Lung Diseases Flashcards
1
Q
Most common cause of respiratory failure in preterm infant?
A
- RDS
2
Q
Incidence and severity seen in males or females?
A
- male infants
- increased circulating androgens, decreased lung maturity, and surfactant production by type II pneumocytes
- more common and more severe in white infants vs black
3
Q
Increased incidence - RFs for RDS?
A
- low gestation
- male sex
- white race
- maternal diabetes: increased insulin decreases lung maturation and surfactant production
- C section pre-onset of labor
- perinatal asphyxia: CV shock and pulm HTN
- maternal HTN
4
Q
Decreased incidence RFs?
A
- prolonged rupture of membranes
- chronic congenital infections
- maternal substance abuse
- antenatal corticosteroid exposure
- female
5
Q
2 major issues in RDS?
A
- immature lungs
- lack of surfactant
6
Q
Diff. lung stages?
A
- canalicular stage: 16-26 wks
- saccular stage: 24-38 wks
- may have primitive airspaces with undiff pneumocytes
- no juxtaposition of airway epithelium and capillaries
7
Q
Surfactant:
when does it appear, when is adequate amt produced?
Fxn?
A
- appears at 23-24 wks
made by type II pneumocyte - adequate amts not produced until about 35 wks
- reduces surface tension in alveolar spaces:
facilitates lung expansion
prevents alveolar collapse
8
Q
Premature infants usually have what other respiratory problems along with RDS?
A
- excessively compliant chest walls
- weakness of the respiratory muscles
- these may further contribute to alveolar collapse
9
Q
PP behind RDS?
A
- alveolar collapse alters normal ventilation/perfusion relationship
- produces pulm shunting - progressive arterial hypoxemia - metabolic acidosis
- hypoxemia and acidosis - lead to vasoconstriction - decreased pulmonary blood flow (pulm HTN)
- may produce R - L shunting through PFO and PDA - worsening hypoxemia
- pulm blood flow may subsequently increase - this leads to decreased vascular resistance and persistence of PDA
- increased pulm blood flow leads to acccum of fluid and protein in interstitial and alveolar spaces
- protein in alveolar spaces deactivates surfactant
10
Q
What is hyaline membrane disease?
A
- lungs appear solid and congested with diffuse atelectasis
- hyaline membranes line most of remaining airspaces
- hyaline membranes are made up of plasma proteins leaked from damaged epithelium
- HMD and epithelial necrosis is less severe in infants tx with surfactant
11
Q
What will you see on PE of child with RDS?
CXR?
ABGs?
A
- progressive tachypnea, subcostal and sternal retractions, grunting, cyanosis, and decreased breath sounds present in minutes to hours of life
- CXR: increased density of both lung fields with reticulogranular infiltrates, air bronchograms, and elevation of diaphragm
- O2 requirement varies with disease severity
- ABGs: hypoxemia, hypercarbia, and metabolic acidosis
12
Q
Clinical course and prognosis of RDS?
A
- severity of resp failure increases during first 2-3 days of life
- in infants greater than 32-33 wks respiratory status usually improves by 1 wk of life
- in infant less than 26-28 wks course usually prolonged and complicated by volutrauma and/or barotrauma, PDA, infection, and intraventricular hemorrhage
13
Q
Tx of RDS?
A
- exogenous surfactant has drastically changed course of disease, rapidly decreases need for O2 and mechanical ventilation,
reduces incidence of gas leaks - careful stabilization in delivery room and NICU, proper monitoring of cardiopulmonary fxn, adequate resp support: O2, CPAP, mechanical ventilation
- proper thermal, metabolic and nutritional support
14
Q
Prevention of RDS?
A
- prevention of premature delivery
- antenatal corticosteroids: rapid change, within 15 hrs in lung structure: improved compliance, increased lung volume, decreased capillary protein leak
- slower (longer than 24 hrs): increased synthesis and secretion of surfactant by type II cells
15
Q
Complications of RDS?
A
- 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
16
Q
DDx of RDS?
A
- pneumonia
- congenital heart disease
- other congenital anomolies
- transient tachypnea of the newborn
- anemia
- polycythemia
- hypothermia
17
Q
What is SIDS?
A
- sudden unexpected death of an infant less than 1 year of age, with onset of fatal episode apparently occurring during sleep, that remains unexplained after a thorough investigation, including performance of a complete autopsy and review of circumstances of death and clinical hx
18
Q
Incidence of SIDS?
A
- leading cause of post-perinatal mortality in developed countries
- accounts for approx 2600 deaths/year in US
19
Q
Most common age of SIDS?
A
- spares 1st month, increase in 2nd month
- peak incidence: 3 months
- 75% of deaths occur b/t 2-4 mo
- 95% occur b/f 9 mo
- age is gestational, not postnatal
- occurs predominantly during the night
20
Q
Maternal RFs of SIDS?
A
- young age
- multiparity
- smoking during pregnancy
- drug abuse
- previous fetal deaths
- anemia during pregnancy
- premature rupture of membranes
- low social class
- low family income
- postnatal depression
21
Q
Infantile RFs of SIDS?
A
- male
- low birth wt
- premature birht
- blood type B
- low APGAR scales
- not using pacifer
- prone or side sleeping position
- bed sharing
- overheating
- not breastfed
- siblings in family
- previous cyanotic episode
22
Q
Most impt preventable RF for SIDS? Effects on baby?
A
- maternal smoking
- increased risk is dose dependent
- risk further increased if both parents smoke
- risks may include:
fetal hypoxemia, inhibition of airway growth and development, decreased ability to arouse to noxious stimuli, increased susceptibility to respiratory tract infections
23
Q
Pacifier recommendation?
A
- shown to reduce arousal threshold
- AAP recommends pacifer use throughout day until 6 months
- at night while sleeping until 12 months
- no evidence to discourage pacifier use
24
Q
Prone position such a risk in RDS?
A
can develop hypercapnia:
- rebreathing of expired air
- hypoxemia
- upper airway closure
- arousal deficit
- back to sleep: decreaed SIDS 50-70% worldwide
- side sleeping 2-6x risk of SIDs versus back
25
PP of SIDS?
- still cause is unknown
see on autopsy:
- intrathoracic petechial hemorrhages
-- frothy secretions around mouth and nose
- URI evidence
- hypoxic tissue markers
- abnorm in brain stem serotoninergic system: not telling baby to breathe
- no arousal rxn, failure of auto resuscitation: gasping and arousal
-bradycardia not primary mechanism
- no marker ID that would ID future SIDS victims
- cessations of breathing movements and cardiac arrhythmias show no relation to SIDS
26
Prevention of SIDS?
- placed supine for every sleep
- firm surface, no pillows or loose bedding in crib
- let baby share your room for sleep but not your bed
- don't smoke during preg, and keep infant in smoke-free enviro after birth
- consider use of pacifer for naps and bedtime
- avoid overheating: bedroom temps should be comfy for lightly clothed adult
27
What is cystic fibrosis? Most commonly affects what pop?
- syndrome of chronic sinopulmonary infections, malabsorption, and nutritional abnormalities
- most common lethal genetic gene in caucasians
- median survival: 37
- CF gene encoudes for CF transmembrane conductance regulator (CFTR) protein - this fxns as an ion channel and controls the movement of salt and wter into and out of cells, mutations in CF gene impairs movement, crictically altering host defense in the lung
28
What organs are affected in CF?
- sinuses: sinusitis, nasal polyps
- lung: endobronchitis, bronchiectasis
- pancreas: exocrine insufficiency CF related diabetes
- intestine: meconium ileus, constipation/DIOS
- liver: focal sclerosis
- vas deferens: failure to develop
- sweat gland: salt losing dehydration
29
Complications related to CF?
- stunting, wasting
- micronutrient deficiencies
- steatorrhea
- intestinal obstruction
- intussusception
- hypoelectrolytemia
- airway infection
- progressive obstructive lung disease
- bronchiectasis
- diabetes
- rectal prolapse**
- sinusitis
- vasculitis
- non-alcoholic steatohepatitis
- non-alcoholic steatohepatitis
- male infertility
- *** many CF complications can be prevented, delayed or ameliorated with recognition and tx
30
Genetics of CF?
- CF gene is large gene on x'some 7
- incidence is 1/3000-1/4500
- carrier rate 1/27-1/34
- 30,000 individuals in US have CF
- genetic testing
31
What does mortalitity of CF depend on?
- dependent on CFTR genotype (type of CF)
32
How do you dx CF?
- clinical dx
- one or more sxs or positive newborn screen
- known mutations
- CFTR dysfxn: sweat chloride (key to dx, over 60 mmol/L= confirmed dx, and 30-59 is possible dx), epithelial potential diff
-
33
Fxn of CFTR?
- fxns as ion channel and controls the movement of salt and water into and out of cells
- mucus isn't getting cleared out of lungs and other organs (mucus clearance is key for normal lung defense)
34
Lung disease pathogenesis in CF?
- abnormal CFTR leads to impaired mucociliary clearance (mucous plugging) which leads to
infection and inflammation
- bronchiectasis and functional airway impairment
-chronic infection and inflammation usually is COD in CF pts
35
How is lung fxn affected in CF? FVC, RV?
- obstuctive disease
- going to have FVC that is larger than FEV1
- increased RV, FRC
- this leads to:
abnorm distribution of ventilation, decreased exercise tolerance and abnormal oxygenation
36
Chronic P aeruginosa endobronchitis prognosis?
- predicts poor survival
37
Tx of CF?
- airway clearance therapy: CPT, Flutter, Acapella, Vest, IPV
- abx: inhaled (TOBI), oral, IV
- inhaled mucolytics: pulmozyme, hypertonic saline
- bronchodilators
- enzyme replacement: pancreas
- Fat soluble vitamins: A, D, E, K
- azithro
- ibuprofen (slows progression of CF)
