Approach to lower airway obstruction (pediatrics): Clinical sciences

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Introduction0:00–0:35

Lower airway obstruction occurs when any part of the airway below the thoracic inlet is blocked or narrowed, resulting in flow limitation and expiratory prolongation.
Clinically, this typically presents with symptoms related to lung overinflation and air trapping, such as wheezing and a prolonged expiratory phase.
Underlying causes of lower airway obstruction can be differentiated by the symptom onset as well as an assessment of triggers.
Now, if your patient presents with a chief concern suggesting lower airway obstruction, first perform an ABCDE assessment to determine if they are unstable or stable.

Unstable patient0:35–1:12

If unstable, stabilize their airway, breathing, and circulation. You might even need to intubate your patient.
Additionally, obtain IV access, and begin continuous vital sign monitoring, including respiratory rate, pulse oximetry, and cardiac monitoring.
Finally, if needed, don’t forget to provide supplemental oxygen. Once you stabilize the patient, obtain a focused history and physical examination.Unstable presentation is typically associated with anaphylaxis.

Anaphylaxis1:12–1:47

In this case, history usually reveals a rapid onset of facial swelling and dyspnea, without a fever. They may also have a known allergy with exposure to a specific food like peanuts or another allergen like insect venom.
Physical exam may reveal hypotension with audible stridor and wheezing. Additionally, you may notice facial edema and a diffuse urticarial rash.
These findings are highly suggestive of anaphylaxis. Now, let’s return to the ABCDE assessment and go over stable patients.

Stable patient1:47–2:32

Again, obtain a focused history and physical exam and check the patient’s pulse oximetry. Patients often report difficulty breathing and may have a cough.
Physical exam findings might include tachypnea and signs of labored breathing, like suprasternal, intercostal, and subcostal retractions, while lung auscultation commonly reveals wheezing.
Finally, in some cases, oxygen saturation might be below 90%. With these findings, you should consider conditions that cause lower airway obstruction.
To start your evaluation, first assess the onset of your patient’s symptoms.If your patient’s symptoms were present from birth, you should consider the possibility of a congenital anomaly.

Congenital anomaly2:32–3:14

History often reveals a hypoechoic pulmonary lesion that was identified on prenatal ultrasound, and affected infants might experience recurrent pulmonary infections.
Physical examination often reveals tachypnea and increased work of breathing starting shortly after birth. These findings are highly suggestive of a congenital anomaly, such as a congenital pulmonary adenomatous malformation or congenital lobar overinflation.
In this case, you may need to order additional imaging to confirm and define the specific lesion.On the other hand, if your patient’s symptoms had an abrupt onset, you should consider foreign body aspiration.

Foreign body aspiration3:14–4:09

Affected children typically have a rapid onset of a cough, and caregivers may describe a witnessed choking event. Physical exam commonly reveals localized wheezing and the unilateral absence of breath sounds.
However, a higher level obstruction may present with stridor. Next, consult the surgical team for a diagnostic and therapeutic bronchoscopy.
If bronchoscopy identifies a foreign body, you can confirm foreign body aspiration.Here’s a high-yield fact! Foreign body aspiration most commonly occurs in the right lung, because the right mainstem bronchus is wider and runs more vertically than the left, making it easier for objects to enter and become trapped.Alright, if your patient’s symptoms had a subacute onset, consider bronchiolitis.

Bronchiolitis4:09–4:52

History typically reveals a patient less than 2 years old, with symptoms of upper respiratory infection, like cough, rhinorrhea, and fever.
In young infants, history might even reveal intermittent apneic episodes. Physical exam reveals diffuse wheezing and crackles.
These findings are highly suggestive of bronchiolitis, which you can usually diagnose clinically. However, if there’s uncertainty about the diagnosis, you can order a chest X-ray, which classically demonstrates hyperinflation and peribronchial thickening in the perihilar region.Now, let’s consider patients whose symptoms had a gradual onset.

Bronchopulmonary Dysplasia4:52–6:06

In this case, you should assess the triggers of your patient’s symptoms to determine the underlying cause. First, let’s discuss premature infants who developed symptoms after treatment for respiratory distress syndrome.
For these patients, you should consider the possibility of bronchopulmonary dysplasia. Affected infants are typically born before 34 weeks of gestation, and have a history of respiratory distress syndrome requiring mechanical ventilation and supplemental oxygen.
On physical examination, you are likely to detect a prolonged expiratory phase and diffuse wheezing, occasionally with crackles and rhonchi.
Your next step is to order a chest x-ray. X-ray results would show hyperinflated lungs with scattered cystic spaces among coarsened, reticular opacities.
In addition, chest x-ray may help determine the severity of bronchopulmonary dysplasia and its complications. Based on these findings, you can diagnose bronchopulmonary dysplasia.
Next, lets look at patient’s whose symptoms are triggered by certain positional changes. In this case you should consider structural abnormalities of the airway, such as tracheobronchomalacia and vascular rings and slings.

Tracheobronchomalacia6:06–7:06

First, let’s discuss tracheobronchomalacia.Tracheobronchomalacia commonly presents in infancy, with a cough and intermittent cyanotic episodes.
Symptoms tend to be worse after bronchodilator use and improve with prone positioning. Meanwhile, physical exam typically reveals a monophonic, central expiratory wheeze, but you may occasionally detect audible biphasic stridor.
With these findings, consider tracheobronchomalacia. Then order a diagnostic bronchoscopy.
If you see dynamic collapse of the tracheobronchial tree, diagnose tracheobronchomalacia.Now, let’s switch our focus to vascular rings and slings.

Vascular Ring/Sling7:06–7:51

These conditions typically present in infancy and are associated with dyspnea, noisy breathing, and difficulty feeding. Keep in mind that symptoms may appear to improve with neck extension and worsen with neck flexion.
If the physical exam reveals a monophonic wheeze, sometimes with biphasic stridor, consider the possibility of a vascular ring or sling.
Then order a barium swallow. If it reveals an anterior indentation of the esophagus, this is highly suggestive of a vascular ring or sling.

GERD7:51–8:21

Now let’s talk about infants for whom symptoms are triggered by feedings. In this case, you should consider gastroesophageal reflux disease, or GERD.
Caregivers typically describe coughing, vomiting, or wheezing after feedings, often with a history of poor weight gain. Physical examination may reveal diffuse wheezing throughout both lung fields.
In this case, you can make a clinical diagnosis of GERD . Next, if your patient’s symptoms appear to be triggered by recurrent infections, you should consider the possibility of chronic lung disease, such as cystic fibrosis and primary ciliary dyskinesia.

Chronic lung disease8:21–8:39

In this case, your next step is to order a chest X-ray. First, let’s discuss patients with cystic fibrosis, or CF.

Cystic fibrosis8:39–9:48

These patients will present with chronic cough, as well as recurrent sinusitis and respiratory infections. Affected children often have poor weight gain and bulky, foul-smelling stools, and may also have a history of pancreatitis or meconium ileus.
Physical exam commonly reveals nasal polyps and digital clubbing, as well as audible crackles and rhonchi. Chest X-ray typically shows bronchiectasis, peribronchial thickening, and mucous plugging with dilated bronchi in a predominantly upper lobe distribution.
These findings should make you consider cystic fibrosis.Next order a sweat chloride test, and consider genetic testing. If the sweat test reveals two positive results, with a sweat chloride of 60 mmol/L or more, and genetic testing demonstrates at least two CF mutations, you can confirm the diagnosis of cystic fibrosis.Now let’s discuss primary ciliary dyskinesia, or PCD.

Primary ciliary dyskinesia9:48–11:10

These patients might have a history of unexplained neonatal respiratory distress, and often report a chronic cough, nasal congestion, and recurrent pansinusitis or otitis media.
Physical exam could reveal middle ear effusions, nasal polyps, and digital clubbing. Some patients with PCD have situs inversus, so don’t be alarmed if you detect heart sounds in the right hemithorax!
Chest X-ray will usually show bronchiectasis, peribronchial wall thickening, as well as middle to lower lobe atelectasis or consolidation.
Radiographs might even reveal situs inversus, with a right-sided cardiac shadow. These findings should make you consider PCD.
To confirm the diagnosis, order either a nasociliary biopsy, genetic testing, or video microscopy. If nasociliary biopsy reveals an ultrastructural ciliary defect, genetic testing detects a mutation in PCD-associated genes, or video microscopy reveals an abnormal ciliary waveform, you can confirm the diagnosis of primary ciliary dyskinesia.Finally, let’s discuss patients whose symptoms have noninfectious triggers, such as environmental factors or exercise.

Asthma11:10–12:20

In this case, consider the possibility of asthma. Patients are typically older than 2 years, and have a dry cough that’s often worse at nighttime.
They might report chest tightness or discomfort as well as exercise intolerance. Symptoms could be triggered by environmental factors such as pollen, smoke, or strong odors, or they could also be triggered by viral respiratory infections.
Physical exam reveals polyphonic wheezing with a prolonged expiratory phase. To confirm your suspicions, have your patient perform spirometry if they’re able.
If the FEV1 is less than 80% of the predicted value, with reversibility after bronchodilator use, you can diagnose asthma.One last clinical pearl!
For children who are unable to complete pulmonary function testing, other tests can be used to support the diagnosis of asthma, such as a measurement of the fraction of exhaled nitric oxide.Alright, as a quick recap… If your patient with lower airway obstruction is unstable and has angioedema, consider anaphylaxis.

Review12:20–13:32

If your patient is stable, first assess the timing of symptom onset. If symptoms were present from birth, consider congenital anomalies like CPAM or CLO.
If symptoms had an abrupt onset, consider foreign body aspiration; and if symptoms had subacute onset in a child under 2 years, along with URI symptoms, consider bronchiolitis.
Next, if there’s gradual symptom onset, assess the triggers. Premature infants treated for RDS most likely have BPD, whereas infants with symptoms related to positional changes may have tracheobronchomalacia or a vascular ring or sling.
If symptoms are related to feedings, suspect GERD; and if symptoms appear with recurrent infections, consider chronic lung diseases like cystic fibrosis or primary ciliary dyskinesia.
Finally, if symptoms have noninfectious triggers like environmental factors
Approach to lower airway obstruction (pediatrics) | Osmosis