Respiratory Flashcards
?In what circumstances might an ABG be used over VBG/CBG in paediatrics?
When able to use umbilical artery (cord – 2 arteries, 1 vein)
Unusual to do ABG from peripheral vein: Arterial line post cardiac surgery, PICU
Wheeze vs. Stridor
Wheeze: a continuous, coarse, whistling sound produced in the respiratory airways during breathing.
Stridor: a high-pitched extra-thoracic breath sound resulting from turbulent airflow through narrowed upper airways.
What is bronchiolitis?
Bronchiolitis describes inflammation and infection in the bronchioles, the small airways of the lungs
What most bronchiolitis?
Respiratory syncytial virus (RSV) is the most common cause.
What aged children are affected by bronchiolitis?
Bronchiolitis is generally considered to occur in children under 1 year.
It is most common in children under 6 months.
It can rarely be diagnosed in children up to 2 years of age, particularly in ex-premature babies with chronic lung disease.
Why do viral illnesses cause more respiratory symptoms in young children than in adults?
When a virus affects the airways of adults, the swelling and mucus are proportionally so small that it has little noticeable effect on breathing.
The airways of infants are very small to begin with, and when there is even the smallest amount of inflammation and mucus in the airway it has a significant effect on the infants ability to circulate air to the alveoli and back out.
This causes the harsh breath sounds, wheeze and crackles heard on auscultation when listening to a bronchiolitic baby’s chest.
Presentation of bronchiolitis?
Coryzal symptoms. These are the typical symptoms of a viral upper respiratory tract infection: running or snotty nose, sneezing, mucus in throat and watery eyes.
Signs of respiratory distress
Dyspnoea (heavy laboured breathing)
Tachypnoea (fast breathing)
Poor feeding
Mild fever (under 39ºC)
Apnoeas are episodes where the child stops breathing
Wheeze and crackles on auscultation
Signs of respiratory distress?
Raised respiratory rate
Use of accessory muscles of breathing, such as the sternocleidomastoid, abdominal and intercostal muscles
Intercostal and subcostal recessions
Nasal flaring
Head bobbing
Tracheal tugging
Cyanosis (due to low oxygen saturation)
Abnormal airway noises (wheezing, grunting, stridor)
Abnormal airway noises
Wheezing is a whistling sound caused by narrowed airways, typically heard during expiration
Grunting is caused by exhaling with the glottis partially closed to increase positive end-expiratory pressure
Stridor is a high pitched inspiratory noise caused by obstruction of the upper airway, for example in croup
Typical course of RSV?
Bronchiolitis usually starts as an upper respiratory tract infection (URTI) with coryzal symptoms.
From this point around half get better spontaneously.
The other half develop chest symptoms over the first 1-2 days following the onset of coryzal symptoms.
Symptoms are generally at their worst on day 3 or 4.
Symptoms usually last 7 to 10 days total and most patients fully recover within 2 – 3 weeks.
Children who have had bronchiolitis as infants are more likely to have viral induced wheeze during childhood.
Most infants with bronchiolitis can be managed at home with advice about when to seek further medical attention. Reasons for admission include what?
Aged under 3 months or any pre-existing condition such as prematurity, Downs syndrome or cystic fibrosis
50 – 75% or less of their normal intake of milk
Clinical dehydration
Respiratory rate above 70
Oxygen saturations below 92%
Moderate to severe respiratory distress, such as deep recessions or head bobbing
Apnoeas
Parents not confident in their ability to manage at home or difficulty accessing medical help from home
Management of bronchiolitis?
Typically patients only require supportive management. This involves:
Ensuring adequate intake. This could be orally, via NG tube or IV fluids depending on the severity. It is important to avoid overfeeding as a full stomach will restrict breathing. Start with small frequent feeds and gradually increase them as tolerated.
Saline nasal drops and nasal suctioning can help clear nasal secretions, particularly prior to feeding
Supplementary oxygen if the oxygen saturations remain below 92%
Ventilatory support if required
There is little evidence for treatments such as nebulised saline, bronchodilators, steroids and antibiotics.
As breathing gets harder, a child with bronchiolitis may get more tired and less able to adequately ventilate themself. They may require ventilatory support to maintain their breathing. This is stepped up until they are adequately ventilated.
What are the management options?
High-flow humidified oxygen via tight nasal cannula (i.e. “Airvo” or “Optiflow”). This delivers air and oxygen continuously with some added pressure, helping to oxygenate the lungs and prevent the airways from collapsing. It adds “positive end-expiratory pressure” (PEEP) to maintain the airway at the end of expiration.
Continuous positive airway pressure (CPAP). This involves using a sealed nasal cannula that performs in a similar way to Airvo or Optiflow, but can deliver much higher and more controlled pressures.
Intubation and ventilation. This involves inserting an endotracheal tube into the trachea to fully control ventilation.
Assessing Ventilation in children
Capillary blood gases are useful in severe respiratory distress and in monitoring children who are having ventilatory support.
The most helpful signs of poor ventilation are:
Rising pCO2, showing that the airways have collapsed and can’t clear waste carbon dioxide.
Falling pH, showing that CO2 is building up and they are not able to buffer the acidosis this creates. This is a respiratory acidosis. If they are also hypoxic, this is classed as type 2 respiratory failure.Assessing Ventilation
What are the most helpful signs on blood gas of poor ventilation?
Rising pCO2, showing that the airways have collapsed and can’t clear waste carbon dioxide.
Falling pH, showing that CO2 is building up and they are not able to buffer the acidosis this creates. This is a respiratory acidosis. If they are also hypoxic, this is classed as type 2 respiratory failure.Assessing Ventilation
Palivizumab and bronchiolitis prevention?
Palivizumab is a monoclonal antibody that targets the respiratory syncytial virus. A monthly injection is given as prevention against bronchiolitis caused by RSV. It is given to high risk babies, such as ex-premature and those with congenital heart disease.
It is not a true vaccine as it does not stimulate the infant’s immune system. It provides passive protection by circulating the body until the virus is encountered, as which point it works as an antibody against the virus, activating the immune system to fight the virus. The levels of circulating antibodies decrease over time, which is why a monthly injection is required.
Which children are given monthly palivizumab and why?
Palivizumab is a monoclonal antibody that targets the respiratory syncytial virus.
A monthly injection is given as prevention against bronchiolitis caused by RSV.
It is given to high risk babies, such as ex-premature and those with congenital heart disease
In paediatric BLS, if the patient is not breathing, you must give rescue breaths first. Why?
Because cardiac arrest in children is more likely to be caused by respiratory pathology than cardiac.
How should artificial surfactant be given?
via intratracheal instillation
Artificial surfactant needs to be given directly into the lungs to be of benefit
Why do small children (typically under 3 years) experience virally-induced wheezes and respiratory distress?
When the small airways encounter a virus they develop a small amount of inflammationg and odema, swelling the walls of the airways and restricting the spay for air to flow. This inflammation also triffers the smooth muscles of the airways to constrict, further narrowing the space in the airway.
This swelling and constriction of the airway caused by a virus has little noticeable effect on the larger airways of an older child or adult, however due to the small diameter of a child’s airway, the slight narrowing leads to a proportionally larger restriction in airflow. This is described by Poiseuille’s law, which states that flow rate is proportional to the radius of the tube to the power of four. Therefore, halving the diameter of the tube decreases flow rate by 16 fold.
Air flowing through these narrow airways causes a wheeze, and the restricted ventilation leads to respiratory distress.
Viral-induced wheeze vs asthma?
Viral: presenting before 3 years, no atopic history, only occurs during viral infections
Asthma can also be triggered by viral or bacterial infections, however it also has other triggers, such as exercise, cold weather, dust and strong emotions. Asthma is historically a clinical diagnosis, and the diagnosis is based on the presence of typical signs and symptoms along with variable and reversible airflow obstruction.
How does a virally induced wheeze present?
Evidence (fever, cough, coryzal symptoms) of viral illness for 1-2 days preceding onset of:
SOB
Signs of respiratory distress
Expiratory wheeze throughout the chest
What does a focal wheeze indicate?
Focal airway obstruction such as inhaled foreign body or tumour
Requires urgent senior review
Neither viral-induced wheeze or asthma cause a focal wheeze.
How does the management of a viral wheeze differ from the management of acute asthma in a child?
Managed the same way
What is meant by an acute exacerbation of asthma?
An acute exacerbation of asthma is characterised by a rapid deterioration in symptoms. This could be triggered by any of the typical asthma triggers such as infection, exercise or cold weather.
How does an acute exacerbation of asthma present?
SOB - progressively worsening
Use of accessory muscles
Tachypnoea
Symmetrical expiratory wheeze on auscultation
‘‘Tight’’ sounding chest on auscultation with reduced air entry
Moderate acute asthma PEFR?
50-75% of predicted
Features of severe acute asthma
PEFR 33-50% predicted
RR:
> 40 in 1-5 years
> 30 in > 5 years
HR:
> 140 in 1-5 years
> 125 in > 5 years
Unable to complete sentences in one breath
Saturations <92%
Severe acute asthma PEFR?
33-50% predicted
Life threatening acute asthma PEFR?
<33%
Features of life threatening acute asthma?
PEFR <33%
Sats <92%
Exhaustion + poor respiratory effort
Hypotension
No wheeze. This occurs when the airways are so tight that there is no air entry at all. This is ominously described as a “silent chest”.
Cyanosis
Alterned conciousness/confusion
What grade of acute asthma is the absence of a wheeze and why?
'’Silent chest’’ occurs when the airways are so tight there is no air entry at all
ABGs in acute asthma?
Initially patients will have a respiratory alkalosis as tachypnoea causes a drop in CO2.
A normal pCO2 or hypoxia is a concerning sign as it means they are tiring and indicates life threatening asthma.
A respiratory acidosis due to high CO2 is a very bad sign in asthma.
Initial ABG in acute asthma
Respiratory alkalosis (tachypnoea causes a drop in CO2)
What does a normal pCO2 or hypoxia in an ABG of a patient with acute asthma indicate?
A normal pCO2 or hypoxia is a concerning sign as it means they are tiring and indicates life threatening asthma.
Most concerning sign on ABG in acute astham?
A respiratory acidosis due to high CO2 is a very bad sign in asthma.
How can you monitor response to treatment in acute asthma?
Respiratory rate
Respiratory effort
Peak flow
Oxygen saturations
Chest auscultation
What should be additionally monitored when using salbutamol to treat acute asthma?
Serum potassium and HR
Salbutamol causes potassium to be absorbed from the blood into the cells
Salbutomol causes tachycardia
What HR indicates a severe acute asthma exacerbation in a child between 1-5 years?
> 140
What HR indicates a severe acute asthma exacerbation in a child older than 5 years?
> 125
What RR indicates a severe acute asthma exacerbation in a child between 1-5 years?
> 40
What RR indicates a severe acute asthma exacerbation in a child over 5 years?
> 30
Staples of management in acute viral induced wheeze or asthma are?
Supplementary oxygen if required (i.e. oxygen saturations less than 94% or working hard)
Bronchodilators (e.g. salbutamol, ipratropium and magnesium sulphate)
Steroids to reduce airway inflammation: prednisone (orally) or hydrocortisone (intravenous)
Antibiotics only if a bacterial cause is suspected (e.g. amoxicillin or erythromycin)
What bronchodilators may be used in acute asthma (in order of stepping up)
Inhaled or nebulised salbutamol (a beta-2 agonist)
Inhaled or nebulised ipratropium bromide (an anti-muscarinic)
IV magnesium sulphate
IV aminophylline
How are mild cases of acute asthma managed?
Mild cases can be managed as an outpatient with regular salbutamol inhalers via a spacer (e.g. 4-6 puffs every 4 hours).
Mod - severe acute asthma management
Moderate to severe cases require a stepwise approach working upwards until control is achieved:
Salbutamol inhalers via a spacer device: starting with 10 puffs every 2 hours
Nebulisers with salbutamol / ipratropium bromide
Oral prednisone (e.g. 1mg per kg of body weight once a day for 3 days)
IV hydrocortisone
IV magnesium sulphate
IV salbutamol
IV aminophylline
If you haven’t got control by this point the situation is very serious. Call an anaesthetist and the intensive care unit. They may need intubation and ventilation. This call should be made earlier to give the best chance of successfully intubating them before the airway becomes too constricted.
Once control of acute asthma is established: you can gradually work your way back down the ladder as they get better - how?
Review the child prior to the next dose of their bronchodilator.
Look for evidence of cyanosis (central or peripheral), tracheal tug, subcostal recessions, hypoxia, tachypnoea or wheeze on auscultation.
If they look well, consider stepping down the number and frequency of the intervention.
A typical step down regime of inhaled salbutamol is 10 puffs 2 hourly then 10 puffs 4 hourly then 6 puffs 4 hourly then 4 puffs 6 hourly.
Consider monitoring the serum potassium when on high doses of salbutamol as it causes potassium to be absorbed from the blood into the cells.
It is also worth noting that salbutamol causes tachycardia and a tremor.
When might you discharge a child admitted of an asthma exaccerbation and what steps might you consider?
Generally, discharge can be considered when the child well on 6 puffs 4 hourly of salbutamol.
They can be prescribed a reducing regime of salbutamol to continue at home, for example 6 puffs 4 hourly for 48 hours then 4 puffs 6 hourly for 48 hours then 2-4 puffs as required.
A few other steps to consider:
Finish the course of steroids if these were started (typically 3 days total)
Provide safety-net information about when to return to hospital or seek help
Provide an individualised written asthma action plan
What are ‘‘atopic conditions’’
Asthma
Eczema
Food alergies
Hay fever
Patients with one of these conditions are more likely to have others. These conditions characteristically run in families, so always ask about family history and don’t be surprised if their brother, mother or “everyone in the family” has asthma, eczema and allergies.
Bronchoconstriction in asthma?
Asthma is a chronic inflammatory airway disease leading to variable airway obstruction.
The smooth muscle in the airways is hypersensitive, and responds to stimuli by constricting and causing airflow obstruction.
This bronchoconstriction is reversible with bronchodilators such as inhaled salbutamol.
Presentation Suggesting a Diagnosis of Asthma
Episodic symptoms with intermittent exacerbations
Diurnal variability, typically worse at night and early morning
Dry cough with wheeze and shortness of breath
Typical triggers
A history of other atopic conditions such as eczema, hayfever and food allergies
Family history of asthma or atopy
Bilateral widespread “polyphonic” wheeze heard by a healthcare professional
Symptoms improve with bronchodilators
What wheeze is heard in chronic asthma?
Bilateral widespread ‘’ polyphonic ‘’ wheeze
Presentation Indicating a Diagnosis Other Than Asthma?
Wheeze only related to coughs and colds, more suggestive of viral induced wheeze
Isolated or productive cough
Normal investigations
No response to treatment
Unilateral wheeze suggesting a focal lesion, inhaled foreign body or infection
Typical triggers of chronic asthma?
Dust (house dust mites)
Animals
Cold air
Exercise
Smoke
Food allergens (e.g. peanuts, shellfish or eggs)
Diagnosing asthma in children?
A diagnosis is made clinically based on a typical history and examination.
When there is a low probability of asthma and the child is symptomatic, consider referral to a specialist for diagnosis.
When there is an intermediate or high probability of asthma, a trial of treatment can be implemented and if the treatment improves symptoms a diagnosis can be made.
There are investigations that can be used where there is an intermediate probability of asthma or diagnostic doubt:
Spirometry with reversibility testing (in children aged over 5 years)
Direct bronchial challenge test with histamine or methacholine
Fractional exhaled nitric oxide (FeNO)
Peak flow variability measured by keeping a diary of peak flow measurements several times a day for 2 to 4 weeks
From what age might a child be dianosed with asthma
Children are usually not diagnosed with asthma until they are at least 2 to 3 years old
Principles of stepwise ladder of long term management of asthma?
Start at the most appropriate step for the severity of the symptoms
Review at regular intervals based on the severity
Step up and down the ladder based on symptoms
Aim to achieve no symptoms or exacerbations on the lowest dose and number of treatments
Always check inhaler technique and adherence at each review
Chronic asthma: medical therapy in children under 5 years?
Start a short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
Add a low dose corticosteroid inhaler or a leukotriene antagonist (i.e. oral montelukast)
Add the other option from step 2.
Refer to a specialist.
Chronic asthma: medical therapy in children from 5-12 years of age?
Start a short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
Add a regular low dose corticosteroid inhaler
Add a long-acting beta-2 agonist inhaler (e.g. salmeterol). Continue salmeterol only if the patient has a good response.
Titrate up the corticosteroid inhaler to a medium dose. Consider adding:
- Oral leukotriene receptor antagonist (e.g. montelukast)
- Oral theophylline
Increase the dose of the inhaled corticosteroid to a high dose.
Referral to a specialist. They may require daily oral steroids.
Chronic asthma: medical therapy in children from over 12 years of age?
Same as adult therapy
Start a short-acting beta 2 agonist inhaler (e.g. salbutamol) as required
Add a regular low dose corticosteroid inhaler
Add a long-acting beta-2 agonist inhaler (e.g. salmeterol). Continue salmeterol only if the patient has a good response.
Titrate up the corticosteroid inhaler to a medium dose. Consider a trial of an oral leukotriene receptor antagonist (i.e. montelukast), oral theophylline or an inhaled LAMA (i.e. tiotropium).
Titrate the inhaled corticosteroid up to a high dose.
Combine additional treatments from step 4, including the option of an oral beta 2 agonist (i.e. oral salbutamol). Refer to specialist.
Add oral steroids at the lowest dose possible to achieve good control under specialist guidance.
How do inhaled corticosteroids affect the growth of children?
There is evidence that inhaled steroids can slightly reduce growth velocity and can cause a small reduction in final adult height of up to 1cm when used long term (for more than 12 months). This effect was dose-dependent, meaning it was less of a problem with smaller doses.
It is worth putting this in context for the parent by explaining that these are effective medications that work to prevent poorly controlled asthma and asthma attacks that could lead to higher doses of oral steroids being given.
Poorly controlled asthma can lead to a more significant impact on growth and development.
The child will also have regular asthma reviews to ensure they are growing well and on the minimal dose required to effectively control symptoms.
Why is inhaler technique important?
Inhaler technique is a key aspect of good asthma management. The better the technique, the more medication reaches the lungs. Poor technique results in medication in the mouth or the back of the throat. This reduces the effectiveness of the medication and leads to complications such as oral thrush with steroid inhalers.
Types of inhalers
Metered dose inhaler
Dry powder inhalers - require patients to inhale quickly and deeply to draw the powder into the lungs
What can be used with an inhaler to maximised the effectiveness?
Spacer device
Metered dose inhaler (MDI) technique without a spacer
Remove the cap
Shake the inhaler (depending on the type)
Sit or stand up straight
Lift the chin slightly
Fully exhale
Make a tight seal around the inhaler between the lips
Take a steady breath in whilst pressing the canister
Continue breathing for 3 – 4 seconds after pressing the canister
Hold the breath for 10 seconds or as long as comfortably possible
Wait 30 seconds before giving a further dose
Rinse the mouth after using a steroid inhaler
Metered dose inhaler (MDI) technique with a spacer
Assemble the spacer
Shake the inhaler (depending on the type)
Attach the inhaler to the correct end
Sit or stand up straight
Lift the chin slightly
Make a seal around the spacer mouthpiece or
place the mask over the face
Spray the dose into the spacer
Take steady breaths in and out 5 times until the mist is fully inhaled
Alternatively exhale fully before putting making a seal with the spacer, spray the dose and take one deep breath in to inhale the mist in one breath before holding for 10 seconds.
How are spacers looked after?
Spacers should be cleaned once a month.
Avoid scrubbing the inside and allow them to air dry to avoid creating static.
Static can interact with the mist and prevent the medication being inhaled.
What is pneumonia
Pneumonia is simply an infection of the lung tissue. It causes inflammation of the lung tissue and sputum filling the airways and alveoli. Pneumonia can be seen as consolidation on a chest xray. It can be caused by a bacteria, virus or atypical bacteria such as mycoplasma.
How might pneumonia present?
Cough (typically productive)
High fever (>38.5)
Tachypnoea
Tachycardia
Increased work of breathing
Lethargy
Delirium
Signs of pneumonia, which may indicate secondary sepsis?
Tachypnoea (raised respiratory rate)
Tachycardia (raised heart rate)
Hypoxia (low oxygen)
Hypotension (shock)
Fever
Confusion
Characteristic chest signs of pneumonia?
Bronchial breath sounds - harsh breath sounds that are qually loud on ispiration and expiration - caused by consolidation of the lung tissue around the airway
Focal coarse crackles - caused by air passing through sputum (similar to using a straw to blow into a drink)
Dullness to percussion - due to lung tissue collapse and/or consolidation
What are bronchial breath sounds and why are they heard in pneumonia?
These are harsh breath sounds that are equally loud on inspiration and expiration. These are caused by consolidation of the lung tissue around the airway.
What are focal coarse crackles and why might they be heard in pneumonia?
Focal coarse crackles caused by air passing through sputum similar to using a straw to blow into a drink.
Why might dullness to percussion be heard in pneumonia?
Lung tissue collapse and/or consolidation
Bacterial causes of pneumonia?
Streptococcus pneumonia is most common
Group A strep (e.g. Streptococcus pyogenes)
Group B strep occurs in pre-vaccinated infants, often contracted during birth as it often colonises the vagina.
Staphylococcus aureus. This causes typical chest xray findings of pneumatocoeles (round air filled cavities) and consolidations in multiple lobes.
Haemophilus influenza particularly affects pre-vaccinated or unvaccinated children.
Mycoplasma pneumonia, an atypical bacteria with extra-pulmonary manifestations (e.g. erythema multiforme).
Most common cause of bacterial pneumonia?
Streptococcus pneumonia
Viral pneumonia causes
Respiratory syncytial virus (RSV) is the most common viral cause
Parainfluenza virus
Influenza virus
Most common cause of viral pneumonia in children?
Respiratory syncytial virus (RSV) is the most common viral cause
Investigating ?pneumonia?
A chest xray is the investigation of choice for diagnosing pneumonia.
It is not routinely required, but can be useful if there is diagnostic doubt or in severe or complicated cases.
Sending sputum cultures and throat swabs for bacterial cultures and viral PCR can establish the causative organism and guide treatment.
All patients with sepsis should have blood cultures.
Capillary blood gas analysis can be helpful in assessing or monitoring respiratory or metabolic acidosis and the blood lactate level in unwell patients.
Management of pneumonia
Pneumonia should be treated with antibiotics according to local guidelines.
Amoxicillin is often used first line.
Adding a macrolide (erythromycin, clarithromycin or azithromycin) will cover atypical pneumonia. Macrolides can be used as monotherapy in patients with a penicillin allergy.
IV antibiotics can be used when there is sepsis or a problem with intestinal absorption.
Oxygen is used as required to maintain saturations above 92%.
Bacterial pneumonia first line antibiotics?
Amoxicillin is often used first line
Macrolides (erythromycin, clarithromycin or azithromycin) can be used as monotherapy in patients with a penicillin allergy or added to cover an atypical pneumonia
When a child is having recurrent admission requiring antibiotics for a lower respiratory tract infections it is worth considering further investigations for underlying lung or immune system pathology.
A thorough history (including family history) and examination is needed to assess for what?
Reflux
Aspiration
Neurological disease
Heart disease
Asthma
Cystic fibrosis
Primary ciliary dyskinesia
Immune deficiency
When a child is having recurrent admission requiring antibiotics for a lower respiratory tract infections it is worth considering further investigations for underlying lung or immune system pathology.
What test can be done?
Full blood count to check levels of various white blood cells.
Chest xray to screen for any structural abnormality in the chest or scarring from the infections.
Serum immunoglobulins to test for low levels of certain antibody classes indicating selective antibody deficiency.
Test immunoglobulin G to previous vaccines (i.e. pneumococcus and haemophilus). Some patients are unable to convert IgM to IgG, and therefore cannot form long term immunity to that bug. This is called an immunoglobulin class-switch recombination deficiency.
Sweat test to check for cystic fibrosis.
HIV test, especially if mum’s status is unknown or positive.
Some patients are unable to convert IgM to IgG, and therefore cannot form long term immunity to that bug. What is this called and how can it be tested for?
This is called an immunoglobulin class-switch recombination deficiency.
This is called an immunoglobulin class-switch recombination deficiency.
What is immunoglobulin class-switch recombination deficiency?
When patients are unable to convert IgM to IgG, and therefore cannot form long term immunity to that bug.
Test immunoglobulin G to previous vaccines (i.e. pneumococcus and haemophilus).
What is croup?
Acute infective respiratory disease affecting young children (typically 6 months to 2 years)
URTI causing odema in the larynx
What type of infection is croup and where does it cause problems?
URTI
Casues odema in the larynx
What ages are typically affected by croup?
6 months to 2 years
What is the classic cause of croup?
Parainfluenza virus
Clinical course of croup?
It usually improves in less than 48 hours and responds well to treatment is steroids, particularly dexamethasone.
Common causes of croup?
Parainfluenza
Influenza
Adenovirus
RSV (respiratory syncytial virus)
What cause of croup leads to epiglottitis and why is it uncommon?
Croup used to be caused by diphtheria.
Croup caused by diphtheria leads to epiglottitis and has a high mortality.
Vaccination mean that this is very rare in developed countries.
Croup management
Most cases can be managed at home with simple supportive treatment (fluids and rest). During attacks it can help to sit the child up and comfort them. Measures should be taken to avoid spreading infection, for example hand washing and staying off school.
Oral dexamethasone is very effective. This is usually a single dose of 150 mcg/kg, which can be repeated if required after 12 hours. Prednisolone is sometimes used as an alternative where dexamethasone in not available (e.g. by GPs).
Stepwise options in severe croup to get control of symptoms:
Oral dexamethasone
Oxygen
Nebulised budesonide
Nebulised adrenalin
Intubation and ventilation
Stepwise options in severe croup to get control of symptoms?
Oral dexamethasone
Oxygen
Nebulised budesonide
Nebulised adrenalin
Intubation and ventilation
What is epiglottitis and why is it a life threatening emergency?
Epiglottitis is inflammation and swelling of the epiglottis caused by infection, typically with haemophilus influenza type B.
The epiglottis can swell to the point of completely obscuring the airway within hours of symptoms developing.
Therefore, epiglottitis is a life threatening emergency.
What typically causes epiglottitis?
Haemophilus influenza type B
Presentation Suggesting Possible Epiglottitis
Patient presenting with a sore throat and stridor
Drooling
Tripod position, sat forward with a hand on each knee
High fever
Difficulty or painful swallowing
Muffled voice
Scared and quiet child
Septic and unwell appearance
Why is epiglottitis rare and which children must you take extra caution and have high suspicision with?
Epiglottitis is now rare due to the routine vaccination program, which vaccinates all children against haemophilus.
You need to be extra cautious and have high suspicion in children that have not had vaccines.
It can present in a similar way to croup, but with a more rapid onset.
Keep a lookout for an unvaccinated child presenting with a fever, sore throat, difficulty swallowing that is sitting forward and drooling and suspect epiglottitis.
Epiglottitis - investigations
If the patient is acutely unwell and epiglottitis is suspected then investigations should not be performed.
Performing a lateral xray of the neck shows a characteristic “thumb sign” or “thumbprint sign”.
This is a soft tissue shadow that looks like a thumb pressed into the trachea. T
his is caused by the oedematous and swollen epiglottis. Neck xrays are also useful for excluding a foreign body.
If the patient is acutely unwell and epiglottitis is suspected then investigations should not be performed. However, what will be seen if a later xray of the neck is done?
Performing a lateral xray of the neck shows a characteristic “thumb sign” or “thumbprint sign”.
This is a soft tissue shadow that looks like a thumb pressed into the trachea.
This is caused by the oedematous and swollen epiglottis.
Management of epiglotitis?
Keep child calm and avoid distressing them (keep them in their comfort zone, do not examine or upset) alert the most senior paediatrician and anaesthetist available.
Secure airway - most do not require intubation but preparations must be made so it can be performed at any time due to the ongoing risk of sudden upper airway closure - intubation is often difficult and needs to be performed in a controlled environment with facilities available to do a tracheostomy (intubating through the neck) if the airway completely closes.
When patients are intubated they are transferred to an intensive care unit.
Additional treatment once the airway is secure:
- IV antibiotics (e.g. ceftriaxone)
- Steroids (i.e. dexamethasone)
Epiglottitis - prognosis/complications
Most children recover without requiring intubation. Most patients that are intubated can be extubated after a few days and also make a full recovery.
Death can occur in severe cases or if it is not diagnosed and managed in time.
A common complication to be aware of is the development of an epiglottic abscess, which is a collection of pus around the epiglottis.
This also threatens the airway, making it a life threatening emergency. Treatment is similar to epiglottitis.
What is laryngomalacia?
Laryngomalacia is a condition affecting infants, where the part of the larynx above the vocal cords (the supraglottic larynx) is structured in a way that allows it to cause partial airway obstruction.
This leads to a chronic stridor on inhalation, when the larynx flops across the airway as the infant breathes in.
Stridor is a harsh whistling sound caused by air being forced through an obstruction of the upper airway.
What is stridor and what causes it?
Stridor is a harsh whistling sound caused by air being forced through an obstruction of the upper airway.
What structural changes occur in laryngomalacia?
SHORTENED ARYEPIGLOTTIC FOLDS
There are two aryepiglottic folds at the entrance of the larynx, running between the epiglottis and the arytenoid cartilages.
They are either side of the airway and their role is to constrict the opening of the airway to prevent food or fluids entering the larynx and trachea. In laryngomalacia the aryepiglottic folds are shortened, which pulls on the epiglottis and changes it shape to a characteristic “omega” shape.
SOTENING AND REDUCED TONE IN THE TISSUE SURROUNDING THE SUPRAGLOTTIC LARYNX
The tissue surrounding the supraglottic larynx is softer and has less tone in laryngomalacia, meaning it can flop across the airway. This happens particularly during inspiration, as the air moving through the larynx to the lungs pulls the floppy tissue across the airway to partially occlude it. This partial obstruction of the airway generates the whistling sound.
What aged patients are affected by laryngomalacia?
Infants - peaking around 6 months
Presentation of laryngomalacia
Inspiratory stridor (harsh whisteling sound when breathing in) - intermittent, more prominent when feeding, upset, lying on their back, URTI
Infants with laryngomalacia do not usually have associated respiratory distress.
It can cause difficulties with feeding, but rarely causes complete airway obstruction or other complications.
Laryngomalacia - disease course and management
The problem resolves as the larynx matures and grows and is better able to support itself, preventing it from flopping over the airway. Usually, no interventions are required and the child is left to grow out of the condition.
Rarely tracheostomy may be necessary. This involves inserting a tube through the front of the neck into the trachea, bypassing the larynx. Surgery is also an option to alter the tissue in the larynx and improve the symptoms.
What is whooping cough?
Whooping cough is an upper respiratory tract infection caused by Bordetella pertussis (a gram negative bacteria). It is called “whooping cough”, because the coughing fits are so severe that the child is unable to take in any air between coughs and subsequently makes a loud whooping sound as they forcefully suck in air after the coughing finishes.
What organism causes whooping cough?
Bordetella pertussis (a gram negative bacteria)
How can whooping cough be prevented?
Children and pregnant women are vaccinated against pertussis. The vaccine becomes less effective a few years after each dose.
How does pertussis (whooping cough) usually present?
Start:
Mild coryzal symptoms, a low grade fever, mild dry cough
More severe coughing fit starts after a week or more:
Paroxysmal cough - Sudden and recurring attacks of coughing with cough free periods in between
Coughing fits are severe and keep building until the patient is completely out of breath
Large, loud inspiratory whoop when coughing ends
Patients can cough so hard they faint, vomit or even develop a pneumothorax
Not all patients will present will ‘whoop’
Infants may present with apnoea rather than a cough
Diagnosis of whooping cough?
A nasopharyngeal or nasal swab with PCR testing or bacterial culture can confirm the diagnosis within 2 to 3 weeks of the onset of symptoms.
Where the cough has been present for more than 2 weeks patients can be tested for the anti-pertussis toxin immunoglobulin G.
(This is tested for in the oral fluid of children aged 5 to 16 and in the blood of those aged over 17)
A nasopharyngeal or nasal swab with PCR testing or bacterial culture can confirm a diagnosis of pertussis within what window?
2 to 3 weeks of the onset of symptoms.
When can anti-pertussis toxin immunoglobulin G be tested for?
Where the cough has been present for more than 2 weeks
Management of pertussis?
Pertussis is a notifiable disease. Therefore Public Health need to be notified of each case.
Management typically involves simple supportive care.
Vulnerable or acutely unwell patients, those under 6 months and patients with apnoeas, cyanosis or patients with severe coughing fits may need to be admitted.
Measures to prevent spread are important, such as avoiding contact with vulnerable people, disposing of tissues and careful hand hygiene.
Macrolide antibiotics such as azithromycin, erythromycin and clarithromycin can be beneficial in the early stages (within the first 21 days) or vulnerable patients. Co-trimoxazole is an alternative to macrolides.
Close contacts with an infected patient are given prophylactic antibiotics if they are in a vulnerable group, for example pregnant women, unvaccinated infants or healthcare workers that have contact with children or pregnant women.
The symptoms typically resolve within
Disease course of pertussis?
The symptoms typically resolve within 8 weeks, however they can last several months. It is also known as the “100-day cough” due to the potential long duration of the cough. A key complication of whooping cough is bronchiectasis.
Key complication of pertussis (whooping cough)?
The symptoms typically resolve within 8 weeks, however they can last several months. It is also known as the “100-day cough” due to the potential long duration of the cough. A key complication of whooping cough is bronchiectasis.
What is CLDP?
Chronic lung disease of prematurity (CLDP) is also known as bronchopulmonary dysplasia.
It occurs in premature babies, typically those born before 28 weeks gestation.
These babies suffer with respiratory distress syndrome and require oxygen therapy or intubation and ventilation at birth.
Diagnosis is made based on chest xray changes and when the infant requires oxygen therapy after they reach 36 weeks gestational age.
Babies born before which gestation are typically affected by chronic lung disease of prematurity?
28 weeks gestation
How is chronic lung disease of prematurity diagnosed?
Diagnosis is made based on chest xray changes and when the infant requires oxygen therapy after they reach 36 weeks gestational age.
Which babies are typically affected bu chronic lung disease of prematurity/bronchopulmonary dysplasia?
It occurs in premature babies, typically those born before 28 weeks gestation.
These babies suffer with respiratory distress syndrome and require oxygen therapy or intubation and ventilation at birth.
Features of Chronic lung disease of prematurity (CLDP)/bronchopulmonary dysplasia.
Low oxygen saturations
Increased work of breathing
Poor feeding and weight gain
Crackles and wheezes on chest auscultation
Increased susceptibility to infection
Minimising the risk of CLDP prior to birth?
Maternal steroids given to mothers showing signs of premature labour at less than 36 weeks gestation (e.g. betamethasone)
Helps speed up the development of the fetal lungs before birth and reduce the risk of CLDP
Minimising the risk of CLDP once the neonate is born?
Using CPAP rather than intubation and ventilation when possible
Using caffeine to stimulate the respiratory effort
Not over-oxygenating with supplementary oxygen
Managing CLDP/BPD
A formal sleep study to assess their oxygen saturations during sleep supports the diagnosis and guides management.
Babies may be discharged from the neonatal unit on a low dose of oxygen to continue at home, for example 0.01 litres per minute via nasal cannula.
They are followed up to wean the oxygen level over the first year of life.
Babies with CLDP require protection against respiratory syncytial virus (RSV) to reduce the risk and severity of bronchiolitis.
This involves monthly injections of a monoclonal antibody against the virus called palivizumab. This is very expensive (around £500 per injection) so is reserved for babies meeting certain criteria.
Where is the genetic mutation in cystic fibrosis?
Genetic mutation of the cystic fibrosis transmembrane conductance regulatory gene on chromosome 7
There are many variants of this mutation, the most common is the delta-F508 mutation. T
his gene codes for cellular channels, particularly a type of chloride channel. Around 1 in 25 are carriers of the mutation and 1 in 2500 children have CF.
Cystic fibrosis (CF) is an autosomal recessive genetic condition affecting mucus glands. It is caused by a genetic mutation of the cystic fibrosis transmembrane conductance regulatory gene on chromosome 7. There are many variants of this mutation, which is the most common?
delta-F508
What are the key consequences of the cystic fibrosis mutation?
Thick pancreatic and biliary secretions that cause blockage of the ducts: resulting in a lack of digestive enzymes such as pancreatic lipase in the digestive tract
Low volume thick airway secretions: reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
Congenital bilateral absence of the vas deferens (males) resulting in male infertility (the sperm have no way of getting from the testes to the ejaculate)
Why are males with cystic fibrosis mutation infertile?
Congenital bilateral absence of the vas deferens in males.
Patients generally have healthy sperm, but the sperm have no way of getting from the testes to the ejaculate, resulting in male infertility
Presentation of cystic fibrosis?
Cystic fibrosis is screened for at birth with the newborn bloodspot test.
Meconium ileus is often the first sign of cystic fibrosis (first stool that a baby passes, usually black and should be passed within 24 hours of birth)
In about 20% of babies with CF, the meconium is thick and sticky, causing it to get stuck and obstruct the bowel.
This is called meconium ileus, and is practically pathognomonic for cystic fibrosis. This presents as not passing meconium within 24 hours, abdominal distention and vomiting.
If cystic fibrosis is not diagnosed shortly after birth it can present later in childhood with typical signs and symptoms, recurrent lower respiratory tract infections, failure to thrive or pancreatitis.
What sign is almost pathognomonic for cystic fibrosis?
Meconium ileus - not passing meconium within 24 hours, abdominal distention and vomiting.
If cystic fibrosis is not diagnosed shortly after birth, how might it present later in childhood?
Recurrent LRTI
Failure to thrive
Pancreatitis
Typical symptoms:
Chronic cough
Thick sputum production
Recurrent respiratory tract infections
Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Abdominal pain and bloating
Parents may report the child tastes particularly salty when they kiss them, due to the concentrated salt in the sweat
Poor weight and height gain (failure to thrive)
Typical signs:
Low weight or height on growth charts
Nasal polyps
Finger clubbing
Crackles and wheezes on auscultation
Abdominal distention
Typical signs and symptoms of CF?
Chronic cough
Thick sputum production
Recurrent respiratory tract infections
Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Abdominal pain and bloating
Parents may report the child tastes particularly salty when they kiss them, due to the concentrated salt in the sweat
Poor weight and height gain (failure to thrive)
Signs of CF?
Low weight or height on growth charts
Nasal polyps
Finger clubbing
Crackles and wheezes on auscultation
Abdominal distention
For what reasons might clubbing be seen in a child?
Hereditary clubbing
Cyanotic heart disease
Infective endocarditis
Cystic fibrosis
Tuberculosis
Inflammatory bowel disease
Liver cirrhosis
Three key methods of establishing CF diagnosis?
- Newborn blood spot testing is performed on all children shortly after birth and picks up most cases
- The sweat test is the gold standard for diagnosis
- Genetic testing for CFTR gene can be performed during pregnancy by amniocentesis or chorionic villous sampling, or as a blood test after birth
What does the sweat test entail?
A patch of skin is chosen for the test, typically on the arm or leg.
Pilocarpine is applied to the skin on this patch.
Electrodes are placed either side of the patch and a small current is passed between the electrodes.
This causes the skin to sweat.
The sweat is absorbed with lab issued gauze or filter paper and sent to the lab for testing for the chloride concentration.
The diagnostic chloride concentration for cystic fibrosis is more than 60mmol/l.
What is the gold standard for diagnosing CF?
Sweat test
Why are patients with cystic fibrosis ‘microbial colonisers’?
Struggle to clear secretions from their airways
Plenty of oxygen and moisture - perfect environment for colonies of bacteria to live and replicate
CF - common colonies
Staphylococcus aureus
Haemophilus influenza
Klebsiella pneumoniae
Escherichia coli
Burkhodheria cepacia
Pseudomonas aeruginosa
What can be done in patients with CF to prevent staph aureus infection?
Long term prophylactic flucloxacillin
What relatively common CF coloniser is hard to treat and worsens prognosis?
Pseudomonas aeruginosa
Why is pseudomonas aeruginosa troublesome in CF?
Once patients become colonised with pseudomonas, it can be very difficult to get rid of.
Often, these bacteria can become resistant to multiple antibiotics.
Colonisation with pseudomonas leads to a significant increase in morbidity and mortality in patients with CF.
CF patients are discouraged from close contact with one another is due to the risk of spreading pseudomonas. Cystic fibrosis clinics have separate clinic rooms for children with pseudomonas to minimise the risk of transmission.
Management of pseudomonas colonisation?
Pseudomonas colonisation can be treated with long term nebulised antibiotics such as tobramycin.
Oral ciprofloxacin is also used.
Cystic fibrosis will be managed by the specialist MDT. There are many aspects to management, such as?
Chest physiotherapy several times a day is essential to clear mucus and reduce the risk of infection and colonisation
Exercise improves respiratory function and reserve, and helps clear sputum
High calorie diet is required for malabsorption, increased respiratory effort, coughing, infections and physiotherapy
CREON tablets to digest fats in patients with pancreatic insufficiency (these replace the missing lipase enzymes)
Prophylactic flucloxacillin tablets to reduce the risk of bacterial infections (particularly staph aureus)
Treat chest infections when they occur
Bronchodilators such as salbutamol inhalers can help treat bronchoconstriction
Nebulised DNase (dornase alfa) is an enzyme that can break down DNA material in respiratory secretions, making secretions less viscous and easier to clear
Nebulised hypertonic saline
Vaccinations including pneumococcal, influenza and varicella
CF - other treatment options
Lung transplantation is an option in end stage respiratory failure
Liver transplant in liver failure
Fertility treatment involving testicular sperm extraction for infertile males
Genetic counselling
CF - monitoring
Patients with cystic fibrosis are managed and followed up in specialist clinics, typically every 6 months.
They require regular monitoring of their sputum for colonisation of bacteria like pseudomonas.
They also need monitoring and screening for:
- diabetes
- osteoporosis
- vitamin D deficiency
- liver failure
CF - prognosis?
Prognosis depends on multiple factors, including severity of symptoms, type of genetic mutation, adherence to treatment, frequency of infection and lifestyle.
Life expectancy is improving and currently the cystic fibrosis trust gives a median life expectancy of 47 years.
- 90% of patients with CF develop pancreatic insufficiency
- 50% of adults with CF develop cystic fibrosis-related diabetes and require treatment with insulin
- 30% of adults with CF develop liver disease
- Most males are infertile due to absent vas deferens
Most common (90%) complication patients with CF go on to develop?
Pancreatic insufficiency
Long term complications of CF?
- 90% of patients with CF develop pancreatic insufficiency
- 50% of adults with CF develop cystic fibrosis-related diabetes and require treatment with insulin
- 30% of adults with CF develop liver disease
Most males are infertile due to absent vas deferens
How is Primary Ciliary Dyskinesia/Kartagner’s syndrome managed?
Management is similar to cystic fibrosis and bronchiectasis with daily physiotherapy, a high calorie diet and antibiotics.
Diagnosis of PCD (Kartagner’s syndrome)
Patients typically present with recurrent respiratory tract infections.
Take a careful family history and a history of consanguinity in the parents.
Examination and imaging (e.g. chest xray) can be used to diagnose situs inversus.
Semen analysis can be used to investigate for male infertility.
The key investigation for establishing the diagnosis is to take a sample of the ciliated epithelium of the upper airway and examine the action of the cilia. A sample can be obtained through nasal brushing or bronchoscopy. Often several samples are required.
What is situs inversus?
Situs inversus is a condition where all the internal (visceral) organs are mirrored inside the body.
Therefore the heart is on the right, the stomach is on the right and the liver is on the left.
Dextrocardia is when only the heart is reversed.
25% of patients with situs inversus will have primary ciliary dyskinesia. 50% of patients with primary ciliary dyskinesia have situs inversus.
Situs inversus on its own does not cause any problems, and patients can expect to live a normal life. A small number have associated congenital heart disease, such as transposition of the great arteries.
Kartagner’s triad describes the three key features of PCD. Not all patients will have all three features. They include?
Paranasal sinusitis
Bronchiectasis
Situs Inversus
What congenital abnormality is commonly associated with primary ciliary dyskinesia (Kartagner’s syndrome)?
Situs inversus
Basic pathophysiology of Kartagner’s syndrome (primary ciliary dyskinesia)?
PCD causes dysfunction of the motile cilia around the body, most notably in the respiratory tract, due to is an autosomal recessive genetic mutiation affecting the cilia of various cells in the body
This leads to a build up of mucus in the lungs, providing a great site for infection that is not easily cleared.
This leads to a similar respiratory presentation to cystic fibrosis, with frequent and chronic chest infections, poor growth and bronchiectasis.
It also affects the cilia in the fallopian tubes of women and the tails (flagella) of the sperm in men, leading to reduced or absent fertility.
What is the major risk factor for primary ciliary dyskinesia (Kartagner’s syndrome)
Consanguinity (parents related to eachother) increases the risk of a child having two copies of the same recessive genetic mutation
What is PCD?
Primary ciliary dyskinesia (PCD) is also known as Kartagner’s syndrome.
It is an autosomal recessive condition affecting the cilia of various cells in the body.
It is more common in populations where there is consanguinity, meaning the parents are related to each-other.
Consanguinity increases the risk of a child having two copies of the same recessive genetic mutation.
Cystic fibrosis: diet
High calorie and high fat with pancreatic enzyme supplementation for every meal
38%
Features of CAP that suggest bacterial vs viral cause
AGE:
- OVER 2, BACTERIAL
- UNDER 2 VIRAL
RHINORRHOEA:
- absent BACTERIAL
- present VIRAL
WHEEZE:
- absent BACTERIAL
- present VIRAL
TEMPERATURE
- over 38.5 - BACTERIAL
- under 38.5 - VIRAL
LOCALISED PAIN
- present - BACTERIAL
- absent - VIRAL
An acute onset (without a
coryzal prodrome) in a toxic child suggests a bacterial infection.
The most common pathogens causing pneumonia - NEWBORNS
organisms from mother’s genital tract e.g. group B streptococcus, gram-negative enterococci and bacilli.
The most common pathogens causing pneumonia - INFANTS AND YOUNG CHILDREN
respiratory viruses (commonly RSV) as well as bacteria such
as Streptococcus pneumonia or Haemophilus influenzae
The most common pathogens causing pneumonia - CHILDREN OVER 5
Streptococcus pneumonia, Mycoplasma pneumonia and Chlamydia
pneumoniae are the main causes
Features of MILD CAP in infants
RR < 50/min
CRT < 2 sec
Mild recessions
Taking full feeds
Features of MODERATE CAP in infants
RR 50-70/min
CRT ~ 2 sec
Moderate recessions
Reduced feeds
Features of SEVERE CAP in infants
RR > 70/min
CRT > 2 sec
Nasal flaring
Intermittent apnoea
Grunting
Unable to feed
Features of MILD CAP in older children
RR < 35/min
CRT < 2 sec
Mild breathlessness
Taking full feeds
Features of MODERATE CAP in older children
RR 35-50/min
CRT ~ 2 sec
Moderate recessions
Reduced feeds
Features of SEVERE CAP in older children
RR >50/min
CRT > 2 sec
Unable to complete
sentences
Severe recessions
Nasal flaring
Signs of dehydration
Evidence based startergies to treat bronchilotis
Nebulised 3% saline
Oxygen
There is no evidence for any other treatment. The following medications are therefore not
recommended: antibiotics, nebulised adrenaline, inhaled bronchodilators (short-acting
beta2-agonists) or ipratropium bromide, oral or inhaled steroids and montelucast.
Physiotherapy is also not useful.
Stridor in epiglotitis
soft inspiratory stridor and muffled voice.
Monitoring efficacy of a new asthma treatment
Clinic review at 6 weeks
Symptom diary
At each patient contact when monitoring asthma symptom control clinicians must always do what?
Enquire about symptoms. Carefully selected questions are more likely to provide useful
information about control than a general question such as ‘How is your asthma today?’ A
question like ‘How often do you use your blue inhaler? Or ‘How many times a week do
you need to use a blue inhaler?’ may be more useful.
- Check concordance. This may include assessing whether repeat prescriptions have been
collected regularly from the patient’s GP between visits. - Assess inhaler technique. Reassessing inhaler technique must be part of each structured
clinical review and should be performed before considering increasing therapy. - Assess for concomitant causes of cough e.g. bronchitis, newly developed rhiniti
. The first-line management of acute exacerbations of asthma is what?
Inhaler SABA NEB and
ipratropium bromide NEB and oral steroids.
