Differential Diagnosis for 80-year-old Male with Respiratory Distress

Single Most Likely Diagnosis

• Heart Failure Exacerbation: Given the patient's past medical history (PMH) of Heart Failure with reduced Ejection Fraction (HFrEF) 35%, the presentation of increased respiratory rate, bilateral pleural effusions, and elevated blood pressure is highly suggestive of an exacerbation of heart failure. The absence of a pulmonary embolism (PE) on CT chest and the presence of these symptoms point towards fluid overload as a cause of respiratory distress.

Other Likely Diagnoses

• Pneumonia: The presence of increased right lung opacities on chest X-ray (CXR) and a slight elevation in white blood cell count (WBC) could indicate a pneumonia, especially in an elderly patient with compromised respiratory status. The absence of fever does not rule out pneumonia, as elderly patients may not always present with typical symptoms.
• Acute Coronary Syndrome (ACS): Although not directly indicated by the provided information, the patient's history of heart failure and the current presentation of tachycardia and hypertension could be related to an ACS, which would need to be ruled out with further testing like troponins.

Do Not Miss Diagnoses

• Tension Pneumothorax: Despite the CXR showing a small right apical pneumothorax, the clinical significance of this finding should not be underestimated. A tension pneumothorax, although less likely given the description, is a life-threatening condition that requires immediate intervention. Clinical correlation with symptoms such as severe respiratory distress and hypotension (not currently present) would be crucial.
• Pulmonary Embolism (PE) with Negative CT: While the CT chest is negative for PE, in a patient with high clinical suspicion (e.g., significant respiratory distress, tachycardia), a negative CT does not completely rule out a PE, especially if the CT was done with a low threshold for detection. However, the clinical presentation and negative CT make this less likely.

Rare Diagnoses

• Lymphangitic Carcinomatosis: This condition, characterized by the spread of cancer to the lymphatic vessels of the lungs, could present with bilateral pleural effusions and respiratory distress. However, it would be less likely without a known history of cancer or other suggestive symptoms.
• Pulmonary Lymphoma: Similar to lymphangitic carcinomatosis, pulmonary lymphoma could present with respiratory symptoms and pleural effusions but would be considered rare and require further diagnostic workup for confirmation.