 months to 1 year (from iron enriched formula or 1 mL multi-vitamin with iron).
- No strong evidence to favor use of erythropoietin.
- Infants with significant respiratory disease or congenital heart disease may need a hematocrit maintained >40 gm%.
- Infants with a hematocrit <25 gm% and symptoms may require red blood cell transfusion.
- For infants requiring blood transfusion:
- [Insert contact information for appropriate specialist or department.]
- Order: PRBC, leukocyte poor, irradiated, CMV negative, 15 ml/kg.
- If the baby is very fluid sensitive (e.g., chronic lung disease), IV lasix 1 mg/kg immediately after transfusion may be indicated.
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Apnea of Prematurity
Characteristics
- Respiratory pause for at least 20 seconds, or a pause that is accompanied by bradycardia (heart rate <100 bpm), cyanosis, or pallor in an infant <37 weeks postmenstrual age (PMA).
- Types of apnea:
- Central: the respiratory center in the immature brain stem does not trigger inspiration; frequently responds to methylxanthine treatment.
- Obstructive: due to impaired tone of larynx/pharynx.
- Mixed: combination of the two; most common type found in neonates.
- Can persist for many weeks in very preterm infants, although resolution typically occurs by 37-43 weeks PMA (resolution tends to be later for extremely low-birthweight infants).
- Periodic breathing: recurrent sequences of pauses in respiration lasting 5-10 seconds, followed by 10-15 seconds of rapid breathing without bradycardia or other symptoms.
- Benign apnea: isolated apneas of 5-10 seconds, without bradycardia or color change; resolve spontaneously.
Home Treatment
- Most infants still having apnea are kept hospitalized; few may be discharged home.
- Methylxanthines: act primarily on the brainstem respiratory structures, producing a central stimulatory effect.
- Caffeine is most commonly used due to its broader therapeutic index and slower excretion rate than theophylline.
Cardiorespiratory Home Monitors
- Infants are generally monitored for a 5- to 7-day apnea-free period after discontinuing methylxanthine therapy before sending an infant home without a monitor.
- Home monitors are rarely indicated for the detection of apnea, because infants with immature respiratory systems are generally still hospitalized until they are no longer at risk for apnea of prematurity.
- Any home cardiorespiratory monitor used must have download capability.
- Monitoring may be prescribed for some preterm infants with an unusually prolonged course of recurrent, extreme apnea.
- Monitoring should be limited to approximately 43 weeks' PMA or after the cessation of extreme episodes, whichever comes last.
Additional Factors
- Preterm infants are known to be at higher risk for SIDS; high-risk period lasts up to 10 months.
- As "a causal relationship between prolonged apnea and SIDS has not been established," home cardiorespiratory monitoring should not be used to prevent SIDS (AAP Task Force on Prolonged Infantile Apnea, 2003).
- Premature infants beyond the immediate neonatal period can experience apnea following ketamine sedation or general anesthesia; they should have cardiorespiratory monitoring in hospital for 24 hours after surgery.
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Bronchopulmonary Dysplasia
Characteristics
- Need for supplemental oxygen at 36 weeks postmenstrual age, with radiographic changes on chest x-ray (bilateral, diffuse hazy lungs; interstitial thickening; increased lung inflation).
- Symptoms: tachypnea, increased work of breathing, chronic wheeze or cough, oxygen dependence, +/- ventilator dependence, hypercarbia with compensated respiratory acidosis.
- Course characterized by acute exacerbations of respiratory distress.
- Overall incidence is unchanged due to increased survival of extremely premature infants.(~7500 new cases/year) but is decreased with surfactant and early extubation to NCPAP.
- Risk factors: premature birth, respiratory failure, O2 supplementation, mechanical ventilation, air leaks, pulmonary edema, PDA ligation, infection causing lung injury, lung hypoplasia.
Treatment
- Oxygen (see home oxygen topic sheet).
- Fluid restriction and diuretics:
- Use of diuretics is reserved for severe BPD and evidence of diuretic responsive disease.
- Furosemide, chlorothiazide, spironolactone (see medication sheet for dosing).
- May need KCl or NaCl supplements to correct electrolyte deficiencies.
- Chronic furosemide use improves both oxygenation and lung compliance, but has not decreased length of hospital stay or need for oxygen therapy.
- Inhaled bronchodilators or corticosteroids (see medication sheet for dosing).
- Only for infants that show evidence of reversible airway obstruction.
- Only patients that have a family history of asthma and have episodic attacks similar to asthma have been shown to have any benefit from inhaled steroids.
- RSV immunoprophylaxis; influenza and pneumococcus vaccinations.
- Higher caloric intake needed to account for increased work of breathing, as well as ongoing tissue repair and tissue deposition; due to fluid restrictions, these patients may need fortified feeds to maintain an adequate growth rate.
Monitoring
- Monitor O2 saturations, resting respiratory rate and effort, presence of retractions, and color.
- Watch for adequate weight gain (15-30 g/day).
- If inadequate, may be due to insufficient caloric intake or hypoxemia.
- Watch for excessive fluid retention (tachypnea, retractions, rales, excessive weight gain, enlarged liver, poor feeding, O2 saturation <92%).
- Watch neurodevelopment closely.
Outcomes
- 50% with CLD require rehospitalization in the first year, and 37% in the second year of life.
- More prone to: frequent lower respiratory tract illnesses, feeding difficulties, growth failure, rehospitalization during infancy.
- Despite treatment, approximately 10% of these children die in the first year of life.
- Increased risk for cognitive, motor, and language impairment, hearing loss, and poor academic performance.
- Lung function generally remains reduced until adolescence, at which point it approaches normal for age; in some, pulmonary function will again deteriorate in adulthood.
- Children with CLD are more likely to develop asthma and require bronchodilator therapy.
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Gastroesophageal Reflux
Characteristics
- Common problem in premature infants.
- Lower esophageal sphincter hypotonia.
- Transient relaxation of the esophageal sphincter.
- Less frequent esophageal peristaltic activity.
- Delayed gastric emptying.
- Decreased gastric compliance.
- Neurologic impairment.
- Is a physiologic event; it is important to distinguish between physiologic and pathologic GER (GERD, or GER disease) before beginning any therapeutic interventions.
- Failure to thrive is usually not associated with physiologic GER in premature infants.
Symptoms of Pathologic GER
- Failure to thrive due to malnourishment.
- Frequent respiratory problems due to aspiration.
- Esophagitis with or without stricture formation.
- Growth delay, poor feeding, irritability.
- Post-prandial vomiting, gagging, coughing, arching, fussiness, feeding refusal.
- Some infants may experience aspiration, cyanosis, and vomiting.
- Sandifer syndrome: excessive hiccups, sleep disturbances, and arching.
- Uncommon symptoms: intermittent stridor, hoarse voice, acute episodes of spasmodic croup, bronchospasm, pneumonia.
- Data and research supporting a causal relationship between GER and apnea is lacking.
Diagnosis of Pathologic GER
- History.
- Barium swallow.
- pH probe.
Treatment
- Medical or surgical therapy is indicated only for pathological GER.
- Therapies may improve symptoms, but generally reflux is not entirely eliminated.
- GER usually self-improves within 6 months of life due to maturation, sitting upright, and intake of more solid foods.
- Antireflux wedge (elevates head by 30 degrees).
- Postprandial prone positioning when awake and under supervision, or left lateral positioning.
- Thickened feeds (rice cereal, 2-3 tsp/oz).
- Concentrating milk for decreased volume of feeds.
- More frequent, smaller volume feeds.
- H2 blockers or proton pump inhibitors.
- Prokinetics.
- Nissen fundoplication is the last resort for selected severe and intractable cases, or for those with severe neurological impairment in whom aspiration is a real risk.
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Nephrocalcinosis
Characteristics
- Renal lithiasis in which calcium deposits form in the renal parenchyma and result in reduced
kidney function and hematuria.
- Seen with renal ultrasound, or occasionally on plain radiographs of the kidneys.
- Results from an imbalance of stone-promoting and stone-inhibiting factors.
- Incidence in very low-birthweight infants (BW<1500g) ranges from 16-64%.
- Risk factors in at risk infants:
- Medications with hypercalciuric effects (furosemide, corticosteroids, aminoglycosides).
- Metabolic acidosis.
- Hypocitraturia.
- Hypercalciuria.
- High urinary oxalate:creatinine ratios.
- High urate:creatinine ratios.
Effects
- Glomerular function: Mean GFR and microalbuminuria in preterm infants is slightly worse
than in healthy infants.
- Proximal tubule function: Phosphate reabsorption is significantly lower in patients with
nephrocalcinosis, but plasma phosphate levels are within reference limits; no firm evidence for
proximal tubular dysfunction.
- Distal tubule function: Urine anion gap of infants with nephrocalcinosis is high, and serum
bicarbonate levels are low, indicating distal tubular dysfunction.
- Blood pressure: Not higher in infants with nephrocalcinosis, but overall higher in preterm
infants than in healthy term infants.
- Hypercalciuria: Significantly more hypercalciuria in infants with nephrocalcinosis.
Monitoring/Treatment
- If associated with a medication that causes hypercalciuria, consider trying to stop the
medication and monitor for resolution.
- Resolves in 75% by 7 years of age.
- Does not appear to have any long-lasting significant health effects.
- Should have:
- Blood pressure checked at every visit.
- Yearly renal ultrasounds until resolution occurs.
- Electrolytes and BUN/Cr checked every 2 years.
- Patients do not need to be followed by renal team unless other issues arise.
- UTI and urolithiasis do not occur any more frequently than in general population.
- Do NOT stop the use of high-calcium containing infant formulas.
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Patent Ductus Arteriosus
Characteristics
- A persistent open connection beyond 3 months of age between the pulmonary artery and the aorta with blood flow from the aorta to the pulmonary artery.
- An open ductus may lead to:
- Congestive heart failure.
- Pulmonary hypertension.
- Increased risk of bacterial endocarditis.
Followup
- A high rate of spontaneous closure occurs during the first 2 years of life.
- If the ductus is open at the time of hospital discharge, followup with a cardiologist should occur within 2 months of discharge to assess well-being and the presence/absence of congestive heart failure.
- Earlier followup should occur if poor weight gain, difficulty feeding, and tachypnea develop.
- Generally do not need a followup echocardiogram, as anatomy is already known.
Management
- If spontaneous closure does not occur, closure should be performed to:
- Eliminate pulmonary overcirculation.
- Eliminate risk of endocarditis.
- If symptomatic:
- Initially, try diuretics and maximize caloric intake to 140 kcal/kg/day.
- If still symptomatic despite optimal medical management and:
- >2.4 kg, surgical ligation or percutaneous closure should be considered.
- <2.4 kg, surgical ligation should be considered.
- If asymptomatic:
- Wait until patient weighs between 10-12 kg, or is close to 2 years of age, then attempt percutaneous closure with Amplatzer occlude or coils.
- Surgery if percutaneous attempt is unsuccessful.
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Short Bowel Syndrome
Pathophysiology
- Functional disorder caused by alterations of normal intestinal anatomy and physiology.
- Shortened bowel combined with malabsorption; dependent on parenteral nutrition >3 months.
- May result from: necrotizing enterocolitis, congenital bowel atresia, volvulus, gastroschisis, Hirschsprung's disease.
- After resection, the residual small bowel undergoes intestinal adaptation, stimulated by hormones and oral nutrients:
- Mucosal hyperplasia.
- Villus lengthening and increased crypt depth.
- Bowel dilatation.
- Jejunum: long villi and large absorptive surface with high concentration of enzymes; site of greatest nutrient absorption.
- If resected, will have transient or permanent nutrient losses.
- Ileum can develop the absorptive capacity of the jejunum for various nutrients.
- Ileum: shorter villi, more lymphoid tissue, tighter epithelium; effective absorption of fluid and electrolytes; responsible for absorption of vitamin B12 and bile salts through receptors.
- Other bowel will never develop ability to absorb B12 and bile salts.
- Resection may impair bowel motility (many GI hormones produced in ileum).
- Intestinal adaptation after massive ileal resection is more difficult than after jejunal.
- Malabsorption of rapidly digested carbohydrates produces osmotic diarrhea.
- Fat soluble vitamins may also be inadequately absorbed.
- No absolute number can be placed on the length of remaining bowel necessary for successful enteral nutrition; remaining bowel may be damaged and act dysfunctional.
- Best prognosis over time is for infants in whom the duodenum, distal ileum, and ileocecal valve can be preserved.
Complications
- Long term TPN use:
- Hepatobiliary disease.
- Catheter-associated sepsis.
- Fluid and electrolyte imbalance.
- Bacterial intestinal overgrowth.
- Malnutrition.
- Failure to thrive.
- Dumping syndrome: post-prandial tachycardia, diaphoresis, lethargy, watery diarrhea.
- Marked increase in stools may indicate poor absorption, and enteral feedings should not be advanced.
- If significant volume loss, rehydration therapy and electrolyte replacement will be needed.
- Mortality of 30-40% from sepsis or liver failure.
Management / Feedings
- Recommend managing with consulting services in pediatric surgery, GI (and possibly the liver team), and neonatal dietitian.
- Attempt to wean off TPN as soon as possible.
- Enteral nutrition should be started promptly to promote intestinal adaptation.
- Usually started on elemental/semi-elemental diets containing free amino acids or small peptides, or breast milk.
- There are no elemental preterm formulas.
- Once they tolerate feeds, can gradually introduce a portion of preterm formula, fortifier, or supplements to improve the mineral and protein content of a term formula.
- These infants may have "leaky gut" with high rates of sensitization to cow's milk or soy protein.
- High proportion of fat in long-chain fatty acids promotes more mucosal adaptation; but those with ileal resection may not be able to absorb these and may need more medium-chain fats.
- Feedings are started slowly and continuously to maximally saturate carrier proteins.
- Higher concentrated formulas may cause osmotic diarrhea.
- Oral feedings should be initiated promptly; may have solids at 4 months CGA (high in protein and fat and low in carbohydrate is preferred).
- For high stomas, may be beneficial to re-feed the proximal stoma effluent through the mucous fistula for additional nutrient and fluid absorption and to stimulate distal gut.
- For bacterial overgrowth, may need intermittent dosing of antibiotics that affect anaerobic bacteria.
- Infants with ileal resection are at risk for B12 deficiency; may need parenteral B12 every 1-3 months.
- Children with enterostomies or diarrhea are at risk for zinc deficiency and may need supplementation:
- Poor growth, diarrhea, impaired wound healing, perianal and perioral skin rash, alopecia.
- Gastric acid hypersecretion:
- More common in larger bowel resections and initiation of enteral feedings.
- Can cause secretory diarrhea.
- Ranitidine may help.
Surgical Treatments
- Goals of surgery:
- Slow intestinal transit.
- Increase mucosal surface area.
- Improve peristaltic function.
- Increase intestinal length.
- May eventually require intestinal +/- liver transplant.
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Vision Screening and Retinopathy of Prematurity
Visual Defects Seen in Preterm Infants
- High-risk infants are more likely to have permanent visual deficits and/or show a delay in visual development that persists until adolescence.
- Deficits in the ability to perform visual discrimination tasks is one of the most striking, persistent deficits.
- Reduced visual fields, amblyopia, myopia (associated with BPD, seizures and asphyxia), and strabismus (associated with intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), periventricular leukomalacia (PVL)).
Retinopathy of Prematurity
- Abnormal blood vessel growth in the incompletely vascularized retinas of premature infants.
- Incidence increases with lower gestational age and birthweight.
- Classification by:
- Zones 1-3: locates the disease from most posterior (Zone 1) to most anterior (Zone 3).
- Stages 1-5: degree of vasculopathy at the vascular-avascular transition (Stage 5 is most severe and involves complete retinal detachment).
- Plus disease: occurs when arrested blood vessel growth resumes abnormally, with tortuous vessels piling up within the retina, forming a thick ridge of tissue.
- Neovascular tissue (i.e., plus disease) may contract and form a scar, which then pulls and distorts the retina, resulting in retinal detachment, especially if ROP is in zone 1.
Screening / Monitoring
- All infants <1500 grams or <30 weeks estimated gestational age (EGA) should be screened prior to discharge.
- If retinal vasculature is completely mature, no further exams are needed.
- Followup is dictated by degree of maturation, severity of ROP, and ophthalmologist.
- Patients with ROP requiring laser therapy, and grade III/IV IVH, PVL, HIE, or hydrocephalus requiring shunting should be seen again at 9-12 months postnatal age by ophthalmology.
- A pediatric ophthalmologic assessment for glasses and possible strabismus or amblyopia therapy should be obtained in the first year of life.
Treatment / Outcomes
- Mild ROP (stage I or II without plus disease) have a somewhat higher incidence of myopia, strabismus, and amblyopia.
- Threshold ROP (residual scar without retinal detachment):
- Associated with severe myopia, glaucoma.
- At risk for slowly progressive retinal degenerations that can lead to retinal detachments and acuity loss in later decades.
- Total retinal detachment equates to no useful vision in that eye, even when vitrectomy is performed to reattach the retina.
- Criteria for laser therapy or cryotherapy:
- Zone 2: plus disease with stage 2 or 3 ROP.
- Zone 1: plus disease with any stage ROP.
- Zone 1: stage 3 ROP with no plus disease.
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