UWORld Flashcards
What kind of channel is the CFTR channel?
Transmembrane ATP-gated chloride channel
What test is done to screen for CF?
Sweat chloride test
What is congenital long QT syndrome due to?
Mutation in voltage gated K+ channel
What are the clinical signs of epiglottitis?
- Distress (tripod position, sniffing position, stridor)
- Dysphagia, dysphonia
- Drooling
- High fever
Does anaphylaxis cause fever?
No
What does alpha1 antitrypsin inhibit in the lung?
Neutrophil elastase
-> Less elastin broken down
What virus most commonly causes croup?
Paramyxovirus
What receptors does dextromorphan act on and what are its effects/
Activates medullary sigma receptors
- Cough suppresant
What is the most common cause of primary lung cancer?
Adenocarcinoma
What are the levels of vasopressin in septic shock?
Suppressed
What fluid may be used in septic shock, outside of 0.9% NaCl?
Lactated Ringer solution
What are the 3 phases of Acute Respiratory Distress Syndrome (ARDS)?
- Exudative phase
- Proliferative phase
- Fibrotic phase
How can ARDS be identified?
Bilateral pulmonary infiltrates and hypoxemia in the absence of HF
What is a characteristic sign of pulmonary fibrosis on CT?
Honeycombing - dilation of terminal bronchioles due to fibrosis
What is elastase contained in/by?
- Macrophage lysosomes
- Azurophilic (primary) granules of neutrophils
What is macrophage elastase inhibited by?
Tissue inhibitors of metalloproteinasis
How may alpha1 antitrypsin deficiency cause liver cirrhosis?
Misfolded alpha1 antitrypsin aggregates in the hepatocytes
What does periodic acid schiff stain glycoproteins such as A1AT?
pink
Is AIAT diatase resistant?
Yes
What is lactulose used for in liver disease?
To prevent hepatic encaphalopathy
What causes desmosine crosslinks?
Lysyl oxidase
What is the most common mutation of CFTR?
delta F508 mutation
- Deletion
How does deltaF508 mutation causes CF?
- Abnormal protein folding
- Channel is degraded before reaching surface
- Also reduces channel opening
- ATP unable to bind
What is the mutation which causes a1AT deficiency?
SERPINA1
- PiZ mutation causes a misfold
What is the normal A1AT?
PiM
What 3 conditions in the lungs can a1AT deficiency cause in the lungs?
- Pan-acinar emphysema
- Chronic bronchitis
- Bronchiectasis
Is elastin hydrophobic or hydrophilic?
Hydrophobic, mostly non-polar
How does surfactant affect the lungs?
- Increases compliance (opening of lungs)
- Decreased surface tension (ability to open)
- Decreased elastic recoil (ability for alveoli to close)
- Decreased alveolar collapse (stay open)
What is methacholine used for?
Bronchoprovocation test
- Diagnosis of asthma
What kind of drug is methacholine?
Non-selective muscarinic receptor agonist
What may cause ARDS?
- Pulmonary trauma - contrusions, irritants
- Indirect nonpulmonary insults - sepsis, pancreatitis, burns
What are symptoms of granulomatosis w. polyangitis?
- Cough w. hemoptysis
- Nephritic syndrome
- Necrotizing inflammation + pulmonary hemorrhage
What are the functions of club/clara cells?
- Degrade toxins via surfactant w. CYP450
- Secrete secretoglobin famiy 1A member 1
- Protects the bronchiolar epithelium
- It is a bronchiolar exocrine cell
What type of emphysema affects smokers vs what type of emphysema affects those with A1AT deficiency?
Centracinar emphysema = Smoking
Panacinar emphysema = A1AT def
What are the ABG values in PE?
- Increased pH
- Normal HCO3-
- Decreased O2 and CO2
What do the lamellar bodies do and what cells are they contained in?
Contained in T2 pneumocytes
- Store and release surfactant
What does intrapulmonary shunting mean?
Adequetly perfused but poorly ventilated
A Lecithin/sphingomyelin (L:S) ratio below what vaule indicates Neonatal Respiratory Distress Syndrome?
< 1.5
> 2 indicates maturity
What are the risk factors for NRDS?
- Prematurity
- Maternal diabetes
- C-section
What are the treatments for NRDS?
- Decreased release of fetal glucocorticoids
- Exogenous surfactant for infant
What can therapeutic supplemental O2 rsult in?
- Retinopathy of prematurity
- Intraventricular hemorrhage
- Bronchopulmonary dysplasia
What do alveolar macrophages releasse?
- Cytokines
- Alveolar proteases
What cells may be found in the setting of pulmonary oedema or alveolar hemorhage?
Hemosiderin-laden macrophages (HF cells)
What will the effects of the HandE stain be on actinomycosis?
basophilic purple/blue appearence on LM
What granules are released in actinomycosis?
Sulfur (formed by calcified mycelial fragments)
What is a major risk factor for actinomycosis infection of the lungs?
Aspiration
- Most commonly found in mouth and may result in cervicofacial abscesses
How does obesity-related restrictive lung disease affect pulmonary function test results?
Restrictive pattern
- Decreased FEV1 and FVC
- Decreased ERV and RV
- Decreased TLC
- Normal Residual Volume
