neonatal diseases

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Neonatal Diseases

RC 290



Respiratory Distress

Syndrome

(RDS)

Also known as Hyaline MembraneDisease

(HMD)



Occurrence

1-2% of all births

10% of all premature births

Greatest occurrence is in the premature and low birth weight infant



Etiology & Predisposing Factors

Prematurity

Immature lung architecture and surfactantdeficiency

Fetal asphyxia & hypoxia

Maternal diabetes

Increased chance of premature birth

Possible periods of reflex hypoglycemia in thefetus causing impaired surfactant production



Pathophysiology

Surfactant deficiency

Decreased FRC

Atelectasis

Increased R-L shunt

Increased W.O.B.

Hypoxemia and

eventuallyhypercapnia becauseof V/Q mismatch



Pathophysiology (cont .)

Atelectasis keeps PVR

high

Increased PAP

Lung hypoperfusion

R-L shunting may re-

occur across the

Ductus Arteriosus andthe Foramen Ovale



The cycle continues until

surfactant levels are adequate to

stabilize the lung

Symptoms usually appear 2-6 hours after

birth

Why not immediately?

Disease peaks at 48-72 hours

Recovery usually occurs 5-7 days after birth



Clinical findings: Physical

Tachypnea

(60 BPM or >)

Retractions

Nasal flaring

Expiratory grunting

Helps generate

autoPEEP

Decreased breath

sounds with crackles

Cyanosis on room air

Hypothermia

Hypotension



Clinical Findings: Lab

ABGs: initially respiratory alkalosis and

hypoxemia that progresses to profound

hypoxemia and combined acidosisIncreased Bilirubin

Hypoglycemia

Possibly decreased hematocrit



CXR: Normal



RDS CXR: Ground Glass Effect



RDS CXR: Air Bronchograms &

Hilar Densities



Time constant is decreased

since elastic resistance is so

high

Increased elastic resistance means

decreased compliance!



RDS Treatment: Primarily

supportive until lung stabilizes

NTE, maintain perfusion, maintainventilation and oxygenation

O2 therapy, CPAP or mechanicalventilation

May require inverse I:E ratios if oxygenationcan not be achieved with normal I:E ratio

Surfactant instillation!!!May cause a sudden drop in elastic resistance!



Prognosis/Complications

Prognosis is good once infant makes it past

the peak (48-72 hours)

Complications possible are:Intracranial Bleed

BPD (Bronchopulmonary Dysplasia)

PDA (Patent Ductus Arteriosus)



Transient Tachypnea of the

Newborn (TTN)

Also known as Type II RDS or

Retained Lung Fluid



Occurrence: Similar to

RDS

More common in term infants!




C-section

These infants do not have the fluid expelled

from their airways as occurs in vaginal delivery

Maternal Diabetes

Increased chance of C-section due to LGA

Cord CompressionAnesthesia



TTN Pathophysiology

Primary problem = retained lung fluid

Fluid not expelled from airways because of C-section

Poor absorption of remaining fluid by pulmonarycapillaries and lymphatics

If retained fluid is in interstitial spaces,compliance and TC are decreased

If retained fluid is in airways,airway resistanceand TC are increased

TTN can be restrictive , obstructive, or both!

Fluid usually clears by itself after 24-48 hoursafter birth



Clinical Signs

Tachypnea (usually rate is greater than seen

in RDS)

Minimal (if any) nasal flaring or expiratorygrunting

ABG’s: mild hypoxemia. PaCO2 depends

on whether problem is restrictive orobstructive



TTN CXR

Coarse peri-hilar streaks

Prominent lung vasculature

Flattened diaphragms if fluid is causingobstruction/air-trapping



TTN Treatment: Like RDS, it is

primarily supportive

Monitoring and O2 therapy

Possibly CPAP or mechanical ventilation



Prognosis/Complications

Prognosis is very good

Main complication is pneumonia

Often initial diagnosis



Patent Ductus Arteriosus

-PDA_

Failure of the D.A. to close at birth or

a re-opening of the D.A. after birth.

Allows shunting between the

pulmonary artery and the aorta



Occurrence

1 per 2000 term babies

30-50% of RDS babies




Prematurity

D.A. not as sensitive to increasing PaO2

Hypoxia

Decreasing PaO2 allows it to re-open for up to three

weeks after birth

Thus, a PDA can occur in a premature infant whois NOT hypoxic or in a term baby who is hypoxic

Worst case is a premature infant who is hypoxic!



Pathophysiology

D.A. fails to close or it re-opens

Then shunting occurs between the pulmonary artery and the aorta

The direction of the shunt depends on whichvessel has the higher pressure

A PDA can cause L-R shunting or R-L

shunting!Clinically, most PDA’s refer to a L-R shunt



Clinical Signs

Tachypnea, bounding pulses, hyperactive

pre-cordium

Decreased breath sounds and possibly somecrackles

Possible murmur over left sternal border

Murmur is loudest when D.A. just startsopening or when it is almost closed



Clinical Signs (cont .)

ABGs – hypoxemia with respiratory acidosis

If R-L shunting, the PaO2 in the upper extremities,ie pre-ductal, will be greater than the PaO2 in the

umbilical artery, ie post-ductal!TC – decreased if L-R shunting causes pulmonaryedema; increased if fluid spills into airways andincreases airway resistance

CXR –

if L-R shunt, butterfly pattern of pulmonaryedema with possible cardiomegaly



PDA Treatment

Basic – NTE, O2, may require CMV if not already

on the ventilator

Medical

L-R shunt that fails to close: Indomethacin (Indocin)

R-L shunt: Priscoline (Tolazoline) to decrease PVR;

also nitric oxide

Surgical – if medical treatment fails, the PDA may be surgically ligated



Meconium Aspiration

Syndrome

-MAS-

Syndrome of respiratory distress that

occurs when meconium is aspirated prior to or during birth



Occurrence

10-20% of ALL births show meconium

staining

10-50% of stained babies may be symptomatic

More common in term and post-term babies




Intra-uterine hypoxic or asphyxic episode

Post-term

Cord compression

h h i l h k l



Pathophysiology: Check Valve

Effect

Causes gas trapping

(obstruction)

If complete obstruction, theneventually atelectasis occurs

Irritating to airways, so edema

and bronchospasm

Good culture ground for

bacteria, so pneumonia

possible



Pathophysiology (cont .)

V/Q mismatch leads to hypoxia and

acidosis which increases PVR

TC increases because it increases airwayresistance

Meconium is usually absorbed in 24-48

hours; there are still many possiblecomplications



Clinical Signs

Respiratory depression

or distress at birth

Hyperinflation

Pallor

Meconium stained

body

Possible cyanosis on roomair

Moist crackles

ABGs – hypoxemia withcombined acidosis

CXR – coarse, patchyinfiltrates with areas ofatelectasis and areas of

hyperinflationMay see flatteneddiaphragms if obstruction issevere



M.A.S. Treatment

Amnioinfusion – artificialamniotic fluid infused intouterus to dilute meconium

Proper resuscitation at

birth(clear meconiumfrom trachea beforestimulating respiration)

Oro-gastric tube

NTEO2

NaHCO3 if severe metabolicacidosis

Broad spectrum antibiotics

Bronchial hygiene

May need mechanicalventilation

Slow rates and wide I:Eratios because of increasedTC

Low level of PEEP mayhelp prevent check valveeffect

May need HFO



Prognosis & Complications

Good prognosis if there are no complications

Complications:Pneumonia

Pulmonary baro/volutrauma

Persistent Pulmonary Hypertension (PPHN)



Persistent Pulmonary Hypertension

-PPHN-

Also known as Persistent Fetal

Circulation-PFC-



Failure to make the

transition from fetal to

neonatal circulation or a

reversion back to the

condition where pulmonaryartery pressure exceeds

aortic pressure

Results in R-L shunting across the

D.A. and the Foramen Ovale




M.A.S – most common

Hypoxia and /or acidosis, eg RDS

Any condition that causes PVR to increase



Pathophysiology

Primary problem is pulmonary artery hypertension

Infants arterial walls are thicker and they are more prone to vasospasm

If pulmonary artery pressure gets high enough, blood will shunt R-L across the D.A. and ForamenOvale

Remember, conditions that drive up PAP usually makethe D.A. open

Lung is hypoperfused resulting in refractoryhypoxemia and hypercapnia



Clinical Signs

Refractory hypoxemia and cyanosis

Shock and tachypnea

Murmur possiblePre-ductal PaO2 > post-ductal PaO2

Hypoxemia with combined acidosis

CXR usually OK when compared to infantscondition




Prognosis depends on how well infant

responds to treatment

ComplicationsShock

Intracranial bleed

Internal bleedingEspecially a problem if Priscoline is used



Wilson – Mikity Syndrome

- Pulmonary Dysmaturity-Respiratory distress that develops

after the first week of life and

presents with definite CXR changes



Occurrence

Usually in <36 weeks gestational age and

birth weight <1500 grams

After first week of life No prior symptoms




Exact etiology unknown

Appears to be due to immature lung and

airways trying to function Not due to O2 toxicity or mechanical

ventilation!



Pathology

Immature alveoli and T-B tree causes V/Q

mismatch

Areas of atelectasis and hyperinflationdevelop



Pathology (cont .)

3 Stages

Stage 1

1-5 weeks after birth

Diffuse areas of atelectasis and hyperinflationStage 2

1-5 months after birth

Cystic (hyperinflated) areas coalesce and cause

flattening of the diaphragmsStage 3

5-24 months after birth

Cystic areas start to clear up



Clinical Signs

Tachypnea


Some retractions and/or nasal flaringDecreased breath sounds with crackles

ABGs – respiratory acidosis with

hypoxemiaCXR consistent with the stage of the disease



Wilson – Mikity Treatment

Is purely supportive-there is no medicinal or

surgical treatment

O2 and NTESome cases require mechanical ventilation

Maintain fluids/electrolytes and caloric

intakeWatch for infection




Prognosis good if infant survives stage 2

Complications

PDACor Pulmonale

CNS damage



Bronchopulmonary Dysplasia

-BPD-A result of RDS and/or its treatment

that results in areas of fibrosis,

atelectasis, and hyperinflation




RDS and prematurity

Triad of O2, ET tube, and mechanical

ventilation



Pathology: 4 Stages

Stage 1

Acute phase of RDS

Stage 2

4-10 days after the onset of

RDSAreas of atelectasis andhyperinflation

Stage 3

2-3 weeks after RDS

Hyperinflated areas start tocoalesce

Fibrosis starts to develop

Stage 4

1 month after the onset of

RDS

Diaphragms start to flatten

Interstitial fibrosis evident

on CXR

PPHN may start to develop

O2 dependency develops



Clinical Signs

Tachypnea

Persistent retractions

A-B spells


Decreased breath sounds with crackles

ABGs – respiratory acidosis (may be

compensated) with hypoxemia

CXR – consistent with stage of disease



BPD: Stage 4 CXR

Interstitial fibrosis and flattened diaphragms



BPD Treatment

Prevention is best! Use the least amount ofintervention for the least amount of time!

Supportive care

O2, NTE, bronchial hygiene, maintainfluids/electrolytes

Diuretics if needed to prevent fluid overloadand heart failure

Possibly vitamin E




Good if infant survives to age 2

50% mortality if PPHN develops

ComplicationsPHTN

Cor Pulmonale

Respiratory InfectionsCNS damage



Diaphragmatic HerniaCongenital malformation of the

diaphragm that allows abdominal

viscera into the thorax



Occurrence

1 per 2200 births




Exact unknown but may be related to

vitamin A deficiency



Clinical Signs

Cyanosis

Severe respiratory distress with retractions andnasal flaring

Bowel sounds in chestUneven chest expansion

Decreased breath sounds on affected side

ABGs – profound hypoxemia with combinedacidosis

CXR – loops of bowel in chest with shift ofthoracic structures towards unaffected side, egdextrocardia



Diaphragmatic Hernia CXR




50% mortality

Complications

PneumothoraxPDA

Hypoplastic lung



Pulmonary Barotrauma&

Air Leak Syndromes



4 Main Types

Pneumothorax

Pneumomediastinum

Pneumopericardium

PIE (Pulmonary Interstitial Emphysema)Gas from ruptured alveoli dissects along perivascularand interstitial spaces

Causes airway compression (obstruction) and alveolar

compression (restriction)May lead to pneumothorax, pneumomediastinum, or

pneumopericardium



Occurrence1-2% of all births

(not all are symptomatic)




Positive pressure ventilation

Increased airway resistance/airway

obstructionRDS



Clinical Signs

Sudden cyanosis

(except with PIE)

Respiratory distress

Mediastinal shift

Sudden hypotension

(except with PIE)

Crepitus (if sub-Q

emphysema develops)

Unequal chest expansion

Decreased breath soundsand hyperressonance

ABGs – hypoxemia with

respiratory acidosis

Transillumination



Transillumination



CXR: Pneumothorax



CXR: Pneumomediastinum

Note how air does NOT outline the apex of the

heart



CXR: Pneumopericardium

Note how air completely outlines the

heart



CXR: PIE



Air Leak Syndrome Treatment

Prevention! Use the least amount of

intervention for the shortest time possible!

Chest tube for pneumothorax

HFO may help prevent and/or resolve PIE



Prognosis and Complications

Good as long as shock and/or cardiac

tamponade does NOT occur

PIE puts infant at risk for BPD



Necrotizing Enterocolitis-NEC-

Necrosis of the intestinal mucosa



Occurrence

20% of all premature births

Males = Females

Most common in low birth weight babieswho experience perinatal distress




Exact cause unknown but seen with the

following:

Intestinal ischemia

Bacterial colonization

Early formula feeding



Pathology

Intestinal ischemia due to hypoperfusion, egshock, or vascular occlusion, eg, clot fromumbilical artery catheter

Bacterial colonization after ischemia startsnecrosis

Early formula feeding may provide

substrate needed for further bacterial growthand further necrosis



Clinical Signs

Abdominal distention

Poor feeding

Blood in fecal material

Lethargy

Hypotension

Apnea

Decreased urine output

Bile stained emesis

CXR – bubbles inintestinal wall



NEC Treatment

NPO and NG suction

IV hydration and hyperalimentation

Broad spectrum antibiotics

Ampicillin, Gentamycin

Minimum pressure on abdomen

No diapers or prone positioning

Monitor for/treat sepsis Necrotic bowel may need surgical resection




Mortality is 20-75%

Best prognosis if infant does NOT require any

surgery

Main complication is sepsis

Infants who have bowel resection may

develop malabsorption syndrome



Congenital Cardiac

Anomalies



Tetralogy of Fallot

VSD

Over-riding aorta

Pulmonary valve

stenosis

Right ventricular

hypertrophy

Significant cyanosis because of R-L shunt

Complete Transposition of the



Great Vessels

Pulmonary artery arisesfrom left ventricle andAorta arises from rightventricle

R-L shunt through PDA,ASD, or VSD needs to be

present for infant tosurvive until correctivesurgery

Balloon septostomy duringcardiac catheterization



Truncus Arteriosus

Aorta and pulmonary

artery are the same

vessel

Large VSDRequires MAJOR

surgical repair

Mortality is 40-50%

neonatal diseases

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