Introduction:
Postprandial hyperinsulinemia hypoglycaemia (PHH) after Roux-en-Y gastric bypass is a complex condition, characterized by increased glucose variability including both hyperglycaemic and hypoglycaemic values. PHH seems to be more prevalent than previously suggested and can be easily misdiagnosed and mismanaged by obstetricians and physicians. The diagnosis is dependent on the choice of diagnostic tool, which has not yet been standardized. Oral glucose tolerance test can be risky and Continuous Glucose Monitoring (CGM) as a diagnosing method is controversial due to a lower accuracy for low glycaemic levels. Maintaining an optimal blood glucose level throughout pregnancy is extremely challenging.
Case description:
A 37-year-old primiparous woman with BMI of 35 was admitted at 12 weeks of gestation with recurrent episodes of symptomatic hypoglycaemia despite adequate glucose replacements, orally and intravenously. She had a past medical history of Type 2 diabetes mellitus, hypertension, and hyperlipidaemia with BMI of 40 on multiple medications. She underwent Roux- en-Y gastric bypass surgery 2 years prior to her pregnancy with weight loss of 24kg and was successfully taken off her medications. Her Hba1c was 5.8% and was on regular iron, calcium, vitamin D, zinc, and multivitamin supplements. During her first antenatal visits, she was started on capillary glucose monitoring and was commenced on metformin by her obstetrician.
Her inpatient stay was complicated with recurrent postprandial hypoglycaemias that were treated with high calorie sugar drinks with worsening symptomatic hypoglycaemia followed by hyperglycaemia that led to being treated with subcutaneous short acting insulins. The obstetric physician consult led to the diagnosis of post gastric bypass related hypoglycaemia. Serum insulin and C peptide levels during the hypoglycaemic episode were borderline high. CGM for 2 weeks confirmed PHH with lack of nocturnal hypoglycaemia. She was successfully treated with small frequent complex carbohydrate high protein diet and acarbose, which reduced the frequency of symptomatic hypoglycaemias and peak hyperglycaemias during her pregnancy.
She delivered a healthy baby girl at 38 weeks gestation. The postprandial hypoglycaemias gradually improved postpartum and she was taken off acarbose and continued diet modification.
Summary:
The data existing on clinical course of PHH during pregnancy and treatment experience are limited based on case reports. Medical nutritional therapy is the main stay of management, but if ineffective, medications such as Acarbose, Somatostatin analogs, Diazoxide, nifedipine have been used with limited experience and varying results. Multidisciplinary team with experienced dietician is important prior to planning pregnancies to achieve good outcomes.