Approach to a cough (acute): Clinical sciences

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.

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. 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. 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. Let’s look at what to do when the chest x-ray is abnormal.

First up, let’s discuss pneumonia! 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!