Case 7_Newborn With Respiratory Distress

8/4/2019 Case 7_Newborn With Respiratory Distress

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Case 7: Newborn with Respiratory Distress

Details of the delivery are always important in assessing a newborn. In

this case, "fair" glucose control, unknown Group B strep status,prematurity, and C-section delivery all point to possible causes of

respiratory distress.

Maternal diabetes is a risk factor for respiratory distress syndrome andother difficulties. Maternal group B strep infection is a risk factor forneonatal sepsis. Prematurity predisposes to respiratory distress

syndrome (RDS) caused by lung immaturity and lack of surfactant,

but most infants born at 36 weeks' gestational age do not have RDS.C-section delivery predisposes to transient tachypnea of the newborn.

Additional risk factors that were NOT present in this case include

- Premature rupture of membranes 18 hours, a risk factor forneonatal sepsis

- Meconium in the amniotic fluid, a risk factor for meconiumaspiration syndrome.

Ms. Mason is taking no medications and has no history of other druguse. While possible this is unlikely based on the history.

Infants who aspirate meconium in utero or at the time of deliveryoften present with symptoms of respiratory distress, including

tachypnea. There was no meconium in the amniotic fluid making thisan unlikely diagnosis.

Asthma is not a diagnoses in the neonatal period, making thisdiagnosis unlikely.

Pulmonary embolism is very rare in children and usually is a resultof a clotting disorder. Pulmonary embolism is only seen in neonates

who have a predisposing condition such as the placement of a centralvenous catheter. Adam does not have this risk factor making this

diagnosis unlikely.

Proceed to the next card and rank the items in the differential

diagnosis.

The most likely diagnosis for Adam is Transient Tachypnea of the

Newborn or TTN. Transient tachypnea of the newborn is the result of

delayed clearance of lung fluid following birth.

Respiratory distress syndrome is the result of lung-surfactantdeficiency and is the most common cause of respiratory distress in

premature infants.

Congestive Heart Failure (CHF) in infants is most often caused by a

congenital heart defect.

Hypothermia should be considered in the differential diagnosis of a

tachypneic newborn.

Pneumothorax is relatively uncommon, but is always an importantconsideration in an infant with respiratory distress.

Neonatal sepsis can present initially with tachypnea and progress tomore severe illness rapidly. Prolonged rupture of the membranes, not

present in this case, is associated with an increased incidence of

neonatal sepsis. Neonatal sepsis is often due to Group B Beta Strep,usually transmitted from the mother during labor. We do not know

whether the mother was a GBBS carrier. This is an importantdiagnosis to consider, especially in premature infants.


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The Apgar score describes the condition of the newborn infantimmediately after birth and, when properly applied, is a tool for

standardized assessment. It provides a mechanism to record fetal-to-neonatal transition.

The Apgar score alone correlates poorly with the future neurologicaloutcome of the term infant. This is because the Apgar score is affected

by gestational age, maternal medications, resuscitation, andcardiorespiratory and neurologic conditions that may be present in the

infant. Low Apgar scores at 1 and 5 minutes alone are not conclusive

markers of an acute intrapartum hypoxic event. Poor neurologicoutcome is better associated with documented asphyxia, and that is

why it is important to obtain arterial blood gases to look for metabolicacidosis. There is a need for health care professionals to be consistent

in assigning an Apgar score during a resuscitation.

A neonate's birth weight is a good indicator of the health of the

intrauterine environment. Plotting the weight against gestational agehelps to identify infants with abnormal growth and allows the

anticipation of potential problems associated with each group.

Adam's birth weight is above the 90th percentile for his presumed 36-week gestational age. If gestational age assessment confirms that he is

indeed 36 weeks, he would be classified as large for gestational age(LGA). This is the term used to identify those newborns with birth

weight above the 90th percentile. Although many LGA infants are

constitutionally large, the most important pathologic etiology is

maternal diabetes mellitus. You will need to defer the gestational ageassessment until his clinical condition stabilizes, but you must beaware of potential clinical problems associated with being LGA:

- Large infants often must be delivered by C-section, by forceps, orvacuum extraction (all of which have associated complications)

- Birth injuries are more common, such as fractured clavicle, brachialplexus injury, and facial nerve palsy

- Hypoglycemia is especially common in LGA infants born to diabeticmothers

Newborns who are appropriate for gestational age (AGA) have birthweights between the 10th and 90th percentiles.

An infant with low birth weight may be premature, but low birth

weight may also result from many other causes. Newborns with birth

weights below the 10th percentile for gestational age are classified assmall for gestational age (SGA) or intrauterine growth restricted

(IUGR). The terms SGA and IUGR are both used in the literature,although the newer literature tends to favor the term intrauterine

growth restriction (IUGR). The SGA baby has unique potentialproblems, which may include:

- Temperature instability (hypothermia)- Hypoglycemia because of inadequate glycogen stores

- Polycythemia and hyperviscosity


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Persistent pulmonary hypertension of the newborn

Persistent pulmonary hypertension of the newborn (PPHN) is theresult of elevated pulmonary vascular resistance to the point that

venous blood is diverted to various degrees through fetal channels (the

ductus arteriosus and foramen ovale) into the systemic circulation and

bypasses the lungs, resulting in systemic arterial hypoxemia.

Link to adiagram illustrating this blood flow.

PPHN can result from several conditions, including meconiumaspiration syndrome, diaphragmatic hernia, hypoplastic lungs, and in

utero asphyxia. The following findings may indicate that an infant has

PPHN:

- Tachypnea

- Tachycardia- Respiratory distress, with findings such as expiratory grunting andnasal flaring

- Generalized cyanosis

- Low oxygen levels, even while receiving 100% oxygen

All of the tests listed above should be considered in the evaluation of acyanotic newborn.

Arterial blood gases help in determining the oxygenation, ventilation,

and acid-base status of the infant. Knowing the pCO2 is very helpful in

understanding the cause of the cyanosis.

The CBC with differential count is useful to rule out neutropenia,leukopenia, abnormal immature-to-total-neutrophil ratio, and

thrombocytopenia as signs of sepsis.

A chest radiograph is an integral part of the initial assessment of the

newborn with respiratory distress. The size and the shape of the heartmay yield some clues to the diagnosis. The appearance of the lungs

may suggest pneumonia, meconium aspiration, RDS, etc. Normalinspiratory films should have eight or more intercostal spaces of lung

fields on both sides.

An echocardiogram is the gold standard in the diagnosis of congenital

cardiac lesions and persistent pulmonary hypertension of the newborn.An echocardiogram is indicated when there is persistent cyanosis and

no indication of lung disease, or when there are other signs suggesting

a heart defect, such as a murmur, an abnormal ECG or a chest X-rayshowing an abnormal cardiac contour.

An oxygen challenge test (hyperoxia test) is a valuable tool that can

help differentiate between cardiac and pulmonary etiology in infantswho are cyanotic. In brief, oxygen will increase the PaO2 of an infant

whose cyanosis is caused by a respiratory condition, but will not

significantly increase the PaO2 if a cardiac lesion causes cyanosis. Thistest is described in some detail in the article by Sasidharan.

Physical examination is critical to identify heart murmurs and

respiratory findings that might be the cause of the cyanosis.

Remember, however, that some murmurs may not be present early inlife because of the elevated pulmonary vascular pressure.
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Pulse oximetry detects the oxygen saturation in the blood.

The findings of tachypnea, retractions and grunting are classicalsymptoms of respiratory distress from any cause. Intercostal and

subcostal retractions reflect the increased work of breathing due to

decreased lung compliance, either due to primary lung pathology oredema. Grunting occurs at the end of expiration, and is the audiblesound of air being expelled through a partially closed glottis as the

infant attempts to increase transpulmonary pressures, increase lung

volumes, and improve gas exchange. For Adams case, physicalexamination helps rule out some of these possibilities.

Congenital diaphragmatic hernia is a congenital malformation

resulting from a defect in the development of the diaphragm. It occurs

in 1 out of every 2,200 to 5,000 live births. The most common type is

the Bochdelek hernia (a posterolateral hernia) that accounts for themajority (> 95%) of cases. This defect allows the passage of organsfrom the abdomen into the chest cavity and severely impairs lung

development. Most defects occur on the left side. Absent breathsounds or presence of bowel sounds on one side of the chest are

important diagnostic clues. Adams physical examination with the

presence of bilateral normal breath sounds makes this diagnosisunlikely.

Pneumothorax is caused by a collection of gas in the pleural space

with resultant collapse of lung tissue. Common risk factors aremechanical ventilation or underlying lung disease (especiallymeconium aspiration or severe infant respiratory distress syndrome).

Absence of breath sounds on one side of the chest in combination withrespiratory distress is an important diagnostic clue. Adams physical

examination with the presence of bilateral normal breath sounds

makes this diagnosis unlikely.

Transposition of the Great Arteries (TGA) is a congenital heartdefect in which the aorta and pulmonary arteries are transposed

resulting in respiratory distress and severe cyanosis at shortly afterbirth as the patent ductus arteriosus closes. One risk factor for

transposition of the great arteries is being born to a diabetic mother.

TGA is often associated with other congenital heart defects such as a

VSD so a murmur may be heard on physical examination. Adamsnormal cardiovascular examination and absence of cyanosis makesthis diagnosis unlikely.

Hypothermia can cause tachypnea and may be associated withneonatal sepsis. Small for gestational age and premature infants are at

increased risk to develop hypothermia. Adams temperature is normaland he is an LGA infant making this diagnosis unlikely.

Severe Coarctation of the Aorta may cause respiratory distress if

there is severe left ventricular outflow tract obstruction. Classically,diminished pulses in the lower extremities or asymmetric bloodpressure readings suggest the diagnosis. In severely ill neonates, there

may be no differences in the pulses because cardiac output is so poor.

Adams general appearance and normal pulses in all extremitiesargues against this diagnosis.

Transient tachypnea of the newborn (TTN) - Because Adam islarge for gestational age, was born by C-section, and his clinical

picture does not fit the other diagnoses well, TTN is a likely diagnosis

for his respiratory distress.

Infant Respiratory distress syndrome (RDS) remains a possibility,

but is less likely than TTN in a 36-week gestation infant. A chest X-

Ray may help to distinguish between TTN and RDS


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Hypoglycemia may be seen in infants of diabetic mothers due to the

chronic hyperinsulinemic state that occurred during gestation.Hypoglycemia may be more pronounced in premature infants.

Tachypnea is a non specific response to this metabolic derangement.

This diagnosis remains a possibility for Adam and could beinvestigated by a serum glucose reading.

Congestive heart failure is unlikely because Adam has a normal

cardiovascular system with no murmur, normal pulses and normaloxygen saturation. This constellation of symptoms rules out most

major cardiac causes of congestive heart failure.

Neonatal sepsis is unlikely (but not impossible) because Adam has

normal temperature, blood pressure and perfusion. In addition, his

mother is well without fever suggesting she does not havechorioamnionitis.

High levels of maternal serum glucose during pregnancy result in

hyperglycemia in the fetus. This stimulates the fetal pancreatic betacells and the development of hyperinsulinemia. Maternal insulin does

not cross the placenta.

Insulin is the primary anabolic hormone for fetal growth. High levels

in the third trimester result in increased growth of the insulin-sensitive

organ systems (heart, liver and muscle) and a general increase in fatsynthesis and deposition. This combination of increased body fat,

muscle mass, and organomegaly produces a macrosomic (LGA)infant. Insulin-insensitive organs, such as the brain and kidneys, are

not affected by the elevated insulin levels, and have appropriate sizefor gestational age.

Control of diabetes during pregnancy is an important predictor of fetal

outcome, especially with regard to the risk of birth defects. The

incidence of major malformations is directly related to the First-

Trimester HbA1C level: Infants born to women with HbA1C levels>12 have at least a 12-fold increase in major malformations.

When discussing medical problems that are evolving, it is important to

be clear about what you know and what the next steps in the

evaluation will be. It is difficult to balance the need to reassure parentsand help them understand the potentially serious causes of their childssymptoms. Each of the above answer represents a reasonable

approach but each could be improved.

A. This answer attempts to explicitly reassure Ms. Mason and

provides the most likely cause of his symptoms. Including

comments like I am sure he will be fine, may be prematureand in most cases should be avoided.

B. This answer explains in lay language what is happening to

Adam and outlines the expected course of the disease howeverit doesnt acknowledge that there is still significant uncertaintyin the diagnosis. It does outline that careful observation will be

included but doesnt explain that additional testing will need to

be done. Leaving this out may cause surprise and anxiety in theparent when the tests are done.

C. This answer outlines the most likely cause and the next steps inthe plan. It also explains that more tests will be done because

uncertainty about the diagnosis exists. It isnt clear what tests

are being done but does outline that additional communication

will be happening soon.D. This answer is more complete in the explanation of the

possible conditions that might be causing the symptoms and

how the tests will help management. It isnt clear what thetimeline will be for reporting back the new information which

will be important to include to help Ms. Mason know what to

expect.


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None of the answers outlined what additional signs would beworrisome and how Ms. Mason could help watch for them.

Demystifying exactly what you will be monitoring to know if Adam isimproving will be simultaneously reassuring and will enlist the parent

as an active partner in their childs care.

The recommendations for feeding infants with respiratory distressvary, depending on the physician's experience or the policy of theneonatal unit. There is no evidence from controlled studies that

feeding a tachypneic infant by mouth is contraindicated, although

many physicians are reluctant to try this because they feel that oralfeedings place the infant under greater stress. Many infants with

respiratory rates of 60-80 per minute tolerate oral feeds, but some mayneed nasogastric feeding or IV fluids if respiratory distress worsens

with feeding. Many infants with respiratory rates of > 80 per minute

will have difficulty with both oral and nasogastric feedings and will

often require intravenous fluid support.

The use of a nasogastric feeding tube will avoid use of a bottle, which

may facilitate Ms. Mason's wish to breastfeed.. (After feeding from abottle, some babies may get frustrated when they breastfeed because

the milk does not flow as fast from the breast as from a bottle.)

Link to the AAP's policy on the benefits of breastfeeding.

See the Expert for links to information about breastfeeding and HIV

and also about transmission of drugs and other chemicals into humanmilk. http://pediatrics.aappublications.org/cgi/content/full/112/5/1196

Glucose is the primary substrate for brain metabolism in the neonate,and even asymptomatic hypoglycemia may have negative

consequences for long-term neurodevelopment.1,2 The precisedefinition of hypoglycemia in the neonate has been difficult to

establish because plasma glucose levels often do not correlate with

symptoms and long-term outcome. A newborn can be hypoglycemic

yet be entirely asymptomatic. This is why it is important to screen allnewborns for glucose level and to monitor closely the glucose levelsof infants of diabetic mothers.

In utero, glucose crosses the placenta, maintaining the fetal bloodglucose at approximately two-thirds of maternal levels. At birth,

separation from the placenta results in a decline in the infant's glucoselevels over the first 1-2 hours of life. Levels then increase and stabilize

by 3-4 hours at mean levels of 65-71 mg/dL. The infant of a diabeticmother has hyperinsulinemia and the glucose level declines

precipitously at birth. Prompt intervention is required to raise glucoselevels. Both the definition of hypoglycemia and identification of athreshold value (below) that signals intervention is indicated have

been revised.3, 4, 5

Currently, most neonatologists attempt to maintain glucose levels

between 41-50 mg/dL. Proposed Threshold Values for initialintervention depend on the clinical situation4:

- Asymptomatic infants and infants at risk for hypoglycemia:


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The glucometer test is a screening test only, and must not be used toconfirm hypoglycemia. Glucose oxidase reagent strips are read by

meter (glucometer) or by eye (Dextrostix, Chemstrip) and measurewhole blood glucose, which is 10-15% lower than plasma glucose

levels. These reagent strips are widely used as screening tools for

hypoglycemia and may also be used for ongoing monitoring of

glucose levels. Any reagent-strip reading of whole blood glucose 40 mg/dL). The frequency of

monitoring will depend on the severity of the hypoglycemia and may

range from every 30 minutes to every 3 hours prior to feeds. If theblood glucose is not >40 mg/dL with the first enteral feeding, most

pediatricians would initiate IV dextrose infusions.

Breast milk is the ideal nutrient for the newborn human. It provides alower renal solute load than formula, has several anti-infective and

anti-allergic properties, and fosters mother-infant bonding. Separationof mother and infant poses a challenge for the successful

establishment of breastfeeding. This most often happens with the birth

of a premature infant, or an infant requiring special care, such as

Adam. Adam's ability to breastfeed will be determined by letting hismother put him to the breast as soon as possible. If he cannotsuccessfully breastfeed because of his tachypnea, it will be important

that Ms. Mason begin pumping her breasts as soon as possible after

delivery. This will initiate milk production and ensure an adequatesupply when Adam is able to feed at the breast. In the meantime,

Adam would be fed expressed breast milk, supplemented with formulaas needed while breast milk volumes are low in the first 2-48 hours

after birth. Pumping breast milk is also psychologically helpful formothers at a very stressful time: Breast milk is the single thing that no

one else can provide for their infants.

A - CBC with differential is appropriate because respiratory distressmay be caused by sepsis.

D - Serum or plasma glucose level is important to confirm theglucometer reading.

E - Tachypnea may be the only sign of early sepsis or pneumonia.

G - Lumbar puncture is part of the evaluation for any newborn in

whom sepsis or meningitis is suspected. It is important to rememberthat the very young infant with sepsis and/or meningitis may have no

localizing signs and only subtle clinical symptoms, such astemperature instability, lethargy, and poor feeding. See: Heath, PT,

Yusoff NK, Baker CJ. Neonatal Meningitis.Arch Dis Child Fetal andNeonatalEd 2003;88(3):173-178.

H - Blood gas or pulse oximetry monitoring should be considered in


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this case because of the tachypnea, which can be a manifestation ofrespiratory distress. Measurement of ABGs is used to assess

oxygenation (PaO2), retention of carbon dioxide (PaCO2), and acid-base states (pH and HCO3). If respiratory distress is mild, the infant

pink in color, and the infant is not otherwise at risk, blood gas

determination is not essential. Other risk factors for hypoxemia would

include shock, severe sepsis, CNS depression, and perinatal asphyxia.This infant has none of these risk factors. See: Brouillette RT,Waxman DH. Evaluation of the Newborn's Blood Gas Status. Clinical

Chemistry 1997;43(1):215-221.

I - Chest X-ray is important because of the tachypnea and respiratory

distress.

Other laboratory tests are not indicated at this time:

B & C - Determination of serum electrolytes and calcium is notrecommended early after birth because the newborn's levels reflect the

mother's status as well as the effect of medications administered to themother during labor. Results at age 12-24 hours are more indicative of

the infant's status.

F - A urine culture in the early neonatal period (birth to 3 days old) is

of little value. It may be more useful for an infant 4 days or older whois suspected of having late-onset sepsis.

The CXR findings are typical of TTN, with "wet" looking lungs, no

consolidation, and no air bronchograms (which would indicaterespiratory distress syndrome). There is no evidence for a

diaphragmatic hernia. A repeat chest X-ray will not be needed as longas Adam shows continued clinical improvement.

X-ray findings similar to those on Adam's films may also be seen withneonatal pneumonia, but this diagnosis is unlikely in the absence of

other clinical signs of sepsis. If respiratory symptoms do not improve,

a repeat chest X-ray should be ordered and intravenous antibioticsshould be initiated.

TEN

An infant with respiratory distress syndrome (RDS) would have

radiographic findings that typically include a diffuse reticulogranularappearance of the lung fields ("ground glass appearance") and air

bronchograms. Link to an X-ray showing a newborn withrespiratorydistress syndrome.
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Diaphragmatic hernia most commonly develops on the left side. Aradiograph shows air-filled loops of bowel in the left side of the chest,

displacing the heart and mediastinum to the contralateral side. Link toan X-ray of a newborn with adiaphragmatic hernia.

Developmental Dysplasia of the Hip (DDH) is the current term for the

condition previously known as Congenital Dislocation of the Hip. It isnow recognized that dislocation of the hips is a developmental process

that is not always detectable at birth. In spite of newborn screeningprograms we continue to see dislocated hips being diagnosed later in

infancy.

Clinical features of DDH include partial or complete dislocation orinstability of the femoral head.

Risk factors for DDH include:- Breech position: 30-50% occur in infants born in the breech position.

- Gender: 9:1 female predominance.

- Family history.

With the goal of decreasing the number of dislocated hips detectedlater in infancy, the American Academy of Pediatrics has developed a

Clinical Practice Guideline for primary care providers. The maincomponents of this guideline are the recognition of risk factors and

regular hip examinations up to age 18 months. Linkto the AAPguideline.

All of these factors are important in planning the discharge of

newborns from the hospital. It is important that the parents beprepared for the discharge, and that appropriate follow-up is arrangedin the first week after birth. Any infant discharged from the nursery

before 48 hours of life must be evaluated by a health care practitioner

within 48 hours. See the references below for AAP policy guidelineson hospital discharge, safe transportation of newborns, breast feeding,

sleeping position and SIDS, and vitamin D supplementation.

The breastfed infant will typically feed on demand every 2-4 hours,feeding 10-15 minutes on each side. Ms. Mason should contact the

pediatrician if Adam does not have at least 6 wet diapers per day. Sheshould also observe for development of jaundice over the next severaldays and contact the physician if it does appear.

The American Academy of Pediatrics recommends that exclusively

breastfed infants receive a daily dose of 200 IU of Vitamin D, because

human milk does not provide adequate intake if it is the sole source ofnutrition. This supplementation should continue until the infant is

weaned to a formula containing vitamin D. Standard formulas allcontain at last 400 IU of vitamin D and meet the infant's needs.

All infants must be transported in a car seat, following the guidelines

in the AAP SAFE Ride Program/Family shopping guide to car seats.

The Back to Sleep program has resulted in a significant decrease in the

incidence of Sudden Infant Death Syndrome. Ensure that parents areaware of the guidelines. Co-bedding of an infant with an adult

increases the risk of death by suffocation should the adult accidentally

roll onto the infant. The AAP recommends that infants not bed shareduring sleep. Infants may be brought into bed for nursing or
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comforting but should be returned to their own bassinet or crib whenthe parent is ready to return to sleep. The infant should not be brought

into bed when the parent is excessively tired or using medications orsubstances that could impair his or her alertness. The task force

recommends that the infants bassinet or crib be placed in the parents

bedroom, which will allow for convenient breastfeeding and contact.

Infants also should not bed share with other children.

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Case 7_Newborn With Respiratory Distress