Focal Hyperinsulinism: Nathaniel's Story

Nathaniel was born at a local community hospital in Georgia after a full-term healthy pregnancy. His weight at birth was 9 pounds, 12 ounces. But a few hours after birth, Nathaniel began having low blood sugars — down to 20 mg/dL.

He was transferred to a nearby major medical center where he required large amounts of dextrose through an intravenous (IV) catheter to keep his blood sugar normal. Over the next few weeks, the IV dextrose could not be stopped without Nathaniel getting low blood sugar.

At 8 weeks old, Nathaniel was transferred to The Children's Hospital of Philadelphia for further management and treatment of the low blood sugar. 

Diagnosis, medical management and surgery

His diagnosis of hyperinsulinism was made based on three factors:

  • His large glucose requirement
  • An elevated insulin level at the same time as a low blood sugar level
  • A positive response to glucagon (his blood sugar rose from 35 mg/dL to 80 mg/dL.)

Nathaniel was receiving IV infusions of dextrose, octreotide, and glucagon to keep his blood sugar normal. As it became obvious that medications were not helping, the decision was made that Nathaniel would need surgery to remove part of his pancreas.

Before the surgery, more testing was performed:

  • Acute Insulin Response (AIR) testing. The results indicated that he had a focal area of hyperinsulinism in the pancreas.
  • Pancreatic Arterial Stimulation with Venous Sampling (ASVS). This procedure was conducted to locate the focal area in his pancreas. The results indicated that the area of hyperinsulinism was located at the head of the pancreas.

After the testing and blood sampling, Nathaniel required a blood transfusion. He was then ready for surgery.

Samples of Nathaniel's pancreas were taken for frozen section and examined under a microscope during the operation. Pieces from the tail, body, and head of the pancreas were sampled.

Once the surgeon was told that Nathaniel had focal disease, he looked for the abnormal part of the pancreas. He found it and removed it, leaving behind most of the normal pancreas.

Recovery and additional tests after surgery

Nathaniel had a very normal course after surgery. He was in the pediatric intensive care unit for a few days. He developed a fever the day after surgery and was treated with antibiotics for four days. He had no further fevers and no infection was found.

The liver and pancreatic enzymes were elevated after surgery but returned to normal within 14 days. There was a nasogastric tube draining fluid from his stomach and another tube draining fluid from the surgical site. The amount of fluid from each tube became smaller each day and the tubes were taken out after about five days.

Nathaniel was first fed by IV nutrition because he was not able to eat immediately after surgery. He began drinking small amounts four days after the surgery and then proceeded to begin drinking formula.

Nathaniel was unable to drink enough formula at first to keep growing, so he was fed partly by nasogastric tube. His parents learned how to use the tube to feed him. All blood sugars taken after surgery were normal, between 70-120 mg/dL. The surgery had eliminated all the focal hyperinsulinism tissue and Nathaniel was cured.

Going home

On the 15th day after surgery, Nathaniel was discharged from the Hospital. Within a few weeks at home, he was able to eat normal amounts by mouth, and the nasogastric tube was no longer needed.

A blood sample was taken before Nathaniel's surgery from which DNA was extracted. The DNA showed that he had a mutation passed from one of his parents consistent with focal disease. This mutation confirms that he has focal disease and that it is unlikely that Nathaniel's family will have another child with HI.

Originally posted: August 2009


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