cystic fibrosis Flashcards
1
Q
ethnicity and CF
A
more common in European descent
2
Q
What is CF?
A
- autosomal recessive genetic disorder
- mutation in a single gene on the long arm of chr 7
- most common mutation is the delta F508 (deletion, pehenylalanine at position 508)
- high salt concs in sweat (‘sweat test’)
- thick and sticky mucous becayse of lack of water
3
Q
CFTR (mutation)
A
cyctic fibrosis transmembrane conductance regulator
4
Q
diagnosis of CF
A
- newborn screening with ‘heel prick’ test - measure immunoreactive trypsinogen levels in blood
- genetic mutation analysis
- sweat test - measures the conc of chloride excreted in sweat (inc in CF)
5
Q
problems CF causes in the body
A
- excessive salt loss in sweat
- OP
- growth retardation
- respiratory failure
- GI disorders
- infertility
6
Q
pulmonary effects of CF
A
- impaired mucociliary clearance
- airways clogged with thick sticky mucous
- impairs clearance of microorganisms
- early colonisation of lungs with Staphylococci or H influenzae
- infections cause large inflam response
- act of neutrophils
- acc of debris from bacteria and neutrophils difficult to clear
- proteases of neutrophils damage airways
- cycle of infection & inflamm continues, lung fxn compromised
7
Q
airway infections
A
- close monitoring of secretions (cough, swab, sputum culture)
- reg mon of lung fxn with spirometry, O2 sats
- without ABX can deteriorate quickly, fatal respiratory failire
- Tx threshold diff to no CF person
8
Q
staphylococcus aureus
A
- usually initial infecting pathogen
- continuous prophylaxis as child
- minor exacerbations - oral flucloxacillin
- severe exacerbation - IV flucloxacillin or vancomycin
9
Q
MRSA
A
- pt/family swabbed
- if in nasal - Tx with Mupirocin
- MRSA causing Sx - fusicid acid + rifampicin/trimethoprim, oral linezolid
- severe/acute exac - IV teicoplanin/vancomycin
10
Q
haemophilus influenzae Tx
A
- oral amoxicillin
(if sensitive and no recent Hx of s/ aureus) - severe infections - chloramphenicol, cefuroxine (cephalosporin, tendonitis, seizure)
11
Q
pseudomonas aeruginosa
A
- recurrent infections eventually lead to chronic colonisation
- chronic colonisation causes rapid decline in lung fxn
- pts have a 2-3 fold inc risk of death over 8yr period
12
Q
exacerbations of P. aeruginosa
A
- treat early infections aggressively (attempt eradication)
- eradication regimens
13
Q
eradication regimens for P aeruginosa
A
- 6 weeks ciprofloxacin and 3-6mth colistin
- 3 mths ciprofloxacin and colistin
- inhaled tobramycin (intol to ciprofloxacin and colitin or early regrowth of P aeruginosa or other Tx failed)
severe exacerbation, broad spec agets:
1. IV Tazocin
2. IV aminoglycosides (comb synergistic effect with beta latams)
14
Q
caution with IV aminoglycosides (gentamycin, tobramycin)
A
nephrotoxicity
ototoxicity
15
Q
nebulised antibiotics
A
- solution of drug into a fine spray
- inhaled, delivering the ABX deep into the lungs
- P. aeruginosa, reduce rate of lung deterioration and the number of IV courses needed
- colistin and tobramycin have been used
16
Q
disadvantages of nebulised colistin and tobramycin
A
expensive
17
Q
doxycycline - counselling
A
- sensitivity to sunlgiht
- swallow whole, remain standing
18
Q
ciprofloxacin - counselling points
A
- interacts with milk, antacids, Fe, Zn
- risk of tendon rupture
- may induce convulsions (caution in epilepsy)
19
Q
nebulised ABX - counselling points
A
- bronchospasm - prevent by taking with bronchodilator (salbutamol)
- 1st dose in hospital (measure lung fxn before and after)
- may need filter to prevent fumes in room
20
Q
usual combination of ABX for CF infection
A
aminoglycoside + beta-lactam
21
Q
When are macrolides used?
A
LT in pts with declining lung function, declining clinical status and chronic colonisation
22
Q
eg of macrolide
A
azithromycin 250-500mg x3 WEEKLY
23
Q
3 mucoactive agents
A
- rhDNase
- hypertonic saline (HS)
- mannitol dry powder for inhalation (Bronchitol 40mg)
24
Q
rhDNase
A
rhDNase (dornase alpha, recombinant human deoxyribonuclease)
- CF sputum contains DNA derived from neutrophils
- aerolised rhDNase is an enzyme that cleaves DNA
- dec sputum viscosity and aid expectoration
25
hypertonic saline (HS)
ST:
- induce sputum in pts where upper airway cultures are -ve
- adjunct to physio
LT:
- mucoactive agent
- adjunct to physio
26
mannitol dry powder for inhalation (Bronchitol 40mg)
- mannitol = sugar alcohol
- inc hydration, aids clearance
- 400mg BD
27
aim for O2 sats
> 93%
28
NIV - non-invasive ventilation
- O2 therapy
- useful for airway clearance with physio techniques
- used LT, can improve gas exchange during sleep in mod/severe disease
29
vaccines in CF
* regular vaccines as per childhood
immunisation schedule
* annual flu vaccination strongly recommended (pt & family)
* pneumococcal vaccination not required but offered if families prefer (not normally a problematic organism)
30
physiotherapy
- important for CF management
- physical exercise
- CV fitness = improved survival
- airway clearance techniques
- monitor MSK problems (posture, bone health)
31
lung transplantation
- option for end stage CF
- criteria: limited life expectanct (<2yrs) & severely impaired QoL
- 9yr survival post transplant
32
pancreatic insufficiency
* 95% of CF pts
* need pancreatic enzyme replacement and fat sol vitamins (A, D, E, K)
* more enzymes needed with fatty meal OR stools loose/frequent/oily/plale
* Creon 10,000 caps in childern/adults
33
CFRD - CF related diabetes
- most common co-morbidity in CF
- usually in adolecance/early adulthood
- destruction of insulin producint islet cells
- delayed and inufficient insulin secretion
- reduced insulin sensitivity
- Tx = insulin
- microvasculat complications develop
34
liver disease
* genetic cholangiopathy
* CFTR - expressed in liver, regulates fluid/electrolyte content of bile
* dec fxn results in biliary cirrhosis
* complications = portal hypertension, oesophageal varised, hepatic failure
35
bone health
* bone disease, low BMD
* delayed puberty
* steroid therapy
* CF related diabetes
* dec physical activity
* Ca & Vit D deficiency
* Vit K deficiency
* poor nutritional status
* chronic inflammaiton
36
fertility
* CBAVD - congenital absence of the vas deferens
* most male CF pts will be infertile (not all(
* normal fertility in females
* interactions with COC (rifampicin)
37
nutrition
* improved nutritonal status = better outcomes & survival
* poor body weight and height related to mottality
* daily energy requirements 100-150% of average for age
* high energy meals and snacks to achieve energy requirements and maintain weight
38
new therapies in CF
* Lumacaftor-ivacaftor (Orkambi) combination tablet
* lumacoftor = CFTR corrector, improves cellular processing
* ivacaftor = CFTR potentiator, inc probability the channel is open
* only if homozygous for F508del mutation
39
triple combination new therapy for CF
elexacaftor + tezacaftor + ivacaftor2
