lecture 6- pediatrics

fetal lungs

filled with fluid and provides NO respiratory function until birth

when does surfactant production start?

20th week of gestation

surfactant purpose

1. reduces alveolar surface tension

2. helps with lung recoil

3. reduces likelihood of atelectasis

4. made up of lipids and proteins

respiratory distress syndrome (RDS)

surfactant deficiency results in high surface tension

what does RDS lead to?

1. increase in pressure needed to open alveoli

2. alveolar instability results in diffuse atelectasis

3. inflammation- pulm. edema and increased airway resistance

what age has highest risk of RDS?

preterm infants

when does RDS typically present?

within first few minutes to hours after birth; if untreated then it will progressively worsen over first 48 hours

clinical presentation of RDS

preterm infant with signs of respiratory distress- tachypnea, central cyanosis, etc.

labs and imaging for RDS

1. CXR

2. ABG

3. CBC

4. blood culture

5. blood glucose

6. EKG or echo if murmur or other abnormal finding

CXR findings of RDS

1. ground-glass haze in lung surrounding air filled bronchi

2. can have airless lung field- whiteout if severe

treatment for RDS

1. resuscitation if needed

2. CPAP

3. surfactant

4. prophylactic antibiotics

prophylactic antibiotics for RDS

ampicillin and gentamicin for 48-72 hours

prevention of RDS

1. maternal cervical cerclage

2. bed rest

3. treatment of infections

4. tocolytic meds to prevent preterm labor

if premature delivery is unavoidable, how can RDS be avoided?

antenatal steroids (betamethasone) to mom to stimulate fetal lung production of surfactant

potential complications of RDS

1. pneumothorax

2. patent ductus arteriosus

3. bronchopulmonary dysplasia

patent ductus arteriosus (PDA)

common complication in low birth weight infants who have RDS

when does ductus arteriosus usually close in term babies?

within 24-48 hours of life

when does ductus arteriosus usually close in preterm babies?

often fails to close

with RDS hypoxemia, what occurs in preterm infants?

oxygen is not present to stimulate closure of ductus arteriosus; it remains open and creates shunt between pulmonary and systemic circulation

acute phase of RDS

1. hypoxia, hypercapnia, acidosis leads to pulmonary arterial vasoconstriction

2. pulmonary and systemic pressures may be equal and flow through ductus may be small or bidirectional

when RDS improves and pulmonary vascular resistance declines...

flow through ductus arteriosus increases in a left to right direction

clinical presentation of PDA

1. murmur- systolic or continuous, machine-like

2. widened pulse pressure

3. bounding peripheral pulses

4. if heart failure- rales, hepatomegaly

CXR findings if large PDA

cardiomegaly and pulmonary edema

doppler findings for PDA

markedly increased left to right flow

how to confirm PDA diagnosis?

echo

treatment for PDA if stable

1. initial- fluid restriction +/- diuretic

2. repeat echo at 36 weeks

treatment for PDA if unstable

1. initial- fluid restriction +/- diuretic

2. no improvement in 1-2 days- prostaglandin synthetase inhibitor

3. if still no response or reopening, surgery

prostaglandin synthetase inhibitor

1. indomethacin

2. ibuprofen

potential complications of PDA

1. pulm. edema

2. bronchopulmonary dysplasia

3. heart failure

4. acute kidney injury

retinopathy of prematurity (ROP)

caused by acute and chronic effects of oxygen toxicity on developing blood vessels of premature infant's retina

when do retinal blood vessels begin to grow?

16 weeks and don't finish until birth

risk factors for ROP

infants <1500 g or ≤30 weeks- tiny, premature babies are at highest risk

clinical features of ROP

1. B/L involvement typically

2. if severe- leukocoria, nystagmus

who gets screened for ROP?

infants who weigh <1500g or ≤30 weeks at birth

when are premature babies screened for ROP?

4 weeks of age or more than 34 weeks gestational age

diagnosis of ROP

comprehensive eye exam by pediatric ophthalmologist

if mild ROP, how is this treated?

90% of cases resolve within first few months of life; observed by ophthalmology

if severe ROP, how is this treated?

1. type 1 ROP- high risk prethreshold ROP

2. laser photocoagulation, anti-VEGF

complications of ROP?

blindness if untreated or long term visual impairment

prevention of ROP?

1. breastfeeding

2. DHA supplementation

3. preventing BPD

meconium

stained fluid- fetal distress

how might a newborn appear if aspiration of meconium occurs in utero?

distressed, gasping

what does meconium in amniotic fluid suggest?

distress with asphyxia, hypoxia, acidosis

risks for meconium aspiration syndrome?

post-term deliveries or any stress in utero such as IUGR, preeclampsia, maternal DM or HTN, etc

clinical features of meconium aspiration syndrome

1. mild to life threatening respiratory distress

2. neuro/respiratory depression

3. resp. distress or failure

4. barrel chest

5. pneumothorax or pneumomediastinum

CXR of meconium aspiration syndrome

initial patchy infiltrates that progress to overdistention, flat diaphragm, pneumomediastinum, pneumothorax

diagnosis of meconium aspiration syndrome

evidence of respiratory distress at birth or shortly after birth plus evidence of meconium stained amniotic fluid, characteristic CXR findings, OR if intubated- meconium in trachea

treatment for meconium aspiration syndrome

1. general neonatal resuscitation

2. hemodynamic support

3. antibiotic therapy until blood culture comes back

4. if severe- intubate, transfusion, surfactant, nitrous oxide, ECMO

complications of meconium aspiration syndrome

1. mortality

2. reactive airway disease

3. significant neurodevelopmental impairment

prevention of meconium aspiration syndrome

1. intrapartum fetal HR monitoring

2. amniofusion

3. preventing post term delivery

hemolytic disease of newborn

caused by destruction of RBCs by maternal IgG antibodies

when does mom produce antibodies against baby's blood?

1. sensitization- if she is Rh negative and she is exposed to fetal Rh+ blood

2. can be Rh or ABO incompatibility

risk factors for hemolytic disease of newborn

1. Rh- mom with Rh+ baby

2. A/B type baby with O mom

3. second/subsequent pregnancy

4. white infants

clinical findings of hemolytic disease of newborn

1. mild hyperbilirubinemia

2. severe life threatening anemia- hydrops fetalis

less severe hemolytic disease of newborn

1. hyperbilirubinemia within first 24 hours after birth

2. ABO incompatibility

hydrops fetalis

1. diffuse edema, pleural and/or pericardic effusion and ascites

2. Rh incompatibility

screening for hemolytic disease of newborn

routine prenatal screening

workup of hemolytic disease of newborn

1. maternal and infant blood type

2. maternal antibody screen

3. direct antiglobulin test- Coombs

4. bilirubin level

5. CBC and peripheral blood smear

6. reticulocyte count

diagnosis of hemolytic disease of newborn (all 3 confirmed)

1. demonstrate incompatible blood type

2. lab evidence of hemolysis

3. positive Coombs test (DAT)

lab evidence of hemolysis

1. unconjugated hyperbilirubinemia

2. anemia with elevated reticu. count

3. peripheral smear consistent with hemolysis

treatment of hydrops fetalis

emergency transfusion using group O, Rh - RBCs

early symptomatic anemia/severe hyperbilirubinemia treatment in newborns

1. exchange transfusion

2. hematocrit <25%

moderate to severe hyperbilirubinemia/ nonsevere hyperbilirubinemia

1. hematocrit between 25-35%

2. simple transfusion

mild anemia and nonsevere hyperbilirubinemia treatment

1. hematocrit >35%

2. mmonitor and treat hyperbilirubinemia

complications of hemolytic disease or newborn

1. kernicterus

2. deafness and fetal death

preventing hemolytic disease or newborn

1. RhoGAM if mom is Rh-

2. one dose at 28 weeks

3. if infant is Rh+- 2 doses, one at 28 weeks and the second within 72 hours after birth

increased production of bilirubin causes

1. hemolytic disease or newborn

2. ABO incompatibility

3. hemorrhage

4. polycythemia

causes of decreased clearance of bilirubin

1. prematurity

2. breast milk jaundice

clinical findings of hyperbilirubinemia

1. jaundice

2. acute bilirubin encephalopathy- lethargic, floppy, irritable

jaundice in the first 24 hours of life is always...

pathological

screening for hyperbilirubinemia

bilirubin level on all newborns within 24-48 hours

treatment of hyperbilirubinemia

1. bilirubin closely followed

2. adequate hydration/nutrition

3. phototherapy

4. if acute bilirubin encephalopathy- exchange transfusion

complications of hyperbilirubinemia

kernicterus- cerebral palsy, learning disabilities and deafness

prevention of hyperbilirubinemia

1. routine bilirubin checks prior to discharge

2. screening maternal/infant blood type

physiologic jaundice

1. benign neonatal hyperbilirubinemia

2. common

3. unconjugated hyperbilirubinemia

clinical findings of physiologic jaundice

mild yellowing of skin/sclera that resolves within 1-2 weeks after birth

mild unconjugated physiologic hyperbilirubinemia

peaks at 48-96 hours

treatment of physiologic jaundice

1. closely followed bilirubin levels

2. adequate hydration/nutrition

3. phototherapy

when does physiologic jaundice usually resolve?

by day 10

breastmilk jaundice

persistant benign physiologic jaundice beyond 2-3 weeks of life (unconjugated)

clinical findings of breastmilk jaundice

jaundice at days 3-5, peaks within 2 weeks after birth and resolves over 3-12 weeks

how is breastmilk jaundice different from lactation failure jaundice?

lactation failure jaundice- suboptimal fluid/caloric intake during first 7 days of life

treatment for breastmilk jaundice

1. typically none

2. follow bili levels

3. adequate hydration/nutrition

4. if threshold met- phototherapy

direct conjugated hyperbilirubinemia

1. never physiologic!

2. involves cholestasis or hepatocellular injury

3. CMV infection or other TORCH infection

clinical presentation of direct conjugated hyperbilirubinemia

jaundice not resolving to phototherapy or exchange transfusion

biliary atresia

1. gray-white stool and dark urine with jaundice after 2nd week of life

2. associated with direct conjugated hyperbilirubinemia

workup for direct conjugated hyperbilirubinemia

1. CMP

2. CBC with diff

3. PT/INR, PTT

diagnosis of direct conjugated hyperbilirubinemia

direct bili >1 mg/dL

treatment for direct conjugated hyperbilirubinemia

based on underlying cause

chronic bilirubin encephalopathy

1. aka kernicterus

2. form of bilirubin induced neuro dysfunction with permanent neuro sequelae

3. total serum bili >35- almost all infants will develop signs

clinical presentation of chronic bilirubin encephalopathy

1. lethargy

2. hypotonia

3. irritable

4. poor Moro response

5. poor feeding

what might an infant develop within the first year due to chronic bilirubin encephalopathy?

1. cerebral palsy

2. sensorineural hearing loss

3. gaze palsies

4. dental enamel hypoplasia

5. learning disabilities

prevention of chronic bilirubin encephalopathy

appropriate treatment of hyperbilirubinemia

congenital infections

acquired via vertical transmission aka transplacentally

what is key for congenital infections?

prevention!!!

TORCH infections

1. toxoplasmosis

2. other- gonorrhea, syphilis, varicella, HBV, HIV, parvovirus

3. rubella

4. CMV

5. HSV

congenital toxoplasmosis

vertical transmission of toxoplasma gondii

risk factors for toxoplasmosis

1. CATS

2. feces in soil- gardening

3. shellfish, undercooked or raw meat

clinical presentation of toxoplasmosis

1. asymptomatic

2. generalized maculopapular rash aka "blueberry muffin rash"

3. jaundice

4. fevers

what is the classic triad of toxoplasmosis?

1. hydrocephalus

2. chorioretinitis

3. intracerebral calcifications