Pediatric Lung Diseases Flashcards
Respiratory Distress Syndrome aka?
Hyaline Membrane Disease
Most common cause of respiratory failure in preterm infant
RDS
- Lung disease in a preterm infant resulting from what?
- Major cause of morbidity and mortality in infants born prior to ___ wks gestation
- What has changed clinical course and decreased morbidity and mortality rates?
- insufficient surfactant
- 30
- Exogenous surfactant
Incidence and severity ↑’d in male infants. Why?
↑’d circulating androgens ↓ lung maturity and surfactant production by type II pneumocytes
Risk factors:
Increased Incidence
in the following?
6
- Low gestation
- Male sex
- White race
- Maternal diabetes
- C-section pre-onset of labor
- Perinatal asphyxia
- Maternal hypertension
Why is maternal diabetes a risk factor for RDS?
↑’d insulin ↓’s lung maturation and surfactant production
Risk factor: Decreased incidence for RDS?
4
- Prolonged rupture of membranes
- Chronic congenital infections
- Maternal substance abuse
- Antenatal corticosteroid exposure
2 Major Issues in PP of RDS?
Immature lungs
Lack of surfactant
Infants may be born in:
what of lung development? (two stages)
At these stages what developmental issues might be a problem? 2
- Canalicular stage
16-26 wks - Saccular stage
24-38 wks - May have primitive airspaces with undifferentiated pneumocytes
- No juxtaposition of airway epithelium and capillaries
What happens during the canalicular phase of development in the fetus for the lungs? 3
- Last generations of the lung periphery formed
- Epithelial differentiation
- Air-blood barrier formed
What happens during the saccular phase of development in the frtus for the lungs? 2
- Expantion of air spaces
2. Surfactant detectable in amniotic fluid
Surfactant:
- Appears in fetal lung at _____wks
- Made by what cells?
- Adequate amounts not produced until about ___ wks
- What are the functions of surfactant? 3
- 23-24
- type II pneumocyte
- 35
- Reduces surface tension in alveolar spaces
- Facilitates lung expansion
- Prevents alveolar collapse
Very premature infants frequently have:
2
These may further contribute to what?
- Excessively compliant chest walls
- Weakness of the respiratory muscles
Alveolar collapse
Pathophysiology of RDS?
7
- Alveolar collapse alters nl ventilation/perfusion relationship
- Produces pulmonary shunting → progressive arterial hypoxemia → metabolic acidosis
- Hypoxemia and acidosis → vasoconstriction → decreased pulmonary blood flow (pulmonary hypertension)
- May produce R→L shunting through PFO and PDA → worsening hypoxemia
- Pulmonary blood flow may subsequently increase
- –Decreased vascular resistance and persistence of PDA - ↑’d pulmonary blood flow leads to accumulation of fluid and protein in interstitial and alveolar spaces
- Protein in alveolar spaces deactivates surfactant
- Atelectasis and ↑’d dead space → ?
- Intrapulmonary and extrapulmonary shunting → ?
- Atelectasis, ↑PaCO2, hypoxemia →?
- ↑PaCO2 → ?
- Hypoxemia → ?
- ↑PaCO2
- hypoxemia
- tachypnea
- respiratory acidosis
- metabolic acidosis
Hyaline Membrane Disease aka?
RDS
- Lungs appear how?2
- _____________ line most of remaining airspaces
- Hyaline membranes are made up of what that has leaked from where?
- HMD and epithelial necrosis is less severe in infants treated with what?
- solid and
- congested with diffuse atelectasis
- Hyaline membranes
- plasma proteins leaked from damaged epithelium
- surfactant
Clinical Course:
- PE? 5
- CXR will show? 3
- Blood gas will show? 3
Physical exam
- progressive tachypnea,
- subcostal and sternal rtxns,
- grunting,
- cyanosis and
- ↓ breath sounds present in minutes to hours of life
CXR
- ↑ density of both lung fields with reticulogranular infiltrates,
- air bronchograms, and
- elevation of diaphragm
Blood gas
- Hypoxemia,
- hypercarbia, and
- metabolic acidosis
- Severity of respiratory failure ↑’s during first ___ days of life
- In infants > ______ wks respiratory status usually improves by 1 wk of life
- In infant less than ____ wks course is usually prolonged and complicated by what? 5
- 2-3
- 32-33
- 26-28
- volutrauma and/or
- barotrauma,
- PDA,
- infection, and
- intraventricular hemorrhage
- Treatment of HMD/RDS?
- What does it decrease the need for?
- Reduces incidence of what?
- Exogenous surfactant has drastically changed course of disease
- Rapidly ↓’s need for oxygen and mechanical ventilation
- Reduces incidence of gas leaks
Other treatment measures:
- Where should treatment take place?
- Monitoring of what?
- Adequate respiratory support that includes?
- Careful stabilization in delivery room and NICU
- Proper monitoring of cardiopulmonary function
- Oxygen,
- CPAP,
- mechanical ventilation
Proper thermal, metabolic and nutritional support
Prevention of RDS?
2
- Prevention of premature delivery
2. Antenatal corticosteroids
How do Antenatal corticosteroids help with prevention of RDS?
3 (on what kind of timeline?)
What happens after 24 hours on steriods?
Rapid change (within 15 hrs) in lung structure
- Improved compliance
- ↑’d lung volume
- ↓’d capillary protein leak
Slower (>24 hrs) ↑ synthesis and secretion of surfactant by type II cells
Complications of RDS? 2
What may this be seen with administration of?
Usually occurs when and with what kind of severity?
- Hemorrhagic pulmonary edema
- Capillary rupture and interstitial fluid
May be seen with exogenous surfactant
- Usually occurs in first 5-7 days of life
- May be rapidly fatal
What kind of pathophysiological features lead to these complications?
- Low lung volumes
- Air bronchograms/atelectasis
- hyponatremia
Need to give O2 early?
SIDS definition?
“the sudden unexpected death of an infant less than 1 year of age, with onset of the fatal episode apparently occurring during sleep, that remains unexplained after a thorough investigation, including performance of a complete autopsy and review of the circumstances of death and the clinical history”
- Relative sparing during ___ month of life with sharp ↑ in ____ month of life
- Peak incidence at ____of age
- 75% of deaths occur between ________ age
- 95% occur before ____ of age
- Age based on what?
- Occurs predominantly during the _____?
- 1st, 2nd
- ~ 3 months
- 2 and 4 mo
- 9 mo
- gestational
- night
Considered the most important preventable risk factor for SIDS
-The ↑ in risk is dose dependent
Risks from this may include? 4
Maternal smoking
-Risk further ↑’d if both parents smoke
- Fetal hypoxemia
- Inhibition of airway growth and development
- ↓’d ability to arouse to noxious stimuli
- ↑’d susceptibility to respiratory tract infections
- Pacifiers: Shown to reduce what?
- AAP recommends pacifier use throughout the day until __ months
- AAP recommends pacifier use at night while sleeping until ___ months
- arousal threshold
- 6
- 12
Prone position is a risk for to develop what?
why?
- hypercapnia
- Rebreathing of expired air
- Hypoxemia
- Upper airway closure
- Arousal deficit
CF: Syndrome of what three things?
- chronic sinopulmonary infections,
- malabsorption and
- nutritional abnormalities
- CF gene encodes for what?
- CFTR functions as an ___________and controls the movement of what?
- Mutations in the CF gene impairs this movement, critically altering ________ in the lung?
- the cystic fibrosis transmembrane conductance regulator (CFTR) protein
- ion channel, salt and water into and out of cells
- host defense
Organ Dysfunction in CF:
1. Sinuses – 2?
- Lung – 2?
- Pancreas – 2?
- Intestine – 2?
- Liver – 1?
- Vas Deferens – 1?
- Sweat gland – 1?
- Sinusitis,
- nasal polyps
- Endobronchitis,
- bronchiectasis
- Exocrine Insufficiency
- CF Related Diabetes
- Meconium ileus
- Constipation/DIOS
- Focal sclerosis
- failure to develop
- salt-losing dehydration
- What kind of inheritance is GF?
- What chromosome is the CF gene found on?
- What is the most common mutation?
- Autosomal recessive inheritance
- CF gene is a large gene on chromosome 7
- ΔF508 is the most common mutation
CF diagnosis:
1. Rosenstein et al, 1998 – Cystic Fibrosis Foundation consensus conference? 3
- Guidelines for Diagnosis of Cystic Fibrosis in Newborns through Older Adults: Cystic Fibrosis Foundation Consensus Report (Farrell et al, 2008)?
3
- One or more symptoms or positive “newborn screen”
- Known mutations
- CFTR dysfunction – Sweat chloride, epithelial potential diff.
- Cystic Fibrosis is a clinical diagnosis
- Newborn screening – Sweat Electrolytes, Mutations
- Emphasis on the Process
-CFTR Carrier Testing
2 tests
-how many mutations do they detect?
-turnaround time?
- Genzyme Genetics
97 CF mutations
Turnaround time ~1-2 weeks
- Ambry Genetics
~1,300 CF mutations
Turnaround time ~ 1 month
“End Stage” Lung Disease in CF
What do you find? 4
- Bronchiectasis
- Infection
- Inflammation
- Mucous Plugging
Severe airflow obstruction
FVC>FEV1>FEF25-75 and
Increased RV, FRC lead to what?
3
- Abnormal distribution of ventilation
- Decreased exercise tolerance
- Abnormal oxygenation
What bacteria is most prevalent in infections in CF patients below the age of 17?
After 17?
Staph aureus
Pseudomonas
Current Treatments
8
- Airway clearance therapy
- Antibiotics – inhaled (TOBI®), oral, IV
- Inhaled mucolytics
- Bronchodilators
- Enzyme replacement
- Fat soluble vitamins – A, D, E, K
- Azithromycin®
- Ibuprofen
What meds are there for airway clearance?
5
- CPT,
- Flutter®,
- Acapella®,
- Vest®,
- IPV
What meds are there for inhaled mucolytics?
2
- Pulmozyme®,
2. hypertonic saline
