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Flashcards in Cystic Fibrosis Deck (14)
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1
Q

What is Cystic Fibrosis?

A

Cystic fibrosis (CF) is a severely life-shortening genetic disease resulting from abnormalities in the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel found in cells lining the lungs, intestines, pancreatic ducts, sweat glands, and reproductive organs.

2
Q

The most common clinical manifestations are

A

pancreatic dysfunction, resulting in calorie malabsorption; and lung disease, resulting from a cycle of mucus retention, infection, and inflammation.

3
Q

membrane mutation

A

• Mutations in cystic fibrosis transmembrane conductance regulator CFTR result in abnormal salt transport by epithelial cells, resulting in thick, sticky secretions.

4
Q

what happens to the pancreas?

A

this leads to blockage of exocrine ducts, early activation of pancreatic enzymes, and eventual autodestruction of the exocrine pancreas. Therefore, most patients require supplemental pancreatic enzymes.

5
Q

what happens in the intestine?

A

bulky stools can lead to intestinal blockage.

6
Q

what happens in the respiratory system?

A

the absence of CFTR function results in mucus retention, chronic infection, and inflammation that eventuate in the destruction of lung tissue.
• Lung disease is the most common cause of morbidity and mortality.

7
Q

Newborn screening for CF.

A
  • It is performed by quantifying serum immunoreactive trypsinogen from a dried heel-stick blood spot.
  • Newborn screening allows for early diagnosis and treatment, and provides significant clinical benefits, including improved nutrition and cognition.
  • It may also decrease lung disease and admissions to hospital.
8
Q

Diagnosis of CF.

A
  • generally present in infancy or early childhood with failure to thrive.
  • will present with prolonged or severe bronchiolitis or recurrent respiratory complaints.
  • Undiagnosed adults with CF, who are usually pancreatic sufficient, may present with chronic or recurrent bronchitis, sinusitis, or pancreatitis.
    • The appearance of malnutrition
    • Nasal polyps.
9
Q

Investigations

A
  • sweat test
10
Q
  • sweat test
A
  • In this test a small amount of pilocarpine is placed on the skin of the forearm to stimulate sweating.
  • To absorb the Pilocarpine into the skin, the area is stimulated by a small current from a battery, for around five minutes. This may produce a tingling sensation, but it does no harm and does not hurt.
  • The stimulated sweat is collected in a microcapillary tube so that its chloride content can be measured.
11
Q

sweat test ranges

A
  • A negative sweat test (defined as a sweat chloride measurement of <30 mmol/L [<30 mEq/L] in all age groups) suggests that CF is unlikely. However, if questions remain, referral to a CF centre is recommended even in the presence of a negative sweat test.
  • A positive sweat test (defined as a sweat chloride measurement of ≥60 mmol/L [≥60 mEq/L]) is consistent with CF and requires immediate referral to a CF centre
12
Q

if sweat test is inconclusive then you use

A
  • an initial ‘screen’ for the most common cystic
    fibrosis transmembrane conductance regulator (CFTR) mutations.
    • If two common mutations are not found, most laboratories have an option for sequencing more of the CFTR gene or the entire CFTR gene.
    • Other ancillary tests include a sinus x-ray, which may show pansinusitis, and a deep throat swab performed after a gag, which may demonstrate respiratory pathogens, although neither of these are specific tests for CF.
13
Q

Management of CF.

A

no cure
• Airway clearance should be performed to mobilise secretions from the airway walls into the lumen, where they can be coughed out.manual chest physiotherapy, active cycle of breathing, high-frequency oscillatory vest device (VEST therapy), flutter valve, or positive expiratory pressure mask.
• Non-invasive ventilation (NIV)

14
Q

Inhaled therapy.

A

• Short-acting bronchodilators (e.g., salbutamol) are generally given before airway clearance