Respiratory Pathology Pt. 1 Flashcards
What are the stages, in order, of fetal lung development?
1) embryonic
2) pseudoglandular
3) canalicular
4) saccular
5) alveolar
What are the main requirements for proper lung development in utero?
- space in the thoracic cavity
- ability to inhale (ex: chest wall must be able to move, and there must be enough amniotic fluid present to inhale)
What makes up most of the lung’s volume?
parenchyma
What is the role of Type 1 pneumocytes?
-facilitate gas exchange
What is the role of Type 2 pneumocytes?
- produce surfactant
- pleuripotent replacement of Type 1 pneumocytes
What is the significance of the Pores of Kohn?
- allow aeration between alveoli
- also allow bacteria, cells, and exudate to pass between alveoli
What are some situations in utero that can cause pulmonary hypoplasia?
- diaphragmatic hernia
- oligohydramnios d/t renal agenesis
- tracheal stenosis
- chest wall motion disorders
True or False: if lung weight is < 40% at birth, immediate death occurs in the neonatal period.
True, there’s not really anything you can do about this.
What are the characteristics of foregut cysts?
-detached outpouchings (respiratory, esophageal, or gastroenteric)
- often found incidentally
- excision is curative
-complications include: rupture, infection, or airway compression
What is a Congenital Pulmonary Adenomatoid Malformation (CPAM)?
- arrested development of pulmonary tissue w/ formation of intrapulmonary cystic masses
- type depends on stage of arrest (ex: tracheobronchial, bronchial, bronchiolar, alveolar duct, distal acinar)
What are the characteristics of CPAM’s?
- communicate w/ tracheobronchial tree
- can be detected on fetal U/S
- can be deadly d/t hydrops or pulmonary hypoplasia
- can get infected later in life
How do you treat a Congenital Pulmonary Adenomatoid Malformation (CPAM)?
-fetal or neonatal lobectomy
What is a Pulmonary Sequestration?
non-functioning lung tissue that forms as an aberrant accessory “lung bud”
(can be intralobar or extralobar)
Where is the most common location for a Pulmonary Sequestration?
-left lower lobe
What are the characteristics of a Pulmonary Sequestration?
- lack of connection to the tracheobronchial tree
- independent systemic arterial supply
What are the characteristics of an Intralobar Pulmonary Sequestration (ILS)?
- more likely to hide from detection than extralobar
- susceptible to infection and abscess formation
What are the characteristics of an Extralobar Pulmonary Sequestration (ELS)?
- presents at birth w/ other congenital anomalies
- independent vessels, airway, AND pleura
What is the main difference between a CPAM and a Pulmonary Sequestration?
- CPAM’s are connected to the tracheobronchial tree
- pulmonary sequestrations obtain their own airway and vasculature
How will Pulmonary Edema show up on an H and E stain?
- -pink material (interstitial fluid) in the alveolar spaces
- -dilated capillaries full of RBC’s
- -hemosiderin-laden macrophages
What is the most common cause of pulmonary edema?
–left-sided heart failure
What are some causes of pulmonary edema, other than left-sided heart failure (the most common cause)?
- pulmonary vv. obstruction
- hypoalbuminemia or liver disease
- bacterial PNA or sepsis
- smoke inhalation
- high altitude
What are the four qualifications that must be met for a diagnosis of Acute Respiratory Distress Syndrome (ARDS)?
- abrupt onset of symptoms
- PO2/FiO2 < 200 (hypoxemia)
- b/L infiltrates
- r/o cardiac cause
In Diffuse Alveolar Damage, what are the components of a hyaline membrane?
- edema
- fibrin
- cell debris
What are the stage of progression of Acute Respiratory Distress Syndrome?
1) exudative (edema, hyaline membranes, neutrophils)
2) proliferative (fibroblasts, PNA, early fibrosis)
3) fibrotic (extensive fibrosis and loss of alveolar architecture which are irreversible) … or sometimes resolution occurs where normal structure and fxn are restored
