Case history: peanut aspiration

PUBLISHED : Tuesday, 18 September, 2012, 12:00am
UPDATED : Tuesday, 18 September, 2012, 12:18pm

Little Danny Lai was having a rough two weeks. The 23-month-old toddler had diarrhoea, low-grade fever and a persistent cough that would not go away.

The gastric flu he seemed to be suffering was exacerbating his asthma, diagnosed just a few months earlier. His breathing sounded like a little whistle was lodged in his windpipe. Danny (whose name has been changed for patient confidentiality reasons) had difficulty breathing, which was consistent with asthma.

When the symptoms surfaced, his mother took him to the family doctor, who prescribed cough suppressants and bronchodilators. But the symptoms persisted. After two weeks, Danny's mother took him to see a paediatrician at Queen Mary's Hospital. She was concerned about the prolonged diarrhoea and fever, and feared her son might suffer a bad asthma attack.

When the paediatrician examined Danny, he expected to hear the wheezing reverberate through the entire chest area. But the doctor was surprised to hear the wheezing only in a localised area.

Danny's symptoms did not seem to add up. No one condition would explain his symptoms, so the paediatrician had to consider other less common possibilities. Having recently encountered another presentation of localised wheezing in a young child, the paediatrician suspected that this was no asthma attack. He investigated the boy's recent history and asked Mrs Lai if her son might have choked on anything recently.

At first, nothing came to mind. Then she remembered that Danny had a seemingly very minor choking incident two weeks ago during a meal. He was eating a peanut when he sputtered and coughed for a bit but seemed fine after that.

The doctor called on Dr Patrick Chung Ho-yu, associate consultant with the University of Hong Kong's Division of Paediatric Surgery.

Given the history of a choking incident, there was a good chance that Danny's symptoms were caused by an obstruction in his airways. It would explain the localised wheezing. If so, he would need immediate surgical intervention.

Meanwhile, the paediatrician had the boy undergo an X-ray, which showed that his left lung was hyperinflated, or larger than normal. If a foreign object was obstructing his airways, it could act like a ball valve, allowing air to enter the lung but not fully leave it, thereby inflating the lung like a balloon.

Moreover, the enlarged lung had displaced his windpipe a little. In the worst-case scenario, an increasingly enlarged lung could compress his heart and blood vessels, giving rise to circulation problems.

Given that Danny also had diarrhoea, which was not typically related to respiratory conditions, the paediatrician also did a computed tomography (CT) scan, which confirmed that an object was lodged in the boy's left main lung airway.

The team put the boy under general anaesthesia before performing a bronchoscopy on him. Given his size, a special endoscope was used to look down his narrow airways. Chung found a 5cm wad of pasty material wedged in the left airway.

The fragment - likely of a peanut based on Mrs Lai's account of the choking incident - had deteriorated over the two weeks. It was extremely fragile and broke apart under the forceps Chung used to extract it. The surgeon used a special suction tool to suck up the fragments.

Chung also had to use a Fogarty balloon, which is a catheter with a deployable balloon on one end, to help remove the crumbling material. The catheter was slid past the obstruction before the balloon at its tip was inflated to fill the width of Danny's airway. This would then prevent the fragments from falling deeper into his airway as Chung extracted the rest of the material.

Although this technique is typically used to remove obstructions from the bloodstream, Chung successfully applied the same technique to clear Danny's airways. Most of the material was removed after one painstaking hour.

Danny remained in hospital for another three days for chest physiotherapy to help him cough up any remnants of the material, and for clinical observation.

He was also given antibiotics as the presence of a foreign object in his airways could have provided a breeding ground for bacteria, which could potentially lead to pneumonia or lung infection.

A few weeks after his discharge, Danny's check-up showed that his lungs were healthy and clear.

Chung says that the presence of foreign matter in the airways, a condition called aspiration, is relatively uncommon. The hospital sees only about one case a year.

Most healthy adults have a natural cough reflex that will attempt to expel any material that touches the airways. However, the cough reflex might be impaired in the elderly and in children with certain medical conditions such as cerebral palsy.

Young children under three are also at risk because they have a tendency to put objects in their mouth, and they are unable to articulate when something is wrong or when they feel unwell.

Chung says it is important for parents to be vigilant about choking hazards, and for doctors, especially general practitioners who are more likely to be the first line of consultation when symptoms arise, to recognise the risks and potential for foreign object aspiration.

Suspected cases should be referred as a matter of urgency to a specialist who has the necessary equipment to manage the problem. The longer the foreign matter remains in the airways, the greater the potential for harm and complications, and the greater the difficulty of removal.