Part 11B. The fetus and neonatal infant

Question 1

The possibility of intestinal obstruction should be considered in any infant who does not pass meconium by…

Answer 1

24 - 36 hrs

Question 2

In 95% of pts with meconium plug, this procedure is both diagnostic and therapeutic.

Answer 2

Gastrografin enema (meglumine diatrizoate, a hyperosmolar, water-soluble, radiopaque solution containing 0.1% polysorbate 80 [Tween 80] and 37% organically bound iodine) will be both diagnostic and therapeutic, inducing passage of the plug, presumably because the high osmolarity (1,900 mOsm/L) of the solution draws fluid rapidly into the intestinal lumen and loosens the inspissated material.

Question 3

Meconium ileus, or impaction of inspissated meconium in the distal small bowel, accounts for up to 30% of cases of neonatal intestinal obstruction. In what patient population is it commonly found?

Answer 3

It is common in patients with CF in whom the lack of fetal pancreatic enzymes inhibits digestive mechanisms, and meconium becomes viscid and mucilaginous. Clinically, neonates present with intestinal obstruction with or without perforation. Abdominal distention is prominent, and vomiting, often bilious, becomes persistent, although occasionally inspissated meconium stools may be passed shortly after birth. Meconium ileus can present as early as in utero.

Question 4

What is the treatment for meconium ileus?

Answer 4

Treatment for simple meconium ileus is a high-osmolarity Gastrografin enema, as described for meconium plugs. If the procedure is unsuccessful or perforation of the bowel wall is suspected, a laparotomy is performed and the ileum opened at the point of largest diameter of the impaction. If meconium ileus is associated with CF, the long- term prognosis depends on the severity of the underlying disease

Question 5

Major risk factors for NEC.

3

Answer 5

1. Prematurity - greatest risk factor
2. bacterial colonization of the gut
3. formula feeding

Question 6

What finding is diagnostic of NEC?

Answer 6

Pneumatosis intestinalis

Question 7

In NEC, ____ is a sign of severe disease, and ____ indicates a perforation.

Answer 7

Portal venous gas; Pneumoperitoneum

Question 8

What is the most effective preventive strategy for NEC?

Answer 8

The use of human milk.

Question 9

Which form of bilirubin is neurotoxic?

Answer 9

Unconjugated bilirubin

Question 10

What are factors that can cause unconjugated bilirubinemia?

Answer 10

any factor that…
* increases the load of bilirubin to be metabolized by the liver (hemolytic anemias, polycythemia, bruising or internal hemorrhage, shortened red blood cell [RBC] life as a result of immaturity or transfusion of cells, increased enterohepatic circulation, infection);
* damages or reduces the activity of the transferase enzyme or other related enzymes (genetic deficiency, hypoxia, infection, thyroid deficiency);
* competes for or blocks the transferase enzyme (drugs and other substances requiring glucuronic acid conjugation); or
* leads to an absence or decreased amounts of the enzyme or to reduction of bilirubin uptake by liver cells (genetic defect, prematurity)

Question 11

When does physiologic jaundice in term infants usually peak?

Answer 11

Between 2nd and 4th day

Question 12

Pathophysiology of physiologic jaundice.

Answer 12

It is believed to be the result of increased bilirubin production from the breakdown of fetal RBCs combined with transient limitation in the conjugation of bilirubin by the immature neonatal liver.

Question 13

What does persistent indirect hyperbilirubinemia beyond 2 wk suggest? hemolysis, hereditary glucuronyl transferase deficiency, breast milk jaundice, hypothyroidism, or intestinal obstruction.

Answer 13

• hemolysis
• hereditary glucuronyl transferase deficiency
• breast milk jaundice
• hypothyroidism, or
• intestinal obstruction.

Question 14

What is the peak level of serum bilirubin in premature infants and when does it usually occur?

Answer 14

8-12 mg/dL
4th to 7th day

Question 15

In general, a search to determine the cause of jaundice should be made if…

Answer 15

1. it appears in the 1st 24-36 hr after birth
2. serum bilirubin is rising at a rate faster than 5 mg/dL/24 hr
3. serum bilirubin is >12 mg/ dL in a full-term infant (especially in the absence of risk factors) or 10-14 mg/dL in a preterm infant
4. jaundice persists after 10-14 days after birth
5. direct bilirubin fraction is >2 mg/dL at any time.

Question 16

In this hyperbilirubinemia of the newborn, the primary problem is probably a deficiency or inactivity of bilirubin glucuronyl transferase rather than an excessive load of bilirubin for excretion

Answer 16

Gilbert syndrome

Question 17

True or false

In breast milk jaundice, significant elevation of unconjugated bilirubin occurs before the 7th day of life.

Answer 17

False.
Significant elevation in unconjugated bilirubin (breast milk jaundice) develops in an estimated 2% of breastfed term infants after the 7th day, with maximal concentrations as high as 10-30 mg/dL reached during the 2nd-3rd wk.

Question 18

True or false

In breastmilk jaundice, if breastfeeding is continued, the bilirubin gradually decreases but may persist for 3-10 wk at lower levels.

Answer 18

True

Question 19

True or false

In breastmilk jaundice, if nursing is discontinued, the serum bilirubin level falls rapidly, reaching normal range within a few days.

Answer 19

True.
With resumption of breastfeeding, bilirubin seldom returns to previously high levels.

Question 20

True or false

In breastfed infants, breastfeeding jaundice occurs after the first week after birth.

Answer 20

False
The late jaundice associated with breast milk should be distinguished from an early onset, accentuated unconjugated hyperbilirubinemia known as breastfeeding jaundice, which occurs in the 1st week after birth in breastfed infants, who normally have higher bilirubin levels than formula-fed infants

Question 21

Pathophysiology

Breastfeeding jaundice

Answer 21

Lower milk intake before breast milk production is established can result in dehydration, which hemocon- centrates bilirubin, while also causing fewer bowel movements, which in turn increases the enterohepatic circulation of bilirubin.

Question 22

Kernicterus, or bilirubin encephalopathy, is a neurologic syndrome resulting from the deposition of unconjugated (indirect) bilirubin in which parts of the brain?

2

Answer 22

the basal ganglia and brainstem nuclei.

Question 23

What are the clinical features of kernicterus in the acute form?

features of each of the 3 phases

Answer 23

• Phase 1 (1st 1-2 days): poor suck, stupor, hypotonia, seizures
• Phase 2 (middle of 1st wk): hypertonia of extensor muscles, opisthotonos, retrocollis, fever
• Phase 3 (after the 1st wk): hypertonia

Question 24

By age 3 yrs, the complete neurologic syndrome is often apparent, which are:

Answer 24

• bilateral choreoathetosis with involuntary muscle spasms,
• extrapyramidal signs,
• seizures,
• mental deficiency,
• dysarthric speech,
• high-frequency hearing loss,
• squinting, and
• defective upward eye movements.

Question 25

Clinical jaundice and indirect hyperbilirubinemia are reduced by exposure to high-intensity light in the visible spectrum. Bilirubin absorbs light maximally in the ____.

Answer 25

blue range (420-470 nm)

Question 26

What approaches may be done in maximal intensive phototherapy?

Answer 26

Such therapy includes using “special blue” fluorescent tubes, placing the lamps within 15-20 cm (6-8 inches) of the infant, and putting a fiberoptic phototherapy blanket under the infant’s back to increase the exposed surface area

Question 27

Phototherapy in contraindicated in the presence of?

Answer 27

Porphyria

Question 28

This refers to a dark, grayish brown skin discoloration sometimes noted in infants undergoing phototherapy.

Answer 28

Bronze baby syndrome, occurs in the presence of direct hyperbilirubinemia. The discoloration may result from photoinduced modification of porphyrins, which are often present during cholestatic jaundice and may last for many months. Despite the bronze baby syndrome, phototherapy can continue if needed.

Question 29

The proposed mechanism of action of this therapeutic adjuct for kernicterus is competitive enzymatic inhibition of the rate-limiting conversion of heme-protein to biliverdin (an intermediate metabolite in the production of unconjugated bilirubin) by heme-oxygenase.

Answer 29

Metalloporphyrin.
A single intramuscular dose on the 1st day of life may reduce the need for subsequent phototherapy. Such therapy may be beneficial when jaundice is anticipated, particularly in patients with ABO incompatibility or G6PD deficiency, or when blood products are objected to, as with Jehovah’s Witness patients.

Question 30

Anemia

Physiologic nadir

Answer 30

Term: 6-12 wks of life (Hgb 9-11 g/dL)
Preterm: 4-8 wks of life (Hgb 7-9 g/dL)

Question 31

What test can identify fetal erythrocytes in the maternal circulation?

Answer 31

Kleihauer-Betke test

Question 32

What is the most common cause of neonatal anemia?

Answer 32

Blood loss

Question 33

What is the most common antenatal presentation of fetomaternal hemorrhage?

Answer 33

Decreased or absent fetal movement.
After delivery, infant pallor, hypotension, and poor perfusion will indicate severe anemia. To diagnose FMH, the classic Kleihauer-Betke test, which identifies fetal erythrocytes containing HbF resistant to acid elution, is technically the gold standard but is labor intensive

Question 34

What is the most common RBC membrane disorder?

Answer 34

Hereditary spherocytosis

Question 35

True or False

Irradiation of PRBCs removes the risk of transfusion-associated graft-versus-host disease (GVHD) and eliminates the risk of CMV transmission.

Answer 35

False. Irradiation of PRBCs removes the risk of transfusion-associated graft-versus-host disease (GVHD) but does not eliminate the risk of CMV transmission.

Question 36

What management reduces HDFN caused by RhD alloimmunization?

Answer 36

The injection of anti-Rh immune globulin (RhoGAM) into the Rh-negative mother, both during pregnancy and immediately after the delivery of each Rh-positive infant, reduces HDFN caused by RhD alloimmunization.

Question 37

Hydrops is typically present when fetal hemoglobin level is <____.

Answer 37

5 g/dL

Question 38

Doppler measurement of the peak velocity of systolic blood flow in the ____ has essentially replaced invasive testing in the management of HDFN.

Answer 38

fetal middle cerebral artery (MCA)

Question 39

This is performed to determine fetal hemoglobin levels and to transfuse packed RBCs into fetuses with serious fetal anemia (hematocrit < 30%) who are immature and not suitable for delivery.

Answer 39

Percutaneous umbilical blood sampling (PUBS)

Question 40

This refers to the rare occurrence of persistent icterus in association with significant elevations in both direct and indirect bilirubin levels in infants with hemolytic disease.

Answer 40

Inspissated bile syndrome.
The cause is unclear, but jaundice clears spontaneously within a few weeks or months with conservative management.

Question 41

A full-term infant is considered to have polycythemia when the hemoglobin concentration is ≥ ____ or Hct is ≥ ____.

Answer 41

22 g/dL;
65%

Question 42

This is a result of failure of closure of the allantoic duct and may be associated with bladder outlet obstruction. Symptoms include drainage, a mass or cyst, abdominal pain, local erythema, and infection of the umbilical cord.

Answer 42

Persistent urachus

Question 43

Granulation tissue at the base of the umbilical cord is treated by?

Answer 43

Cauterization with silver nitrate

Question 44

When is surgery advised for umbilical hernia?

Answer 44

Surgery is advised when the hernia persists to age 4-5 yr, causes symptoms, becomes strangulated, or becomes progressively larger after age 1-2 yr.

Question 45

The first line of treatment for all opioid-exposed infants is ?

Answer 45

Nonpharmacologic support, which includes swaddling, placing the infant in a dark and quiet environment (e.g., dimmed lights, muted televisions), holding and Kangaroo care, reducing stimulation, and breastfeeding.

Question 46

True or False

Maternal methadone or buprenorphine use and hepatitis C are contraindications to breastfeeding.

Answer 46

False. Maternal methadone or buprenorphine use and hepatitis C are not contraindications to breastfeeding.

Question 47

Pharmacologic treatment for neonatal abstinence syndrome (NAS), when necessary, is typically ?

2

Answer 47

morphine or methadone

Question 48

Adjuvant therapy is initiated when the primary opioid is not effective in controlling the signs of NAS. The 2 most common medications used as adjuvant therapy are ?

Answer 48

phenobarbital and clonidine

Question 49

Use of these antidepressants during pregnancy are thought to have the highest risk of birth defects?

2 drugs

Answer 49

Paroxetine, Fluoxetine (SSRIs)

Question 50

What are the most common causes of preventable developmental delay and intellectual disability?

Answer 50

Fetal alcohol spectrum disorders

Question 51

This disorder / malformation is characterized by:
* Intellectual disability
* Broad thumbs and halluces; valgus deviation of these digits
* Hypoplastic maxillae
* Prominent nose and columella
* Congenital heart disease

Answer 51

Rubinstein-Taybi Syndrome.
Autosomal dominant; caused by deleterious sequence variants in CBP and EP300

Question 52

Prenatal alcohol exposure (PAE) in the ____ trimester leads to the classic facial dysmorphia associated with FAS and other structural defects.

Answer 52

first

Question 53

Drug of choice for congenital hypothyroidism

Answer 53

Levothyroxine, ideally started within 30 days of life

Question 54

This may manifest as tetany or seizure of the newborn

Answer 54

Transient hypoparathyroidism.
This is due to hypocalcemia and is associated with low levels of parathyroid hormone and hyperphosphatemia. Testing for DiGeorge syndrome should be considered.

Question 55

Diagnosis for congenital adrenal hyperplasia is confirmed with?

Answer 55

An elevated 17-hydroxyprogesterone level for gestational age.
CAH is suggested by vomiting, diarrhea, dehydration, hyperkalemia, hyponatremia, shock, ambiguous genitalia, or clitoral enlargement. Some infants have ambiguous genitalia and hypertension.

Question 56

Female infants with webbing of the neck, lymphedema, hypoplasia of the nipples, cutis laxa, low hairline at the nape of the neck, low-set ears, high-arched palate, deformities of the nails, cubitus valgus, and other anomalies should be suspected of having?

Answer 56

**Turner Syndrome. **
Karyotype to confirm diagnosis

Question 58

This is a severe neuronal migration defect that causes a smooth brain with reduction or absence of gyri and sulci in males and that gives rise to a variable pattern of intellectual disability and seizures in females.

Answer 58

X-linked lissencephaly, caused by deleterious sequence variants in DCX. The DCX protein regulates the activity of dynein motors that contribute to movement of the cell nucleus during neuronal migration.

Question 59

The pattern of multiple anomalies that occurs when a single primary defect in early development produces multiple abnormalities because of a cascade of secondary and tertiary developmental anomalies is called?

Answer 59

a sequence

Question 60

This is a pattern of multiple anomalies produced by mandibular hypoplasia.

Answer 60

Pierre-Robin Sequence. Because the tongue is relatively large for the oral cavity, it drops back (glossoptosis), blocking closure of the posterior palatal shelves and causing a U-shaped cleft palate.

Question 61

This pathway is developmentally important during embryogenesis to induce controlled proliferation in a tissue-specific manner; disruption of specific steps in this pathway results in a variety of related developmental disorders and malformation. Activation of this pathway in the adult leads to abnormal proliferation and cancer.

Answer 61

Sonic Hedgehog (SHH) pathway

Question 62

This is a variably severe, midline defect associated with clinical effects ranging from cyclopia to a single maxillary incisor with hypotelorism or close spacing of the ocular orbits.

Answer 62

Holoprosencephaly, caused by deleterious sequence variants in SHH.

Question 63

What duration is the appropriate cutoff for increased risk of neonatal infection due to rupture of membranes?

Answer 63

18 hrs

Question 64

The most important neonatal factor predisposing to infection is?

Answer 64

Prematurity or LBW

Question 65

A 7-day old infant delivered at home by a hilot was brought to your clinic due to inability to suck. The baby was apparently sucking well until one day prior, she was noted to have poor suck with occasional note of stiffness of the extremities. What is the likely diagnosis?

Answer 65

Neonatal tetanus.
It results from unclean delivery and unhygienic management of the umbilical cord in an infant born to a mother who has not been immunized against tetanus. The surveillance case definition of neonatal tetanus requires the ability of a newborn to suck at birth and for the 1st few days of life, followed by an inability to suck. Neonatal tetanus typically occurs in infants 5-7 days after birth (range: 3-24 days), difficulty swallowing, spasms, stiffness, seizures, and death. Broncho- pneumonia, presumably resulting from aspiration, is a common complication and cause of death.

Question 66

What has the best sensitivity of the neutrophil indices for predicting neonatal sepsis?

Answer 66

An immature- to-total phagocyte count (I/T ratio) (≥0.2).
After the newborn period, serum C-reactive protein (CRP) and procalcitonin have dem- onstrated reasonable sensitivity and specificity for serious bacterial infection (SBI). CRP may be monitored in newborn infants to assess response to therapy.

Question 67

The largest fraction of bloodstream infections (BSIs) in the NICU are caused by ?

Answer 67

coagulase-negative staphylococci

Question 68

The most common cause of viral infection in the NICU.

Answer 68

Rotavirus, followed by RSV, enterovirus, HAV, adenovirus, and influenza. GI illness is the most frequently reported virus-associated condition.

Question 69

True or False

Prophylactic administration of fluconazole during the 1st 6 wk of life reduces fungal colonization and invasive fungal infection in ELBW infants (< 1000 g)

Answer 69

True

Question 70

Congenital infections; Organism causing

Limb hypoplasia, cicatricial skin lesions, ocular abnormalities, cortical atrophy

Answer 70

VZV

Question 71

Congenital infections; organism causing

Nonimmune hydrops fetalis

Answer 71

Parvovirus B19

Question 72

Congenital infections; organism causing

Severe thrush, failure to thrive, recurrent bacterial infections, calcification of basal ganglia

Answer 72

HIV

Question 73

Congenital infections; organism causing

Microcephaly, lissencephaly, cerebellar hypoplasia, akinesia syndrome, macular scarring, retinal mottling, subcortical calcifications, hypertonia

Answer 73

Zika virus

Question 74

Screening test for Down syndrome in pregnant women in their 2nd trimester.

Answer 74

“Quad screen” , can detect up to 80% of Down syndrome pregnancies
* free β-human chorionic gonadotropin [β-hCG],
* unconjugated estriol,
* inhibin, and
* α-fetoprotein

Question 75

Clinical findings in the newborns of this chromosomal disorder can include small size for gestational age, webbing of the neck, protruding ears, and lymphedema of the hands and feet, although many newborns are phenotypically normal.

Answer 75

Turner Syndrome (45,X)
Older children and adults have short stature and exhibit variable dysmorphic features. The gonads are generally streaks of fibrous tissue (gonadal dysgenesis). There is primary amenorrhea and lack of secondary sex characteristics. These children should receive regular endocrinologic testing. Most patients tend to be of normal intelligence, but intellectual disability is seen in up to 6% of affected children.

Question 76

Differentiate Noonan Syndrome from Turner Syndrome.

Answer 76

Noonan syndrome is an autosomal dominant disorder resulting from mutations in several genes involved in the RAS-MAPK (mitogen-activated protein kinase) pathway. In contrast to Turner syndrome, Noonan syndrome affects both sexes and has a different pattern of congenital heart disease, typically involving right-sided lesions.

Question 77

Most common heart defects associated with Turner syndrome.

Answer 77

The most common heart defects are bicuspid aortic valves, coarctation of the aorta, aortic stenosis, and mitral valve prolapse.

Question 78

This syndrome is the most common cause of hypogonadism and infertility in males and the most common sex chromosome aneuploidy in humans

Answer 78

Klinefelter syndrome.
(80% 47,XXY; the rest have multiple sex chromosome aneuploidies (48,XXXY; 48,XXYY; 49,XXXXY), mosaicism (46,XY/47,XXY), or structurally abnormal X chromosomes; the greater the aneuploidy, the more severe the mental impairment and dysmorphism.

Question 79

The main clinical manifestations of ____ in affected males are intellectual disability, autistic behavior, postpubertal macroorchidism, hyperextensible finger joints, and characteristic facial features, which include a long face, large ears, and a prominent square jaw, become more obvious with age.

Answer 79

Fragile X syndrome

Question 80

This occurs when the phenotypic expression of a gene depends on the parent of origin for certain genes or in some cases entire chromosome regions.

Answer 80

Genomic imprinting

Question 81

A classic example of imprinting disorder is seen in these 2 disorders.

Answer 81

Prader-Willi syndrome and Angelman syndrome
These syndromes are usually associated with deletion of the same region in the proximal long arm of chromosome 15. A deletion on the paternally derived chromosome causes Prader-Willi syndrome, in which the maternally derived copy is still intact, but some of the imprinted genes within this region normally remain silent. Prader-Willi syndrome can be diagnosed clinically and confirmed with genetic testing. A maternal deletion of the same region as in Prader-Willi syndrome causes Angelman syndrome, leaving intact the paternal copy that in this case has genes that are also normally silent.