Budd-Chiari syndrome (BCS) is a group of rare conditions in which veins in the liver become blocked. An ultrasound for BCS may show atypical, narrowed, or potentially blocked veins inside the liver.

Groeller, 17, and her mother, Allyson Moulton, 37, from Atlanta, spoke to Newsweek about the life-altering diagnosis of Chiari malformation. "She had a continuous migraine for 48 days," Moulton said.

In most cases, the problem is present at birth (congenital). There are several types of Chiari malformations, but type I is the most common. In type I, the cerebellum bulges through the normal opening ...