CF, Bronchiectasis, Bronchiolitis

Question 1

A mutation of what gene causes cystic fibrosis?

Answer 1

CFTR (cystic fibrosis transmembrane conductance regulator) gene
On long arm of chromosome 7
Expressed in all epithelial cells
Effects transport of Cl- ions across membranes

Question 2

What CFTR gene mutation is most common?

Answer 2

F508

Question 3

What inheritance pattern does CF follow?

Answer 3

Autosomal recessive

Requires both parents to be carriers

Question 4

What is the most common life-threatening autosomal recessive disease among Caucasians?

Answer 4

CF

Question 5

What are the pulmonary effects of mucus hyperviscosity in CF?

Answer 5

Difficult for cilia to remove mucus
Viruses and bacteria become trapped
Air trapping
Decreased perfusion, hypoxia

Question 6

What are some general effects of CF?

Answer 6

Failure to thrive
Vitamin deficiency
Infertility (CBAVD) in men

Question 7

How do CF patients typically present?

Answer 7

Acute and persistent respiratory symptoms (ie multiple dx of bronchitis, bronchiolitis, pneumonia)
Failure to thrive
Meconium ileus
Abnormal stools
Nasal polyps (usu not until older)
Rectal Prolapse (tho rare in children)

Question 8

What respiratory features do CF pts experience later in disease?

Answer 8

Cough - constant, worse in AM
Wheezing
Repeated infections
Exercise intolerance
Shortness of breath
Nasal polyps
Cor pulmonale
Respiratory failure
Opportunistic infections - namely P. aeruginosa

Question 9

How would you test a pt you suspect has CF?

Answer 9

Sweat chloride test
Mutation analysis
Nasal test

Question 10

Who should your newly diagnosed CF patient be referred to first?

Answer 10

CF care center

Question 11

What treatments are available to CF patients?

Answer 11

Chest physiotherapy
Mucolytics (N-acetylcysteine, dornase alpha, 7% hypertonic saline)
Bronchodilators - check PFTs for reversibility before prescribing regular use
Anti-Inflammatories (Prednisone in those with underlying reactive airway with acute exacerbation but otherwise avoid corticosteroids; Ibuprofen)
Antibiotics - acute infections (Azithro, Cipro or Levo for at least 2 weeks
Chronic maintenance - tobramycin or colistin
CFTR Potentiators and Correctors - Ivacaftor, Ivacaftor/Lumacaftor combo

Question 12

What are the signs and symptoms of CF acute exacerbation?

Answer 12

Symptoms: increased cough, increased sputum, dyspnea, decreased exercise tolerance, decreased appetite
Signs: Increased respiratory rate, use of accessory muscles, new crackles or wheezes, weight loss, changes on chest xray, decline in PFT measures

Rx: Increase chest physiotherapy and start antibiotics

Question 13

Dicloxacillin, Cephalexin, Amoxicillin-clavulanate and Azithromycin are treatments for what type of CF acute exacerbation infection?

Answer 13

Staphylococcal infection

Question 14

What is the treatment for MRSA infection causing acute exacerbation of CF?

Answer 14

Vancomycin or linezolid

Question 15

What is the treatment for severe pseudomonas infection causing acute exacerbation of CF?

Answer 15

IV Tobramycin and piperacillin

Question 16

What is the most common treatment of pseudomonal infection causing acute exacerbation of CF?

Answer 16

Tobramycin (inhaled) and ceftazidime

Question 17

What is the pathophysiology of CF related diabetes?

Answer 17

insulinopenia from beta cell apoptosis (not insulin resistance)

Rx: Insulin, Pancreatic enzyme replacement therapy

Question 18

What is the most common cause of death in patients with CF?

Answer 18

Respiratory failure

Question 19

What can cause bronchiectasis and what is it?

Answer 19

Bronchiectasis - abnormal irreversibly dilated and thick walled bronchi
Presentation - chronic cough, copious mucopurulent expectoration (presents similar to chronic bronchitis)

Pathologic processes: 
Prior lung infection
Systemic inflammatory disorders
Genetic disorders of immune system
Idiopathic

Question 20

How is a diagnosis of bronchiectasis confirmed after initial studies (CBC with diff, IgG IgM IgA, sputum culture)?

Answer 20

Non-contrast chest CT

Question 21

What findings are expected to be seen on CXR and chest CT in patient with bronchiectasis?

Answer 21

Chest X-Ray:
“tram track” opacities
finger in glove sign

Chest CT:
bronchus larger than corresponding arteries
tree in bud appearance
dilated and thickened airways

Question 22

How is bronchiectasis treated?

Answer 22

Treat the underlying condition
Control infection (oral respiratory fluoroquinolone such as levofloxacin, moxifloxacin or gemifloxicin for 10-14 days)
Reduce inflammation (bronchodilators: SABA such as albuterol or levalbuterol, LABA such as formoterol or salmeterol or fomoterol/budesonide, Anticholinergics such as ipratropium or tiotropium; Anti-inflammatories such as fluticasone)
Improve bronchial hygiene (chest physiotherapy, self-directed therapy)
Surgical resection
Lung transplant (but post op life expectancy <10 years)

Question 23

What is bronchiolitis?

Answer 23

Inflammation of the small airways (<2mm diameter)

Seen mostly in infants and young children

Question 24

What are some infectious etiologies of bronchiolitis?

Answer 24

RSV
Parainfluenza
Adenovirus
Rhinovirus

Question 25

What are the signs and symptoms of bronchiolitis?

Answer 25

Increased respiratory effort (nasal flaring, tachypnea, retractions, accessory muscle use)
Evidence of small airway obstruction (wheezing, hypoxia SpO2 <93%)

Question 26

What WBC findings would you expect to see in CBC done on patient with bronchiolitis?

Answer 26

Normal WBC
If high, look for another dx such as reactive airway/hypersensitivity if high eosinophils or acute bacterial bronchitis if high neutrophils

Question 27

Should CXR be ordered if suspicious for bronchiolitis?

Answer 27

No, unnecessary radiation in babies = bad

But if completed, would expect to see air trapping and peribronchial thickening (“cuffing”)

Question 28

What is treatment of bronchiolitis?

Answer 28

Symptom relief
Maintenance of hydration and oxygenation
Consider hospital admission if <3mo, <2 yrs but premature, SpO2<93%, RR >70-80, Resp distress, h/o chronic lung disease or congenital heart disease, poor feeding, social factors