Paeds - Resp Flashcards
What is the mechanism of asthma?
Dendritic cells activate TH2 (T Helper Cells), and stimulate the release of cytokines,
which activates the humoral immune system,
which causes proliferation of mast cells, eosinophils and dendritic cells.
Cytokines also contribute to bronchoconstriction eg. Leukotriene C4 is toxic to epithelial cells.
Histamine released from mast cells contribute to production of exudate.
What is preschool wheeze?
Up to half of children will have atleast one significant episode of wheeze by their 5th bday.
Most preschoolers outgrow their wheeze, but up to 40% will have a wheeze that persists into older childhood.
2 patterns of preschool wheeze:
Episodic viral wheeze = wheezing only in response to viral infection and no interval symptoms
Multiple trigger wheeze = wheeze in response to viral infection but also to other triggers like exposure to aeroallergens and exercise
How does asthma present (+ on examination)
- wheeze, cough, breathless, chest tightness
- symptoms commonly episodic, worse at night or early morning
- triggered/exacerbated by exercise/ viral infection/ exposure to cold air or allergens/ emotion or laughter in kids
Examination
- expiratory polyphonic wheeze on auscultation
- finger clubbing (more suggestive of CF or Bronchiectasis)
- Chest shape = hyperinflated suggests poorly controlled asthma
- wheeze
- examine throat for tonsillar enlargement = infectious cause?
What kind of symptoms would point you towards asthma in particular?
- episodic symptoms with intermittent exacerbations
- Diurnal variability (worse at night and early morning)
- dry cough + wheeze + SOB
- typical triggers eg. dust, animals, cold air, exercise, smoke, food allergens
- hx of other atopic conditions eg. eczema, hayfever, food allergies
- fhx of asthma or atopy
- bilateral widespread “polyphonic” wheeze heard on auscultation
- symptoms improve with bronchodilators
How would you investigate asthma?
- Spirometry if over 5 years old = obstructive pattern (FEV1:FVC <70%)
- and improvement in FEV1 of >12% after bronchodilators
- Exercise testing to assess where there is exercise induced symptoms
- skin prick test, blood eosinophilia >4%, raised allergen specific IgE can indicate atopic status
- Can consider Fractional Exhaled Nitric Oxide Testing to confirm eosinophilic airway inflammation
- FENO of 35ppb or over is positive.
Rule out other diagnoses
- Oesophgeal pH study to investigate GO Reflux
- Bronchoscopy to exclude structural abnormality
- Chloride sweat test to rule out CF
- Nasal Brush Biopsy to exclude Primary Ciliary Dyskinesia
- Serum IgG, IgA, IgM and response to vaccinations to exclude immunodeficiency
- High Resolution CT to exclude bronchiectasis
- Sputum Culture
How would you generally follow up asthma in children in the longterm?
- Assess baseline asthma status using Asthma Control Questionnaire or lung function tests like Spirometry/ Peak Expiratory Flow
- Up to date on vaccinations + annual influenza vaccine
- Support Resources eg. Asthma UK
- Advise parents on dangers of smoking and cessation
- Monitor Peak Flows/ Spirometry at annual Asthma Reviews
- Symptom score using Childhood Asthma Control Test
- Monitor growth (height and weight centiles)
- Demonstrate correct inhaler technique
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What would you prescribe in an asthma patient under 5 years old?
- SABA eg. salbutamol as required
- Add low dose ICS or a leukotriene antagonist eg. oral montelukast
- If uncontrolled, add a ICS/LA (triple therapy)
- Refer to specialist
What would you prescribe in a 5-16 year old with asthma
Medication for 5-16 years old
- 1st line = Short Acting B2 Agonist as reliever therapy PRN (salbutamol)
- 2nd line = Inhaled regular low dose Corticosteroid as preventer therapy
- If using SABA 3x or more a week, or asthma symptoms 3x or more a week, or woken up at night by asthma symptoms 1x or more weekly
- 3rd line = additional therapy
- add LABA (eg. salmeterol)
- If improvement but not enough, increase ICS to medium dose
- If LABA isn’t helping, swap to leukotriene receptor antagonist (montelukast)
- If still uncontrolled, increase ICS dose to high dose
How would you classify asthma exacerbations?
Moderate
- PEFR at least 50%
- normal speech
- no features of acute severe or life threatening
Acute Severe
- PEFR 33-50%
- RR atleast 25/min if >12 years old, 30/min from 5-12, 40/min in 2-5 year olds
- HR atleast 110/min if >12 years old, 125/min from 5-12, 140/min in 2-5 year olds
- Inability to complete sentences in one breath, accessory muscle use, inability to feed (infants)
- O2 sats at least 92%
Life Threatening
- PEFR less than 33%
- O2 sats <92%
- altered consciousness, exhaustion, cardiac arrhythmia, hypotension, cyanosis, poor resp effort, silent chest, confusion
How would you manage a mild acute exacerbation of asthma?
- as an outpatient
- regular salbutamol inhalers via a spacer
How would you manage a moderate-severe case of acute asthma?
Stepwise until control is acheived:
- salbutamol inhalers (SABA bronchodilator) via a spacer device. Start with 10 puffs every 2 hours.
- Nebulisers with salbutamol/ Ipratropium Bromide (antimuscarinic bronchodilator)
- IV Hydrocortisone (steroids to reduce airway inflammation). Oral prednisolone if they want oral.
- IV Magnesium sulphate (bronchodilators)
- IV aminophylline (bronchodilators)
- Call an anaesthetist and ICU for intubation/ ventilation!!!
Monitor serum K+ when high dose Salbutamol has been given.
Salbutamol SE = tachycardia and tremor
How would you discharge an asthma patient?
- consider discharge when the child is well on 6 puffs at 4 hourly intervals of salbutamol
- prescribe a reducing regime of salbutamol at home
- SaO2> 94% in air
- finish the course of steroids if they were started
- provide safety net info about when to return to seek help
- provide a written asthma action plan and explain to parents
- assess/teach inhaler technique by asthma nurse
- ask questions of compliance if symptoms were uncontrolled
- GP to review the child 2 days after discharge
What is good inhaler technique?
- remove cap
- shake the inhaler
- sit or stand up straight
- lift chin slightly
- fully exhale
- make a tight seal around the inhaler with your lips
- press canister while taking a steady breath
- continue breathing for 3-4s after pressing canister
- hold breath for 10 seconds
- wait 30s before giving another dose
- rinse mouth after using steroid inhaler to avoid oral thrush
What is bronchiolitis?
Viral infection of the bronchioles,
causes inflammation + mucus to obstruct small airways = wheeze and crackles,
generally affects children under 1 year,
commonly caused by respiratory syncytial virus (RSV)
pathophysiology of bronchiolitis
Starts with an Upper Resp Tract Infection with Coryzal symptoms.
Half get better, the other half develop chest symptoms within 1-2 days following onset of coryzal symptoms.
- proliferation of goblet cells = excess mucus production
- IgE mediated type 1 allergic reaction = inflammation
- Bronchiolar constriction
- Infiltration of lymphocytes = submucosal oedema
- Infiltration of cytokines and chemokines
Mucus + Oedema + Infiltration of cells = Hyperinflation, increased airway resistance, atelectasis (lung collapse), ventilation perfusion mismatch
How would bronchiolitis present as symptoms?
Give some differentials
First present with URTI + Coryzal symptoms
- typical viral URTI symptoms of runny nose, sneezing, mucus in throat, watery eyes
Increasing symptoms
- Low grade fever <39C
- poor feeding
- dyspnoea
- apneoa episodes
- signs of resp distress
- hyperinflated chest
Differential = pneumonia, croup, CF, HF, bronchitis
How would you recognise respiratory distress?
- Abnormal airway noises eg. inspiratory crackles, expiratory wheeze
- Raised RR
- Accessory muscles when breathing eg. SCM, Abdo, Intercostal Muscles
- Intercostal and Subcostal recessions
- Nasal flaring
- Grunting (exhaling with the glottis partially closed to increase +ve end-expiratory pressure)
- Head bobbing
- Tracheal tugging
- Cyanosis
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How would you investigate bronchiolitis?
- Nasopharyngeal aspirate or throat swab for RSV rapid testing and viral cultures
- Blood and urine cultures if pyrexic
- FBC
- ABG if severely unwell
- CXR if diagnostic uncertainty
- Hyperinflation, Focal atelectasis, Air trapping, Flattened diaphragm, peribronchial cuffing
How would you manage bronchiolitis at home?
Initial
- examine chest, record RR, HR, BP, O2 sats, Hydration status by measuring cap refill time/ skin turgor/ dryness of mucous membranes/ urine output
Home
- paracetamol/ ibuprofen to treat child who is distressed due to fever
- fluids and check on the child regularly especially at night
When would you admit a patient with bronchiolitis?
- aged <3 months
- pre-existing conditions like prematurity, Downs syndrome, CF
- RR >70
- O2 sats <92%
- Mod-Severe Resp Distress eg. deep recessions, head bobbing
- Apnoeas
- 50-75% or less of their normal intake of milk
- clinical dehydration (reduced skin turgour, cap refill >3s, dry mucous membranes, reduced urine output)
- Parents need help
How would you manage a bronchiolitis patient in hospital?
Supportive management
- ensuring adequate intake (oral, NG, IV)
- do not overfeed as a full stomach can restrict breathing
- Saline nasal drops and nasal suctioning prior to clear secretions
- supplementary O2 if sats remain <92%
- Ventilatory support if required
- high flow humidified O2 via nasal cannula ie. Airvo
- delivers air + o2 continuously and adds positive end-expiratory pressure to prevent airways from collapsing
- OR CPAP (delivers higher and more controlled pressures than Airvo)
- OR Intubation + ventilation
- high flow humidified O2 via nasal cannula ie. Airvo
How woudl you try and protect high risk babies from RSV?
- Palivizumab is a monoclonal antibody that targets Respiratory Syncytial Virus
- Monthly injection given as prevention against bronchiolitis caused by RSV
- Provides passive protection (need monthly top ups as the circulating antibody levels decrease over time.)
- Give to high risk babies eg. ex-premature or congenital heart disease babies
How would a viral induced wheeze present as opposed to asthma?
Evidence of a viral illness (fever, cough, coryzal symptoms) for 1-2 days preceeding onset of..
- SOB
- signs of resp distress
- Expiratory wheeze throughout the chest
Differentiates from asthma…
- presents before 3 years of age
- no atopic hx
- only occurs during viral infections
- asthma can also be triggered by infections, but also exercise/ cold weather/ dust/ strong emotions
What would you need to think when hearing a focal or widespread wheeze in the chest?
Widespread wheeze = viral induced wheeze or asthma
Focal wheeze = urgent senior review, investigate for focal air obstruction like an inhaled foreign body or tumour
