Jaundice

Question 1

elevated levels of bilirubin in the serum

Answer 1

hyperbilirubinemia

Question 2

yellowish discoloration of the skin and mucous membranes

Answer 2

jaundice

Question 3

enzyme that liberates chelated iron from heme structure

Answer 3

heme oxygenase

Question 4

indirect vs direct bilirubin

Answer 4

indirect = bilirubin-albumin complex (water insoluble)

direct bilirubin = conjugated bilirubin (water soluble)

Question 5

enzyme the conjugates bilirubin with glucoronic acid

Answer 5

udp glucuronyl transferase

Question 6

most common morbidity in the newborn period

Answer 6

bilirubin levels >12.8 mg/dl (physiologic jaundice)

jaundice = >5 mg/dl

Question 7

neonatal vs adult metabolism values

Answer 7

production 6-8 mg/kg/d vs 3-4
rbc volume 16-18 mg% vs 12-14 mg%
rbc lifespan 90 d vs 120 d

Question 8

neonatal vs adult bilirubin metabolism

Answer 8

lower concentration of albumin
lower concentration of enzyme transferase
large bilirubin pool in the meconium (1 g meconium = 1 mg bilirubin)

Question 9

meconium starts to be excreted by ___

Answer 9

10-16 wks aog

Question 10

characteristics of unconjugated (indirect) bilirubin

Answer 10

lipid soluble = neurotoxic
poorly soluble in water, non-polar
passes the bbb readily
albumin bound in plasma

Question 11

characteristics of conjugated (direct) bilirubin

Answer 11

water-soluble
actively transported to biliary tree

neonatal cholestasis/cholestatic jaundice = >20% of total bilirubin is conjugated (>2 wks)

Question 12

bilirubin levels in physiologic jaundice

Answer 12

3rd day: 7-7.5 mg%
3rd-5th day: peak
5-th-7th day: < 2 mg/dl

Question 13

onset and factors for breastfeeding jaundice

Answer 13

onset: 3-4 days of life
factors: inadequate nursing, decreased stool output, increased enterohepatic circulation

Question 14

jaundice where the onset is at the end of the first week of life

Answer 14

breastmilk jaundice

Question 15

what to do if baby is still jaundiced at 1-2 mos

Answer 15

• check if direct hyperbilirubinemia
• if direct >20% total or >2 mg/dl = neonatal cholestasis
• if direct is less + no hemolysis = breastmilk jaundice

Question 16

causes of pathologic jaundice

Answer 16

overproduction of bilirubin
undersecretion of bilirubin
mixed

Question 17

levels of hyperbilirubinemia

Answer 17

significant: >95th percentile, >17 mg/dl at 72 hrs
severe: 99th percentile, >20 mg/dl
extreme: >99.5th percentile, >25 mg/dl

Question 18

causes of overproduction of bilirubin

Answer 18

increased rbc breakdown due to

• hemolytic disorders (rh/abo, genetic, drugs)
• extravasated blood
• polycythemia
• exaggerated enterohepatic circulation (reduced peristalsis, mechanical obstruction)

Question 19

causes of undersecretion of bilirubin

Answer 19

decreased hepatic uptake
decreased bilirubin conjugation
impaired transport of conjugated bilirubin out of hepatocyte
obstruction to bile flow

Question 20

mixed causes of pathologic jaundice

Answer 20

intrauterine infection (torch, syphilis, hepa/b)
postnatal infections
multi-system disorders

Question 21

complications of hyperbilirubinemia in newborns

Answer 21

• bilirubin toxicity
• kernicterus
• active bilirubin encephalopathy (abe)
• bilirubin-induced neurologic dysfunction (bind)
• chronic bilirubin encephalopathy (cbe)
• subtle bilirubin encephalopathy

Question 22

important cause of cerebral palsy, developmental delay, or hearing impairment and the most preventable cause of cerebral palsy

Answer 22

bilirubin toxicity

Question 23

pathologic findings of bilirubin toxicity in the brain (staining/necrosis)

Answer 23

kernicterus

bilirubin induces lipid peroxidation -> neuroinflammation and mitochondrial failure (loss of atps) -> apoptosis and neuronal death

Question 24

phases of acute bilirubin encephalopathy

Answer 24

first days and weeks following hyperbilirubinemic event

1: poor sucking, lethargy, stupor, hypotonia, seizure
2: middle of the week, alternating hyper/hypotonia, opisthotonus, fever, upward gaze paralysis
3: after 1 week, hypertonia

Question 25

abe tests and imaging results

Answer 25

``` abnormal baer (brainstem auditory evoked response) lesions in globus pallidum on mri ```

Question 26

the subtle form of brain injury due to the effects of bilirubin toxicity but comprising less obvious neurologic manifestations

Answer 26

bilirubin induced neurologic dysfunction

Question 27

bind scoring system

Answer 27

mental status muscle tone cry =6 reversible 7-9 irreversible

Question 28

clinical triad of post icteric sequelae in chronic bilirubin encephalopathy (permanent)

Answer 28

4E: EXTRAPYRAMIDAL, EYES, EARS, EEE (smile) extrapyramidal abnormalities (athetoid cp and spasticity) deafness or diminished hearing impaired upward gaze dental enamel dysplasia

Question 29

t/f for those who have abe, 50% will die and those who will survive will have bind

Answer 29

false, cbe

Question 30

most preventable cause of cerebral palsy

Answer 30

chronic bilirubin encephalopathy

Question 31

manifestation of subtle bilirubin encephalopathy in school aged children/adults

Answer 31

subtle bilirubin encephalopathy

Question 32

clinical manifestations of subtle bilirubin encephalopathy

Answer 32

isolated hearing loss gaze abnormality gait abnormality

Question 33

why is bilirubin produced?

Answer 33

- iron salvage pathway: carbon monoxide, iron, biliverdin - potent scavenger of peroxyl radicals - inhibit the effects of mutagens - anti-oxidants

Question 34

basic principles of preventing severe hyperbilirubinemia

Answer 34

- recognize risk factors - vigilant in-hospital monitoring - post-discharge monitoring - adequate breastfeeding support - parenteral and nursing education

Question 35

what to check to prevent sever hyperbilirubinemia

Answer 35

- risk factors - jaundice - follow up 48-72 hrs if discharged <72 hrs - einc and lactation counselors - written and oral information in the nicu

Question 36

clinical assessment of jaundice after birth

Answer 36

visual assessment: monitor as a vital sign at 8h bilirubin testing in nbs check risk factors (late preterm, bruising, race)

Question 37

t/f if the baby is jaundiced, you can't reliably estimate the bilirubin levels

Answer 37

true

Question 38

transcutaneous bilirubin can be tested on __

Answer 38

>35 weeks | postnatal age >24 hrs

Question 39

indications for serum bilirubin test

Answer 39

tcb reading > 250 mg/dl jaundice in first 24 hrs <35 wks aog

Question 40

t/f forehead tcb has better correlation efficient

Answer 40

false, chest has better due to less exposure to sunlight

Question 41

risk factors for the development of severe bilirubinemia in infants >35 weeks

Answer 41

``` age 35-36 wks exclusive breastfeeding abo incompatibility g6pd deficiency east asian race ```

Question 42

risk stratification depends on ___ approach

Answer 42

hour of life approach

Question 43

t/f late preterm babies act like term babies

Answer 43

false, they can act like preterm despite having the size of a term baby have an 8 fold increase in developing tsb of >20 mg/dl

Question 44

t/f hyperbilirubinemia in east asians are more prevalent, more pronounced, and more protracted

Answer 44

true

Question 45

indications for phototherapy

Answer 45

24 hol > 12 48 hol >15 72 hol > 18

Question 46

indications for exchange transfusion

Answer 46

24 hol > 19 48 hol > 22 72 hol > 24 >72 hol >/= 25

Question 47

process where water insoluble bilirubin is converted into water soluble forms without conjugation in the liver

Answer 47

phototherapy

Question 48

what is photooxidationi

Answer 48

bleaching reaction where oxidation of bilirubin into polar and water soluble products is done

Question 49

what is photoisomerization

Answer 49

configurational (fast/major) | structural: form lumirubin, irreversible (slow)

Question 50

ideal wavelength of phototherapy

Answer 50

450 nm (blue)

Question 51

t/f circumferential therapy has more exposure, but conventional has less treatment failures

Answer 51

true

Question 52

a cheaper phototherapy alternative for low resource areas

Answer 52

led phototherapy

Question 53

t/f turning is necessary when doing phototherapy

Answer 53

false, there's no difference

Question 54

t/f there is a difference between continuous and intermittent phototherapy

Answer 54

false, no difference

Question 55

if bilirubin is ___, they can carry their child to the wards and still do intermittent phototherapy

Answer 55

<20 mg/dl

Question 56

t/f sunlight exposure can be done to the baby

Answer 56

false, aap recommends against it. sunlight exposure 6-9 am daily in first week of life is ok avoid 10 am - 2 pm sun exposure

Question 57

exchange transfusion can decrease bilirubin by ___

Answer 57

50% exchanging blood of the infant with type o or o-

Question 58

t/f phototherapy can be shortened and less exchange transfusions can be done if ivig is done with phototherapy

Answer 58

true

Question 59

a lipid reducing substance that can reduce total bilirubin

Answer 59

clofibrate

Question 60

drug that can induce glucuronyl transferase as ancillary therapy

Answer 60

phenobarbital - take 5-7 days to effect - prophylactic and not sued in severe levels

Question 61

inhibits heme oxygenase

Answer 61

tin-mesoporphyrin