How not to miss inhaled foreign bodies

Worst outcomes if missed

In the acute situation, there can be serious and sometimes fatal complications if the diagnosis of inhaled foreign body is delayed or missed. The rate of serious acute complications – including pneumonia, pneumothorax, and subglottic oedema – is 2.5 times higher when diagnosed more than 24 hours after inhalation (67%) than when diagnosed within 24 hours (27%).¹

Long-term complications of a delayed or missed diagnosis include recurrent pneumonia, lung abscesses and bronchiectasis.

Epidemiology

The commonest age group affected is one to three years (55% of cases) followed by children under one year (21% of cases).² In 2010-11, just over 500 admissions in England were due to foreign body inhalation in children under 14 years. Inhalation of foodstuff is most common and nuts are the most troublesome – particularly the oils in peanuts, which cause an intense inflammatory response – but a variety of small objects can be found in children’s airways.³

Symptoms and signs

A severe choking episode that provoked the witness to action should always be taken seriously. If followed by cough or wheeze, or if there are unilateral decreased breath sounds on auscultation then inhalation should be assumed. However, choking is not always observed in young children and the classic triad of coughing/choking, wheezing and unilateral reduced breath sounds is found in just over 50% of cases. The most specific finding is localised decreased lung sounds (positive predictive value of 74%).⁴ The child may therefore present with new-onset cough or wheeze without a clear history and without URTI symptoms, so it is important to ask specifically about prior choking episodes, particularly if there are unilateral chest signs. Persistent cough, wheeze, sputum production and dyspnoea may develop over weeks if diagnosis is delayed.

Five red herrings

Choking events are not reported in one in six cases of confirmed foreign body inhalation⁴
Inhaled objects that do not cause an intense inflammatory response (such as plastic toys) can be the most difficult to detect
An inhalation episode at the time a child clearly has a viral infection can be very difficult to distinguish
Children can breathe through the ‘hole’ in a hollow object so symptoms such as wheeze may be present only on exertion
Chronic persistent wet cough with chest X-ray changes that do not respond to antibiotics
may be a presentation of
a missed foreign body

Differential diagnoses

• Reactive airways disease – generally have bilateral wheeze that responds to salbutamol.

• Lobar pneumonia – generally have high fever, systemic illness and often chest pain.

Five key questions

Was there a choking event in the days before presentation? Parents do not always associate a choking episode with the respiratory symptoms if the child seemed to recover fully
If there is no choking history, was the child unattended shortly before the symptoms began?
Are breath sounds decreased on one side?
Is there unilateral wheeze? This is present when there is partial obstruction of an airway
Is there new-onset cough or wheeze without viral infection?

Investigations

If inhalation of a foreign body is suspected the child should be referred urgently to hospital. Chest X-ray is the initial investigation of choice, but more than three-quarters of inhaled foreign bodies are radiolucent and will not show on chest X-ray.

Where the GP has a low level of suspicion in an otherwise well child, it may be appropriate for them to arrange an urgent CXR, noting on the request form the suspicion of a foreign body and requesting a CXR in expiration if the child is old enough to co-operate.

Other radiological findings in foreign body inhalation include air trapping, atelectasis, pneumothorax and lobar pneumonia, although these findings are neither specific nor sensitive.

If the patient has a suggestive history with normal clinical and CXR findings, monitor clinically for further symptoms over the next few days and if they occur, consider the need for further investigation which may include bronchoscopy.

If the patient has suggestive history with abnormal clinical or CXR findings, they need bronchoscopy under general anaesthetic with a plan to proceed to foreign body removal.

Dr Rhiannon Furr is a registrar in paediatric respiratory medicine and Dr Anne Thomson is a consultant in paediatric respiratory medicine. Both are based at the John Radcliffe Hospital, Oxford