ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2014) 34 P276 | DOI: 10.1530/endoabs.34.P276

A pathway to investigate and manage patients complaining of symptoms suggestive of hypoglycaemia post Roux-en-Y gastric bypass surgery

George Tharakan, Harvinder Chahal, Alex Miras, Preeshila Behary, Sanjay Purkayastha, Sherif Hakky, Jo Boyle, Candace Bovril-Taylor, Asta Julnaite, Sarah Allen, Jonathan Cousins, Krishna Moorthy, Ahmed Ahmed & Tricia Tan

Imperial Weight Centre, London, UK.

Bariatric surgery for obesity remains the most effective method to achieve weight loss and improvements in mortality. However, as the number of procedures increases to match the rising burden of obesity, unusual metabolic complications are now coming to the fore. One example of this is postprandial hypoglycaemia (PPH). The incidence of PPH has been reported as <1% although this problem is underreported. A correct diagnosis is essential as the condition can be extremely disabling.

Intervention: At the Imperial Weight Centre, we have established a pathway to investigate patients who complain of hypoglycaemic symptoms. The purpose of these tests is to i) confirm the presence of hypoglycaemia; ii) determine whether this is postprandial or fasting; and iii) guide management. All patients undergo continuous glucose monitoring (CGMS) for 5 days, attend our investigation unit for a mixed meal tolerance test (MMT), followed by a prolonged oral glucose tolerance test (OGTT). If fasting hypoglycaemia is noted on CGMS, a 72 h fast is also performed.

Results: To date, 16 patients have undergone this standardised diagnostic algorithm. The results show that most patients do not develop hypoglycaemia after MTT, but do so after OGTT. None of the patients that had fasting hypoglycaemia on CGMS had a formally proven hypoglycaemia during a 72 h fast.

Impact: This standardised pathway avoids further unnecessary and invasive investigations for pancreatic insulinomas. If the metabolic tests are completely normal, alternative aetiologies should be sought.

Conclusions: Successful management is often accomplished by avoidance of high glycaemic index foods and a small amount of weight increase, to increase insulin resistance. In more resistant cases therapies may include acarbose, diazoxide and octreotide. These measures have avoided the need for invasive surgical interventions (e.g. gastric bypass reversal or pancreatectomies). PPH remains an under-recognised problem and effective management should be delivered through a multidisciplinary clinic.