First Aid: Pathology Pt 2 Flashcards
What is mesothelioma? What is it associated with and what can it result in?
What is mesothelioma? What is it associated with and what can it result in?
What is mesothelioma? What is it associated with and what can it result in?
Smoking
What can be seen on histology of mesothelioma,
Name one other positive finding in almost all mesotheliomas
Psammoma bodies
Calretinin and cytokeratin 5/6 is positive in almost all mesotheliomas
Describe the pathophysiology of ARDS
- Alveolar insult results in the release of pro-inflammatory cytokines
- leading to neutrophil recruitment, activation and release of toxic mediators (i.e ROS, proteases, etc)
- This causes capillary endothelial damage and increased vessel permeability
- allowing for leakage of protein-rich fluid into the alveoli and forming intra-alveolar hyaline membranes and noncardiogenic pulmonary edema
What else contributes to alveolar collapse in ARDS?
Loss of surfactant
What are intra-alveolar hyaline membranes composed of and what do they cause?
Dead cells, surfactant and proteins - they deposit along the walls of the alveoli making gas exchange difficult
Name four causes for ARDS
STAPP: Sepsis, trauma, aspiration, pneumonia, pancreatitis
How is ARDS diagnosed?
Diagnosis of exclusion with the following criteria
A: abnormal CXR (i.e bilateral lung opacities)
R: Resp failure within 1 week of alveolar insult
D: decreased PaO2/FiO2 (the ratio is <300, this indicates hypoxemia due to increased intrapulmonary shunting and diffusion abnormalities)
S: symptoms of resp failure are NOT due to HF/fluid overload
Define a pulmonary shunt, what does it cause?
When parts of the alveoli are filled with fluid, so parts of the lung are unventilated but still perfused. Intrapulmonary shunting is the main cause of hypoxemia
What happens to the lungs as a result of ARDS?
Impaired gas exchange, decreased lung compliance and pulmonary hypertension
How is ARDS managed?
By treating the underlying cause and with mechanical ventilation
Define sleep apnea and describe its complications
What are the 3 types?
Repeated cessation of breathing for >10 seconds during sleep, this leads to disrupted sleep and daytime somnolence
Sleep apnea leads to
- Hypoxia: stimulates EPO and erythropoiesis
- Nocturnal hypoxia: can cause systemic and pulmonary hypertension, arrhythmias and sudden death
3 types: obstructive sleep apnea, central sleep apnea and obesity hypoventilation syndrome
Define obstructive sleep apnea, what are its commonly associated features (including how it can be caused in adults and children)? How does it affect daytime PaO2?
A respiratory effort against airway obstruction
Associated with: obesity, loud snoring and daytime sleepiness and can be caused by excessive parapharyngeal tissue in adults and adenotonsillar hypertrophy in children
Normal daytime PaO2
How is obstructive sleep apnea treated?
Weight loss, CPAP and dental devices
What is central sleep apnea and what can it be caused by? How can it be treated?
Impaired respiratory effort due to the 3 Cs…
- CNS injury/toxicity
- Congestive HF
- Cheyne-stokes respirations (changing between apnea (not breathing) and hyperpnea (increased depth and rate of breathing))
Treated with positive airway pressure
How does obesity hypoventilation syndrome affect daytime and nocturnal PaO2 and PaCO2 and why? What else is it known as?
Also known as Pickwickian syndrome
When BMI>30 -> leads to hypoventilation and increased PaCO2 during waking hours and increased PaCO2 and decreased PaO2 during sleep
What is the normal pulmonary artery pressure, and what pressure defines pulmonary hypertension?
Normal: 10-14 mmHg
PH: >25 mmHg at rest
What can pulmonary hypertension result in?
*both in terms of arterial damage and longer-term?
I AM P: Arteriosclerosis, medial hypertrophy, intimal fibrosis of pulmonary arteries and plexiform lesions
Longer-term: severe respiratory distress -> cyanosis and RVH and death from decompensated cor pulmonale
What are the causes of pulmonary arterial hypertension?
HPHDCSIC: Have pulmonary hypertension? Damn cocaine sure is crazy
- Often Idiopathic
- Heritable: inactivating mutation in the BMPR2 gene (which normally inhibits vascular smooth muscle proliferation)
- Portal hypertension
- HIV disease
- Drugs (i.e cocaine and amphetamines)
- CT disease
- Congenital heart disease
- Schistosomiasis
What happens as a result of the pulmonary vasculature endothelial dysfunction in pulmonary arterial hypertension?
Increased vasoconstrictors (i.e endothelin) and decreased vasodilators (i.e NO and prostacyclins)