Bronchiectasis/CF Flashcards
What are the baseline bloods for bronchiectasis investigation?
alpha1 antitripysin, aspergillus IgG and IgE, total IgE and IgG, IgG subclasses, serum electrophoresis, ANA, ANCA, anti-parietal ab, RF, MPO, PR3
What are the most common gene mutations in CF?
F508del (most common)
G551D
W1282X
G542X
N1303K
What is a class 1 and 2 CFTR gene mutation mean?
reduction in the quantity of expressed CFTR protein
Class 1- nonsense and frame-shift mutations, as well as mRNA splicing defects eg G542X
Class 2- folding or maturation defects, which can result in premature CFTR degradation eg F508del
What does class 3 and 4 gene mutations mean?
aberrant channel function rather than reduced quantities of CFTR
Class 3- limited channel gating that arises from ineffectual binding of nucleotide eg G551D
Class 4- able to open and close. However, Cl- and HCO3 ions are unable to freely pass
What does Class 5 gene mutation in CF mean? and the novel Class 6?
Class 5- normal CFTR, a limitation of transcriptional regulation results in a reduced quantity of the protein being produced
Class 6- high turnover of CFTR at the channel surface
Which class of gene reduces function of CFTR at the cell surface?
class 3 and 4
which class of gene reduces the quantity of CFTR at the cell surface?
class 1, 2, 5 and 6
What do CF modulators target?
potentiators- work in class 3. Ivacaftor specifically targets G551D, but also works in homozygous F508del
correctors- work in class 2 eg. tezacaftor and elexacaftor both work on F508del
premature stop codon suppressors or read-through agents- work in Class 1 (ataluren and gent)
what is the sweat test cut off for CF?
60 mmol/L
40-60 is intermediate
Where can I look up whether a CFTR mutation gene causes CF?
CFTR2 database
What are the three subspecies of m. Absessus?
Absessus, bolletii and massilisence. Massilisence has the worst prognosis
How does ceftrio affect the eyes?
Increase lens opacity- increased cataract
How is the liver affected in CF?
The cholangiocytes have CFTR in the membranes
Biliary: Lead to stones, dyskinesia, malignancy
Liver: portalHTN cirrhosis
What is special about CF gut?
Nothing. It is the same as IBD gut. And the management is as such
If sweat test is equivocal what can we do to diagnose?
A PD- give amiloride followed by isoprenaline and something else and the chloride increases if not CF otherwise it stays down
