Approach to a cough (pediatrics): Clinical sciences

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Introduction 0:00–0:32

A cough is a protective airway reflex that clears the airway of mucus or other irritants. This reflex is a common feature of conditions affecting the upper and lower airway, such as infection, inflammation, or airway obstruction.
Depending on its duration, you can classify cough in pediatric patients as acute, chronic, or episodic. Now, if a pediatric patient presents with a cough, first perform an ABCDE assessment to determine if your patient is stable or unstable.

Unstable patient 0:32–1:09

If unstable, stabilize their airway, breathing, and circulation, and consider intubation for apnea or shallow, ineffective respirations.
Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, respiratory rate, and pulse oximetry.
Finally, provide supplemental oxygen, if needed. Let’s move on to stable patients When it comes to stable patients, obtain a focused history and physical examination.

Stable patient 1:09–1:43

History usually reveals a cough, possibly with wheezing and dyspnea. On physical exam, you might notice signs indicating increased work of breathing, like tachypnea, nasal flaring, or retractions.
Additionally, you may hear wheezing, stertor, or stridor. Your next step is to assess the cough’s duration.
First, let’s look at patients with an acute cough, meaning it started no more than 2 weeks ago. Here, assess the onset of the cough.

Acute with Abrupt Onset 1:43–3:06

If it began abruptly, consider foreign body aspiration. Caregivers may have witnessed a choking event, and physical exam could reveal localized wheezing, unilateral absence of breath sounds, and possibly stridor.
Next, get a neck and chest X-ray, which might reveal a foreign body. However, since a lot of them are radiolucent, you should look for indirect signs like atelectasis or air trapping.
If you see any of these, diagnose foreign body aspiration. Here’s a clinical pearl!
The abrupt onset of cough, stridor, and wheezing can also be seen in anaphylaxis. You can differentiate anaphylaxis from foreign body aspiration based on history and exam findings.
Anaphylaxis can occur at any age and is associated with urticaria, facial swelling, bilateral wheezing, and shock. On the flip side, foreign body aspiration is most common in older infants and toddlers and typically causes unilateral wheezing without rash or swelling.
Alright, let’s discuss acute cough with a gradual onset. In this case, consider infection.

Acute with Gradual Onset/URI3:06–3:53

First up is upper respiratory infection, or URI for short. These patients report rhinorrhea; a cough that might be productive; and occasionally, fever, headache, or body aches.
Physical exam usually demonstrates nasal congestion, enlarged nasal turbinates, and possibly facial and sinus tenderness.
With these findings, diagnose URI which encompasses infections involving the respiratory tract from the nose to the trachea, such as nasopharyngitis, also known as the “common cold”.
Now let’s look at croup, which involves the upper and lower respiratory tract. These patients are generally between 6 months and 3 years of age.

Croup 3:53–4:43

Their caregivers usually report low-grade fever and hoarseness, with a barking, seal-like cough that worsens at night. On physical exam, you might find tachypnea with normal oxygen saturation and possibly inspiratory stridor.
Additionally, you may notice signs indicating increased work of breathing, such as suprasternal, intercostal, and subcostal retractions.
With these findings, diagnose croup, also called laryngotracheobronchitis, which is commonly caused by the parainfluenza virus.
Finally, let’s discuss lower respiratory infection. Patients typically report a fever, while physical exam may reveal tachypnea and adventitious breath sounds, like crackles, rhonchi, or wheezing.

Lower Respiratory Infection 4:43–5:36

Your patient may also have a decreased oxygen saturation. With these findings, diagnose lower respiratory infection, which includes bronchiolitis and pneumonia.
Here’s another clinical pearl! You don’t always need imaging to diagnose a lower respiratory infection, but if the diagnosis is unclear, order an X-ray.
The presence of hyperinflation suggests bronchiolitis, while lobar consolidation suggests bacterial pneumonia, and bilateral patchy infiltrates suggest viral pneumonia.
Let’s switch gears and discuss chronic cough, which lasts more than 4 weeks. Your next step here is to assess the cough’s triggers.

Chronic/Positional Changes 5:36–6:44

If a cough is triggered by positional changes, consider structural airway anomalies or airway compression. Patients with structural airway anomalies usually present during infancy with a cough that might be accompanied by intermittent cyanotic episodes.
Symptoms improve while the patient is lying prone and worsen after bronchodilator use. Physical exam reveals monophonic, central expiratory wheezes and occasionally, biphasic stridor.
In this case, consider an airway anomaly and obtain a bronchoscopy. If you notice abnormal airway structure, diagnose structural airway anomaly.
Common examples include tracheomalacia and laryngomalacia, which are structural weaknesses that cause airways to collapse during crying or supine positioning.
As for airway compression, these patients present with dyspnea and cough while lying supine. If the exam reveals lymphadenopathy, consider airway compression from an anterior mediastinal mass; such as thymoma or lymphoma; and obtain a chest X-ray, CT scan, or MRI.

Airway compression 6:44–7:15

A mass in the anterior mediastinum confirms the diagnosis of mediastinal mass. Alright, let’s switch gears and discuss patients whose cough is triggered by recurrent infections.

Recurrent Infections/CF 7:15–9:24

In this case, consider chronic lung diseases like cystic fibrosis and primary ciliary dyskinesia. These patients often report a daily cough that’s described as “wet” or “productive”, and many experience poor weight gain.
Physical exam reveals nasal polyps, digital clubbing, and occasionally, audible rhonchi. At this point, consider cystic fibrosis and obtain a sweat chloride test.
If it’s positive, diagnose cystic fibrosis. Here’s a clinical pearl!
Sometimes the sweat chloride test returns with an intermediate result. In this case, repeat the test, obtain a genetic analysis for mutations of the CFTR gene, and consider obtaining CFTR physiologic testing.
On the other hand, if a sweat chloride test is negative, consider primary ciliary dyskinesia and obtain a nasal nitric oxide measurement if possible.
Alternative and confirmatory testing options include genetic testing and a nasociliary biopsy for transmission electron microscopy or high-speed video microscopy with ciliary beat pattern analysis.
If the nasal nitric oxide measurement is below the reference range, the genetic testing reveals PCD-associated mutations, transmission electron microscopy shows ultrastructural ciliary defects, or the video microscopy demonstrates abnormal ciliary waveform; diagnose primary ciliary dyskinesia.
Here’s a clinical pearl! Persistent bacterial bronchitis is a common cause of chronic wet cough that’s harder to recognize.
You can diagnose this condition in an otherwise healthy child whose chronic cough resolves after antibiotic treatment. Now, let’s discuss patients whose cough is triggered by chronic heart disease.

Congestive Heart Failure 9:24–9:53

In this case, consider congestive heart failure. These patients might have an unrepaired heart defect with a left-to-right shunt, and possibly poor weight gain.
Physical exam demonstrates wheezing, crackles, hepatomegaly, and possibly a heart murmur. These findings suggest congestive heart failure.
Finally, some patients with chronic cough have no identifiable triggers. In this case, consider pertussis.

No Identifiable Trigger 9:53–11:02

History usually reveals an incompletely immunized infant or child with spontaneous, forceful, whooping cough that might be productive, occasionally with post-tussive emesis or apneic episodes.
On physical exam, you’ll often notice decreased oxygen saturation and signs indicating increased work of breathing, like tachypnea, nasal flaring, and retractions.
Next, obtain a nasopharyngeal PCR, and if it’s positive for Bordetella pertussis, diagnose pertussis. Time for another clinical pearl!
Pertussis is rarely diagnosed during the acute or subacute phase, since the classic “whooping cough” appears later in the course of illness.
Even after antibiotic treatment, the cough can linger for weeks or months, which explains its nickname, “the hundred-day cough”.
Switching gears let’s talk about coughs that are episodic in nature, which means they come and go. Here, your next step should be to assess for triggers preceding the cough’s onset.

Episodic cough/Feedings 11:02–11:45

First up are feedings. If oral intake triggers coughing episodes, consider microaspiration, which can be caused by conditions like gastroesophageal reflux and certain types of tracheoesophageal fistula.
History includes coughing, vomiting, or wheezing after feeds; and possibly poor weight gain; while physical exam demonstrates diffuse wheezing.
These findings are highly suggestive of microaspiration. Next, let’s talk about coughs that are triggered by environmental factors.

Environmental/Asthma 11:45–12:29

Here, you should consider asthma or allergic rhinitis. Let’s start with asthma.
Affected children are typically over 2 years of age and have a dry or nighttime cough; chest tightness or discomfort; and possibly exercise intolerance.
If lung auscultation reveals polyphonic wheezes and a prolonged expiratory phase, consider asthma. Then, order spirometry.
If the FEV1 is reduced but improves after bronchodilator use, diagnose asthma. When it comes to allergic rhinitis, affected children are usually over 2 years of age with rhinorrhea and a cough that’s triggered by environmental factors, like animals, dust, or pollen.

Allergic rhinitis 12:29–13:19

The exam reveals nasal congestion, pale and boggy nasal turbinates, and conjunctival injection. These findings should make you consider allergic rhinitis.
Next, encourage allergen avoidance, and if your patient’s symptoms improve, you can make a clinical diagnosis of allergic rhinitis.
Here’s a high-yield fact! Always ask about smoke exposure, since many children exposed to secondhand smoke experience chronic cough and frequent respiratory illnesses.
Finally, if your patient has an episodic cough with no identifiable triggers, consider habit cough. In this case, most patients are school-aged children with a honking cough that disappears during distraction or sleep; and exam findings are unremarkable.

No Identifiable Trigger 13:19–14:03

With these findings, diagnose habit cough. Here’s one last clinical pearl!
Some conditions can cause a cough that’s either acute or chronic, depending on the timeline of the illness. For example, tuberculosis can cause either a subtle cough for weeks or months before diagnosis, or a severe cough early in the course of infection.
Alright, as a quick recap… If a pediatric patient presents with a cough, assess its duration and onset. Abrupt onset of an acute cough should make you consider foreign body aspiration.

Review 14:03–14:52

However, acute cough with a gradual onset suggests infection, such as URI, croup, or a lower respiratory infection. For chronic coughs, think about structural airway anomaly, anterior mediastinal mass, cystic fibrosis, primary ciliary dyskinesia, congestive heart failure, or even pertussis.
When it comes to episodic coughs, consider microaspiration, asthma or allergic rhinitis, or in some patients, habit cough.
Approach to a cough (pediatrics): Video and Steps | Osmosis