VLC Peds 1: Infant (0-6mo) Flashcards
Where does bilirubin come from?
RBC breakdown → Hb release → converted to unconjugated bilirubin → binds to albumin in blood stream (not soluble in water)
How is bilirubin processed?
Albumin-bound unconjugated bilirubin → Liver: bilirubin extracted by hepatocytes → conjugated (with gluconuride, by UDPGT): now it’s water soluble!
→ bile → intestines
How is bilirubin excreted in adults?
conjugated bilirubin in bile in intestines → urobilin → excreted in stool
What is different about bilirubin excretion in neonates?
Same process up till intestines, but: Babies: ø GI flora
Bilirubin is de-conjugated (by an enzyme in meconium), reabsorbed into the bloodstream.
What is the most serious problem that can result when a newborn infant has high levels of unconjugated bilirubin?
Kernicterus, neurologic impairment, brain damage, or encephalopathy
What is kernicterus (etiology/pathology)?
staining of the basal ganglia and cranial nerve nuclei by bilirubin, due to high levels of unconjugated bilirubin
What is kernicterus (clinically)?
Chronic clinical condition due to high levels of unconjugated bilirubin. Results in:
- abnormalities in tone and reflexes
- choreoathetosis
- tremor
- oculomotor paralysis
- sensorineural hearing loss
- cognitive impairment
When does acute bilirubin encephalopathy occur?
First few weeks of life
What are the initial signs of acute bilirubin encephalopathy?
Initial signs include: poor suck high-pitched cry hypotonia lethargy seizures
What are are late signs of acute bilirubin encephalopathy?
extensor hypertonia, opisthotonus
What is opisthotonus?
abnormal posturing: rigidity and severe arching of the back, with the head thrown backward
(From Greek “drawn backwards”)
What has made kernicterus less common?
- Prevention: Rh screening and RhoGAM (preventing erythroblastosis fetalis)
- Treatment of hyberbilirubinemia with phtootherapy
What is erythroblastosis fetalis / neonatorum?
hemolytic anemia in the fetus/neonate due to maternal Ab to fetal RBC. (Ab transmitted via placenta).
Usually d/t incompatible blood groups, often Rho(D) antigens
What are the major etiologies of early newborn jaundice
- Physiologic Jaundice
- Jaundice associated with breastfeeding
- Hemolysis
- Non-hemolytic red cell breakdown
- Metabolic errors
- Neonatal sepsis
- Congenital infection
When is physiologic jaundice first noticed in a full-term baby, and when does the bilirubin level peak?
First noticed day 2-3, bilirubin peak day 3-4
What is physiologic jaundice?
This is defined as a total bilirubin level [elevated – check values ≤ 15 mg/dL (≤ 257 μmol/L)] in full-term infants who are otherwise healthy and have no other demonstrable cause for elevated bilirubin.
What factors promote enterohepatic circulation in a newborn?
- fetal RBC break down
- Relative deficiency of hepatocyte proteins and UDPGT
- High levels of β-glucuronidase in meconium
- minimal oral intake in first 2-4d –> slow excretion of meconium
What is breastfeeding jaundice?
Could be considered “lack-of-breastfeeding jaundice”.
Minimal oral intake → delayed passing of meconium → increased enterohepatic circulation.
Happens in the first week of life (esp with breastfeeding, as maternal milk comes in)
What is breast milk jaundice?
Not well understood; one theory is that breast milk has β-glucuronidase.
Begins in day 4-7, may not peak till day 10-14, and can persist up to 12w.
Bilirubin rarely reaches concerning levels.
What are the most forms of Ab-positive hemolysis?
Rh incompatibility, ABO incompatibility, and (much less common) incompatibilities with minor blood group antigens
What causes Ab-negative hemolysis in newborns?
- blood cell membrane defects (eg spherocytosis
- RBC enzyme defects (eg G6PD)
What are some causes of non-hemolytic RBC breakdown in a neonate?
- Extensive bruising from birth trauma
- Large cephalohematoma or other hemorrhage (e.g., intracranial)
- Polycythemia
- Swallowed blood (large amounts) during delivery.
What are TORCH infections?
(T)oxoplasmosis (O)ther Agents (R)ubella (C)ytomegalovirus (H)erpes Simplex
“Other” keeps getting added to – syphilis, varicella, coxsackievirus, HIV, parvovirus B19, some now say Zika
What in utero infectious exposure can lead to jaundice? What other findings might there be?
TORCH infections
May have hepatomegaly, microcephaly, and/or rash
What are some basic features of breastfeeding technique to assess?
- Mother’s comfort
- Baby’s latch, and vigour in feeding
- Problems with breathing, choking, or spitting up
How often does a breastfed baby nurse?
8-12 times in 24h
How long do feedings last (of breastfeeding)?
Initially up to 60min, but gradually shorter to about 20-30min (10-15min each breast)
What are some benefits to infants of breastfeeding?
- Maternal-infant bonding
- Protection against some infections (e.g. otitis media, respiratory infections, diarrhea)
- Reduced rates of SIDS
- Reduced rates of some allergic reactions
What are some benefits to mothers of breastfeeding?
- Decreased postpartum bleeding and more rapid uterine involution
- Lactational amenorrhea and delayed resumption of ovulation
- Earlier return to pre-pregnant weight
- Improved bone remineralization postpartum (reduction in hip fractures in the postmenopausal period)
Why is it important that the infant empty one breast before taking the other?
Lipid concentration in breast milk increases as the nursing episode proceeds
What are some common breastfeeding problems?
- enlarged, tender breasts
- improper latch or suckle
- prolonged feedings
- infants falling asleep before finishing
- maternal anxiety
What are some common reasons for enlarged, tender breasts in a breastfeeding woman?
engorgement
mastitis
plugged ducts (galactocele)
What group of conditions, though causing hemolysis, is not commonly associated with neonatal jaundice?
Hemoglobinopathies (eg the thalassemias, sickle cell)
What is the most common enzyme problem affecting red blood cell metabolism worldwide?
G6PD deficiency (Glucose-6-phosphate dehydrogenase)
What is the inheritance pattern of G6PD deficiency, and in what populations is it most prevalent?
X-linked recessive
Mediterranean or West African origin
What food should not be consumed while nursing an infant with G6PD deficiency?
Fava beans!
In areas where it is very prevalent, consider warning parents
What is biliary atresia?
Obstruction of the biliary tree due to progressive sclerosis of the extrahepatic bile duct
Seen in neonates
What are presenting symptoms of biliary atresia?
jaundice
dark urine
acholic stools
between three and six weeks of age
Any infant who develops jaundice after 2w must have bilirubin assessed
What is the treatment for biliary atresia?
Surgery
If done early, can restore flow and prevent liver damage
(Kasai procedure: anastomosis of the intrahepatic bile ducts to a loop of intestine to allow bile to drain directly into the intestine)
What is the urination pattern in a 3d infant? 6d infant?
3d: 4-6 per day
6d: 6-8 per day
Urine should be pale yellow
What is the stool pattern in a 3d infant? 6-7d?
3d: No more meconium, & stools should start to appear yellow
6-7d: Most have 3-4 stools/day, many pass stool with each feeding, and some stool as little as 1/wk (with breastfeeding)
Stool from breastfed infants has little odor
If an infant’s stool gradually loses colour and becomes more pale, what might this indicate?
Biliary atresia
What does “acholic” mean?
“without bile” – in context of stool, pale or clay-coloured
Should breastfeeding be ceased or paused in jaundiced infants?
No
Some clinicians will recommend 24-48h pause, but not AAP
Which newborns should be assessed for risk of hyperbilirubinemia before discharge?
All: Canadian Peds Soc says, Either TSB (total serum bilirubin) or TcB (transcutaneous bilirubin) concentration should be measured in all infants during the first 72 h of life
What supplementation should breastfed infants receive?
Vitamin D 400 IU daily
Canadian Paediatric Society recommends 800 IU intake per day – from all sources – between October and April depending upon where the family lives
How much of birth weight do breastfed neonates lose, and in what time frame?
7-10% in the first 4-5d
By what time should breastfed infants have regained their birth weight?
Two weeks
What is a caput succedaneum?
Edematous swelling over the presenting portion of the scalp of an infant
Commonly seen in babies born vaginally in vertex position. Because the scalp overlies the periosteum, this boggy swelling crosses suture lines. The swelling consists of serum
What is a cephalohematoma?
subperiosteal hemorrhage that is localized to the cranial bone that was traumatized during delivery. Does not extend across a suture line
What features on exam might suggest birth trauma leading to hyperbilirubinemia?
Any indication of bleeding, eg cephalohematoma, bruising
What surprising breast findings can be normal in a neonate?
A term infant may have 0.5–1.0 cm of palpable breast tissue.
Unilateral or bilateral engorgement of the breasts can occur in both male and female infants within several days and last for several weeks.
The breasts may even have a colostrum-like secretion.
What is normal liver edge finding in a newborn?
Palpable 1 cm below the inferior costal margin
What features exclude Dx of breastfeeding jaundice?
Weight, feeding, and stooling history indicating adequate breast milk
In what time frame does ABO incompatibility cause jaundice?
Within the first 24h of life