Cryptogenic

Derivation: Greek
Meaning: "We have no idea what caused this."
Example: "Will's stroke was cryptogenic."

Strokes can be hemorraghic: the doctors found no bleeding in Will's brain.
Strokes can be embolic: they found no detectable blood clot remnants in the affected area of the brain. They found no clots in his extremities or pelvis, where clots form.
Strokes can have other rare causes: every screening for a rare cause has been negative.

But they did find a patent foramen ovale (PFO). This is a hole between the right and left sides of the heart that everyone has in utero. The flap over the hole usually closes at birth because blood pressure on the left side is greater than on the right.

The PFO is the only evidence in support of the embolism theory of Will's stroke. Will's cardiologist recommends that it be closed. The procedure will probably be done in 3 to 6 months, and probably will be done in Utah.

The cardiologist tried to get Will enrolled in a two-year clinical trial of methods to close PFO's. Will was rejected because he cannot give informed consent to participate, and because the trial sponsors will not accept parents' consent.