cystic fibrosis

what is cystic fibrosis

genetic condition causing build up of thick sticky mucus

what does the gene mutation causing CF do?

• Affecting ability to move salt and water out of cells

• NaCl is NOT reabsorbed at the same rate as in non CF individuals and so this causes a thick sticky mucus

what are the 3 ways to diagnose CF

antenatal testing 

new born screening 

sweat test 

what is involved in antenatal testing 

• If both parents are known carriers

• The test where needle goes into amniotic fluid

• Amniocentesis

what is involved in new born testing 

• Heel prick test

• Sweat test if this comes back positive

• Tests for 20 most common CF mutations

• Doesn’t check for all the other mutations

what is involved in the sweat test

• At any age

• May also be done in failure to thrive, recurrent chest infections

• Electrodes on 2 parts of the arm

• Electrical current through arm which induces sweat

• Collecting device used to collect sweat

• 20-30 mins

• No pain by tingly

what is the cause of CF

• Inheritance of a faulty gene from both parents

what is class 1 gene mutation

no CTFR protein is produced

class 1 mutations can be due to early termination of CTFR protein production or large regions of mutated CTFR DNA 

what is class 2 gene mutation

defective trafficking of CFTR

which does not reach the surface of the cell

F508del is a class 2 mutation 

what is a class 3 gene mutation 

the CTFR protein reaches the cell surface but it does not function 

G551D is a class 3 mutation 

what is a class 4gene mutation

the CTFR protein reaches the cell surface but chloride transport through the channel is defective 

what is a class 5 mutation

the CTFR channel is normal but the amount of protein at the cell surface is decreased 

what is a class 6 gene mutation

the CTFR channel is not stable at the cell surface so the amount of protein at the cell surface Is decreased

what is the most common type of CTFR gene mutation

class 2

what are the lung symptoms of CF

people with CF are susceptible to a range of infections and reduced lung function 

owing to an increased risk posed by infections, people with CF should not meet face to face

what are the digestive system symptoms of CF

including the pancreas and digestion, CF and meconium ileum (bowel obstruction), DIOS and gastro-oesophageal reflux

what causes cystic fibrosis related diabetes

inflammation and scarring of the pancreas can prevent the effective production of insulin 

what are the liver symptoms from CF

CF can cause the blockage of the small ducts in the liver, leading to liver disease 

what are the bone symptoms of CF

including joint pain and arthritis, osteopenia, osteoporosis and low bone mineral density

what are the fertility symptoms of CF

both men and women may struggle to conceive

what is the general dietary advice for CF

healthy balanced diet

what is the relationship between BMI and lung function

healthy BMI improves lung function

what can CF increase body energy needs to (likely when not on modulators)

150-200%

what is the likely dietary advice on modulators 

fortifying, ONS 

what is the relationship between pancreatic insufficiency and CF

90% of people with CF have pancreatic insufficiency

managed with PERT 

what is the advice for managing mealtimes

• same as fussy eating 

• Good eating routine

• 3 regular meals , 2-3 snacks per day

• Family meals

• Food play

• Time limits

• Avoid other distractions

• If child refuses to eat, dont make a different meal or offer a preferred snack

• If child completely refuses to eat and appears to be seeking attention, food should be removed without comment and child should wait for next meal/snack time. No alternative to be offered.

• Ignore when food isn’t eaten

• Dont use bribery

• Try a reward chart

• No food rewards

why does pancreatic insufficiency occur

small tubes that transport enzymes out of the pancreas become blocked with mucus

enzymes build up in the pancreas

instead of reaching the digestive system causing pancreas to become inflamed 

what treatment might be needed for a lung problem

antibiotics to prevent and treat chest infections

medicines to make the mucus in the lungs thinner and easier to cough up (hypertonic saline and mannitol dry powder)

bronchodilators to wider the airway and make breathing easier

what airway clearance techniques may be used in CF

active cycle of breathing techniques (breathing, huffing, coughing, relaxed breathing) to move mucus 

autogenic drainage (controlled breathing techniques that clear mucus from lungs) 

airway clearance devices (handheld device that using breathing, vibrations and air pressure to remove mucus from the airways. 

what symptoms may someone with pancreatic insufficiency experience

Greasy and bulky stools (steattoreah )

• Frequent and or difficult bowel movements

• Constipation

• Nausea

• Swollen abdomen

• Loss of appetite

how is creon given in babies 

with pear/apple puree

what considerations are needed for a baby taking creon granules

• If feeding lasts over 20 minutes more enzymes may be needed

• Check no granules left on baby’s mouth or on nipples

• Enzyme does needs to be changed regularly as baby grows

• Enzyme should be swallowed whole, not crushed or chewed

• Taken before or during snacks and meals

• For meals eaten over a longer period spend throughout the meal

• Might need more enzymes with high fat food

what vitamins are likely needed to be supplemented

fat soluble

A

D
E

K

what other dietary adaptation may CF patients need

more salt in diet

what % of energy should fat make up

35%

how many calories in 1g of fat

9kcal

what can low salt in diet lead to

thicker mucus

what factors affect the amount of fluid needed

• Illness and chest infections

• Sweat

• Exercise

• Raised blood glucose levels

what is the relationship between bones and CF management

poorly managed CF is likely to have an effect on bones, less of a risk when on modulators 

why are DEXA scans done?

to assess bone health

what is DIOS

• Blockage in distal intestine

what is DIOS characterised by

rapid onset of pain

what are the risk factors for DIOS development

• CF genotype

• Pancreatic insufficiency

• Not taking enzymes

• Dehydration

• Meconium ileus as a new born

• Post lung or liver transplant

• CFRD

• Previous DIOS

how does CF affect liver function 

mucus causes bile to be secreted differently and to become sticky causing inflammation and irritation which leads to scarring and cirrhosis  which can cause hypertension in portal vein. 

Enlargement of surrounding tissues 

what is ERSO

medication that alters composition of bile

what is the incidence of CF diabetes

• 1/3 patients >10 will develop CFD and chances increase with age

when and how is CFD assessed 

• 10 and 14 using CGM and OGTT

what causes a CFD diagnosis

high BG for more than 2 Horus