Respiratory: Laryngomalacia; Croup Flashcards
What are the differences in anatomy in children that can make them susceptible to respiratory disease? [4]
Airways:
- Narrow, large occiput (back of head): readily obstructed
- reduced tone in neck (as babies)
- obligate nasal breathers (breathing w blocked nose becomes difficult!)
Compliant chests
Fatiguable respiratory muscles
Prone to apnoea
What are symptoms and signs of respiratory distress in (younger child) [+]
Nasal flaring
Coryza
Poor feeding
Tracheal tug
Rapid breathing
Abdominal breathing
Paradoxical breathing
Crackles
Sternal recession
Intercostal recession
Subcostal recession
If you have upper or lower airwway problem then what is resp symptom most likely to be? [2]
Upper: stridor
Lower: wheeze
If both - then both!
The most likely dx of a baby presenting with stridor is? [1]
Laryngomalacia
Describe what is meant by laryngomalacia [1]
Describe the structural changes that causes this condition [+]
Laryngomalacia:
- 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.
Structural changes:
- There are two aryepiglottic folds at the entrance of the larynx. They run 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.
- 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.
Draw the difference between normal anatomy and LM [1]
Describe the presentation of laryngomalacia [2]
Laryngomalacia occurs in infants, peaking at 6 months. It presents with:
inspiratory stridor, a harsh whistling sound when breathing in.
Usually this is intermittent and become more prominent when feeding, upset, lying on their back or during upper respiratory tract infections.
- Infants with laryngomalacia do not usually have associated respiratory distress.
Symptomatic relief may be provided by hyperextending the neck during episodes of stridor
It can cause difficulties with feeding, but rarely causes complete airway obstruction or other complication
Describe the disease course of Laryngomalacia [3]
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.
Describe the three types of laryngomalacia [3]
Type I Laryngomalacia (Curling Type):
* Characterised by inward curling of the mucosa overlying the arytenoid cartilages during inspiration. This creates an omega-shaped laryngeal inlet instead of the normal V-shape.
* It’s the most common type, accounting for approximately 75% of cases.
Type II Laryngomalacia (Prolapsing Type):
* Involves prolapse of the mucosa overlying the cuneiform and corniculate cartilages into the glottis during inspiration.
* This type accounts for around 15% of laryngomalacia cases.
Type III Laryngomalacia (Posterior Displacement Type):
* Less common, only observed in about 10% of cases. It involves posterior displacement or malpositioning of the epiglottis and aryepiglottic folds.
* This type is often associated with more severe symptoms and may require early surgical intervention.
What is this ddx of LM? [1]
What previously has likely occured to this patient? [1]
How would it present differently? [2]
What is likely caused by? [1]
Subglottic stenosis
- likely previous intubations
- presents with biphasic stridor and is not limited to inspiration like laryngomalacia.
- It may also present with respiratory distress that is disproportionate to the degree of stridor.
Causes:
- The underlying causes are diverse including congenital malformations, prolonged intubation trauma or systemic diseases like Wegener’s granulomatosis.
- This differentiates it from laryngomalacia which is believed to be due to neuromuscular immaturity.
What is this ddx of LM? [1]
Laryngeal cleft
What is this ddx of LM? [1]
Laryngeal web
What is this ddx of LM? [1]
Laryngeal cyst
How would you distinguish LM from vocal cord paralysis? [3]
Vocal Cord Paralysis
* Unlike laryngomalacia, vocal cord paralysis often presents with a weak cry or voice, aspiration or feeding difficulties and can cause biphasic stridor or even complete airway obstruction.
* It is commonly unilateral and the result of birth trauma, neurological disorders or iatrogenic injury post-thoracic surgery.
* In contrast to laryngomalacia where endoscopic examination shows omega-shaped epiglottis and floppy arytenoids during inspiration, vocal cord paralysis reveals immobile or poorly mobile vocal cords in a paramedian position.
What is you next ddx for noisey breathing as get older? [1]
Describe what this is x [1]
Croup
- 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 is an upper respiratory tract infection causing oedema in the larynx.
Describe the presentation of croup [4]
What is the classic cause of croup? [1] Which tx does it respond well to? [1] What are other common causes? [3]
Presentation:
* Increased work of breathing
* “Barking” cough, occurring in clusters of coughing episodes
* Hoarse voice
* Stridor
* Low grade fever
The classic cause of croup that you need to spot in your exams, is parainfluenza virus. It usually improves in less than 48 hours and responds well to treatment is steroids, particularly dexamethasone. Also by:
* Influenza
* Adenovirus
* Respiratory Syncytial Virus (RSV)
Describe the differences between mild, moderate and severe croup with regards to [+]
- behaviour
- Stridor
- RR
- Accessory muscle use
- Oxygen sats
Which factors would make you admit a patient with croup? [3]
CKS suggest admitting any child with:
moderate or severe croup
* < 3 months of age
* known upper airway abnormalities (e.g. Laryngomalacia, Down’s syndrome)
* uncertainty about diagnosis (important differentials include acute epiglottitis, bacterial tracheitis, peritonsillar abscess and foreign body inhalation)
How would you differentiate croup from URTI and brionchiolitis [2]
Viral upper respiratory tract infection (URTI)
Similarities:
* Common in young children
* Causes coryza, cough and respiratory distress
Differences
* Seal-like barking cough less common
Bronchiolitis
Similarities:
* Causes cough, fever, and respiratory distress
Differences
* Affects children < 2 years old
* Causes wheeze
* No barking quality to cough
How would you differentiate croup from epiglottis and foreign body aspiration [+]
Epiglottitis
Similarities
* Stridor
Differences
* Usually seen in children 3-5 years of age
* Absence of barking cough
* Muffled hot potato voice
* Tripod or sniffing position
* An incomplete vaccination history more likely to be present
Foreign body aspiration
Similarities
* Often < 3 years of age
* Stridor
* Dysphonia depending on location of foreign body
Differences
* History suggestive of possible foreign body
* Abrupt onset during daytime (croup usually night-time)
* Minimal response to adrenaline nebuliser
How would you differentiate croup from Bacterial tracheitis [3]
Bacterial tracheitis
Similarities
* Stridor
Differences
* Usually school-age
* Soft stridor 2-7 days after onset of URTI symptoms
* Significant tracheal tenderness on palpation
* Reluctant to cough because of pain
NICE guidelines, last updated in 2019, suggest the following algorithm for the management of croup:
- Primary Care [3]
- Secondary care [4]
Primary care (mild illness):
* Supportive care
* Oral dexamethasone
Parents should be advised regarding:
* The expected course of croup, including that symptoms usually resolve within 48 hours.
* The need to take the child to hospital if stridor can be heard continually, the skin between the ribs is pulling in with every breath, and/or the child is restless or agitated.
* The use of antipyretics in children distressed due to fever.
* The need to check on the child regularly, including through the night.
* Arrange follow-up, using clinical judgment to determine the appropriate interval.
Secondary care (moderate - severe illness)
* All children with moderate-severe illness should be admitted
* Supportive care
* Oral dexamethasone
* Nebulised epinephrine
* Supplemental oxygen
* The above advice should also be given
Bacterial tracheitis is most likely cause by which organism? [1]
Haemophilus influenza
Lecture
Name three further ddx for croup and how you would differentiate between them [+]
Retropharyngeal/peritonsillar abscess
* dysphagia, drooling, stridor (occasionally), dyspnoea, tachypnoea, neck stiffness, and unilateral cervical adenopathy.
* Onset is typically more gradual than with croup and is often accompanied by fever.
Angioneurotic oedema
* acute swelling of the upper airway that may cause dyspnoea and stridor.
* Fever is uncommon. Swelling of face, tongue, or pharynx may be present. Can occur at any age.
Allergic reaction
* rapid onset of dysphagia, stridor, and possible cutaneous manifestations (urticarial rash).
* Can occur at any age
* Known allergies
