croup Flashcards
what is coup?
Croup, or acute laryngotracheobronchitis, is an upper respiratory tract infection that in most cases has a viral aetiology. Key symptoms include a barking cough, hoarse voice and inspiratory stridor.
who is affected by croup?
6 months old to 3 years old
peak incidence at 2yrs
causes of croup?
The commonest cause is the parainfluenza virus. Other viral causes include adenovirus, respiratory syncytial virus (RSV), rhinovirus and influenza. Rarely, bacteria can cause croup (e.g. Mycoplasma pneumoniae).
pathophysiology of croup?
The pathophysiology involves infection and resulting inflammation of the subglottic and laryngeal mucosa which causes partial obstruction of the airways leading to respiratory distress and stridor.
features of croup?
The prodromal phase of coryzal symptoms, fever and a non-specific cough usually lasts 12-72 hours.
Characteristic symptoms of croup such as the harsh barking cough, hoarse voice or cry and inspiratory stridor then develop - these tend to be worse at night.
In severe cases, children may become drowsy and lethargic, or conversely more agitated.
The usual course of disease is resolution of symptoms within 48 hours (up to a week at most).
what red flag features may indicate resp failure in croup?
Signs of respiratory distress e.g. intercostal recessions, accessory muscle usage, tachypnoea
Cyanosis
Decreased level of consciousness
Stridor may decrease due to worsening airway obstruction
Decreased air entry on auscultation of the chest
Tachycardia
ix for croup?
Pulse oximetry should be done to determine if supplementary oxygen is required.
Chest X-ray may be of use if a differential diagnosis such as an inhaled foreign body is suspected. - In croup, an X-ray may show a steeple sign, where the upper trachea is seen to taper.
mx for mild croup?
Mild cases with no stridor or chest wall recessions at rest may be treated at home with a single dose of oral dexamethasone (0.15mg/kg). In children treated at home, families should be safety-netted on signs of deterioration and advised to check on the child regularly and encourage fluids. Paracetamol or ibuprofen can be used for fever and pain.
which kids with croup get admitted to hospital?
Stridor and/or sternal recession at rest
High fever
Respiratory rate > 60
Cyanosis
Lethargy or agitation
Fluid intake < 75% of normal or no wet nappies for 12 hours
Aged under 3 months
Chronic conditions such as immunodeficiency, chronic lung disease or neuromuscular disorders
what is the supportive mx for croup?
Supplementary oxygen if low saturations - consider how best to deliver this so as not to distress the child (e.g. a parent holding an oxygen mask to the face)
Steroids for all - if unable to swallow oral dexamethasone or prednisolone can give nebulised budesonide
Nebulised adrenaline for temporary symptom relief
Anaesthetics +/- ENT input if concerns regarding airway or respiratory failure
complications of croup?
Dehydration secondary to poor fluid intake during illness
Pneumonia due to secondary bacterial infection
Respiratory failure
Death is very rare (1 in every 30,000 cases)
what is mild croup?
Seal-like barking cough but no stridor or sternal/intercostal recession at rest.
what is moderate croup?
Seal-like barking cough with stridor and sternal recession at rest; no (or little) agitation or lethargy.
what is severe croup?
Seal-like barking cough with stridor and sternal/intercostal recession associated with agitation or lethargy.
what is impending resp failure?
Minimal barking cough, stridor may become harder to hear. Increasing upper airway obstruction, sternal/intercostal recession, asynchronous chest wall and abdominal movement, fatigue, pallor or cyanosis, decreased level of consciousness or tachycardia. The degree of chest wall recession may diminish with the onset of respiratory failure as the child tires. A respiratory rate of over 70 breaths/minute is also indicative of severe respiratory distress.
