Approach to a cough (subacute and chronic): Clinical sciences

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Introduction0:00–0:56

Coughing is a protective physiologic response that facilitates the clearing of secretions and debris from the airways of the lungs.
The distinction between acute, subacute, and chronic cough is based on duration. An acute cough lasts less than three weeks, while a subacute cough lasts for three to eight weeks, and a chronic cough lasts more than eight weeks.
For subacute or chronic coughs, an abnormal chest X-ray is usually seen in atypical pneumonia, bronchiectasis, lung cancer, and interstitial lung disease.
On the flip side, a normal chest X-ray is typically seen in gastroesophageal reflux disease, non-asthmatic eosinophilic bronchitis, upper airway cough syndrome, asthma, and chronic obstructive pulmonary disease.

History & Physical0:56–1:34

Now, if your patient presents with a subacute or chronic cough, first perform a focused history and physical examination.
Your patient will report a cough lasting at least three weeks and perhaps eight weeks or more, which might be accompanied by shortness of breath.
They may also have a history of tobacco use, as well as known pulmonary conditions, like asthma or COPD. Additionally, the physical exam might reveal labored breathing and adventitious breath sounds such as wheezing or rales.
With these clinical findings, diagnose subacute or chronic cough! Here’s a high yield fact!

CXR abnormal1:34–2:06

One of the most common non-disease related causes of cough is ACE inhibitor-induced cough. Individuals who are taking ACE inhibitors for hypertension or heart disease can develop a dry and hacking cough that typically occurs in 1 to 2 weeks after starting the medication; but in some cases, it might occur after 6 months!
This is likely due to the accumulation of bradykinin and it typically resolves within a few days of stopping the medication.
Alright, once you diagnose subacute or chronic cough, your next step is to obtain a chest X-ray! If your patient’s chest X-ray is abnormal, meaning there’s radiographic evidence of airway or lung involvement, your next step is to assess the underlying cause.

CXR2:06–2:24

Atypical pneumonia2:24–3:38

Let's look at all abnormal cases starting with atypical pneumonia! Along with a cough, your patient will typically report fever, chills, sore throat, and possibly headache.
On physical exam, lung auscultation might reveal scattered rales and wheezes; and in some cases, you might even observe a rash!
Finally, the chest X-ray will show bilateral patchy infiltrates, which confirms the diagnosis of atypical pneumonia! Here’s a clinical pearl to keep in mind!
Atypical pneumonia is caused by atypical bacteria, like Mycoplasma, Chlamydia, or Legionella. With these pathogens, clinical manifestations develop gradually, in contrast to typical pneumonia caused by Streptococcus pneumoniae, which is more rapid in onset.
Additionally, you can usually diagnose atypical pneumonia based on history and chest X-ray findings, but you could also consider ordering Chlamydia and Legionella urinary antigens, as well as Mycoplasma cold agglutinin testing to confirm the causative bacteria, to help you guide antibiotic management!

Bronchiectasis3:38–4:31

Now, let’s move on to bronchiectasis! These patients typically report copious sputum production.
On physical exam, lung auscultation typically reveals crackles, rhonchi, and inspiratory wheezes. Chest X-ray usually shows tram-track opacities, which indicate dilated airways with thickened walls that run in parallel like a tram track.
At this point, consider bronchiectasis, and order a chest CT! If the chest CT reveals thickened bronchial walls and dilatation of the bronchial lumen, you can diagnose bronchiectasis!
While bronchiectasis is a chronic condition, your patient may have occasional acute flare-ups, typically triggered by a respiratory infection, which will result in acute cough!
Okay, now let’s discuss lung cancer! In this case, your patient will typically report pleuritic chest pain, unintentional weight loss, and fatigue.

Lung cancer4:31–5:13

In some cases, they might report hemoptysis. Additionally, the physical exam might reveal tachypnea and clubbing of the distal extremities; while the chest X-ray will show a lung nodule or mass, with or without pleural effusion.
At this point, consider lung cancer as a cause of chronic cough, and order a bronchoscopy with a biopsy of the mass or nodule.
If the biopsy reveals malignant cells, you can diagnose lung cancer. Finally, let’s take a look at interstitial lung disease!

Interstitial lung disease5:13–6:54

These patients will report shortness of breath on exertion, while the physical exam will reveal wheezing and diffuse inspiratory crackles on lung auscultation.
You might also see finger clubbing, cyanosis, and low oxygen saturation. The chest X-ray usually reveals reticular or nodular opacities.
Next, order pulmonary function tests, which will show reduced diffusing capacity for carbon monoxide, sometimes in combination with a restrictive pattern on spirometry.
At this point, consider interstitial lung disease, and order a high-resolution chest CT scan. On the chest CT, look for reticular or ground glass opacities, nodules, or honeycombing, which appear as clusters of enlarged air spaces surrounded by thickened and fibrotic walls.
With these findings, you can diagnose interstitial lung disease! And here’s another clinical pearl to keep in mind!
Individuals with congestive heart failure usually present with a productive cough associated with pink frothy sputum. This clinical presentation is typically seen in the setting of acute pulmonary edema, but less commonly, it could occur in chronic or compensated congestive heart failure.
In these patients, a chest X-ray will reveal an enlarged cardiac silhouette, pulmonary vascular congestion, and Kerley B lines that indicate septal thickening from pulmonary edema.
Alright, now that we’ve reviewed patients with abnormal chest X-ray findings, let’s discuss patients with a normal chest X-ray.

CXR Normal6:54–7:15

In a normal chest x-ray, meaning there is no evidence of airway or lung involvement on imaging. In this case, your next step is to assess the underlying cause of the cough.
First, let’s take a look at gastroesophageal reflux disease, or GERD! In this case, history commonly reveals heartburn, as well as acid regurgitation, which can manifest as a sour or bitter taste in the mouth, hoarseness, and throat clearing.

GERD7:15–8:05

The physical exam might reveal epigastric tenderness and wheezing on lung auscultation. You might also note oropharyngeal changes, such as erythema, dental erosions, or halitosis.
With these findings, consider GERD. Start empiric treatment which includes proton pump inhibitors for two weeks.
Next, assess your patient’s response, and if there’s an adequate response, meaning improvement or resolution of cough, you can clinically diagnose GERD!
Okay, moving on to non-asthmatic eosinophilic bronchitis! Along with a chronic cough, these patients may report a history of seasonal allergies or recent allergen exposure.

NAEB8:05–8:53

Additionally, their physical exam will reveal clear lungs with no wheezing or evidence of airflow limitation. At this point, consider non-asthmatic eosinophilic bronchitis...
Then obtain a sputum analysis. If the sputum analysis reveals eosinophils, start your patient on inhaled corticosteroids for two weeks and assess their response.
If your patient shows an adequate response with improvement of their cough, diagnose non-asthmatic eosinophilic bronchitis!
Now, switching gears and moving to upper airway cough syndrome! These patients may describe an abnormal sensation in their throat, commonly described as something “stuck,” and post-nasal drip.

UACS8:53–9:50

History might also reveal rhinorrhea, nasal stuffiness, and sputum production. Additionally, the physical exam usually reveals nasal and posterior pharynx discharge, as well as a cobblestone appearance of the oropharyngeal mucosa due to irritation from post-nasal drip.
At this point, consider upper airway cough syndrome. Then start a trial of an H1 antihistamine and decongestant for two weeks.
After two weeks, assess your patient’s response, and if there’s an adequate response with improvement of their cough, diagnose upper airway cough syndrome.

Asthma vs. COPD9:50–11:03

Finally, let’s discuss asthma and COPD! These patients typically report chest tightness, shortness of breath, and sputum production.
They might also report rhinorrhea and nasal stuffiness, indicating possible exposure to allergic triggers or a recent viral upper respiratory infection.
On physical exam, your patient will have tachypnea, tachycardia, and wheezing. Next, perform spirometry to assess the FEV1 to FVC ratio.
If the ratio is reduced, consider an obstructive lung disease Then perform bronchodilator reversibility, or BDR testing.
BDR testing consists of giving an inhaled dose of a short-acting beta agonist, or SABA, followed by repeat spirometry, paying particular attention to the FEV1.
If BDR testing reveals an improvement in FEV1 of 12 percent or more, diagnose asthma. On the other hand, if there’s no FEV1 improvement, diagnose COPD!
Alright, as a quick recap… If your patient presents with a subacute or chronic cough, first use their clinical presentation and findings from a chest X-ray to determine the underlying cause.

Review11:03–11:44

If the chest X-ray has radiographic evidence of airway or lung involvement, then the cough is either due to atypical pneumonia, bronchiectasis, lung cancer, or interstitial lung disease.
On the flip side, if the chest X-ray has no radiographic evidence of underlying airway or lung involvement, then the cough is due to either GERD, non-asthmatic eosinophilic bronchitis, upper airway cough syndrome,
Approach to a cough (subacute and chronic): Video | Osmosis