Pediatric aspiration syndromes

Table of content

Definition

A spectrum of conditions resulting from inhalation of foreign contents (with respect to the respiratory system) into the airways and lungs. It can be content from inside the body such as vomitus, secretions, or outside such as meconium.

The spectrum varies from asymptomatic conditions to acute life-threatening events,

Conditions Predisposing to Aspiration Lung Injury in Children

Anatomical and mechanical

1. Tracheoesophageal fistula
2. Laryngeal cleft
3. Vascular ring
4. Cleft palate
5. Micrognathia
6. Macroglossia
7. Achalasia
8. Esophageal foreign body
9. Tracheostomy
10. Endotracheal tube
11. Nasoenteric tube
12. Collagen vascular disease (scleroderma, dermatomyositis)
13. Gastroesophageal reflux disease
14. Obesity

Neuromuscular

1. Altered consciousness
2. Immaturity of swallowing/prematurity
3. Dysautonomia
4. Increased intracranial pressure
5. Hydrocephalus
6. Vocal cord paralysis
7. Cerebral palsy
8. Muscular dystrophy
9. Myasthenia gravis
10. Guillain-Barré syndrome
11. Werding-Hoffmann disease
12. Ataxia-telangiectasia
13. Cerebral vascular accident

Miscellaneous

1. Poor oral hygiene
2. Gingivitis
3. Prolonged hospitalization
4. Gastric outlet or intestinal obstruction
5. Poor feeding techniques (bottle propping, overfeeding, inappropriate foods for toddlers)
6. Bronchopulmonary dysplasia
7. Viral infection

Chronic and Recurrent Aspiration

Clinical features

The recurrent aspiration of small quantities of gastric, nasal, or oral contents can lead to several clinical presentations.

These include

1. Recurrent bronchitis or bronchiolitis,
2. Recurrent pneumonia,
3. Persistent telectasis,
4. Chronic wheezing
5. Persistent Cough
6. Apnea in small children, and
7. Choking and gagging while or after eating
8. Laryngospasm.
9. Failure to thrive
10. Irritability and excessive cry
11. Pulmonary fibrosis and bronchiectasis in long-standing aspirations

Pathologic outcomes may include

• o Granulomatis inflammation,
• o Interstitial inflammation,
• o Fibrosis,
• o Lipoid pneumonia,
• o Bronchiolitis obliterans

Lipoid pneumonia may occur after the use of home/folk remedies involving oral or nasal administration of animal or vegetable oils to treat various childhood illnesses.

Investigation plan and diagnosis of recurrent aspirations

Clues from history

• Underlying predisposing factors are frequently clinically apparent but may require specific further evaluation.

• The caregiver should be asked about spitting, vomiting, arching, or epigastric discomfort in an older child. The timing of symptoms in relation to feedings, positional changes, and nocturnal symptoms such as coughing or wheezing can give important clues.

Coughing or gagging may be minimal or absent in a child with a depressed cough or gag reflex.

• Observation of feeding is an essential part of the examination when considering a diagnosis of recurrent aspiration.

• Particular attention should be given to nasopharyngeal reflux, difficulty with sucking or swallowing, and associated coughing and choking.

Physical examination

The oral cavity should be inspected for gross abnormalities and stimulated to assess the gag reflex.

Drooling or excessive accumulation of secretions in the mouth suggests dysphagia.

Lung auscultation may reveal transient crackles or wheezes after feeding, particularly in the dependent lung segments.

Plan of investigation

The diagnosis is challenging because of the lack of highly specific and sensitive tests. 

A plain chest radiograph is the usual initial study for a child suspected of recurrent aspiration.

Chest X-ray

The classic findings of CXR in pediatric aspiration

Segmental or lobar infiltrates localized to dependent areas may be apparent in most cases.

Other findings

The following findings can be seen in isolation or in combination

1. Diffuse infiltrates,
2. Lobar infiltrates,
3. Bronchial wall thickening,
4. Hyperinflation,
5. Even normal-appearing chest x-rays can be seen, the findings can become apparent on CT chest

Barium swallow or esophagogram

Barium studies are useful for anatomic abnormalities such as

1. vascular ring, stricture,
2. Hiatal hernia,
3. Tracheoesophageal fistula.
4. It also yields qualitative information about esophageal motility and, when extended, with the gastric emptying study.

The esophagogram is insensitive and nonspecific for aspiration or gastroesophageal reflux.

Modified barium swallow with videofluoroscopy (VFS)

This is the gold standard for evaluating the swallowing mechanism and provides direct evidence of aspiration in real-time.

This study is preferably done with the assistance of a pediatric feeding specialist and a caregiver to try to simulate the usual feeding technique of the child.

Gastroesophageal “milk” scintiscan

Offers theoretical advantages over a barium swallow in being more physiological and providing a longer window of viewing than the barium esophagogram for detecting aspiration and gastroesophageal reflux.

 This procedure has been relatively insensitive for detecting aspiration.

Salivagram

Useful in assessing aspiration of esophageal contents, although its sensitivity has not been well studied. Used in patients with cerebral palsy and those with excessive salivation and secretions.

Fiberoptic endoscopic evaluation of swallowing

Used effectively in adults and has been reported to be useful in pediatric patients.
The swallowing is observed directly, without radiation exposure.
The endoscope may alter the assessment of function, depending on the level of comfort and cooperation.

CT Thorax

Generally not indicated to establish a diagnosis of aspiration. It may show infiltrates with decreased attenuation suggestive of lipoid pneumonia.

Useful to see the extent of damage with recurrent aspiration, prognosticate, and to see associated pulmonary pathologies.

Tracheobronchial aspirates study

Quantitation of lipid-laden alveolar macrophages from bronchial aspirates has been shown to be a sensitive test for aspiration. Bronchial washings may also be examined for various food substances, including lactose, glucose, food fibers, and milk antigens.

For patients with artificial airways like ET tubes and tracheostomy, the use of an oral dye and visual examination of tracheal secretions is useful.

Treatment

Treatment should be aimed to resolve the underlying medical condition first.

Medical management

Milder cases associated with feeding difficulties or dysphagia can be treated with:

• o Alteration of feeding position,
• o Changing texture of foods to those who have best tolerated on modified barium esophagogram (usually thicker foods),
• o Limiting quantity per feeding.

Nasogastric tube feedings can be utilized temporarily during periods of transient vocal cord dysfunction or other dysphagia.

Post-pyloric feedings may also be helpful, especially if gastroesophageal reflux is present.

Surgical

Fundoplication with gastrostomy or jejunostomy feeding tube reduces the probability of gastroesophageal reflux–induced aspiration, but recurrent pneumonia often persists because of dysphagia and presumed aspiration of upper airway secretions especially in cerebral palsy cases where aspiration is multifactorial.

Aggressive surgical intervention with salivary gland excision, ductal ligation, laryngotracheal separation, or esophagogastric disconnection can be considered in severe, unresponsive cases.

Tracheostomy, although sometimes predisposes to aspiration, it may on other hand, provide overall benefit from improved bronchial hygiene and the ability to suction aspirated material.

Pharmacotherapy

• o Anticholinergics: glycopyrrolate or scopolamine,
• o Botulism toxin.

Poor prognostic factors

•    In hydrocarbon poisoning, if prior lavage is given,
•    Hypoxemia at admission,
•    Need for ventilation,
•    Secondary pneumonia
•    Ventilator-related complications

Aspiration of Gastric contents in children

1. Large volume aspiration of gastric contents usually occurs after vomiting.
2. It is an infrequent complication of general anesthesia, gastroenteritis, and an altered level of consciousness.

Pathophysiologic consequences depend primarily on

• o The pH
• o Volume of the aspirate
• o The amount of particulate material.

Increased clinical severity is noted with volumes greater than approximately 0.8 mL/kg and/or pH < 2.5.

Hypoxemia, hemorrhagic pneumonitis, atelectasis, intravascular fluid shifts, and pulmonary edema all occur rapidly after massive aspiration. WIth acid aspiration, these occur earlier, are more severe, and last longer.

Most clinical changes present within minutes to 1–2 hr after the aspiration event.
In the next 24–48 hr, there is a marked increase in lung parenchymal neutrophil infiltrations, mucosal sloughing, and alveolar consolidation that often correlates with increasing infiltrates on chest radiographs.

Infection after aspirations

1. Infection usually does not have a role in initial lung injury after aspiration of gastric contents.
2. Aspiration impairs pulmonary defenses, predisposing the patient to secondary bacterial pneumonia.
3. In the patient who has shown clinical improvement but then develops clinical worsening, especially with fever and leukocytes, secondary bacterial pneumonia should be suspected

Treatment of gastric aspiration

1. If a patient has had a large volume or highly toxic substance aspiration it is important to perform immediate suctioning of the airway.
2. When immediate suctioning cannot be performed, later suctioning or bronchoscopy is usually of limited therapeutic value. An exception to this is if significant particulate aspiration is suspected.
3. Attempts at acid neutralization are not warranted because acid is rapidly neutralized by the respiratory epithelium.

Patients suspected of large volume or toxic aspiration should

1. Be observed,
2. Have oxygenation measured by oximetry or blood gas analysis,
3. Have a chest radiograph taken, even if asymptomatic.

Asymptomatic patient

If the chest radiograph and oxygen saturation are normal, and the patient remains asymptomatic, home observation, after a period of observation in the hospital is adequate.

No treatment is indicated at that time, but the caregivers should be instructed to bring the child back in for medical attention should respiratory symptoms or fever develop.

Symptomatic patient

1. For those patients who present with or develop abnormal findings during observation, oxygen therapy is given if hypoxemia is present.
2. Endotracheal intubation and mechanical ventilation are often necessary for more severe cases.
3. Bronchodilators may be tried, although they are usually of limited benefit.
4. corticosteroids do not appear to have any benefit unless given nearly simultaneously with the aspiration event; also their use may increase the risk of secondary infection.
5. Prophylactic antibiotics are not indicated, although, in the patient with very limited reserve, early antibiotic coverage may be appropriate.
6. If used, antibiotics should be used that cover anaerobic microbes as well.
7. If the aspiration event occurs in a hospitalized or chronically ill patient, coverage of Pseudomonas and enteric gram-negative organisms should also be considered for HAI.

Prognosis of gastric aspirations

A mortality rate of ≤5% is seen if 3 or fewer lobes are involved.
Unless complications develop, such as infection or barotrauma, most patients will recover in 2–3 wk, although prolonged lung damage may persist, with scarring and bronchiolitis obliterans.

Hydrocarbon Aspiration

1. The most dangerous consequence of acute hydrocarbon ingestion is usually aspiration and resulting pneumonitis.
2. Hydrocarbons with lower surface tensions (gasoline, turpentine, naphthalene) have more potential for aspiration toxicity than heavier mineral or fuel oils.
3. Ingestion of >30 mL (approximate volume of an adult swallow) of hydrocarbon is associated with an increased risk of severe pneumonitis.
4. Clinical findings of chest retractions, grunting, cough, and fever may occur as soon as 30 min after aspiration or may be delayed for several hours.

Diagnosis

1. Lung radiograph changes usually occur within 2–8 hr, peaking in 48–72 hr.
2. Pneumatoceles and pleural effusions may occur.
3. Patients presenting with cough, shortness of breath, or hypoxemia are at high risk for pneumonitis.
4. Persistent pulmonary function abnormalities can be present many years after hydrocarbon aspiration.
   Other organ systems, especially the liver, central nervous system, and heart, may suffer serious injury.
5. Cardiac dysrhythmias may occur and be exacerbated by hypoxia and acid-base or electrolyte disturbances.

Treatment

Gastric emptying is nearly always contraindicated because the risk of aspiration is greater than any systemic toxicity.

1. In Case volumes >30 mL, such as might occur with intentional overdose, may benefit from gastric emptying
2. Treatment is generally supportive with oxygen, fluids, and ventilatory support as necessary. 

Note- The child who has no symptoms and a normal chest radiograph should be observed for 6–8 hr to ensure safe discharge. 

• Certain hydrocarbons have more inherent systemic toxicity. 
• The pneumonic CHAMP refers collectively to these: camphor, halogenated carbons, aromatic hydrocarbons, and those associated with metals and pesticides. 
• The cuffed endotracheal tube can be placed without inducing vomiting, this should be considered, especially in the presence of altered mental status.

Other substances that are particularly toxic and cause significant lung injury when aspirated or inhaled include

1. Baby powder,
2. chlorine,
3. shellac,
4. beryllium, and
5. mercury vapors.

Repeated exposure to low concentrations of these agents can cause chronic lung diseases, such as interstitial pneumonitis and granuloma formation. Corticosteroids may help reduce fibrosis development and improve pulmonary function, although the evidence is limited.

Prevention

• Prevention of aspiration should always be the goal when airway manipulation is necessary for intubation or other invasive procedures.
• Feeding with enteral tubes passed beyond the pylorus and elevating the head of the bed in mechanically ventilated patients have been shown to reduce the incidence of aspiration complications in the intensive care unit.

Author

Ranjith C S. | DNB (Pediatrics), DM (Medical Oncology)

Ranjith has completed Pediatric Residency from Kanchi Kamakoti Childs Trust Hospital and further trained in Medical Oncology from JIPMER

Editor

Ajay Agade | DNB(Pediatrics), FNB(Pediatric Intensive Care), Fellowship in Pediatric pulmonology and LTV

Ajay is a Paediatric Intensivist, currently working in Pediatric Pulmonology & LTV at Great Ormond Street Hospital NHS, London