There may be a link between migraines with aura in children and a common heart defect called patent foramen ovale (PFO), says a new study published online in the Journal of Pediatrics this week.

About 15% of children suffer with migraines, and of these, about one third have migraine with aura, where symptoms can include blind spots, weakness and even hallucinations. Although the causes of migraine are unclear, some studies of adults have suggested there could be a link with PFO.

In a fetus, oxygen gets into the blood not from the lungs but from the mother's placenta, and during this time a valve called the foramen ovale allows blood from the left upper chamber or atrium in the heart to flow into the right.

As the fetus develops, a layer of tissue grows to cover the foramen ovale so that when the baby is born, and gets its oxygen via its own lungs, the oxygen-rich blood in the left atrium (ready to go to the rest of the body via arteries) does not mix with oxygen-poor blood in the right atrium (which has just returned from the rest of the body via veins).

But in about 25% of people, the foramen ovale does not close completely, leading to patent foramen ovale or PFO.

PFO is not necessarily dangerous and affects about one in four Americans.

For the study, Dr Rachel McCandless and colleagues from the University of Utah in Salt Lake City in the US, studied 109 children aged from 6 to 18 who were diagnosed with migraines between 2008 and 2009 and were being treated at the Primary Children's Medical Center in Salt Lake City. The Center takes children from Utah and a number of nearby states.

They took two-dimensional echocardiograms of each child's heart to look for a PFO.

They found 50% of the 38 children who had migraines with aura also had a PFO, approximately twice the rate as in the general population.

However, only 27% of the 71 children who had migraine without aura had a PFO, which is similar to the rate in the general population.

A feature of PFO that determines the extent of blood flow from one chamber to the other is called atrial shunt size. The researchers said they found no link between this and the presence or absence of aura.

They concluded that:

"These data suggest that PFO may contribute to the pathogenesis of migraine with aura in children and have implications for clinical decision making."

If further studies prove that PFO does cause migraine, then McCandless and colleagues suggest a possible treatment for migraine, and particularly migraine with aura, could be to close the PFO with a catheter device.

McCandless told the press she hopes that their "study will help guide future research about this difficult problem".

"Patent Foramen Ovale in Children with Migraine Headaches."
Rachel T. McCandless, Cammon B. Arrington, Douglas C. Nielsen, James F. Bale Jr., L.LuAnn Minich.
Journal of Pediatrics, published online 31 March 2011.
DOI 10.1016/j.jpeds.2011.01.062

Additional source: Elsevier Health Sciences (31 Mar 2011).

: Catharine Paddock, PhD