It is not unusual for a GP to be presented with a young child with croup, a condition that often causes much parental anxiety. It is usually associated with an upper respiratory viral infection involving the larynx and trachea, and there may be other signs of URTI, such as nasal discharge or cough.
The cough accompanying croup is often described as 'barking', but the most distressing problem is stridor, the typically rasping sound produced when inhaled air passes through a larynx and trachea that is narrowed through inflammation.
There is no stridor on exhalation, as there is with a wheeze produced from narrowing in the lower respiratory tract.
1. Age groups affected
Croup is rare in babies aged less than six months. It mostly affects children from six months to three years, but may occur in older children up to the age of six or seven.
It may be gradual in onset, accompanied by URTI symptoms, such as cough and runny nose, and last several days (viral croup), or consist of short repetitive episodes, often at night, that resolve with little or no evidence of infection (spasmodic croup).
With viral croup, the offending organism is usually a parainfluenza virus, but other viruses that may be implicated include influenza A and B, measles and varicella viruses, adenoand rhinoviruses and respiratory syncytial virus.
Rarely, croup can be associated with allergies or acid reflux. If there is sudden onset and no evidence of URTI, it is worth thinking about the possibility of an inhaled foreign body.
Most cases are mild, and last only a few hours or days, but some cases are severe and can lead to emergency admission. It tends to affect boys more than girls.
Epiglottitis should be excluded. The child with epiglottitis usually appears ill, and is more comfortable sitting or leaning forward. The child may also refuse to swallow. The differentiation is important, as epiglottitis is a more serious situation that may be life threatening. Although croup leads to several thousands of emergency admissions each year, death is rare, with only eight deaths attributable to croup in 2008.
Exclude epiglottitis: X-ray showing thickening of the epiglottis in an infant (arrow) (Photograph: SPL)
2. Warning signs
Most cases can be managed at home, but if the child shows evidence of respiratory distress, admission to hospital is advisable.
Signs and symptoms of severe croup include difficulty with breathing with intercostal muscle indrawing, breathlessness that prevents feeding, crying or talking, a silent chest on auscultation with few or no breath sounds, and any evidence of cyanosis, abnormal drowsiness, pyrexia, tachycardia or bradycardia.
Parents should be advised that croup is self-limiting.
Appropriate use of paracetamol or ibuprofen will help control fever and pain. Tepid sponging is not recommended. The child should be reviewed after a few hours, usually by telephone.
Parents should seek urgent medical advice if any of the warning signs occur, and to call an ambulance if there is cyanosis, profound lethargy or struggling for breath.
Cough medicines and decongestants are not effective, and antibiotics are not helpful.
The use of steam to alleviate symptoms is controversial. There is a lack of scientific evidence to support its use and there are concerns about scalding from the boiling water. However, anecdotally many practitioners feel it is worth trying. A source of cool air may also be effective.
If intervention is required, it is generally accepted that all children presenting with mild, moderate or severe croup should be given a single dose of oral dexamethasone (0.15mg per kg body weight).
If the weight is unknown, a rough guide would be 1.5-2mg for a child of average size aged 12 to 15 months and 2-3mg for a child of average size aged three to four years. Dexamethasone should therefore be included in the GP's bag.
Oral administration appears just as effective as intramuscular dexamethasone or inhaled budesonide. Oral prednisolone may be used instead (1-2mg per kg body weight), but evidence suggests it may not be as effective at preventing further medical intervention.
While most cases of croup can be safely managed at home, there are few guidelines that help a GP to decide when to admit. It is obvious when the child has evidence of impending respiratory failure, and it may be wise to consider admission more readily if there is uncertainty about the diagnosis.
Complicating factors, such as a child who is less than six months old, is immunocompromised, is refusing liquids or has a poor response to initial treatment, may also heighten the need for admission.
There may be a circumstantial case for considering admission with a late evening presentation where the child is a long way from hospital with no transport and there is a high level of parental anxiety.
- Dr Barnard is a former GP from Fareham, Hampshire