CLIPP case 7. Newborn (respiratory distress, hypoglycemia, discharge)

Question 1

Risk factors for respiratory distress of newborn

Answer 1

-Maternal GDM, drug exposure
-Infection, GBS
-Prematurity
-PROM >/= 18 hours before delivery
(neonatal sepsis)
-C-section
-Meconium in amniotic fluid

Question 2

APGAR score

Answer 2

-appearance, pulse, grimace, activity, respiration
-significance is fetal-to-neonatal transition
-correlates poorly with the future neurological
outcome

Question 3

Classification of birthweight

Answer 3

• LGA: >90%ile
  
  • DM mothers
  • Cx: traumatic delivery with C-section/ forceps/ vacuum, injury of clavicle/brachial plexus/facial nerve, hypoglycemia
• Appropriate: 10-90%ile
• SGA: <2500g
  
  • Cx: Hypothermia, hypoglycemia (inadequate glycogen stores), polycythemia
  • (IUGR: Diagnosis of fetus)

Question 4

Ballard assessment

Answer 4

-Assessment of gestational age
-Should be performed on every infant within 24hr life
+/- 2 weeks accuracy

Question 5

Fetal circulation

Answer 5

In utero, oxygenated blood from the placenta is transported to the fetus by the umbilical vein. A portion of this blood perfuses the liver. The remainder bypasses the liver through the ductus venosus and enters the IVC.

One-third of this vena caval blood crosses the PFO to the left atrium and is pumped to the coronary, cerebral and upper body circulations. The remaining two-thirds combines with venous blood from the upper body in the right atrium, and is directed to the right ventricle and out the pulmonary artery.

Vasoconstricted pulmonary arterioles produces high PVR, allowing only 8-10% of the blood from the RV to flow through the pulmonary vasculature. The remaining 90-92%, is shunted through the PDA to the descending aorta.

Question 6

Transition to extrauterine respiration

Answer 6

• Vaginal delivery uterine contractions squeezes fluid out of lungs, and lymphatics absorb it. *Delayed absorption causes TTN.
• Cutting the umbilical cord removes the low-resistance placental circulation
• Breathing replaces lung fluid with air
• Pulmonary arterial resistance drops
• PFO and PDA close

Question 7

Signs of respiratory distress

Answer 7

Tachypnea, retractions, and grunting

• Intercostal and subcostal retractions reflect the increased work of breathing due to decreased lung compliance, either due to primary lung pathology or edema.
• Grunting occurs at the end of expiration, and is the audible sound of air being expelled through a partially closed glottis as the infant attempts to increase transpulmonary pressures, increase lung volumes, and improve gas exchange.

Question 8

Differential of the cyanotic newborn

Answer 8

• Pulmonologic: TTN, RDS, less commonly pneumothorax, diaphragmatic hernia, choanal atresia, pulmonary hypoplasia
• CHD: Tetralogy of Fallot, Transposition, less commonly truncus arteriosus, tricuspid atresia, total anomalous pulmonary venous return, pulmonary atresia
• CNS: Hypoxemic-ischemic encephalopathy, intraventricular hemorrhage, sepsis/meningitis
• Other: Septic shock or meningitis, depression from maternal meds, hypothermia, polycythemia/hyperviscosity syndrome

Question 9

Oxygen challenge test

Answer 9

• Hyperoxia test
• In cyanotic infants, helps differentiate pulmonary and cardiac etiology based on PaO2 increase (less increase if cardiac)

Question 10

Maternal hyperglycemia

Answer 10

Maternal hyperglycemia causes fetal hyperglycemia (fetal BG = about 2/3 maternal BG), but insulin does not cross the placenta. Fetal pancreatic beta cell stimulation and hyperinsulinemia results.

First trimester A1c >12% increases malformation risk 12x.

Third trimester insulin is the primary anabolic hormone for fetal growth. Causes growth of fat, heart, liver, muscle. LGA results. Brain and kidneys normal.

Question 11

Advantages of breastfeeding

Answer 11

• Lower renal solute load than formula
• Ant-infective and anti-allergic
• Bonding

Question 12

TTN on CXR

Answer 12

-Perihilar streaking (interstitial fluid and engorged lymphatics), pleural fluid, coarse fluffy densities (fluid filled alveoli)

Question 13

RDS on CXR

Answer 13

-Air bronchograms, diffuse reticulogranular appearance of lung fields (“ground-glass
appearance”)

Question 14

Hip dysplasia tests

Answer 14

• Barlow (in adduction, push down to test for dislocation)
• Ortolani (in abduction, push up to test for relocation)
• Examine regularly up to 18 months old

Question 15

Hip dysplasia risk factors

Answer 15

• Breech birth
• Female 9:1
• Family history

Question 16

Newborn hospital discharge considerations

Answer 16

• Exam without major defects
• Minimal/no jaundice
• No blood group incompatibility
• Breast feeding every 2-4 hours
• Transition from meconium to seedy soft tan/yellow stools
• Wt loss < 10%
• 6 wet diapers per day
• Vitamin D rX, review co-bedding and Back to Sleep program, car seat and adequate home support, PCP follow-up at 48hr and within week 1

Question 17

34-week-gestation premature infant is delivered via Caesarean section with no meconium and no premature rupture of
membrane (PROM) from a diabetic mother with fair glucose control and unknown
GBS status. He presents with respiratory distress. APGAR scores were 8 at 1 minute and 9 at 5 minutes. On exam, he is LGA, tachypneic, with no heart murmur, good
perfusion, and equal breath sounds. CXR shows “wet”-looking lungs, no consolidation, and no air bronchograms. Labs show he is hypoglycemic.

Answer 17

• Transient tachypnea of the newborn
• DDx:
  
  • Respiratory distress syndrome
  • Sepsis/pneumonia
  • Pneumothorax
  • Congestive heart failure
  • Hypothermia
• Hypoglycemia: too tachypneic to breastfeed, so given breastmilk and formula via feeding tube

Question 18

Acrocyanosis

Answer 18

If not resolved within 8 hours or with warming, may be sign of cyanotic congenital heart disease

Question 19

RDS of newborn

Answer 19

• Deficiency in lung surfactant
• Most common cause of respiratory distress in premature infants
• Risk factors:
  
  • Prematurity up to 37 weeks
  • GDM due to delayed lung maturation
  • Sibling with history of RDS
  • Male
  • C-section delivery without labor
  • Perinatal asphyxia
• CXR can help distinguish between TTN and RDS

Question 20

TTN of newborn

Answer 20

• Delayed clearance of lung fluid after birth causing early onset mild respiratory distress. *Benign, self-limited disease related to newborn transition. No long-term dysfunction. *Disorder of term infants, but can occur in premature infants
• Risk factors:
  
  • C-section delivery
  • Male
  • Macrosomic
  • GDM
• CXR can help distinguish between TTN and RDS
• If respiratory symptoms do not improve, suspect pneumonia -> repeat CXR and abx

Question 21

CHF

Answer 21

• Important cause of tachypnea
• Most often caused by a congenital heart defect
• Increased risk of heart defect if GDM, and therefore increased risk of CHF
• Usually presents with heart murmur

Question 22

Sepsis/pneumonia

Answer 22

*Early signs of neonatal sepsis are subtle and
nonspecific - poor feeding, lethargy, irritability *May also present initially with tachypnea and progress to more severe illness rapidly *Risk factors:
- PROM
- GBS

Question 23

Hypoglycemia in infants

Answer 23

*GDM due to the chronic hyperinsulinemic
state that occurred during gestation
*Tachypnea is non-specific response

• Send serum BG (glucometer is 10-15% lower)
• Breastfeed > bottle if can -> NG tube feeds -> IV dextrose if BG remains <45. Maintain BG 41-50 mg/dL

Question 24

Congenital diaphragmatic hernia

Answer 24

• Rare. Bochdalek hernia (posterolateral hernia) accounts for majority (> 95%) of cases:
  
  • Allows passage of abdominal organs into chest cavity and severely impairs lung development
  • Most defects occur on the left side
• Absent breath sounds or presence of bowel sounds on one side
• CXR: Air-filled loops of bowel in left side of chest, displacement of heart to contralateral side

Question 25

Pneumothorax

Answer 25

• Caused by a collection of gas in the pleural space with resultant collapse of lung tissue. *Risk factors:
  
  • Mechanical ventilation
  • Meconium aspiration or severe RDS
• Absent breath sounds on one side of the chest in combination with respiratory distress

Question 26

Meconium aspiration syndrome

Answer 26

• Passage of meconium in utero may indicate fetal stress and hypoxia. Aspiration of meconium may occur in utero with fetal gasping, or at first breath at delivery.
• Often presents with symptoms of respiratory distress, including tachypnea

Question 27

Transposition of the great arteries

Answer 27

• Congenital heart defect in which the aorta and pulmonary arteries are transposed, resulting in respiratory distress and severe cyanosis shortly after birth as PDA closes.
• Risk factor: IDM. Often associated with other congenital heart defects such as a VSD. *Murmur may be heard

Question 28

Hypothermia of newborn

Answer 28

• Should be considered in the differential of a tachypneic newborn
• May be associated with neonatal sepsis
• Risk factors:
  
  • SGA and premature infants because of small body size and relatively large surface area

Question 29

Severe coarctation of the aorta

Answer 29

• May cause respiratory distress if there is severe LVOT obstruction
• Classically, diminished pulses in the lower extremities or asymmetric blood pressure readings suggest the diagnosis
• In severely ill neonates, there may be no differences in the pulses because cardiac output is so poor.

Question 30

Echo in newborn

Answer 30

• Gold standard in diagnosis of congenital cardiac lesions and persistent pulmonary hypertension of the newborn
• Indicated when there is persistent cyanosis and no indication of lung disease, or when there are other signs suggesting a heart defect, such as a murmur, abnormal electrocardiogram (ECG), or chest X-ray showing abnormal cardiac contour