The 5-year-old is having a complication called Veno-occlusive Disease, or VOD, as she undergoes stem cell treatment at the Children’s Hospital of Philadelphia.

VOD is when microscopic veins are blocked in the liver; it tends to be a side effect of the very high doses of chemotherapy that are part of a stem cell transplant.

With her cancer in remission, the stem cell treatment is an important step in her recovery, designed to rebuild her cells and rid any cancer hiding in her body, her dad said.

He wrote he’s hopeful doctors will be able to treat the complications because they caught it early: