Cystic Fibrosis and Bronchiectasis Flashcards
What is the approximate median life expectancy for homozygous F508-del cystic fibrosis?
UK median survival of 46 years for males and 41 years for females in homozygous F508-del cystic fibrosis sufferers
In adults who should we consider investigating for CF?
- Persistent isolation of Staph Aureus in sputum
- Feature of malabsorption
- Male primary infertility
- Upper lobe bronchiectasis (not lower lobe)
- History of childhood steatorrhoea
- Screening investigations should include two measurements of sweat chloride and CFTR genetic mutation analysis
How is CF diagnosed ?
Blood spot (babies) ; immunoreactive trypsin test
OR
Clinical manifestation supported by sweat or gene test
OR
Clinical manifestation alone in rare case of people with symptoms who have normal sweat or gene test
What are the complications of CF?
Being underweight
Meconium Ileus (affects between 1 in 7 new babies)
Fat soluble vitamin deficiencies (ADEK)
DIOS
Muscle pain and arthralgia
Male infertility (almost all males with CF are infertile)
Reduced female fertility
Upper airway complications
Chronic liver disease
Urinary stress incontinence
CF related diabetes
Reduced bone mineral density
(Less common - CF related arthritis , delayed puberty and renal calculi)
What are the mucoactive agents used in CF?
Dornase Alpha - first choice, if inadequate response with dornase alone can add in Hypertonic saline
If unable to use can think about mannitol
Outline Staph Aureus infection in CF
Give Flucloxacillin as prophylaxis from diagnosis to 3 years and consider upto 6
If test positive start treatment dose anti S.Aureus abx
NB this is MSSA ; if MRSA will need micro advice (don’t routinely use abx to suppress chronic MRSA in those with chronic pulmonary disease)
MRSA assoc with accelerated lung function decline and increase mortality
Outline approach to Pseudomonas Aeruginosa in CF patients
If clinically well: Oral or IV plus inhaled anti-pseud abx ; followed by extended oral + inhaled
If clinically unwell: IV plus inhaled anti pseud, followed by oral and inhaled
If CF pt on colistin nebs but still deteriorating due to Pseud , what can be trialled ?
Aztreonam
Nebulised Tobramycin
Tobramycin DPI
Outline DIOS
Distal Intestinal Obstruction Syndrome - 10% risk for CF patients , once had , more likely to recur (50%)
Suspect in those with CF who have acute onset of peri umbilical or RLQ abdo pain and :
- palpable mass in the RLQ
- faecal loading in the RLQ on plain x ray
- clinical fx of partial or complete intestinal obstruction such as vomiting
Ix: US or CT
Tx: IVF ; gastrograffin as first line treatment , if not effective can consider PEG solution orally ** surgery is last resort
To try to avoid DIOS optimise pancreatic enzyme replacement and regular Tx with stool softener
What should make you think of CF diabetes ?
Increased weight loss, reduced lung function, increased frequency of exacerbations, excess tiredness
What is Kaftrio?
Triple combination drug for CF
Contains:
- Ivacaftor
- Tezacaftor
- Elexacaftor
(ITE)
Need to be:
- Age over 3
- 2 copies of the F508 del mutation or one copy of the F508 del and any other mutation
(Approx 90% have mutation)
In trials , increase in FEV1
What is Symkevi?
Ivacaftor and Tezacaftor
(IT)
Need to be:
- Aged over 2
- Two copies of F508 del mutation
- One copy of F508 del and another residual function mutation
(Approx 55% CF population)
Increase in FEV1
What is Orkambi?
- Ivacaftor and Lumacaftor
(IL) - two copies of F508 del mutation
- slows decline in lung function
(Approx 50% have mutation)
What is Kalydeco?
Ivacaftor
Effective in anyone with one of nine gating mutations
(Improvement in lung function and reduction in sweat chloride levels)
Outline the genetics for CF
Autosomal Recessive condition - need 2 copies of the disease causing mutation
CFTR gene located on long arm of chromosome 7
90% of patients have ≥ 1 copy of F508del ; 48% are homozygous for F508 del
What is the carrier rate for CF in UK?
1 in 25
What is the live birth rate of CF in UK?
1 in 2500
How do you interpret sweat test results ?
<30 NORMAL
30-60 INTERMEDIATE
> 60 ABNORMAL
NB can have CF and have a normal sweat test but this is less than 1%
If intermediate result can do nasal potential difference
Genetic panel CF50 is first line
What is the dominant pathogen for CF patients in childhood ?
Staph Aureus
What is the dominant pathogen for CF patients in teens/adulthood ?
Pseudomonas