Question

The most common cause of acute cor pulmonale is:

• A. Pneumonia.
• B. Pulmonary thrombo-embolism.
• C. Chronic obstructive pulmonary disease.
• D. Primary spontaneous pneumothorax.

Hint:

Acute onset plus sudden right heart strain should point straight to a large pulmonary embolus.

Answer 1

The Correct Option is B

Cor pulmonale is right heart strain caused by lung disease, and it comes in an acute form and a chronic form, each with a different usual cause.

1. Pneumonia: severe infection can stress the right heart, but it is not the typical trigger for acute cor pulmonale.
2. Pulmonary thrombo-embolism: a large clot suddenly blocks a major pulmonary artery branch, so pulmonary pressure spikes within a very short time. The right ventricle has no time to adapt, dilates rapidly, and can fail, which is exactly why this is the leading cause of the acute form.
3. Chronic obstructive pulmonary disease: COPD does cause cor pulmonale, but through years of hypoxic vasoconstriction and vessel remodeling, which makes it the classic cause of the chronic form, not the acute one.
4. Primary spontaneous pneumothorax: this can occasionally cause sudden cardiorespiratory compromise, especially if tension develops, but it is a far less frequent trigger of acute cor pulmonale than a large embolus.

Because a large pulmonary embolus raises right-sided pressure almost instantly, it is the most common cause of the acute presentation.

Let's summarize:

• Acute cor pulmonale: usually from a large pulmonary embolus.
• Chronic cor pulmonale: usually from long-standing lung disease such as COPD.

So the answer is pulmonary thrombo-embolism.