Pathology - Resp Flashcards
List 6 causes of ALI or ARDS:
Infection, trauma (inc. fat embolism), toxic exposure, pancreatitis, uraemia, and immune reactions.
What are “heart failure” cells?
Haemosiderin-laden macrophages which occur with chronic congestion and are therefore indicative of heart failure.
Overall mortality rate in ARDS?
Compared to AIP?
40% compared with 50% in AIP, which is essentially ARDS with no identifiable cause.
What are the anatomical classifications of emphysema and what are the associated conditions/risk factors?
Centriacinar - heavy smokers
Panacinar - A1 anti-trypsin def
Distal acinar - near peripheral fibrosis.
Neutrophils mediate emphysema by releasing cellular proteases. Name them:
Elastase
Proteinase-3
Cathepsin-G
Why do NSAIDS trigger asthma?
These agents inhibit COX (without affecting LOX) and therefore tip the balance of arichidonic acid metabolism towards bronchoconstrictor leukotrienes.
Describe the acute, late, and remodelling phases of asthma:
Acute - IgE coated mast cells cause primary (leukotriene) and secondary (cytokine) mediator release which cause bronchospasm, oedema, mucus secretion, and leukocyte recruitment.
Late - mediated by leucocytes, this is characterised by persistent spasm and oedema with infiltration and epithelial loss.
Remodelling occurs due to SMC and mucus gland hypertrophy, increased vascularity, and increased collagen.
What is the most dangerous size bracket for respiratory particles?
Why?
1-5 micrometers. These particles can reach the terminal alveoli and settle in the lungs.
What is the hallmark of sarcoidosis?
3 histological features
Non-caseating granulomas.
Schaumann bodies and asteroid bodies commonly occur but are not pathognomonic.
Sarcoidosis is a diagnosis of…
Exclusion.
What is Loeffler’s syndrome?
Simple pulmonary eosinophilia.
95% of PE comes from DVT.
What are the other 5% from?
Pulmonary HTN
Pulmonary atherosclerosis
Heart failure
How frequent is pulmonary infarction in PE? Why is this? Who is at risk?
Occurs ~10%
Occurs in patients with heart failure as these patients fail to supply the tissue via the bronchial arteries.
What is the most common serotype of H. influenzae to cause pneumonia?
Serotype B (A-F).
Classification and virulence factors of H. influenzae?
Gram negative, encapsulated, pleomorphic organism.
Adhesive pili, a factor that dysregulates ciliary beating, and an IgA protease.