Differential Diagnosis for Cough when Lying Down

• Single Most Likely Diagnosis
  • Gastroesophageal Reflux Disease (GERD): This condition is characterized by the backflow of stomach acid into the esophagus, which can trigger coughing, especially when lying down due to increased pressure on the stomach and relaxation of the lower esophageal sphincter.
• Other Likely Diagnoses
  • Postnasal Drip: Also known as upper airway secretion syndrome, this condition involves the dripping of mucus from the back of the nose down into the throat, which can cause coughing, especially when lying down as gravity facilitates the flow of mucus.
  • Asthma: Asthma can cause coughing that worsens at night or when lying down due to various factors, including increased airway resistance and exposure to allergens like dust mites in bedding.
  • Chronic Bronchitis: This condition, often associated with smoking, involves inflammation of the bronchial tubes, leading to a persistent cough that can be exacerbated by lying down.
• Do Not Miss Diagnoses
  • Heart Failure: Congestive heart failure can lead to pulmonary edema, where fluid accumulates in the lungs, causing a cough that worsens when lying down (orthopnea) due to increased venous return and pulmonary congestion.
  • Pulmonary Embolism: Although less common, a pulmonary embolism can cause sudden onset of cough, which may worsen when lying down due to increased pressure on the lungs and potential for further clot dislodgement.
• Rare Diagnoses
  • Aspiration Pneumonia: This condition occurs when food, liquids, or other materials are inhaled into the lungs, which can happen more easily when lying down, especially in individuals with dysphagia or altered mental status.
  • Laryngopharyngeal Reflux (LPR): A subtype of GERD that affects the larynx and pharynx, causing symptoms like chronic cough, which can be worse when lying down due to acid reflux reaching the upper airways.