Fetus and the Newborn Flashcards
0
Q
Harmless cyanosis of the hands and feet
A
acrocyanosis
1
Q
Division of the body from the forehead to the pubis into red and pale halves is known as
A
harlequin color change
2
Q
Deep, blue masses that, if large, may trap platelets and produce disseminated intravascular coagulation or interfere with local organ function
A
Cavernous hemangiomas
3
Q
Slate-blue, well-demarcated areas of pigmentation seen over the buttocks, back, and sometimes other parts of the body
A
Mongolian spots
- tend to disappear within the 1st year
4
Q
Fine, soft, immature hair frequently covers the scalp and brow and may also cover the face of premature infants
A
Lanugo
- replaced by vellus hair in term infants
5
Q
Benign rash characterized as small, white papules on an erythematous base which develop 1-3 days after birth
A
Erythema toxicum
- persists for as long as 1 wk, contains eosinophils, and is usually distributed on the face, trunk, and extremities
6
Q
A benign lesion seen predominantly in black neonates, contains neutrophils and is present at birth as a vesiculopustular eruption around the chin, neck, back, extremities, and palms or soles; it lasts 2-3 days
A
Pustular melanosis
7
Q
Soft areas that are occasionally found in the parietal bones at the vertex near the sagittal suture
A
craniotabes
- more common in premature infants and in infants who have been exposed to uterine compression
8
Q
Premature fusion of skull sutures, identified as a hard nonmovable ridge over the suture and an abnormally shaped skull
A
craniosynostosis
9
Q
In the PE of the newborn, take note of symmetric facial palsy, which suggests absence or hypoplasia of the 7th nerve nucleus, otherwise known as
A
Mobius Syndrome
10
Q
Pupillary reflexes are present from what age of gestation?
A
28-30 wks AOG
11
Q
On the hard palate on either side of the raphe, there may be temporary accumulations of epithelial cells called
A
Epstein pearls
12
Q
The newborn’s tongue appears relatively large; the frenulum may be short. When is it indicated to repair a tongue-tie (ankyloglossia)?
A
If there are problems with feedings (breast or bottle) and the frenulum is short, frenulotomy may be indicated
13
Q
Premature infants may breathe periodically, with complete irregularity, also known as
A
Cheyne-Stokes rhythm
14
Q
A solid flank mass, which becomes clinically apparent with hematuria, hypertension, and thrombocytopenia may be caused by
A
renal vein thrombosis
- Renal vein thrombosis in infants is associated with polycythemia, dehydration, maternal diabetes, asphyxia, sepsis, nephrosis, and hypercoagulable states such as antithrombin III and protein C deficiency
15
Q
Abdominal wall defect that occurs through the umbilicus
a. omphalocoele
b. gastroschisis
A
a. omphalocele
A membrane often covers an omphalocele, and care should be taken to prevent its rupture.
Omphaloceles are associated with other anomalies and syndromes such as Beckwith-Wiedemann, conjoined twins, trisomy 18, meningomyelocele, and imperforate anus
16
Q
Abdominal wall defect that occurs lateral to the midline
a. omphalocoele
b. gastroschisis
A
b. gastroschisis
- Gastroschisis is the more common defect and typically the intestines are not covered by a membrane. The exposed intestines should be gently placed in a sterile clear plastic bag after delivery.
17
Q
The normal umbilical cord contains 2 arteries and 1 vein. What pathology is suggested with a single umbilical artery?
a. cardiac
b. respiratory
c. renal
A
c. renal
- A single umbilical artery increases the risk for an occult renal anomaly.
18
Q
Genital defect that usually results in hydrometrocolpos and lower abdominal mass
A
imperforate hymen
19
Q
True or False. The APGAR score is used to predict neurologic outcome.
A
False
- the score is normal in most patients in whom cerebral palsy subsequently develops, and the incidence of cerebral palsy is low in infants with Apgar scores of 0-3 at 5 min (but higher than in infants with Apgar scores of 7-10)
20
Q
Low Apgar scores and umbilical artery blood pH predict neonatal death. Which is a better predictor of neonatal death in both term and preterm infants?
A
Low Apgar score
- An Apgar score of 0-3 at 5 min is uncommon but is a better predictor of neonatal death (in both term and preterm infants) than an umbilical artery pH ≤ 7.0; the presence of both variables increases the relative risk of neonatal mortality in term and preterm infants
21
Q
What are the 5 objective signs being evaluate in the Apgar score?
A
Heart rate Color Respiration Muscle tone Response to catheter in nostril
22
Q
Mechanisms of heat loss in newborns (4)
A
Convection
Conduction
Heat radiation
Evaporation
1) convection of heat energy to the cooler surrounding air
2) conduction of heat to the colder materials touching the infant
3) heat radiation from the infant to other nearby cooler objects
4) evaporation from skin and lungs.
23
Q
What is the most common cause of oligohydramnios?
A
Rupture of membranes
24
What is the most serious complication of chronic oligohydramnios?
pulmonary hypoplasia
25
Ancillary procedure used in the second trimester (15-18 wks) to screen for open neural tube defects, gastroschisis, omphalocele, congenital nephrosis, twins, and other abnormal conditions
maternal serum alpha-fetoprotein (MSAFP)
- Low MSAFP is associated with incorrect gestational age estimates, trisomy 18 or 21, and intrauterine growth restriction
26
Periodic accelerations or decelerations of the fetal heart rate in response to uterine contractions may be monitored to assess fetal status. Which of the ff conditions reflect early, late, or variable decelerations?
a. associated with cord compression
b. associated with fetal hypoxemia
c. associated with head compression
a. cord compression - variable deceleration
b. fetal hypoxemia - late deceleration
c. head compression - early deceleration
27
What maternal condition would predispose the fetus to neonatal hypoglycemia, hypocalcemia, respiratory distress syndrome and other respiratory problems, polycythemia, macrosomia, myocardial dysfunction, jaundice, and congenital malformations?
Maternal diabetes
- There is increased risk for incidence of uteroplacental insufficiency, polyhydramnios, and intrauterine death in poorly controlled diabetic mothers.
28
What maternal conditions would predispose the fetus to IUGR, prematurity, and intrauterine death, all probably caused by diminished uteroplacental perfusion? (3)
1. Eclampsia-preeclampsia of pregnancy
2. chronic hypertension
3. chronic renal disease
29
What maternal condition is responsible for relative infertility, spontaneous abortion, premature labor, and fetal death?
Uncontrolled maternal hypothyroidism or hyperthyroidism
30
A pregnant woman taking prednisone may put the fetus at risk for?
oral clefts
31
Administration of oxytocin to a pregnant woman may affect the newborn, putting the baby at risk for?
hyperbilirubinemia and hyponatremia
32
By 35 wks AOG, what is the lecithin:sphingomyelin (L:S) ratio indicative of lung maturity?
2: 1
- Lecithin is produced in the lungs by type II alveolar cells and eventually reaches the amniotic fluid via the effluent from the trachea. Until the middle of the 3rd trimester, its concentration nearly equals that of sphingomyelin; thereafter, the sphingomyelin concentration remains constant in amniotic fluid while the lecithin concentration increases
33
Which antielpileptic drugs taken during pregnancy predisposes the fetus to neural tube defects?
valproate and carbamazepine
- Women taking these medications should ingest 1-5 mg of folic acid/day in the preconception period.
34
Define very low birthweight infants
<= 1500 g
35
Define low birthweight infants
<= 2500 g
36
What is the difference between symmetric and asymmetric IUGR and what are its implications on the fetus?
In symmetric IUGR, head circumference, length, and weight are equally affected while in asymmetric IUGR there is relative sparing of head growth.
Symmetric: earlier onset; associated with diseases that seriously affect fetal cell number, eg conditions with chromosomal, genetic, malformation, teratogenic, infectious, or severe maternal hypertensive etiologies
Asymmetric: late onset, demonstrates preservation of Doppler waveform velocity to the carotid vessels, and is associated with poor maternal nutrition or with late onset or exacerbation of maternal vascular disease (preeclampsia, chronic hypertension)
37
What is the optimal environmental temperature for minimal heat loss and oxygen consumption for an unclothed infant?
one that maintains the infant's core temperature at 36.5-37.0 C
- depends on an infant's size and maturity; the smaller and more immature the infant, the higher the environmental temperature required
38
What supplements should be given to LBW and preterm infants?
Vitamin C, E, D, A, folic acid, iron
- Although formula in amounts necessary for adequate growth probably contains adequate quantities of all vitamins, the volume of milk sufficient to satisfy these requirements may not be ingested for several weeks
- Fat soluble vitamins are usually supplemented because premature infants have decreased fat absorption increased fecal fat loss
- Anemia develops earlier in premature and LBW infants due to low iron stores and greater expansion of blood volume from more rapid growth
39
Infants with birthweight > the 90th percentile for gestational age
large for gestational age
- Neonatal mortality rates decrease with increasing birthweight until approximately 4,000 g, after which they increase
- higher incidence of birth injuries
40
Early recognition of anomalies is important from birth. What congenital anomaly should be suspected in a patient born in respiratory distress and NGT cannot be passed through the nares?
choanal atresia
consider CHARGE syndrome(coloboma of the eye, heart anomaly, choanal atresia, retardation, and genital and ear anomalies)
41
A patient was born with micrognathia, cleft palate, airway obstruction. What should you suspect?
Pierre Robin syndrome
42
What should you suspect in a patient born with a scaphoid abdomen, with bowel sounds present in chest, and in respiratory distress?
Diaphragmatic hernia
43
A patient born with known polyhydramnios perinatally developed aspiration pneumonia. On suctioning, there was note of excessive salivation and upon insertion, a nasogastric tube cannot be placed in the stomach. What is your initial impression?
Tracheoesophageal fistula
Suspect VATER (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia) syndrome
44
What should you suspect in a patient born with oligohydramnios, anuria, pulmonary hypoplasia, and pneumothorax?
Renal agenesis, Potter syndrome
45
Patient was born cyanotic and hypotensive with murmur on chest PE. What is your initial impression?
ductus-dependent congenital heart disease
46
A diffuse, sometimes ecchymotic, edematous swelling of the soft tissues of the scalp involving the area presenting during vertex delivery. It may extend across the midline and across suture lines
Caput succedaneum
- Molding of the head and overriding of the parietal bones are frequently associated with caput succedaneum and become more evident after the caput has receded; they disappear during the 1st weeks of life.
47
A subperiosteal hemorrhage, hence always limited to the surface of one cranial bone
Cephalohematoma
- Cephalohematomas require no treatment, although phototherapy may be necessary to treat hyperbilirubinemia
48
A collection of blood beneath the aponeurosis that covers the scalp the entire length of the occipitofrontalis muscle; firm fluctuant mass that increases in size after birth
subgaleal hemorrhage
- Many patients have a consumptive coagulopathy owing to massive blood loss. Patients should be monitored for hypotension and the development of hyperbilirubinemia. These lesions typically resolve over 2-3 week
49
What are the major neuropathologic lesions associated with VLBW infants?
intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL)
50
Infants born to mothers receiving phenobarbital or phenytoin are at increased risk for developing what neurologic condition?
intracranial bleeding
51
What is the preferred imaging modality in neonates with HIE because of its increased sensitivity and specificity early in the process and its ability to outline the topography of the lesion?
Diffusion-weighted MRI
- CT scans are helpful in identifying focal hemorrhagic lesions, diffuse cortical injury, and damage to the basal ganglia; CT has limited ability to identify cortical injury during the 1st few days of life.
- Ultrasonography has limited utility in evaluation of hypoxic injury in the term infant; it is the preferred modality in evaluation of the preterm infant.
- Amplitude-integrated electroencephalography (aEEG) may help to determine which infants are at highest risk for long-term brain injury
52
Clinical and lab parameters in HIE that indicate an increased risk for death or impairment
Low Apgar (0-3) at 5 min
high base deficit (>20-25 mmol/L)
decerebrate posture
lack of spontaneous activity
53
What diagnostic modalities are useful in predicting outcome in term infants with HIE?
combined use of early EEG and MRI
54
What are the parameters indicative of brain death after neonatal HIE?
1. coma unresponsive to pain, auditory, or visual stimulation;
2. apnea with Pco2 rising from 40 to >60 mm Hg without ventilatory support
3. absence of brainstem reflexes (pupillary, oculocephalic, oculovestibular, corneal, gag, sucking)
* * absence of cerebral blood flow on radionuclide scans and of electrical activity on EEG (electrocerebral silence) is inconsistently observed in clinically brain-dead neonatal infants
* * Persistence of the clinical criteria for 2 days in term infants and 3 days in preterm infants predicts brain death in most asphyxiated newborns
55
Peripheral nerve injury that is limited to the 5th and 6th cervical nerves. The infant loses the power to abduct the arm from the shoulder, rotate the arm externally, and supinate the forearm
Erb-Duchenne paralysis
- characteristic position consists of adduction and internal rotation of the arm with pronation of the forearm
56
Rare form of brachial palsy, in which injury to the 7th and 8th cervical nerves and the 1st thoracic nerve produces a paralyzed hand and ipsilateral ptosis and miosis (Horner syndrome) if the sympathetic fibers of the 1st thoracic root are also injured
Klumpke paralysis
57
A newborn in the delivery room was received with poor activity and depressed respiration. The mother was known to have been given an analgesic narcotic drug 4 hrs prior to delivery. What should you give?
Naloxone
0.1mg/kg, should be given intravenously or intramuscularly. Naloxone is contraindicated in infants born to mothers with opiate addiction because it precipitates acute neonatal withdrawal with severe seizures.
58
Newborn with estimated weight of 1.5 kg was received apneic and limp. What should you do first? What ET size and level of insertion should be anticipated should endotracheal intubation be needed?
Warm, clear the airway, dry, stimulate and reposition
ET 3 L 7.5
WT : ET size
3 kg. : 4
Depth of insertion: weight (kg) + 6
59
What is the dose and frequency of administration of epinephrine in the resuscitation of a newborn?
0.1-0.3 mL/kg of a 1:10,000 solution, given intravenously or intratracheally, given every 3-5 min
60
When should tracheal suctioning be performed in a patient delivered with meconium stained amniotic fluid?
In the absence of randomized, controlled trials, there is insufficient evidence to recommend a change in the current practice of performing endotracheal suctioning of nonvigorous babies with meconium-stained amniotic fluid (Class IIb, LOE C). However, if attempted intubation is prolonged and unsuccessful, bag-mask ventilation should be considered, particularly if there is persistent bradycardia
61
What procedure is performed to allow time to secure the airway in an infant known to have airway obstruction for a variety of causes, including laryngeal atresia or stenosis, teratomas, hydromas, and oral tumors, before the infant is separated from the placenta
EXIT procedure (EX utero Intrapartum Treatment procedure)
62
Upon delivery, describe what happens at first breath
1. Compression of thorax during delivery facilitates removal of lung fluid
2. Lung surfactant helps lower surface tension in alveoli to help lower the pressure needed to open the alveoli
3. The first few spontaneous breaths generate high pressures to help establish a functional residual capacity, and are required to overcome opposing forces of surface tension and the viscosity of liquid remaining in the airways, as well as to introduce air into the lungs
4. Air entry into the lungs displaces fluid, decreases hydrostatic pressure in the pulmonary vasculature, and increases pulmonary blood flow
5. The greater blood flow, in turn, increases the blood volume of the lung and the effective vascular surface area available for fluid uptake
63
What is the most important determinant of respiratory control?
Gestational age
- frequency of apnea is inversely related to gestational age
- In preterm infants, serious apnea is defined as cessation of breathing for longer than 20 sec or for any duration if accompanied by cyanosis and bradycardia
64
What are the treatment options for recurrent apnea of prematurity?
theophylline (oral) or aminophyline (IV)
caffeine citrate
NCPAP (2-5 cm H2O)
- Higher doses of methylxanthines are more effective, do not result in frequent side effects, and tend to reduce major neurodevelopmental disabilities.
- doxapram may be given if unresponsive to methylxanthines
65
What is the primary cause of RDS?
surfactant deficiency
- The failure to attain an adequate FRC and the tendency of affected lungs to become atelectatic correlate with high surface tension and the absence of pulmonary surfactant
66
What are the major constituents of surfactant?
lecithin (dipalmitoyl phosphatidylcholine)
phosphatidylglycerol
apoproteins
cholesterol
- With advancing gestational age, increasing amounts of phospholipids are synthesized and stored in type II alveolar cells
67
Mature levels of pulmonary surfactant are present usually at what age of gestation?
after 35 wks
- Surfactant is present in high concentrations in fetal lung homogenates by 20 wk of gestation, but it does not reach the surface of the lungs until later. It appears in amniotic fluid between 28 and 32 wk
68
When is antenatal corticosteroids indicated?
In all women 24-34 wks AOG in preterm labor, who are likely to deliver a fetus in 1 wk
- Betamethasone and dexamethasone have been used antenatally. Dexamethasone may result in a lower incidence of IVH than betamethasone
69
To maintain normal tissue oxygenation while minimizing the risk of oxygen toxicity, O2 saturation should be kept in what range for premature newborns?
85-95% saturation
If oxygen saturation cannot be kept > 85% at inspired oxygen concentrations of 40-70% or greater, applying CPAP at a pressure of 5-10 cm H2O via nasal prongs is indicated and usually produces a sharp improvement in oxygenation
70
What are the acceptable blood gas parameters in a preterm infant on assisted ventilation, being treated for HMD?
Pao2 40-70 mmHg, Paco2 45-65 mmHg, and pH 7.20-7.35
- The goal of mechanical ventilation is to improve oxygenation and elimination of carbon dioxide without causing pulmonary injury or oxygen toxicity
71
Oxygenation in assisted ventilation can be increased by increasing which parameters?
PIP
PEEP
I:E ratio
- excessive PEEP may impede venous return, thereby reducing cardiac output and decreasing oxygen delivery despite improvement in Pao2
- PEEP levels of 4-6 cm H2O are usually safe and effective
72
Carbon dioxide elimination is achieved in mechanical ventilation by adjusting which setting?
Increase PIP (tidal volume) or ventilatory rate
- The strategy most evaluated with conventional mechanical ventilation is the use of high rates and presumably small tidal volumes as Paco2 levels were kept in comparable ranges
- high ventilatory rate strategy led to fewer air leaks and a trend for increased survival
- High-frequency ventilation (HFV) achieves desired alveolar ventilation by using smaller tidal volumes and higher rates (300-1,200 breaths/min or 5-20 Hz)
73
A strategy for the management of patients receiving ventilatory support in which priority is given to the prevention or limitation of lung injury from the ventilator by tolerating relatively high levels of Paco2 rather than maintenance of normal blood gas values
permissive hypercapnea
- permissive hypercapnia (target Paco2 >50 mm Hg) during the 1st 10 days led to a trend for lower rates of BPD or death at 36 wk
74
Infants with respiratory failure or persistent apnea require assisted mechanical ventilation, based on what parameters?
(1) arterial blood pH <85% at oxygen concentrations of 40-70% and CPAP of 5-10 cm H2O
75
What are the anatomic landmarks that denote the correct placement of an umbilical artery catheter?
The tip of an umbilical artery catheter should lie just above the bifurcation of the aorta (L3-L5) or above the celiac axis (T6-T10).
76
Some neonates with RDS may have clinically significant shunting through a patent ductus arteriosus. What are the treatment options for closure of PDA?
Fluid restriction
Use of indomethacin or ibuprofen
Surgical closure
- Contraindications to indomethacin include thrombocytopenia (1.8 mg/dL).
77
A disease primarily of infants with birthweight <1,000 g born at less than 28 wk gestation, some of whom have little or no lung disease at birth but experience progressive respiratory failure over the 1st few weeks of life.
new BPD (bronchopulmonary dysplasia)
- Vitamin A supplementation (5,000 IU intramuscularly 3 times/wk for 4 wk) in VLBW infants reduces the risk of BPD. Early use of nasal CPAP and rapid extubation with transition to nasal CPAP are associated with a decreased risk of BPD.
78
A disease of more mature preterm infants with RDS who were treated with positive pressure ventilation and oxygen. Instead of showing improvement on the 3rd or 4th day, which would be consistent with the natural course of RDS, some infants demonstrate an increased need for oxygen and ventilatory support
classic BPD
Four distinct pathologic stages of classic BPD have been identified: acute lung injury, exudative bronchiolitis, proliferative bronchiolitis, and obliterative fibroproliferative bronchiolitis
79
Acceptable blood gas for BPD
Acceptable blood gas concentrations include hypercapnia with pH >7.20 and a Pao2 of 50-70 mm Hg with an oxygen saturation of 88-95%
80
What is the basic therapeutic regimen for BPD?
```
bronchodilator therapy
oxygenation
diuretics and fluid restriction
nutritional support
prompt treatment of infection
```
BINonDO
81
Following an uneventful preterm or term vaginal or CS delivery, characterized by the early onset of tachypnea, sometimes with retractions, or expiratory grunting and, occasionally, cyanosis that is relieved by minimal oxygen supplementation (<40%).
transient tachypnea of the newborn
- frequently a diagnosis of exclusion
- fast recovery
- chest radiograph shows prominent pulmonary vascular markings, fluid in the intralobar fissures, overaeration, flat diaphragms, and, rarely, small pleural effusions
- believed to be secondary to slow absorption of fetal lung fluid, resulting in decreased pulmonary compliance and tidal volume and increased dead space
82
PPHN is the persistence of fetal circulatory pattern of right-to-left shunting through the PDA and foramen ovale after birth due to excessively high PVR. How is right to left shunting in PPHN determined?
Apart from real time echocardiography, a Pao2 gradient between a preductal (right radial artery) and a postductal (umbilical artery) site of blood sampling >20 mm Hg suggests right-to-left shunting through the ductus arteriosus, as does an oxygenation saturation gradient >5% between preductal and postductal sites on pulse oximetry.
* hyperoxia test to determine etiology and differentiate it from cardiac causes
83
Anteromedial diaphragmatic defect where the transverse colon or small intestine or liver is usually contained in the hernial sac
Foramen of Morgagni diaphragmatic hernia
- accounts for 2-6% of diaphragmatic hernias
84
When should rectal gas be seen on radiograph?
by the 24th hour
- absence of rectal gas beyond 24th HOL is abnormal
85
The possibility of intestinal obstruction should be considered in any infant who does not pass meconium by?
24-36 hrs
- More than 90% of full-term newborn infants pass meconium within the 1st 24 hr.
86
Type of intestinal obstruction associated with small left colon syndrome in infants of diabetic mothers and with CF, rectal aganglionosis, maternal opiate use, and magnesium sulfate therapy for preeclampsia
meconium plug
- treat with suppository, rectal irrigation or Gastrografin
87
The most common life-threatening emergency of the gastrointestinal tract in the newborn period.
Necrotizing enterocolitis
88
What part of the gut is most frequently involved in NEC?
distal part of the ileum and the proximal segment of colon are involved most frequently
89
What is the classic triad of risk factors linked to NEC?
1. intestinal ischemia (injury)
2. enteral nutrition (metabolic substrate)
3. bacterial translocation
90
What is the greatest risk factor for NEC?
prematurity
91
Plain abdominal radiographs are essential to make a diagnosis of NEC. What radiographic finding confirms the diagnosis of NEC and is diagnostic?
pneumatosis intestinalis (air in the bowel wall)
92
What is the neonatal production rate of bilirubin?
6-8 mg/kg/24 hrs
93
Dermal pressure may reveal the anatomic progression of jaundice, but clinical examination cannot be depended on to estimate serum levels.
What are the estimated bili level if jaundice is noted in the following areas?
1) face
2) mid-abdomen
3) soles
face, ≈5 mg/dL
mid-abdomen, ≈15 mg/dL
soles, ≈20 mg/dL
94
Physiologic jaundice usually occurs on the 2nd to 3rd day of life. At what rate does indirect bilirubin rise in this case?
<2 mg/dL between the 5th and 7th days of life
- Jaundice associated with these changes is designated physiologic and is believed to be the result of increased bilirubin production from the breakdown of fetal red blood cells combined with transient limitation in the conjugation of bilirubin by the immature neonatal liver.
95
Give examples of conditions associated with persistent indirect hyperbilirubinemia beyond 2 wks of life
hemolysis
hereditary glucuronyl transferase deficiency breast milk jaundice
hypothyroidism
intestinal obstruction
Crigler-Najjar syndrome - total deficiency of glucuronyl transferase
Gilbert syndrome - deficiency or inactivity of bilirubin glucuronyl transferase
96
Indications for further evaluation of jaundice in the newborn
a search to determine the cause of jaundice should be made if
(1) it appears in the first 24-36 hr of life,
(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 of life, or
(5) direct bilirubin fraction is >2 mg/dL at any time
97
Risk factors for elevated indirect bilirubin
maternal age
race (Chinese, Japanese, Korean, and Native American)
maternal diabetes
prematurity
drugs (vitamin K3, novobiocin)
altitude, polycythemia, male sex
trisomy 21
cutaneous bruising, blood extravasation (cephalohematoma), oxytocin induction, breast-feeding, weight loss (dehydration or caloric deprivation)
delayed bowel movement
family history of or a sibling who had physiologic jaundice
98
What is the greatest risk associated with indirect hyperbilirubinemia?
development of bilirubin-induced neurologic dysfunction
- development of kernicterus (bilirubin encephalopathy) depends on the level of indirect bilirubin, duration of exposure to bilirubin elevation, the cause of jaundice, and the infant's well-being
99
Define breastmilk jaundice
a significant elevation in unconjugated bilirubin AFTER the 7th DOL, due to presumed presence of a substance in the breast milk that inhibits uridine diphosphoglucuronic acid (UDPGA) glucuronyl transferase (exact mechanism unknown).
- bili levels may reach up to 10-30 mg/dL during the 2nd to 3rd wk.
- With continued BF, levels will decrease gradually, but may persist for 3-10 wks. If nursing is discontinued for a few days, bilirubin reaches normal levels and when BF resumed, bilis seldom return to previous elevated level
100
Define breastfeeding jaundice
an early-onset, accentuated unconjugated hyperbilirubinemia which occurs in the 1st week of life in breast-fed infants
- may be due to decreased milk intake with dehydration and/or reduced caloric intake
101
In kernicterus, where does indirect bilirubin deposit?
the basal ganglia and brainstem nuclei
BG and BSN
102
At what bilirubin level does kernicterus usually occur?
>20 mg/dl
- more than 75% of infants die, and 80% of affected survivors have bilateral choreoathetosis with involuntary muscle spasms
103
How does phototherapy work to decrease bilirubin levels?
through photoisomerization, toxic form of unconjugated bilirubin is converted to a nontoxic form that can be excreted in the bile without the need for conjugation in the liver. Lumirubin is another product of this isomerization, which is excreted by the kidney in the unconjugated state
- biliubin absorbs light maximally in the blue range
104
When is phototherapy contraindicated?
in the presence of porphyria
- phototherapy causes transient porphyrinemia
105
At what age is physiologic anemia observed in infants (term and preterm)?
8-12 wk in term infants (hemoglobin, 11 g/dL)
| 6 wk in premature infants (7-10 g/dL)
106
What maneuver at birth may be beneficial in otherwise well newborns in preventing anemia in full-term infants, with effects extending beyond the neonatal period?
delayed cord clamping (≈1-2 min or after cessation of cord pulsation)
- Late clamping may result in delivery of an extra 20-40 mL of blood and 30-35 mg of iron to the newborn.
107
What is now being given to the mother immediately after the delivery of each Rh-positive infant, which has been a successful strategy to reduce Rh hemolytic disease?
RhoGAM
- injection of anti-D gamma globulin (RhoGAM) into the mother -- prevents B-cell activation and memory cell formation
108
What is the most common cause of hemolytic disease of the newborn?
ABO incompatibility
109
What laboratory test helps determine presence of significant amounts of fetal hemoglobin and red blood cells (RBCs) in maternal blood on the day of delivery (proves transplacental hemorrhage as a possible cause of fetal hydrops)
Kleihauer-Betke test or by flow cytometry methods to detect fetal cells in maternal blood.
110
Plethora is observed in newborns frequently with polycythemia, which is defined as a central Hct of?
65% or higher
- Clinical manifestations include irritability, lethargy, tachypnea, respiratory distress, cyanosis, feeding disturbances, hyperbilirubinemia, hypoglycemia, and thrombocytopenia.
111
When should polycythemia be treated?
MOST infants with polycythemia are asymptomatic.
If with symptoms, partial exchange transfusion (using normal saline) is performed if the Hct is ≥70-75% or even lower if signs of hyperviscosity are present
112
A particularly severe form of deficiency of vitamin K–dependent coagulation factors has been reported in infants born to mothers receiving what kind of anticonvulsive medications during pregnancy?
phenobarbital and phenytoin
(others: warfarin, rifampin, isoniazid)
- Infant may have severe bleeding, with onset within the 1st 24 hr of life; the bleeding is usually corrected by vitamin K1, although in some the response is poor or delayed.
113
What laboratory test can be performed to determine if bloody stool from a newborn is due to swallowed maternal blood or hemorrhage from the GI tract?
Apt Test
114
The umbilical cord sloughs off after birth usually within 2 weeks. How many days does the cord vessels remain anatomically patent (but functionally closed)?
10-20 days
- Delayed cord separation of usually more than 1 month is associated with neutrophil chemotactic defects and overwhelming bacterial infection
115
What becomes of the umbilical cord vessels?
umbilical arteries become the lateral umbilical ligaments;
umbilical vein becomes the ligamentum teres; and
the ductus venosus, the ligamentum venosum
116
fetal transfusion syndrome
5 g/dL hemoglobin and 20% body weight differences can be noted in this syndrome
117
Initiation of the 1st breath is due to (3)
decline in Pao2 and pH and a rise in Paco2 as a result of interruption of the placental circulation, a redistribution of cardiac output, a decrease in body temperature, and various tactile and sensory inputs.
