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Flashcards in Lec 12 Bronchiectasis Deck (37):

What is the definition of bronchiectasis?

permanent abnormal dilation of bronchi

pathologic/radiological diagnosis


What is vicious cycle hypothesis of bronchiectasis?

external insult --> causes resp tract damage --> more prone to infection --> more inflammation --> more damage etc


What are infectious causes of bronchiectasis?

measles/pertussis pneumonia

other bacteria/viruses --> TB, mycobacterium

allergic bronchopulmonary aspergillosis


Who gets allergic bronchopulmonary aspergillosis?

patients with asthma or cystic fibrosis


What are some causes of recurrent airway infection?

- airway obstruction
- impaired mucous clearance
- defect in host defense


What are the 3 patterns of bronchiectasis?

- cylindrical = smooth dilation of bronchus
- varicose = focal narrowings along a dilated bronchus
- cystic = progressive dilation of bronchus which terminates in cysts or saccules


What signs of bronchiectasis?

permanently dilated airways
purulent sputum
recurrent infections


What causes hemoptysis in bronchiectasis?

inflammation causes increased blood supply

- bronchial arteries enlarge and increase in number; new anastamoses form between bronchial + pulm artery circulations

erosion/truama leads to rupture/hemoptysis


What do you see on physical exam with bronchiectasis?

- may have normal lugn exam or wheezing
- clubbing


What do you see on pulm function tests with bronchiectasis?

low FEV1/FVC

high RV and RV/TLC ratio


What is treatment for bronchiectasis?

- antibiotics with exacerbation
- bronchopulmonary drainage
- bronchodilators if co-existing asthma


What is epidemiology of CF?

- autosomal recessive
- mutation in gene for cystic fibrosis transmembrane conductance regulator [CFTR]
- most prevalent in pple of northern/central europe descent


What is function of CFTR?

- ion channel regulates Cl and H2O absorption/secretion

in sweat duct = Na but not fluid absorbing
in airways = fluid absorption
in pancreas/intestine = fluid secretion


What happens in lungs in CF?

- lung epithelium dried out = cilia can't move as well and stuff gets stuck
- less airway surface liquid volume

normally when high liquid volume: channels open allow Na/Cl absorption and H2O to follow in but close when low volume and net water out

in CF = can't regulate; channels always open and bring fluid in even when there is already low volume


What happens in CF in pancreas?

- CFTR is needed to secrete HCO3 and water into pancreatic ducts

in CF --> acidic secretions lead to retention of enzymes in pancreas and destruction of pancreatic tissue


What happens in CF in intestine?

intestinal epithelium can't flush secreted mucin and other macromolecules

have intestinal obstruction


What happens in CT in sweat glands?

- CFTR needed to reabsorb Cl from sweat secretions

in CF --> Cl not reabsorbed have isotonic [rather than hypotonic] sweat


What are the 6 types of CFTR mutations?

type 1 = no functional CFTR protein
type 2 = CFTR trafficking defect, never reaches surface
type 3 = defective channel regulation
type 4 = decreased channel conductance
type 5 = reduced synthesis of CFTR
type 6 = decreased CFTR stability


What is type 2 CFTR mutation?

normal transcription but abnormal folding --> have trafficking defect and CFTR never makes it to cell surface


What is type 1 CFTR mutation?

transcription abnormal = no protein produced


What is type 3 CFTR mutation?

transcription/translation normal but abnormal regulation


What is type 4 CFTR mutation?

decreased conductance of chloride in channel


What is type 5 CFTR mutation?

have some corent + some incorrect RNA due to splicing defect
so end up with reduced synthesis of CFTR


What is type 6 CFTR mutation?

have decreased CFTR membrane stability


What is major mutation causeing 70% of CF?

F508 mutation

- 3 nt deletion
- causes protein misfolding = class II defect


What doe you always have if homozygous dF508 mutation?

always have exocrine pancreatic insufficiency


What is pulmonary pathology of CF?

- thick mucous plugs in bronchi
- early airway changes mostly in bronchioles plugged by secretions


What is pulmonary pathophysiology of CF?

- recurrent episodes of tracheobronchial infection
- leads to bronchiectasis
- get pseudomonas + MRSA colonization
- get obstructive airway disease


What are presenting features of CF?

- 10-20% develop first clinical problem in neonatal period --> usually meconium ileus = obstructed intestine

- rest have childhood presentation --> pancreatic insufficiency or recurrent bronchial infections

- occasionally diagnosed when adults


What are pulmonary complications of CF?

- pneumothorax
- hemoptysis
- allergic bronchopulmonary aspergillosis
- pulmonary HTN
- resp failure


What are non-pulmonary clinical features of F?

- nasal polyps
- chrnoic pancreatisis
- intestinal obstruction
- exocrine pancreas insuffiency [malabsorption of vit A, D, E, K]
- rectal prolapse
- infertility in males


How do you diagnose CF?

- abnormal sweat electrolytes [high Na, Cl, K]
- identify mutation in CFTR gene


What is treatment for CF?

manage complications
for lungs: antibiotics, bronchopulmonary drainage, bronchodilators; give N-acetylcysteine to loosen mucus plugs


What is use of inhaled recombinant doexyribonuclease in CF?

- DNAse decreases mucus viscosity + improves clearance of secretions


What is ivacaftor?

increases time activated CFTR channels at cell surface remain open

improves respiratory symptoms in pts with G511D mutation


What is primary ciliary dyskinesia?

autosomal recessive group of structural deficits involving cilia


What is kartagener's syndrome?

- autosomal recessive ciliary dyskinesia syndrome
- characterized by
---- bronchiectasis,
---- sinusitis
----- situs inversus [in 50%]