Prevalence of dumping after bariatric surgery

Bariatric surgery, especially gastric bypass, has a few complications in the
long term. One of these complications is dumping. A few hours after a meal
patients can get symptoms which can be explained by dumping. Two types of
dumping are described in literature:
Early dumping; based on undigested food which enter directly in the short
bowel. Therefore fluid enters the short bowel from the circulation and patients
develop a hypovolemia. this started within an hour after a meal.
Late dumping; based on an increased insulin and therefore hypoglycemia
(hyperinsulinemic hypoglycemia). Cause of this increase in insulin is probably
due to positive and nagative feedback mecahnisms to the pancreas are changing
after bariatric surgery. The precise mechanism behind these changes are not
fully understood.
The incidence and prevalence of late dumping (or hyperinsulinemic hypoglycemia)
are not known. In literature the prevalence of severe hypoglycemia is estimated
on < 1%. Severe hypoglycemia is defined as hypoglycemia for which treatment in
hospital is necessary. Possibly the prevalence of milde dumping is about 30%.

The gold standard for the diabnose of hyperinsulinemic hypoglycemia is the
Mixed Meal Tolerance Test. A standardised meal of fat, protein and
carbohydrates give better hyperinsulinec respons than the older glucose
tolerance test. on standardised moments blood samples are taken, every 30
minutes after the meal. Sometimes the exact lowest measrurement of glucose can
be missed. Probable a continu glocose monitoring system (CGMS) gives us the
opportunity to see the exact time of dipping in glucose. A disadvantage of the
MMTT is the extensiveness of the test. Probably it is possible with help of the
continuus glucose mointroing system we can develop a more simple test.

To review complaints of dumping Sigstad developped a questionnary. The
diagnostic Ter beoordeling van dumping klachten zijn ook vragenlijsten
ontwikkeld. De Sigstad score is hiervoor de meest gebruikte vragenlijst.
Diagnostische accuracy is never validated in a bigger population of bariatric
patients.

Primary Objective:
Prevalence of hyperinsulinemic hypoglycemia after gastric bypass.

Secondary Objective(s):
Determination of diagnostic acuurace of a dumping questionnary (Bepaling
modified Sigstad score).
Descriptive research to the value of CGMS as a tool in the MMTT.
Determination of the extensiveness a the MMTT can be reduced in a more
practical test.

A cross-sectional study.

Testpersons may not eat from the evening before the test. The whole test takes
5 hours and is performed on the ward for diagnostic blood puncturesof the
Medical Center Leeuwarden.
Testpersons get an intravenous excess and a part of the patients get a
Continuous Glucose Monitoring System in the skin of their abdomen. In total 12
bloodsamples are taken.
Testpersons can get complaints of hypoglycemia, but this is temporarly.