Paediatric Respiratory Flashcards
What is the inheritance pattern for CF
Autosomal recessive
What is the most common CF mutation? What is the most severe?
The most common form is F508del (50%)
Most severe = G551D (11%)
What is the pathophysiology of CF?
Mutations in CFTR gene cause defected chloride channels. Chloride is normally released where water follows and hence creating a mucus where cilia will perform a sweeping motion that moves the mucus out of the airways. in del F508, the protein is misfolded, preventing it from being expressed on the membrane. in CF, there is reduced volume being excreted and its hyper viscosity makes it difficult to clear and hence builds up. This impairment of airway clearance increases the risk for infection which would cause inflammation and hence lung damage worsening the situation. This also affects the GI system as the mucus prevents the release of enzymes from the pancreas leading to pancreatic insufficiency, pancreatitis, and reduced absorption =>absorption symptoms)
What is an early indication of CF in the neonate?
Meconium Ileus
How is CF screened and how is it diagnosed?
Heel prick blood spot test in neonates for screening
Diagnosis is usually done via sweat test as CF causes increased Na and Cl secretion making sweat salty. A sweat chloride concentration >60mmol/L confirms the diagnosis. Alternatively, CF can be confirmed via genetic screening of mutations affecting the CFTR gene
What are the main clinical features of CF. Start with giving some for the newborn and then the ones for older children. Go system by system.
Newborn: Meconium ileus, prolonged neonatal jaundice, faltering growth and steatorrhea (from malabsorption), recurrent chest infections.
Older:
Resp: Recurrent chest infections => bronchiectasis, hemoptysis, and pneumothorax
GI: Pancreatic insufficiency (+thick mucus) => malabsorption => steatorrhoea + Distal Intestinal Obstruction Syndrome. (meconium ileus => distention, constipation, and vomiting)
Endocrine: Pancreatic insufficiency also allows for Cf-related Diabetes Mellitus
Hepatic: Hepatomegaly on palpation (may progress to cirrhosis and portal hypertension)
Genital: Male infertility
A blood test is conducted on a patient with CF. Results show markedly raised glucose levels. Why is this occurring and how is this treated? How does this usually present
CF causes pancreatic insufficiency => preventing the action of insulin => CF-related Diabetes. They typically present with failure to gain weight. Treated with insulin
A male CF patient asks you about getting a child. What do you tell them?
How would this affect females?
CF causes male infertility due to complete bilateral absence of the Vas Deference but sperm can still be harvested.
With females it is subfertility due to cilia along fallopian tubes being impacted as well as inhospitable cervical mucus.
What is the psychological aspect of CF
Mainly it is difficult to balance treatment burden with necessity of care
1) parental distress due to burden of care on children.
2) Non-compliance in teenagers
3) Chronic non-curable illness
What is your full management plan of CF
1) Input from MDT concerning all aspects of care
2) Psychology input key
3) Resp -> Resp Physio 2/day, Mucolytics (DNase/hypertonic saline), Antibiotic prophylaxis (flucloxacillin)
4) Dietary input: Give Oral Enteric-coated pancreatic replacement therapy AND fat-soluble vitamin supplements (ADEK)
5) CFTR modulators: 1 potentiator (Ivacaftor) and 2 correctors (Tezacaftor and Elexacaftor) for Trikafta (triple therapy).
Is croup a URTI or LRTI? What are the symptoms of an URTI and LRTI?
Croup or laryngotracheobronchitis is an URTI => sore throat, low grade fever, sore throat
LRTI (pneumonia, bronchitis, bronchiectasis) => Wheezing, fever, chest pain/tightness
What is the most common pathogen that may cause croup? Any others?
Parainfluenza (75%). Others include influenza, adenovirus, RSV, and COVID-19
What are the clinical features of croup
URTI => sore throat, low grade fever, sore throat
Characteristic features: Inspiratory stridor (subglottal laryngitis/narrowing), hoarseness of voice/crying, and seal-like barking cough
In more severe cases, it may also cause hypoxemia (sx of resp distress), suprasternal recession, pulsus paradoxis
What is pulsus paradoxis?
It is the pathological drop of >10mmHg of systolic BP during inspiration
Why should you not examine a throat of a child with suspected croup
Any agitation even from inserting a line (unless absolutely necessary) may cause complete airway obstruction
What are the differential diagnoses for stridor?
Croup
Epiglottitis (acutely unwell, H. influenzae, high grade fever, supraglottic laryngitis)
Spasmodic croup (allergy => sudden)
Diptheria laryngitis (acutely unwell, diptheria)
Foreign body aspiration
What imaging would you conduct for ddx of inspiratory stridor? What do you expect to find?
Xray neck and chest AP and lateral. There should be narrowing of the ariway shown via Steeple sign.
A patient presents to you with a barking cough. What are your investigations and management?
Ix: Xray nach and chest AP and lateral with steeple sign, PCR for detection, FBC with differentials and CRP, Blood gas
Management: Keep patient comfortable in an upright position and provide supportive therapy
Give all patients a single dose of Dexamethasone PO (or IV if necessary)
In severe cases, nebulized racemic epinephrine
What are atopic diseases? give 2 examples
Eczema, hayfever
It is the predisposition to develop an allergic reaction to otherwise harmless environmental substances
What is asthma?
What are the main RFs?
Chronic inflammation of the airways or bronchioles causing narrowing and wheeze
RFs: Family hx of asthma
Family/personal history of atopic disease
Smoking and anything suggesting a dust-filled home (carpets, plush toys)
Obesity
Post-infection (bacterial or viral)
Why is it easier to diagnose asthma above the age of 5
Ability to do pulmonary function tests
A patient comes in with a wheeze. What are your differentials by age?
<1 = Bronchiolitis
>1 = Viral induced wheeze
>5 = Athma
Why wouldnt you prescribe salbutamol to a patient with bronchiolitis (<1)
Shows no improvement as salbutamol receptors tend to becomes more active and in higher concentrations to use the medication after the age of 1
What are important history taking questions for asthma/allergy (as many as you can quickly)
1) Number of times to the GP
a) Chest infection? recurrent? given antibiotics?
b) Given bronchodilator (salbutamol) or steroids before?
2) Cough: Worse at night? or morning?
3) SOB: On exertion? simple activities? Trigger?
4) Sleep: Wheeze during sleep, awakening with cough or wheeze?
5) Aspiration risk: GORD (acid aspiration), food aspiration => infection risk
6) Triggers: Smoking at home, pets, atopy, carpets, soft toys
7) What are your triggers
