Paeds - Respiratory Flashcards
Most common cause of Croup vs Bronchiolitis
Croup - Tolders with barking cough and stridor- usually caused by parainfluenza virus
Bronchiolitis - infants with SOB and wheeze- most commonlly caused by respiratory syncytial virus
mnemotic - croup ends in p - for parainfluenza
bronchiolitis ends in an S for syncytial
What age children get bronchiolitis?
why is this?
Infants
Bronchiolitis is very common in winter. 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.
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.
An infant presents with:
- coryzal symptoms
- signs of respiratory distress
- dyspnoea
- poor feeding
- mild fever (under 39)
- apnoeas
- wheeze and crackles on auscultation
Diagnosis
Bronchiolitis
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.
One of the foundations of paediatrics is being able to spot the 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
Wheeze vs grunt vs stridor
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 (gasp noise) is a high pitched inspiratory noise caused by obstruction of the upper airway, for example in croup
Note from lecture - Wheeze is poltphonic because multiple calibres of lower airways invovled and also expiratory because during expiration the intrathroacic pressure increases and it causes the walls of the smaller airways (already narrowed by inflamation) to collapse.
In contrast stridor is inspiratory because the negative intrathoracic pressure is greatest causes the upper airways to vibrate.
Reasons for admission of infants with bronchilitis - approx 7
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
Patients typically only require supportive management:
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. Remeber that when feeding, harder to ventilate so poor feeding is sign of a respiratory/cardiovascular issue in infants (think about going blue in CHD)
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.
Types of ventilatory support in children - Low yield
As breathing gets harder, the child gets more tired and less able to adequately ventilate themselves. They may require ventilatory support to maintain their breathing. This is stepped up until they are adequately ventilated:
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.
Capillary blood gases are useful in severe respiratory distress and in monitoring children who are having ventilatory support. Ovs dont forget that sats are the main thing used, this is just extra info for you aaron x
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.
KEY
Prophalaxis of bronchiolitis in premature babies and babies with congenital heart defects
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.
What is croup?
Who does it affect and how does it present?
Cause?
Rx?
Croup is an acute infective respiratory disease affecting young children. It typically affects children aged 6 months to 2 years, however they can be older. It typically presents with increased work of breathing, low grade feverl barking cough/horse voice and inspiratory stridor.
It is an upper respiratory tract infection causing oedema in the larynx, NOT THE EPIGLOTIS!
The classic cause of croup that you need to spot in your exams, is parainfluenza virus. Other causes are adenovirus, influenza and RSV (RSV causes bronchiolitis)
Most cases can be managed at home with simple supportive treatment (fluids and rest). It usually improves in less than 48 hours and responds well to treatment with a single sode of dexamethasone (can be repeated after 12 hours).
Stepwise options in severe croup to get control of symptoms:
Oral dexamethasone
Oxygen
Nebulised budesonide (steroid)
Nebulised adrenalin
Intubation and ventilation
Important not to examine the throat - can cause them to get aggitated and desaturate.
A popular exam question is: both parents are healthy, one sibling has cystic fibrosis and a second child does not have the disease, what is the likelihood of the second child being a carrier?
Remember that cystic fibrosis is autosomal recessive.
We know the child doesn’t have the condition, so the answer is two in three.
XX/XX = XX, Xx, Xx, xx . Since doesnt have it they can’t be xx, so they have a 2/3 chance of being Xx (a carrier)
What chromosome is the cystic fibrosis transmembrane conductance regulatory gene found on and what is the inheritence pattern.
Autosomal recessive - Chromosome 7
The most common mutation is the delta-F508 mutation
This gene codes for cellular channels, particularly a type of chloride channel.
What are the consequences of the cystic fibrosis mutation? 3 key things
Symptoms?
The muation affects mucus flands and leads to:
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 that reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
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
Presenation:
Poor weight and height gain (failure to thrive)
Finger clubbing
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
A newborn presents as not passing meconium within 24 hours, abdominal distention and vomiting, what is the most likely diagnosis?
cystic fibrosis
Meconium ileus is often the first sign of cystic fibrosis. The first stool that a baby passes is called meconium. This is 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
///
EXAM QUESTION: A CONTRAST ENEMA SHOWS:
- Microcolon: A narrow, underdeveloped colon due to lack of fetal bowel content passing through.
- Impacted meconium pellets, visible in the distal ileum.
Key Differentiating Point:
- In Hirschsprung’s disease, the colon is primarily affected, and meconium backs up in the colon.
- In cystic fibrosis, the problem is in the distal ileum, causing obstruction there, with a microcolon downstream.
///
Cystic fibrosis is screened for at birth with the newborn bloodspot test.
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.
Meconium ileus is also associated with hirshprungs disease but i think that is far less common? be vigilant in exams me - In fairness this is similar to hirsprungs asscoiated enterocolitis but that is a few weeks not 24 hours in.
Causes of Clubbing in Children -6
Hereditary clubbing
Cyanotic heart disease
Infective endocarditis
Cystic fibrosis
Tuberculosis
Inflammatory bowel disease
Liver cirrhosis
Cystic fibrosis - There are three key methods for establishing a diagnosis that you should remember for your exams?
Interpretation of the gold standard?
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
The sweat test is the key investigation to remember for cystic fibrosis. It is the gold standard for confirming the diagnosis. 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.
Patients with cystic fibrosis struggle to clear the secretions in their airways. This creates a perfect environment with plenty of moisture and oxygen for colonies of bacteria to live and replicate. What are some examples of common colonisers? - name the 2 key ones and hwo they are treated?
Staphylococcus aureus
Pseudomonas aeruginosa
Others:
Haemophilus influenza
Klebsiella pneumoniae
Escherichia coli
Burkhodheria cepacia
TOM TIP: The key colonisers to remember for your exams are staph aureus and pseudomonas. Patients with cystic fibrosis take long term prophylactic flucloxacillin to prevent staph aureus infection. Pseudomonas should be remembered as a particularly troublesome coloniser that is hard to treat and worsens the prognosis of patients with cystic fibrosis.
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. In the past there were gatherings and social events organised for children with cystic fibrosis to meet up and share their experiences, however this was stopped due to the risk of spreading pseudomonas. The general advice is now to avoid contact with other children with cystic fibrosis. Cystic fibrosis clinics have separate clinic rooms for children with pseudomonas to minimise the risk of transmission.
Pseudomonas colonisation can be treated with long term nebulised antibiotics such as tobramycin. Oral ciprofloxacin is also used.
Management of Cystic fibrosis? 6
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
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
Monitoring and prognosis of cystic fibrosis
Monitoring for:
- pseudomonas colonisation
- diabetes
- osteoporosis
- Vitamin D deficiency
- liver failure
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
What typically causes epiglottitis?
Presentation?
Investigation?
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.
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.
Presentation- THIS CAME UP:
In you exams keep a lookout for an unvaccinated child presenting with
- fever
- sore throat
- stridor
- difficulty swallowing
- sitting forward (tripod position)
- drooling
Ix:
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. This is caused by the oedematous and swollen epiglottis. Neck xrays are also useful for excluding a foreign body.
Management of epiglottitis
Epiglottitis is an emergency and there is an immediate risk of the airway closing. A key point that is often talked about with epiglottitis is the importance of not distressing the patient, as this could prompt closure of the airway. Don’t examine them and don’t make them upset.
Management of epiglottis centres around ensuring the airway is secure. Most patients do not require intubation, however there is an ongoing risk of sudden upper airway closure, so preparations need to be made to perform intubation/tracheostomy at any time.
Additional treatment once the airway is secure:
IV antibiotics- ceftriaxone
Steroids (i.e. dexamethasone)
TEST BASED ON CEF AS THE ANSWER!
Most children recover without requiring intubation. 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.
Pathophysiology of a viral-induced wheeze?
When these small airways encounter a virus (commonly RSV or rhinovirus) they develop a small amount of inflammation and oedema, swelling the walls of the airways and restricting the space for air to flow. This inflammation also triggers 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. For some reason, certain children are much more prone to this airway swelling than others. There seems to be a hereditary element, so when assessing a wheezy child ask about a family history of viral-induced wheeze. These children are at higher risk of developing asthma in later life.
This is really similar to the pathophysiology of bronchiolitis
A 3 year old presents with SOB, signs of respiratory distress, and an expiratory wheeze throughout the chest two days after having a fever and cough.
Diagnosis?
Management?
Evidence of a viral illness (fever, cough and coryzal symptoms) for 1-2 days preceding the onset of:
Shortness of breath
Signs of respiratory distress
Expiratory wheeze throughout the chest
TOM TIP: Neither viral-induced wheeze or asthma cause a focal wheeze. If you hear a focal wheeze be very cautious and investigate further for a focal airway obstruction such as an inhaled foreign body or tumour. These patients will require an urgent senior review.
The distinction between a viral-induced wheeze and asthma is not definitive. Generally, typical features of viral-induced wheeze (as opposed to asthma) are:
Presenting before 3 years of age
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.
Management of viral-induced wheeze is the same as acute asthma in children - oxygen, salbutamol, steroids.
What is Pneumonia? KEY
Causes of pneuomonia in children?
Pneumonia is simply an infection of the alveoli. 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.
Bacterial
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).
Viral
Respiratory syncytial virus (RSV) is the most common viral cause
Parainfluenza virus
Influenza virus
