Cystic Fibrosis Flashcards

1
Q

What is cystic fibrosis?

A

Genetic disease resulting from abnormalities in the cystic fibrosis transmembrane conductance regulator. A chloride channel found in cells lining the lungs, intestines, pancreatic ducts, sweat glands and reproductive organs

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2
Q

What are some of the common clinical manifestations of Cystic Fibrosis?

A

Calorie malabsorption, lung disease which results from a cycle of mucus retention, infection and inflammation.

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3
Q

Describe the pathophysiology of cystic fibrosis

A

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) which results in abnormal salt transport by epithelial cells. Resulting in thick, sticky secretions

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4
Q

How does CF affect the pancrease?

A

Blockage of exocrine ducts, early activation of pancreatic enzymes and eventual autodestruction of exocrine pancreas. Leads to need for supplemental pancreatic enzymes

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5
Q

How does it impact the intestinal system?

A

Abnormal salt and water imbalance can lead to inspissations of stool and intestinal mucus which results in intestinal obstruction

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6
Q

What is the impact of CF on the lungs?

A

The absence of CFTR function results in mucus retention, chronic lung infections and inflammation which eventually leads to destruction of lung tissue. Lung disease is the most common cause of mortality

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7
Q

How do people commonly present with CF

A

Generally presents in infants or early childhood with faltering growth. Some may present with prolonged or severe bronchiolitis or recurrent respiratory complaints. Adults may present with chronic or recurrent bronchitis, sinusitis or pancreatitis.

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8
Q

When enquiring about birth history what should you ask about?

A

Passage of meconium (because delayed passage may be a sign) and the place of birth (many countries offer CF screening.

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9
Q

What should you enquire about with respiratory tract history?

A
  • Resp rate, presence of retractions, cough or wheeze.
  • Presence of cough and quantity and quality of sputum.
  • History of lower airway infections
  • Haemoptysis
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10
Q

What should you enquire about with GI tract history?

A
  • Appetite, typical diet, stool habits, gastro-oesophageal reflux.
  • Presence on insatiable appetite along with large, bulky or greasy stools. This is consistent with fat and calorie malabsorption.
  • History of decreasing stools over time with/without abdo distention and vomiting as this may signal bowel obstruction.
  • Recurrent pancreatitis/acute appendicitis
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11
Q

Name some of the findings on physical examination?

A
  • Appearance of malnutrition.
  • Increased anteroposterior diameter of the chest and crackles at auscultation.
  • Clubbing of the hands
  • Palpation of abdoment may reveal stool mass (RLQ), enlarged liver, spleen or both.
  • Males - bilateral absense of vas deferens
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12
Q

Describe some of the investigations

A
  • Sweat test
  • Genetic testing (looking for most common CFTR mutations but there are over 2000 mutations that cause it)
  • Sinus X-ray, deep throat swab
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13
Q

Describe features of the sweat test?

A

Small amount of pilocarpine is placed on the skin and the area is then stimulated by a small current for 5mins to stimulate sweating. The sweat is collected in a microcapillary tube and chloride content is measured. Considered the most conclusive test for diagnosis. Negative sweat test <30mmol/L. Positive sweat test >60mmol/L

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14
Q

What are the advantages of the sweat test?

A

Painless, relatively inexpensive, provides results in a few hours and accurate.

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15
Q

Describe the management of cystic fibrosis in regards to respiratory disease

A
  • Augmented airway clearance and use of antibiotics to treat pulmonary clearance. The airway clearance should be preformed to mobilise secretions so they can be coughed out.
  • Mucus thinners
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16
Q

Describe the methods of airway clearance

A
  • Manual chest physiotherapy,
  • Active cycling of breathing,
  • VEST therapy
  • Flutter valve
  • Positive expiratory pressure mask,
  • Non-invasive ventilation
17
Q

Describe features of inhaled therapy for CF

A
  • Short acting bronchodilators like salbutamol can be given
  • Mucolytics which degrades DNA from inflammatory cells in the airway
  • Inhaled antibiotics
  • Inhaled corticosteroids
  • Anti-inflammatory agents are used to control inflammation in airway
18
Q

What are CFTR modulator therapies?

A

Small molecules that can partially restore function in mutated CFTR but because there are so many different mutations these drugs only work in patients with specific mutations.

19
Q

Who is able to get given a lung transplant?

A

Patients that have exhausted all other alternative therapies.

20
Q

What are the four CFTR modulators?

A

Ivacaftor, Lumacaftor, teza caftor and elexacaftor. Different combinations are used.

21
Q

Describe the management of acute pulmonary exacerbation

A
  • Antibiotic therapy (use is based on sputum culture results and sensitivities). The general duration of antibiotics is 14days.
  • Oral antibiotics for mild, eg, amoxicillin, trimethoprim and linezolid.
  • Moderate to severe exacerbations are treated with IV antibiotics. AN aminoglycoside is usually combined with antibiotics with S.Psudomonas coverage
22
Q

Describe the management of pancreatic insufficiency

A

Pancreatic enzyme replacement therapy (given before meals/snacks) and fat-soluble vitamin supplementation (A, D, E and K). Prothrombin time is used to asses levels of vit K

  • H2 antagonists create a more alkaline environment for pancreatic enzymes supplements. Improves enzyme function.
23
Q

Describe the management of liver disease

A
  • Obstruction of biliary ducts leads to periportal inflammation and fibrosis which can lead to multilobular cirrhosis and portal hypertension. Therapy is limited to oral bile acids
24
Q

Describe the management of intestinal disease

A
  • Surgery is indicated in situations such as complete intestinal obstruction, signs of peritonitis or failure of medical management
  • In neonates, obstructive episodes can be managed by using water soluble enemas and oral administration of osmotic agents
25
Q

How does CF affect the reproductive system?

A

Men - Sperm duct is blocked, preventing movement of sperm.

Women - Women can have thick levels of mucus which can block the cervix so sperm cannot reach the egg.

26
Q

Describe the long term management of CF

A
  • Seen at CF centre every 3 months where they need a physical exam,
  • evaluation by nutritionist
  • When symptoms dictate and on a yearly basis; CXR, blood work and full pulmonary function test.
  • Spirometry to monitor lung function,
  • IV aminoglycosides to treat lung infections but kidney function needs monitored via weekly serum creatinine levels.
27
Q

What is the prognosis for CF patients?

A

No cure however the prognosis has greatly improved. Patients now live up to around 40years old.