Paediatrics 4 Flashcards
1
Q
Cystic fibrosis pathophysiology
A
- Cystic fibrosis (CF) is an autosomal recessive disorder causing increased viscosity of secretions (e.g. lungs and pancreas).
- It is due to a defect in the CFTR gene, which codes a cAMP-regulated chloride channel.
- Causes excess sodium and water re-absorption resulting in dehydration and impaired clearance of respiratory secretions.
- The airway becomes obstructed with respiratory secretions causing infection, inflammation and eventual tissue destruction.
- This leads to bronchiectasis and eventual respiratory failure.
2
Q
Cystic fibrosis genes
A
In the UK 80% of CF cases are due to delta F508 on the long arm of chromosome 7. Cystic fibrosis affects 1 per 2500 births, and the carrier rate is c. 1 in 25
3
Q
Organism which may colonise CF patients
A
- Staphylococcus aureus
- Pseudomonas aeruginosa
- Burkholderia cepacian i.e. Pseudomonas cepacia
- Aspergillus
4
Q
CF diagnosis: sweat test
A
- Patients with CF have abnormally high sweat chloride
- Normal value <40 mEq/l, CF is indicated by >60 mEq/l
5
Q
CF presenting features
A
- neonatal period: meconium ileus (diagnosed and treated with gastrograffin enema), less commonly prolonged jaundice.
- Infants: salty sweat, faltering growth and recurrent chest infections
- Chronic cough, thick sputum, abdo pain and bloating
- malabsorption: steatorrhoea, failure to thrive. Due to pancreatic insufficiency, can be confirmed with a stool sample to perform a faecal elastase test. Low level suggests insufficiency (<200 ug E1/g faeces)
- other features (10%): liver disease
- Most screened at neonatal blood spot test then confirmed with sweat test or genetic testing
6
Q
Complications and problems of CF
A
- Signs: Finger clubbing, Crackles and wheeze on auscultation
- abdominal distension
- short stature
- diabetes mellitus
- osteoporosis
- delayed puberty
- rectal prolapse (due to bulky stools)
- nasal polyps
- male infertility, female subfertility
- Life expectancy: 45
- Followed up every 6 months
7
Q
CF management conservative
A
- regular (at least twice daily) chest physiotherapy and postural drainage. Deep breathing exercises
- Vaccinations
- high calorie diet, including high fat intake
- patients with CF should try to minimise contact with each other to prevent cross infection with Burkholderia cepacia complex and Pseudomonas aeruginosa
- vitamin supplementation
- Fertility treatment and genetic counselling
- Exercise
8
Q
CF: medical management
A
- Prophylatic antibiotics (flucloxacillin), bronchodilators and medicines to thin secretions (i.e. dornase alfa)
- CREON: pancreatic enzyme supplements taken with meals
- Bilateral lung transplantation in end stage pulmonary disease: contraindication is chronic infection with Burkholderia cepacia
- Nebulised DNase: thins respiratory secretions
9
Q
CF: medication
A
- Sodium chloride: aids growth until on a fully weaned diet. Require additional salt if they are in a hot climate for a period of time
- Mucolytics (dornase alfa) and Bronchodilators
- Flucloxacillin: used as prophylaxis against staph aureus in the lungs
- Abidec: a multivitamin to reduce issues related to malabsorption
- Vitamin A, D & E: fat soluble vitamins for pancreatic insufficient patients only
10
Q
Lumacaftor/Ivacaftor (Orkambi)
A
- is used to treat cystic fibrosis patients who are homozygous for the delta F508 mutation
- lumacaftor increases the number of CFTR proteins that are transported to the cell surface
- ivacaftor is a potentiator of CFTR that is already at the cell surface, increasing the probability that the defective channel will be open and allow chloride ions to pass through the channel pore
11
Q
CF infection
A
- Common organisms: Staph aureus, Haemophillus influenzae, Moraxella Catarrhalis
- Treatment: 2 weeks of oral antibiotics (amoxicillin/co-amoxiclav). If don’t respond to antibiotics or have signs of LRTI use two weeks of IV Cefuroxime
- Organisms which can have a long term impact on lung function: Pseudomonas Aeroginosa, Mycobacterium Abscessus, Burkholderia Cepacia
- Mycobacterium Abscessus & Burkholderia Cepacia are very significant and always require IV antibiotics
12
Q
Pseudomonas Aeuroginosa treatment
A
- Requires months of treatment with nebulised antibiotics like tobramycin, oral ciprofloxacin is also used
- After 3 separate growths of Pseudomonas a child is considered to be colonised. When a child isolates Pseudomonas they must be seen in a Pseudomonas positive clinic to prevent cross contamination.
13
Q
Advanced CF
A
- Barrel shaped chest with crepitations
- Clubbing
- Reduced FEV1
- Hyperinflation and bronchiectasis- the airways become abnormally widened and scarred with a build up of thick mucus which is prone to infection
- May have a portocath for IV administration of antibiotics
14
Q
Oral rehydration in gastroenteritis
A
- Age under 5: 50ml/kg of ORS over 4 hours (~2ml/kg every 10 minutes) in addition to maintenance volume
- Age over 5: 200ml of ORS after each diarrhoeal episode (in addition to normal fluids)
15
Q
Formula for fluid deficit and age
A
Fluid deficit: % dehydration x weight (kg) x 10
Formula for weight (up to age 10)= (age in years + 4) x 2
16
Q
Paediatrics fluid to give
A
- In children give 0.9% sodium chloride + 5% glucose
- In neonates: 10% dextrose
- Monitor U&E and glucose every 24hrs
Over a 24 hour period, males rarely need more than 2500ml and females rarely need more than 2000ml of fluids
17
Q
Paediatrics K+
A
- Add in to maintenance fluids for patients who are not eating/patients on insulin/patients with low potassium
- Aim for 1-3 mmol K/kg over 24 hours
- Usually given in alternate bags in paeds
- Can be added to fluid as either 10 or 20 mmol
18
Q
Red flags for dehydration
A
- Oliguria
- Sudden weight loss
- Tachycardia, Hypotension, peripheral vasoconstriction, tachypnoea
- Reduced capillary refill time
- Eyes sunken and tearless
- Sunken fontanelles
- Reduced level of consciousness
- Dry mucous membranes
- Reduced tissue turgor
19
Q
Assessing dehydration/shock
A
Oral fluid challenge 2ml/kg every 10 minutes with ORS in clinically dehydrated but not shocked children. Reassess at 2h. If a child has impaired BP and perfusion they will receive a bolus (10ml/kg).
20
Q
Replacing fluid defecit
A
- For dehydrated children who need IV fluids (e.g. they received a bolus, or cannot maintain adequate hydration enterally)
- 100 ml/kg for children who were initially shocked (10% deficit) over 48h
- 50 ml/kg for children who were not initially shocked but were dehydrated (5% deficit) over 48h
- g. If a 10kg child requires a bolus initially, they will get an extra 100ml x 10kg rehydration = 1000ml/48h
- You will need to do maintenance fluid on top of
Total fluid requirements = Maintenance fluid + fluid deficit
