Differential Diagnosis for Cough

The differential diagnosis for cough is broad and can be categorized based on the likelihood and potential impact of missing a diagnosis. Here's a structured approach:

• Single Most Likely Diagnosis
  • Upper Respiratory Tract Infection (URTI): This is often the most common cause of cough, especially in the context of a recent viral infection. Justification: URTIs are prevalent, and cough is a hallmark symptom, making it a likely diagnosis in many cases.
• Other Likely Diagnoses
  • Asthma: Chronic cough can be a symptom of asthma, especially if it's associated with wheezing or shortness of breath. Justification: Asthma is common, and cough can be a predominant symptom, especially in cases where wheezing is not prominent.
  • Gastroesophageal Reflux Disease (GERD): GERD can cause cough due to the reflux of stomach contents into the esophagus, irritating the throat. Justification: GERD is a common condition, and its symptoms can include cough, especially after eating or at night.
  • Chronic Obstructive Pulmonary Disease (COPD): COPD can cause a chronic cough, often productive, due to the inflammation and damage in the lungs. Justification: COPD is a significant cause of morbidity and mortality, and cough is a key symptom, especially in smokers or those with a history of exposure to lung irritants.
• Do Not Miss Diagnoses
  • Pneumonia: While not the most common cause of cough, pneumonia is a potentially life-threatening condition that requires prompt diagnosis and treatment. Justification: The severity and potential for rapid progression make pneumonia a "do not miss" diagnosis, even if it's less likely than other causes.
  • Pulmonary Embolism: A cough can be a symptom of a pulmonary embolism, especially if it's sudden in onset and associated with other symptoms like chest pain or shortness of breath. Justification: Pulmonary embolism is a medical emergency with high mortality if not promptly treated, making it crucial not to miss this diagnosis.
  • Lung Cancer: Chronic cough can be an early symptom of lung cancer. Justification: Given the significant implications of a delayed diagnosis, lung cancer must be considered, especially in high-risk individuals like smokers.
• Rare Diagnoses
  • Cystic Fibrosis: This genetic disorder can cause chronic cough due to the production of thick, sticky mucus. Justification: While rare, cystic fibrosis is an important consideration, especially in young patients or those with a family history.
  • Sarcoidosis: This condition can cause cough due to the inflammation of various parts of the body, including the lungs. Justification: Sarcoidosis is less common but can present with cough among other symptoms, making it a rare but potential diagnosis to consider.
  • Tuberculosis (TB): TB can cause a chronic cough, often with other symptoms like weight loss or night sweats. Justification: Although less common in some regions, TB remains a significant global health issue, and its diagnosis requires consideration, especially in high-risk populations or areas with high prevalence.