Differential Diagnosis for Morning Cough

The patient presents with a cough that worsens in the mornings and improves during the day, is initiated upon deep breathing, and follows a recent upper respiratory infection (URI). Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Postnasal drip syndrome or chronic cough due to post-viral syndrome: This is a common cause of prolonged cough after a URI, where the cough is worse in the mornings due to the accumulation of secretions overnight and improves as the day progresses.

• Other Likely Diagnoses

  • Asthma: Cough can be a sole symptom of asthma, and it can be exacerbated by deep breathing or cold air, which might explain the worsening with deep breathing.
  • Gastroesophageal reflux disease (GERD): GERD can cause a chronic cough, especially in the mornings, due to the reflux of stomach contents into the esophagus during sleep.
  • Allergic rhinitis: Similar to postnasal drip syndrome, allergic rhinitis can cause chronic cough due to the constant irritation of the nasal passages and subsequent postnasal drip.

• Do Not Miss Diagnoses

  • Pulmonary embolism: Although less likely, a cough that worsens with deep breathing (pleuritic chest pain) could be indicative of a pulmonary embolism, which is a life-threatening condition.
  • Pneumonia or other infections: Despite recent recovery from a URI, it's crucial not to miss a complicating or secondary infection, such as pneumonia, which could present with a prolonged cough.
  • Tuberculosis: A chronic cough, especially if accompanied by other symptoms like weight loss, night sweats, or hemoptysis, necessitates consideration of tuberculosis, particularly in high-risk populations.

• Rare Diagnoses

  • Bronchiectasis: A condition characterized by the irreversible dilation of parts of the airways, leading to chronic cough and sputum production, which could fit the patient's symptoms if other causes are ruled out.
  • Cystic fibrosis: Although more commonly diagnosed in childhood, cystic fibrosis can present in adulthood with chronic cough, among other symptoms, and should be considered in the differential diagnosis of chronic cough of unclear etiology.
  • Interstitial lung disease: A broad category of diseases that affect the interstitium of the lung, potentially causing a chronic cough, although this would typically be accompanied by other symptoms like shortness of breath.