Respiratory Flashcards
Primary Ciliary Dyskinesia
- Autosomal recessive
- Due to mutations in genes responsible for normal flagellar and ciliary function
- Impaired mucociliary function leads to chronic cough, sinusitis, otitis media, and bronchiectasis.
- Situs inversus: randomized left and right body asymmetry
- Infertility from impaired function of sperm and fallopian tube cilia
Kartagener Syndrome
Triad of:
Situs Inversus
Chronic Sinusitis
Bronchiectasis
What is the most common cause of bronchiolitis in children under 2 years old?
- Respiratory Syncytial Virus
- Presents with low grade fever, cough, tachypnea and increased work of breathing (nasal flaring).
- Exam shows diffuse wheezes and crackles
- May lead to apnea and/or respiratory failure
What respiratory component allows the terminal bronchioles to clear foreign debris and particles?
- The cilia or mucociliary clearance
What portion of the respiratory tree is covered by cilia?
What is its purpose?
- From the trachea to the proximal portion of the respiratory bronchioles
- Allows for mucociliary clearance of foreign particles by the action of cilia beating towards the pharynx
What are goblet cells?
What is their function?
- Mucus secreting cells interspersed through the respiratory mucosa from the trachea to the large bronchioles
- ## Not found in terminal bronchioles
How are particles cleared beyond the terminal bronchioles? That is to say how are they cleared from the respiratory bronchioles and on?
- Dependent on phagocytosis by alveolar macrophages
- Destroy some inhaled particles via lysosomal degradation
- Nondigested material is transported by macrophages to pulmonary lymphatics or to the terminal bronchioles for clearance by mucociliary clearance
Where are submucosal and mucoserous glands found within the respiratory tract?
What is their function?
- They are found in the trachea and bronchi
- Not found in bronchioles
- They help form the mucous layer in the larger aiways
What are type I pneumocytes?
- Squamous, thin cells that line the alveoli
- Make up 97% of the alveolar surface
- Facilitate gas diffusion
What are type II pneumocytes?
- Cuboidal and clustered cells
- Secrete surfactant from lamellar bodies
- Serve as a precursor to type I pneumocytes and other type II cells
- Proliferate when lung is damaged
- Decrease alveolar surface tension
- Prevent alveolar collapse
- Decrease lung recoil
- Increase lung compliance
What is surfactant made out of and when is it made?
- Complex mix of lecithins (Dipalmitoylphosphatidylcholine)
- Synthesis begins week 26 of gestation
- Mature levels not achieved until week 35 of gestation
What are club cells?
Nonciliated; low columnar cuboidal cells with secretory granules
- Located in the small airways
- Secrete a component of surfactant
- Degrade toxins
- Act as reserve cells
What is infant respiratory distress syndrome?
What are the risk factors?
What are the complications?
How is it treated?
- A surfactant deficiency
- Leads to increased surface tension and alveolar collapse
- Ground glass appearance on lung fields x-ray
- Risk factors are prematurity, maternal diabetes (due to increased fetal insulin), C-section delivery (decreases fetal glucocorticoid steroids because it is less stressful than vaginal delivery)
- Complications are patent ductus arteriosus and necrotizing enterocolitis
- Treat with maternal steroids before birth and exogenous surfactant for infant
- O2 supplementation can result in (RIB) Retinopathy, Intraventricular hemorrhage and Bronchopulmonary displasia
How do you screen for fetal lung maturity?
1. Lecithin sphingomyelin (L/S) ratio in amniotic fluid > 2 is healthy < 1.5 predictive of NRDS 2. Foam stability index test 3. Surfactant albumin ratio
What increases the risk of patent ductus arteriosus?
Persistently low O2 tension
