Pulmonary Pathology I Flashcards
What are the histological layers of the trachea?
- Respiratory Epithelium
- Lamina Propria
- Submucosa
- Tracheal Cartilage
What cells is the primary bronchus mainly made of?
Pseudostratified columnar epithelium
Type I cells
Squamous pneumocytes - gas exchange
Type II cells
Granular pneumocytes -secrete surfactant
What pneumocyte can regenerate?
Type II
What cell type makes up most of the alveolus?
Type I
What is the function of respiratory units?
Respiratory units are responsible for the transport of oxygen from the airspace into the blood, and transport of carbon dioxide from the blood to the airspace.
Where does the mudcillary escalator end?
Below the respiratory bronchioles, there is no mucociliary escalator
Bronchogenic Cyst
Foregut buds that become separated and disconnected from the tracheobronchial tree, progressively enlarging, and forming a cystic mass.
Congenital Cystic Adenomatoid Malformation (CCAM) AKA Congenital Pulmonary Airway Malformation (CPAM)
“Hamartomatous lesions” - Benign, focal malformation composed of tissue elements normally found at that site, but which are growing in a disorganized mass. Usually in the lower lobes.
What is seen on histology as a result of CCAM?
Large dilated spaces caused by cysts
Pulmonary Sequestration
Discrete mass of lung tissue without connection to the
airway system.
Atelectasis
Collapse or closure of the lung
What are the 3 types of atelectasis?
Resorption or obstruction
Compression
Contraction
When is resorption/obstruction atelectasis seen?
Asthma, COPD, bronchiectasis, aspiration, postop patients
When is compression atelectasis seen?
Effusions, air, tumors, CHF
When is contraction atelectasis seen?
Fibrosis of lung/pleura
Where does the mediastinum shift in resorption/obstruction atelectasis?
Towards the affected lung
Where does the mediastinum shift in compression atelectasis?
Away from the affected lung
What is a pneumothorax most commonly seen with?
Emphysema, asthma , TB
Pneumothorax
Causes compression, collapse, and atelectasis, leading to respiratory distress
What is the most common place for the lodging of foreign objects in the respiratory tract?
Lodged in the R lower lobe - through the R main bronchus
What are some causes of pulmonary edema?
- Hemodynamic or cardiogenic edema
- Edema due to microvascular injury
- Edema of undetermined origin
What is seen on histology of an edematous lung?
Pink will be seen filling the alveolar sacs
What are the manifestations of acute lung injury?
a) Acute onset dyspnea
b) Hypoxemia
c) Development of bilateral pulmonary infiltrates in the absence of cardiac failure
What can acute lung injury progress to if it is severe?
Acute Respiratory Distress Syndrome (ARDS)
Acute Respiratory Distress Syndrome (ARDS)
- Rapid onset of life-threatening respiratory insufficiency
- Cyanosis
- Severe arterial hypoxemia –refractory to oxygen therapy
What are some of the possible causes of ARDS?
A – Aspiration, acute pancreatitis, air/amniotic fluid embolism
R – Radiation
D –Drug overdose, DIC, drowning
S – Shock, sepsis, smoke inhalation
What is the pathological term associated with ARDS?
Diffuse Alveolar Damage
Diffuse Alveolar Damage
Pneumocyte and endothelial cell necrosis with hyalin membrane formation causing type 2 pneumocyte proliferation
What is seen on histology with DAD?
Hyaline membrane is thick and seen as dark pink
What are the causes of Neonatal Respiratory Distress Syndrome (NRDS)?
- Due to a deficiency of surfactant - Hyaline Membrane Disease
- Fetal injury during delivery
- Aspiration of blood and amniotic fluid,
- Cord compression
- Excessive sedation of the mother
What is the pathological term associated with NRDS?
Hyaline Membrane Disease
What are some risk factors for NRDS?
- prematurity
- maternal diabetes
- C-section
What is the composition of surfactant?
Dipalmitoyl phosphatidylcholine/ lecithin (DPPC), unsaturated phosphatidyl cholines (PC) and phosphatidylglycerol (PG) and surfactant specific proteins SP-A, SP-B, SP-C and SP-D.
What are the functions of surfactant?
- Stabilizing the lung by reducing surface
tension
- Host defense mechanism as a barrier for inhaled particles
When are sufficient amounts of surfactant produced in the fetus?
At 34 weeks
Glucocorticoid effect on surfactant synthesis…
Increases
Insulin effect on surfactant synthesis…
Decreases - this is why diabetic mothers put infant at a greater risk
A 30-year-old woman develops multiple organ failure, bleeding diathesis post-partum. Sputum and blood cultures are negative. Nevertheless, she requires intubation with mechanical ventilation, but it becomes progressively more difficult to maintain her oxygen saturations. Ventilatory pressures must be increased. A portable chest radiograph shows increasing opacification of all lung fields. Capillary wedge pressure is normal. Which of the following pathologic processes is most likely now to be present in her lungs?
A Emphysema
B Diffuse alveolar damage
C Extensive neutrophilic alveolar exudates (i.e. Pneumonia)
D Extensive intra-alveolar fluid (i.e. pulmonary edema)
E Normal lung
B Diffuse alveolar damage
Acute Interstitial Pneumonia
Rapidly progressive disease clinically similar to ARDS with no identifiable cause; death usually within 2 months
Adults with influenza-like illness followed by shortness of breath
Pathogenesis of ARDS
Imbalance of pro- inflammatory and anti-inflammatory mediators
Pathogenesis of NRDS
Surfactant deficiency
