What is the cause of Centriacinar emphysema? Location? – Correct
Answer – smoking (upper lobes); destruction of central portion of acini
“smoke rises to the UPPER LOBES”
What is the cause of pan acinar emphysema? Location – Correct Answer
- alpha-1 antitrypsin (A1AT) deficiency (lower lobes); destruction of entire
acini
What is A1AT, and what is its function? – Correct Answer – alpha1-
antitrypsin, inherited in an autosomal co-dominant pattern; neutralizes
proteases (i.e. elastase) in the lower lobes
What is the result of A1AT deficiency? – Correct Answer – misfolding of
protein –>
(1) lack of antiprotease –> air sacs vulnerable to protease mediated
damage –> pan acinar emphysema
(2) accumulation of mutant A1AT in endoplasmic reticulum of hepatocytes
–> liver damage
Describe the pathway once the A1AT deficiency goes into effect – Correct
Answer – increased elastase activity-> loss of elastic fibers-> increase lung
compliance
What will a biopsy of the liver in A1AT deficiency emphysema reveal? –
Correct Answer – Note the pink, PAS-positive globules in hepatocytes
Where in the lung is pan acinar emphysema most severe? – Correct
Answer – lower lobe
Where in the lung is Centriacinar emphysema most sever? – Correct
Answer – upper lobes
What is the normal allele in A1AT deficiency? – Correct Answer – PiM; two
copies are usually expressed (PiMM)
What is the most common clinically relevant mutation in A1AT deficiency? –
Correct Answer – PiZ
What heterozygotes in A1AT deficiency are usually asymptomatic? What
greatly increases this individual’s risk for emphysema? – Correct Answer –
PiMZ; smoking
Which homozygotes are at significant risk for panacinar emphysema and
cirrhosis? – Correct Answer – PiZZ
What are the clinical features of emphysema? – Correct Answer – –
dyspnea and cough with minimal sputum, hyperventilation, wheezing
-prolonged expiration with pursed lips (“pink puffer;” this increases airway
pressure and prevents airway collapse during respiration)
-weight loss
-Barrel-shaped chest
- CXR shows increased AP diameter, flattened diaphragm, increased lung
field lucency
What are the late complications of emphysema? – Correct Answer –
destruction of capillaries in the alveolar sac –> hypoxemia
cor pulmonale
Describe asthma – Correct Answer – Bronchial hyper-responsivesness
that causes REVERSIBLE bronchonconstriction
What happens to the smooth muscle during asthma? – Correct Answer –
hypertrophy (b/c muscles are working harder)
Key findings in asthmatic patients? – Correct Answer – Curschmann
spirals (shed epithelium forms whorled mucus plugs)
Charcot_Leyden crystals (eosinophilic, hexagonal, double-pointed, needlelike crystals formed from breakdown of eosinophils in sputum)
What are the triggers of asthma? – Correct Answer – viral URIs
allergens
stress
What type of hypersensitivity reaction is asthma? – Correct Answer – Type
I
Clinical diagnosis of asthma? – Correct Answer – supported by spirometry
& methacholine
What are the clinical features of asthma? – Correct Answer – cough
wheezing
tachypnea
SOB
hypoxemia
decreased inspiratory/expiratory ratio
pulsus paradoxus (drop in SBP > 10 mmHg during inspiration)
What is a finding on CXR during asthma? – Correct Answer –
peribronchial cuffing
I say “Curschmann’s spirals,” you say…? – Correct Answer – asthma
I say “Charcot-Leyden crystals in sputum,” you say…? – Correct Answer –
note the numerous eosinophils also
asthma