Differential Diagnosis for 78-year-old Male with Shortness of Breath

Single Most Likely Diagnosis

• Pulmonary Embolism (PE): Given the patient's history of COPD and recent onset of shortness of breath, along with the finding of right-sided pleural effusion, PE is a highly plausible diagnosis. The patient's history of coronary artery disease (COD) status post coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) also increases the risk for venous thromboembolism.

Other Likely Diagnoses

• Exacerbation of Chronic Obstructive Pulmonary Disease (COPD): The patient's history of COPD and presentation with shortness of breath could indicate an exacerbation of COPD, potentially triggered by an infection or other factors.
• Congestive Heart Failure (CHF): Given the patient's history of coronary artery disease and the presence of an automated implantable cardioverter-defibrillator (AICD), CHF is a possible diagnosis, especially if there are signs of fluid overload or decreased cardiac function.
• Pneumonia: The patient's symptoms and the finding of a pleural effusion could also suggest pneumonia, which would require prompt antibiotic treatment.

Do Not Miss Diagnoses

• Cardiac Tamponade: Although less likely, cardiac tamponade is a life-threatening condition that could present with shortness of breath and could be related to the patient's AICD or history of cardiac surgery.
• Aortic Dissection: This is a rare but potentially fatal condition that could present with shortness of breath and chest pain, and is more likely in patients with a history of hypertension or aortic disease.
• Pulmonary Edema: Acute pulmonary edema could present with shortness of breath and pleural effusions, and is a critical condition that requires immediate attention.

Rare Diagnoses

• Lymphangitic Carcinomatosis: This rare condition involves metastatic cancer spreading to the lymphatic vessels in the lungs, leading to shortness of breath and pleural effusions.
• Pulmonary Vasculitis: Conditions such as Wegener's granulomatosis or other forms of vasculitis could present with respiratory symptoms and pleural effusions, although these are less common.

Initial Assessment and Plan

1. History and Physical Examination: Detailed history focusing on the onset of shortness of breath, associated symptoms, and review of systems. Physical examination to assess respiratory and cardiac status.
2. Laboratory Tests:
   • Complete Blood Count (CBC)
   • Basic Metabolic Panel (BMP)
   • Troponin
   • D-dimer (if PE is suspected and there are no contraindications)
   • Arterial Blood Gas (ABG)
3. Imaging:
   • Chest X-ray
   • Computed Tomography Pulmonary Angiography (CTPA) if PE is suspected
   • Echocardiogram to assess cardiac function and rule out tamponade
4. Initial Orders:
   • Oxygen therapy as needed
   • Monitoring of vital signs and oxygen saturation
   • Consider empiric antibiotic therapy if pneumonia is suspected
   • Anticoagulation if PE is confirmed, unless contraindicated

This approach aims to rapidly identify and manage life-threatening conditions while also considering other potential causes of the patient's symptoms.