The hunt for the exact type of hyperinsulinism (HI) that caused Zoë Dueñas’ low blood sugar continues, but that’s not the main concern of Carolyn and Juan, Zoë’s parents. They’re simply thrilled that after their time at the Congenital Hyperinsulinism Center at CHOP, Zoë’s symptoms are gone and it’s a normal childhood full steam ahead.
While most children with HI have low blood sugar in the first few days of life, Zoë’s first six months progressed normally. Born at 7 pounds, 1 ounce, Zoë developed typically, reaching her developmental milestones. At her 6-month pediatrician’s appointment, Zoë had an episode of being disorientated. “She couldn’t focus,” Carolyn says. “She was looking all around. She couldn’t follow the pediatrician’s penlight. The pediatrician sent us to Miami Children’s Hospital immediately.”
In the Emergency Department there, Zoë’s blood sugar came back at 37 — dangerously low. “The nurse practitioner was really on the ball,” Juan says. “She told us, ‘Low glucose with no ketones — it could be HI.’ We’re really grateful to her because Zoë’s case is not typical. It was like Zoë was a time bomb. If the nurse hadn’t recognized it, the ER would have given her fluids and sent us home. Then Zoë could have had a seizure and ended up with brain damage.”
Instead, Zoë was admitted to Miami Children’s, where she had more tests. Her insulin levels were high. She was given glucagon and fluids, more tests, more fluids. Her glucose rose to the 50 to 60 range, then dropped. Carolyn and Juan convinced the doctors to allow Zoë to eat normally and see what happened. Zoë’s blood sugar dropped to the 40s. In the meantime, they had started searching online and watched the HI Center’s video. “I told my wife, ‘I think she may have HI. We’re in denial,’” Juan says.
Atypical disease meets unparalleled expertise
Their Florida endocrinologist, Alejandro Diaz, MD, ordered a rush genetics test, and first tried diazoxide, which failed, and then octreotide, which worked. The genetic result indicated a paternal defect for focal disease. Before long, Zoë and Carolyn were on a medical flight to CHOP, one of the few places in the world to offer an 18F-DOPA PET scan that can pinpoint the area in the pancreas where a focal lesion is located.
Zoë’s flare for the unusual came through again. The PET scan didn’t show clear a focal lesion. “She’s unique in all things,” Juan says. “She presented later. She’s active and eats and sleeps well. Then the inconclusive PET scan. But the low blood sugar numbers don’t lie.”
Given Zoë’s genetics, surgery was still the best option. Juan’s uncle is a doctor in Mexico, and when he heard that CHOP surgeon-in-chief N. Scott Adzick, MD, MMM, would be the surgeon, he told Juan, “Your daughter is in good hands,” Juan says.
Biopsies of areas of the pancreas during surgery did not reveal focal disease or LINE, another type of HI, and looked overall “normal.” Adzick, who has performed more than 450 pancreatectomies — more than any other surgeon — determined the tail of her pancreas looked a little suspicious. He removed it, a total of 15 percent of her pancreas. Juan says, “Even Dr. Adzick told us, ‘This one puzzles me.’”
Post-surgery, Zoë’s numbers stayed steady. She passed a 12-hour fast before being discharged, and 19 days after being admitted, she went home to Florida without any medications. Since then, Zoë has continued to have normal blood sugar without medication or dextrose.
Her parents have tried to think back through Zoë’s first six months to see if there were signs of hypoglycemia they could have missed. Carolyn is a labor and delivery nurse, and her sister is a NICU nurse. Neither noticed anything out of the ordinary. Zoë’s pediatrician has racked his brain, looking for a symptom he missed. Nothing.
“We believe she had a small focal lesion that didn’t show up in the pathology,” says Diva D. De León-Crutchlow, MD, MSCE, director of the HI Center. “We cannot declare her cured, but she went home without any therapies. We don’t have all the answers in her case, but she went home better than when she came in.”
As the most active HI Center in the world, if a team is going to figure out Zoë’s exact type of HI, it will be CHOP’s doctors and researchers.
“We feel so lucky,” Carolyn says. “If we hadn’t been alerted in the ER to look for HI, we wouldn’t have insisted they check for it. We wonder how many other children with Zoë’s form of HI are out there undiagnosed. We also feel lucky we found CHOP. Experience means so much when you’re dealing with unique cases.”