Differential Diagnosis

The patient's presentation suggests a complex respiratory condition with a history of heavy smoking. The following differential diagnoses are considered:

• Single most likely diagnosis
  • Chronic Obstructive Pulmonary Disease (COPD) with possible cor pulmonale: The patient's history of heavy smoking, obstructive pattern on pulmonary function tests (FEV1/FVC ratio), and symptoms such as dyspnea, cyanosis, and finger clubbing support this diagnosis. The presence of a loud P2 and right parasternal heave also suggest cor pulmonale, a common complication of COPD.
• Other Likely diagnoses
  • Bronchiectasis: The patient's history of chronic cough, greenish sputum, and obstructive pattern on pulmonary function tests could also suggest bronchiectasis.
  • Acute exacerbation of COPD: The patient's symptoms of difficulty breathing, greenish sputum, and elevated JVP could indicate an acute exacerbation of COPD.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Bronchogenic carcinoma: Although less likely, the patient's history of heavy smoking and symptoms such as cough and dyspnea could also suggest lung cancer.
  • Pulmonary embolism: The patient's symptoms of dyspnea, cyanosis, and elevated JVP could also indicate a pulmonary embolism, which would require immediate attention.
• Rare diagnoses
  • Cystic fibrosis: Although rare in adults, cystic fibrosis could present with similar symptoms, including chronic cough, greenish sputum, and obstructive pattern on pulmonary function tests.
  • Alpha-1 antitrypsin deficiency: This rare genetic disorder could also present with similar symptoms, including COPD and liver disease.