Hyperinsulinism (HI) occurs in two forms: diffuse and focal. In the diffuse form, all beta cells in the pancreas are affected and overproduce insulin. In the focal form, a single mass of beta cells overproduce insulin. The diffuse form, when not responsive to medical therapy, is treated with a near-total pancreatectomy. In contrast, the focal form can be cured by surgically removing the lesion. Distinguishing between the two forms is very important, because the treatments and outcomes are different. Doctors can distinguish between the two forms using genetic testing and imaging with a specialized PET scan. However, the specialized PET scan is only available in a few centers worldwide, including the Congenital Hyperinsulinism Center at The Children’s Hospital of Philadelphia.

Researchers at CHOP’s HI Center conducted a research study comparing the clinical features, treatments and short-term outcomes of children with HI who underwent pancreatectomies from 2004 to 2012. During this period, 223 children underwent surgery at CHOP: 44 percent with diffuse HI, 51 percent with focal HI and 5 percent with other/undetermined disease.

The study looked for clinical differences between patients with diffuse disease and those with focal HI. Researchers found that children with diffuse HI had heavier birth weights and were born on average one week earlier than those with focal HI. Children with focal HI were less likely to be identified with HI prior to discharge home after birth. They were identified at an older age than those with diffuse HI, and they were also more likely to have seizures. Children with diffuse HI had higher insulin levels and needed more aggressive medical treatment with dextrose and glucagon infusions than those with focal HI.

Children with diffuse HI required on average 98 percent of their pancreas surgically removed, and 40 percent required continued treatment for hypoglycemia after surgery. In contrast, children with focal HI required on average 27 percent of their pancreas surgically removed, and 94 percent of the children required no additional blood sugar treatments after surgery. This study, which was published in November 2013 issue of The Journal of Clinical Endocrinology & Metabolism, showed that there are clinical differences between children with diffuse and focal HI. The correct diagnosis must still be confirmed through genetic testing and imaging studies.