Hypoglycemia

Over the years I have seen a number of patients with a chief complaint of low blood glucose and insatiable appetite. If the blood glucose measured in the clinic is normal, I send them home with a new blood glucose meter and instructions to measure their blood glucose whenever they feel it is low. I ask them to return to the clinic the first time they document a blood glucose <70 mg/dL or when they have used up the 10 test strips that are provided with each new meter. It is extremely uncommon for these patients to ever document hypoglycemia.

In the past month I have seen one hospitalized patient admitted with blood glucose of 35 mg/dL and one outpatient who was hypoglycemic at the time of the first clinic visit. Both have been diagnosed with an insulinoma and have been referred for surgery.

I encountered a third patient who presented with a very different scenario. She had long-standing type 2 diabetes and had undergone gastric bypass surgery in 2004. She was very pleased to have shed more than 80 lb after surgery, but over the past year she regained 40 lb pounds because she had episodes of unexplained low blood glucose without any change in her therapy for diabetes. A careful history revealed a pattern of hypoglycemia about 4 or 5 hours after a meal — late post-gastric-surgery dumping syndrome.

This is a well-recognized complication of gastric surgery that is, fortunately, not very common. My reading of the literature suggests that this is usually seen in the first year post-surgery, but it can occur at any time. The treatment that has worked well is acarbose, an alpha-glucosidase inhibitor, taken with the first bite of each meal. It is important to emphasize the need to take the drug exactly as prescribed — not an easy task. I am always amazed at the number of patients who “forget” to take their premeal rapid acting insulin and the absence of symptoms is not a reminder. The patient who forgets first bite acarbose learns very quickly not to forget.

It is not enough to simply prescribe therapy and monitor the patient. I have referred her to the bariatric surgery program where she was initially treated so that the program can make a decision about further evaluation and management. Even if no further intervention is recommended, it is important for the program to keep track of possible early and late complications.

For more information:

Imhof A. Swiss Med Wkly. 2001;131:81-83.
Moreira RO. Obes Surg. 2008;18(12):1618-1621.
Yamada M. J Am Geriatr Soc. 2005;53(2):358-359.