Approach to a cough (acute): Clinical sciences

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Introduction 0:00–0:50

Coughing is a protective physiologic response that facilitates the clearing of excessive secretions and debris from the airways.
The distinction between acute, subacute, and chronic cough is based on duration. An acute cough lasts less than three weeks, while a chronic cough lasts for more than eight weeks, and a subacute cough lies in between.
Most commonly, acute cough is due to an upper respiratory infection. If not, an abnormal chest X-ray is usually seen in pneumonia, bronchiectasis exacerbation, and congestive heart failure, whereas a normal chest X-ray is typically seen in acute bronchitis, pulmonary embolism, asthma exacerbation, and COPD exacerbation.
Okay, if your patient presents with an acute cough, you should first perform an ABCDE assessment to determine whether your patient is unstable or stable.

Unstable patient 0:50–1:41

If they’re unstable, stabilize their airway, breathing, and circulation, which might require intubation and mechanical ventilation.
Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry.
Finally, if needed, don’t forget to provide supplemental oxygen! Now, here’s a clinical pearl!
Even in stable patients, always evaluate patients with an acute cough for features like abnormal vital signs, symptoms of serious diseases like pulmonary embolism or pneumonia, and risk factors for serious diseases like lung cancer, which will require a different approach than patients without these features.
Alright, now that we’ve addressed unstable patients, let’s go back to the ABCDE assessment and discuss stable ones. If your patient is stable, perform a focused history and physical examination.

Stable patient 1:41–2:51

Your patient will report a cough lasting less than three weeks, which might be accompanied by sputum production, chest pain, and shortness of breath.
They can also have a history of tobacco use, as well as known pulmonary conditions like asthma or COPD. Additionally, the physical exam might reveal adventitious breath sounds on lung auscultation such as wheezes or rales.
With these clinical findings, diagnose acute cough! Here’s a high yield fact!
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 one to two weeks after starting the medication, but in some cases, it might occur even after 6 months.
This is likely due to the accumulation of bradykinin and it typically resolves within a few days of stopping the medication!
Once you diagnose acute cough, first, assess for upper respiratory tract infection. Upper respiratory tract infection is one of the most common causes of acute cough that does not require an extensive workup because it’s a clinical diagnosis.

Assess for URTI 2:51–4:03

Your patient typically will report fatigue, runny nose, sore throat, and sneezing, and in some cases facial pain and pressure.
On physical exam, lung auscultation is normal with clear breath sounds; while head and neck exam might reveal local signs of infection like pharyngeal erythema and cobblestoning, tonsillar hypertrophy, and cervical lymphadenopathy.
With these findings, diagnose upper respiratory tract infection! Here’s another clinical pearl!
Pertussis, also known as whooping cough, is an upper respiratory tract infection caused by the bacterial pathogen Bordetella pertussis.
It presents with paroxysmal episodes of severe coughing. However, given widespread vaccination with the DTap vaccine, it is typically seen in children not yet immunized; in immunocompromised states such as pregnancy, HIV, and malignancy; or in developing countries where vaccination is not widely available.
Okay, now if you rule out an isolated upper respiratory tract infection, you should next obtain a chest X-ray! If your patient’s chest X-ray is abnormal, indicating radiographic evidence of airway or lung involvement, then assess for the underlying cause.

CXR 4:03–4:20

Let’s look at what to do when the chest x-ray is abnormal. First up, let’s discuss pneumonia!

Pneumonia 4:20–5:33

Along with an acute cough, your patient will report pleuritic chest pain and shortness of breath. On physical exam, they will appear ill with elevated body temperature, tachypnea, and tachycardia.
Additionally, the pulmonary exam will reveal rales and decreased breath sounds, and they might even have decreased oxygen saturation on pulse oximetry.
Chest X-ray findings will often show an infiltrate or lung consolidation. With these findings, you can confirm the diagnosis of pneumonia!
Here’s a high yield fact! If your patient presents with cough, reported episodes of vomiting, or suspicion for impaired swallowing; don’t forget to include aspiration pneumonia in your differential diagnosis!
This occurs when food, liquid, or stomach contents are inhaled into the respiratory tract. Chest X-ray typically shows an infiltrate in the dependent lung segments.
Risk factors include patients with dysphagia due to a prior stroke, recent anesthesia, excess drug or alcohol use, and immunocompromised disease states!
Now moving on to bronchiectasis exacerbation! These patients report copious phlegm production and physical exam reveals crackles, rhonchi, and inspiratory wheeze on lung auscultation.

Bronchiectasis exacerbation 5:33–6:13

Chest X-ray typically shows tram track opacities. which indicate a dilated airway with thickened walls that run in parallel like a tram track.
At this point, consider bronchiectasis so be sure to order a chest CT! If the chest CT reveals thickened bronchial walls and dilatation of the bronchial lumen, you can confirm the diagnosis of bronchiectasis exacerbation, typically triggered by a respiratory infection.
Okay, now let’s move on to congestive heart failure. Your patient will typically report a cough with pink frothy sputum, dyspnea on exertion, and possibly orthopnea.

Congestive heart failure 6:13–7:45

On the flip side, physical exam commonly reveals tachypnea, an S3 heart sound, and rales. Finally, a chest X-ray shows an enlarged cardiac silhouette and pulmonary vascular congestion.
Now, with these findings. You should consider congestive heart failure.
Order B-type natriuretic peptide, or BNP for short; and a transthoracic echocardiogram, or TTE. BNP will likely be elevated as a response to high ventricular filling pressures, and the TTE findings are usually consistent with ventricular dysfunction, reduced ejection fraction, and structural abnormalities.
These findings all support the diagnosis of congestive heart failure! Here’s a high yield fact!
Tuberculosis is an example of a lower respiratory tract infection that has abnormal chest X-ray findings such as cavitary lesion and hilar lymphadenopathy.
Remember to always screen for tuberculosis risk factors which include being immunocompromised; living in a facility like a nursing home, homeless shelter, or correctional facility; having a family member or close contact with tuberculosis; or spending time in a country with a high prevalence of tuberculosis.
Alright, let’s now discuss patients with normal chest X-rays. Normal chest x-rays indicate no radiographic evidence of underlying airway or lung involvement.

Acute bronchitis 7:45–8:20

So, if your patient’s chest X-ray is normal, your next step is to assess the underlying cause. First, let’s focus on acute bronchitis.
Your patient will report fatigue and shortness of breath; while the physical exam reveals an ill appearing individual with coarse breath sounds that clear with cough, and possibly wheezing on lung auscultation.
With these findings, diagnose acute bronchitis! Next up is pulmonary embolism, or PE for short!

PE 8:20–8:50

History typically reveals dyspnea, pleuritic chest pain, and possibly hemoptysis. On the other hand, physical exam might reveal tachypnea, tachycardia, and low-grade fever.
You might even observe unilateral calf swelling, pain, and erythema. If these findings are present, you should consider PE, so your next step is to obtain a CT angiogram, which if positive for PE, confirms your diagnosis!
Finally, let’s move on to asthma and COPD exacerbations! These patients will report chest tightness, shortness of breath, and sputum production.

Asthma/COPD exacerbation 8:50–10:28

Your patient might also report rhinorrhea and nasal stuffiness, indicating possible exposure to allergic triggers or a viral upper respiratory infection.
They may also have a history of previously diagnosed obstructive lung disease, such as asthma or COPD. On physical exam, your patient will have tachypnea, tachycardia, and wheezing.
Next, perform peak expiratory flow measurement; if it’s reduced, diagnose obstructive lung disease exacerbation. Here’s a clinical pearl!
Treatment for COPD and asthma exacerbation is pretty similar with oxygen, bronchodilators, and systemic steroids. Once the exacerbation has been managed and resolved, you can perform spirometry to assess the FEV1 to FVC ratio to confirm the diagnosis.
If the ratio is reduced, you can diagnose obstructive lung disease. Next, to determine if it’s asthma or COPD, perform bronchodilator reversibility or BDR testing.
This 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% or more after SABA administration, you can make a confident diagnosis of asthma exacerbation.
On the other hand, if there’s no FEV1 improvement, diagnose COPD exacerbation. Alright, as a quick recap… If your patient presents with an acute cough, meaning that it’s present for less than 3 weeks, first, you should rule out an upper respiratory tract infection.

Review 10:28–11:04

If your patient’s presentation is not explained by an upper respiratory tract infection, obtain a chest X-ray. If the chest X-ray is abnormal, assess for the underlying cause including pneumonia, bronchiectasis exacerbation, and congestive heart failure.
On the flip side, if the chest X-ray is normal, the underlying cause is likely acute bronchitis, pulmonary embolism, asthma exacerbation, or COPD exacerbation.