Cystic Fibrosis

Question 1

What is cystic fibrosis?

Answer 1

An autosomal recessive disorder affecting mucus production in the lungs & digestive system

Question 2

In what ethnicity is cystic fibrosis most common?

Answer 2

Caucasians

Question 3

What genetic abnormality causes cystic fibrosis?

Answer 3

Defect in long arm of chromosome 7 causing problems with the coding of a protein

Question 4

What is the name of the incorrectly coded protein?

Answer 4

CFTR: cystic fibrosis transmembrane regulator

Question 5

What is the usual role of the protein that is affected in CF?

Answer 5

It is a transport protein that transports chloride (and thiocynate) ions

Question 6

How does the genetic mutation cause CF?

Answer 6

The mutation causes a faulty protein (CTFR)

This causes problems with chloride ion transport in many organs

Leading to thickened, sticky secretions in these organs

Question 7

Which organs are involved in CF?

Answer 7

Any organs that produce mucus: lung, small and large intestine, pancreas

Question 8

List the problems that CF causes in the respiratory system.

Answer 8

Dry, sticky, thick mucus

Acute + chronic infections

Inflammation

Bronchitis and bronchiectasis

Fibrosis

Pneumothorax

Haemoptysis

Respiratory failure

Question 9

List the problems that CF causes in the alimentary system.

Answer 9

Reduced secretions of enzymes, HCO3-,

Decreased motility

Mal-absorption

Malnutrition, poor growth, weight loss

Hepatic failure

Biliary sludging

Pancreatitis, fibrosis

Question 10

List the problems that CF causes in the urogenital system.

Answer 10

Males: atrophy of vas deferens

Females: cervical mucus + polyps

Both: renal failure due to treatment, infertility

Question 11

List the problems that CF causes in the skin.

Answer 11

Loss of salt via sweat

Heat prostration: overheating

Question 12

List the problems that CF causes in the central nervous system.

Answer 12

Neuropathy
Night blindness
Delayed puberty
Hypothalamus problems

Question 13

List the problems that CF causes in the skeletal system.

Answer 13

Osteoporosis
Clubbing
Arthropathy
Delayed bone age
Impaired peak bone density

Question 14

What two ways can you diagnose CF? Just name them.

Answer 14

Clinical

Genetic

Question 15

How would you diagnose CF clinically?

Answer 15

Sweat test: if sodium + chloride levels are above 60mmol/l

Faecal elastase: checks for pancreatic dysfunction

Symptoms

Question 16

How would you diagnose CF genetically?

Answer 16

History in a sibling

Positive screening test: immunoreactive trypsinogen

Question 17

Which microbes do you need to be particularly careful of in CF?

Answer 17

Pseudomonas aeruginosa

Burkholderia cepecia complex

Mycobacterium abscessus

Question 18

What is so bad about pseudomonas aeruginosa?

Answer 18

It forms a biofilm
It is very resistant
It stays in the lungs

Question 19

What is so bad about mycobacterium abscessus?

Answer 19

Once infected with this, CF sufferers will never get a transplant

Question 20

What would you see on a CXR of a CF patient?

Answer 20

Hyperinflation of the lungs

Bronchiectasis

Question 21

What would a spirometry test show in a CF patient?

Answer 21

Obstructive defect

Question 22

What would an abdominal USS show in a CF patient?

Answer 22

Fatty liver
Cirrhosis
Chronic pancreatitis

Question 23

Management of a CF patient

Answer 23

Prevent infection

• prophylaxis
• segregation
• antibiotics

Anti-inflammatories

Physical therapies: postural drainage

Support: nutrition

Transplant

Question 24

What is the typical life expectancy of CF patients?

Answer 24

40 years