Question 1

Which of the following drugs should the therapist give before administering nebulized 7% saline to a patient with CF?

Accepted Answer

Because hypertonic saline causes bronchospasm in some patients,it is generally recommended to premedicate with a beta-2 agonist.

Question 2

A sweat chloride test is performed in a 14-year-old child who has adrenal insufficiency.What effect can this condition have on the results of this diagnostic test?

Accepted Answer

The sweat is obtained by stimulating the skin on the forearm with pilocarpine iontophoresis (see Figure 28-1 in the textbook).Technical error can result in false-negative and false-positive results.In addition to inadequate sweat collection,malnutrition,edema,and hypoalbuminemia can also give false-negative results.Therefore,patients with clinical features suggestive of CF but normal or borderline sweat test results should have the test repeated.Conditions that can produce false-positive results include malnutrition,eczema,adrenal insufficiency,pseudohypoaldosteronism,and hypothyroidism.

Question 3

A 10-year-old child has had two sweat tests,each indicating a sweat chloride concentration of 30 mEq/L.How should the therapist interpret these data?

Accepted Answer

The gold standard for the diagnosis of CF is the sweat chloride test.Normal secretion and resorption of chloride in the sweat glands are dependent on adequate CFTR function.A sweat chloride concentration ³60 mmol/L confirms the diagnosis.A concentration between 40 and 59 mmol/L in infants older than 6 months is considered intermediate and should be repeated along with CFTR mutation analysis.Normal individuals can occasionally have elevated sweat chloride concentrations not related to CFTR dysfunction.

Question 4

Which of the following is the earliest pathologic change that causes airway dysfunction?

Accepted Answer

Airway dysfunction begins during the first year of life,with the earliest pathologic change being thickened mucus and plugging of the submucosal gland ducts in the large airways.These changes appear to precede infection and inflammation.

Question 5

What are the chances of two CFTR gene carriers having a normal child?

Accepted Answer

An individual with CF is a homozygote,or an individual possessing two abnormal CFTR alleles.Each parent of a child with CF is an obligate carrier (or heterozygote),possessing one normal CFTR allele and one mutated allele.Each child of two carriers has a 1 in 4 chance of having CF,a 2 in 4 chance of being a carrier,and a 1 in 4 chance of having two normal alleles.

Question 6

Approximately what percentage of patients with cystic fibrosis present with pulmonary symptoms?

Accepted Answer

Nearly half of all patients with CF are diagnosed as a result of pulmonary symptoms.The diagnosis of CF should be considered in every patient who presents with chronic or recurrent lower respiratory tract disorders,including bronchitis,bronchiectasis,pneumonia,and refractory asthma.Children with CF have frequent pulmonary exacerbations,with the most consistent feature being a chronic cough.

Question 7

Which of the following medications should the therapist routinely administer during the management of hospitalized patients with cystic fibrosis?
I.Albuterol
II.Hypertonic saline
III.DNAse
IV.Salmeterol

Accepted Answer

Aerosol therapy is an important aspect of CF respiratory care in the hospital and in the home.A number of medications are designed to address specific aspects of CF pulmonary disease.Put together,a commonly utilized sequence is as follows: bronchodilator,hypertonic saline,recombinant human DNAse,airway clearance therapy,maintenance medication (inhaled corticosteroid and/or antibiotic).

Question 8

Which of the following microorganisms commonly colonize the airways of patients with cystic fibrosis?
I.Actinomyces israelii
II.Haemophilus influenzae
III.Pseudomonas aeruginosa
IV.Staphylococcus aureus

Accepted Answer

The presence of endobronchial pathogens changes with age.Staphylococcus aureus and Haemophilus influenzae typically appear early in life,with S.aureus reaching maximum prevalence at ages 6 to 17 years and H.influenzae peaking at 2 to 5 years of age.

Question 9

Which of the following respiratory signs and symptoms should prompt the therapist for evaluation of cystic fibrosis in a child?
I.Recurrent wheezing
II.Frequent thick sputum production
III.Chronic cough
IV.Nasal polyps

Accepted Answer

Box 28-1 Signs and Symptoms That May Prompt Evaluation for Cystic Fibrosis
Recurrent wheezing
Chronic cough
Frequent thick sputum production
Severe,prolonged,or recurrent sinopulmonary infections
Respiratory infections with pathogens associated with cystic fibrosis
Persistently abnormal chest radiograph
Nasal polyps
Clubbing of the nail beds

Question 10

A sweat chloride test and CFTR mutation analysis performed in a 10-year-old child with signs and symptoms consistent with CF are inconclusive.Which of the following tests should the therapist suggest at this time?

Accepted Answer

Measuring the difference in voltage potentials across the nasal epithelium is another method used in the diagnosis of CF,particularly when sweat chloride and/or CFTR mutation analysis results are inconclusive.

Question 11

On pulmonary function testing,which of the following lung abnormalities is/are common in patients with severe cystic fibrosis?
I.Obstructive pattern
II.Restrictive pattern
III.Airway hyperreactivity
IV.Normal pattern when asymptomatic

Accepted Answer

Pulmonary function testing initially demonstrates air flow obstruction.As the disease progresses,both a restrictive and an obstructive pattern can be seen,along with a decrease in air flow.About 50% of patients with CF have a positive methacholine challenge test,which indicates airway hyperreactivity.

Question 12

Which of the following aerosolized antibiotics is nebulized to treat infections caused by Pseudomonas aeruginosa in patients with CF?

Accepted Answer

Aerosolized antibiotics such as tobramycin are frequently used as chronic suppressive therapy to treat patients infected with P.aeruginosa to prolong the time between pulmonary exacerbations and to slow the progression of lung function decline.A Cochrane review of inhaled tobramycin for CF concluded that aerosolized antipseudomonal antibiotics improved lung function.A unit dose of 300 mg/5 mL is considered standard.It is given twice a day for 28-day cycles every other month.

Question 13

Which of the following therapeutic interventions should be the focus of the treatment of patients with cystic fibrosis?

Accepted Answer

Treatment of the pulmonary manifestations of CF focuses on routine therapy aimed at physically removing thickened mucus from the airways.Pharmacologic control of infection with the aggressive use of antibiotics is crucial.

Question 14

What are the primary characteristics of cystic fibrosis?
I.Chronic obstruction and inflammation of the airways
II.Exocrine pancreatic insufficiency
III.Malabsorption and small bowel obstruction
IV.Decreased sweat chloride concentration

Accepted Answer

The signs and symptoms of classic CF are related to the overproduction of thick,viscous secretions in multiple organ systems:
Chronic obstruction,infection,and inflammation of the airways;
Exocrine pancreatic insufficiency with malabsorption and small bowel obstruction;
Infertility in males;
Elevated sweat chloride levels.

Question 15

Which of the following antiinflammatory agents should be considered in patients with CF to slow the progression of the lung disease?

Accepted Answer

Ibuprofen has been demonstrated to slow the progression of lung disease over a 2-year period.However,specific dosing and close pharmacokinetic monitoring is required when using this medication.

Question 16

Which of the following methods is the most commonly recommended for newborn screening?

Accepted Answer

As of January 2010,all 50 states and the District of Columbia included CF in standard newborn screening.The most common method is measurement of serum immunoreactive trypsinogen (IRT)obtained from a dried heel-stick blood sample.

Question 17

Which of the following radiographic features is consistent with CF?

Accepted Answer

The chest radiograph initially shows hyperinflation with flattened diaphragms secondary to air trapping (see Figure 28-2 in the textbook).Mucus plugging and patchy atelectasis can also be seen.Diffuse fibrosis,bronchial wall thickening,and bronchiectasis are found predominantly in the upper lobes.However,over time all lung fields are involved.

Question 18

What percentage of patients with adult cystic fibrosis are chronically infected with Pseudomonas?

Accepted Answer

More than 73% of adults with CF in the United States are chronically infected with Pseudomonas.It is strongly associated with accelerated lung function decline and survival.

Quiz 28: Cystic Fibrosis