Friday, December 21, 2007

The Answer is Stroke

A forty year old woman presents with a stroke, but doesn't have the traditional risk factors (smoking, hypertension, or hypercholesterolemia). Instead, she presents with a swollen tender right calf after an 18 hour plane ride. She is currently on oral contraceptives. When you look at her hands, you notice cyanosis and the following finding:

Challenge: What's the cause of the stroke? What's the status of her lungs? What's the physiology of her heart?

Related Questions:
1. What is shown on the image?

This case idea contributed by Alex Penn.
Image is in the public domain.

2 comments:

Future doctor scientist said...

Oral contraceptives cause hypercoagulablilty, predisposing the woman to DVTs especially with stasis from a plane ride. But since this resulted in a stroke and not a PE she must have a ASD or VSD causing the clot to travel to the left heart and lodge in the brain vasculature instead of the lungs.

Not sure what the image is, peripheral edema?

Craig said...

The Answer is Stroke

The classic findings of stasis (the plane ride) and hypercoagulability (the contraception) suggest Virchow’s triad (the third is trauma) and deep vein thrombosis (DVT). This is supported by the swollen, tender right calf. The question is how a DVT or venous thromboembolism causes a stroke (rather than a pulmonary embolism). This is a paradoxical embolism causing a cryptogenic stroke. The embolus crosses from the venous circulation to the arterial circulation through a congenital heart defect; in this case, an atrial septal defect (other congenital heart defects like a PFO or VSD may work too).

The cyanosis and clubbing (seen in the image) suggest Eisenmenger’s syndrome. Normally, in atrial septal defect (ASD), left sided pressures are higher than right sided pressures and some blood is shunted L->R. The pulmonary vasculature is able to accommodate the extra volume by recruiting previously unperfused vessels. However, with increased degree and duration of right heart volume overload, pulmonary hypertension can develop. With severe irreversible pulmonary hypertension, Eisenmenger’s syndrome develops. In this case, right sided pressures exceed those of the left side, and the shunt reverses R->L (allowing the embolus to bypass the pulmonary circulation). The shunting of the deoxygenated blood to the left heart leads to cyanosis and clubbing.

Sources: UpToDate; Wikipedia; Alex Penn.
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good job!