Diagnosis and Treatment > Signs and Symptoms
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Summary
There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). Histopathologic findings from such patients who underwent partial/total pancreatomy, however, can vary widely from minimal changes to classic nesidioblastosis, making the pathologic diagnosis challenging. PGBH typically presents as postprandial hypoglycemia, as opposed to insulinoma, which presents as fasting hypoglycemia. Herein, we describe an unusual case of a patient with PGBH who initially presented with postprandial hypoglycemia three years after surgery, but later developed fasting hyperinsulinemic hypoglycemia as the disease progressed. Our hypothesis for this phenomenon is that this disease is progressive, and later in its course, the insulin release becomes dissociated from food stimulation and is increased at baseline. Future studies are needed to investigate the prevalence as well as etiology of this progression from postprandial to fasting hypoglycemia.
Learning points:
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There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH).
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Histopathologically, PGBH can vary from minimal changes to nesidioblastosis.
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Although uncommon, patients with PGBH after Roux-en-Y gastric bypass may present with both postprandial and fasting hyperinsulinemic hypoglycemia as disease progresses.
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Our hypothesis for this phenomenon is that the insulin release becomes dissociated from food stimulation and is increased at baseline with disease progression.
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Department of Medicine, Division of Endocrinology and Metabolism, Taipei Veterans General Hospital, Taipei, Taiwan
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Summary
Insulin antibodies (IA) associated with exogenous insulin administration seldom caused hypoglycemia and had different characteristics from insulin autoantibodies (IAA) found in insulin autoimmune syndrome (IAS), which was first described by Dr Hirata in 1970. The characteristic of IAS is the presence of insulin-binding autoantibodies and related fasting or late postprandial hypoglycemia. Here, we report a patient with type 1 diabetes mellitus under insulin glargine and insulin aspart treatment who developed recurrent spontaneous post-absorptive hyperinsulinemic hypoglycemia with the cause probably being insulin antibodies induced by exogenous injected insulin. Examinations of serial sera disclosed a high titre of insulin antibodies (33%, normal <5%), high insulin concentration (111.9 IU/mL) and undetectable C-peptide when hypoglycemia occurred. An oral glucose tolerance test revealed persistent high serum levels of total insulin and undetectable C-peptide. Image studies of the pancreas were unremarkable, which excluded the diagnosis of insulinoma. The patient does not take any of the medications containing sulfhydryl compounds, which had been reported to cause IAS. After administering oral prednisolone for 3 weeks, hypoglycemic episodes markedly improved, and he was discharged smoothly.
Learning points:
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Insulin autoimmune syndrome (IAS) or IAS-like situation should be one of the differential diagnosis in patients with hyperinsulinemic hypoglycemia.
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Although less reported, insulin antibodies (IA) caused by exogenous insulin analog should be considered as the cause of hypoglycemia.
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Patients with suspected insulin autoimmune syndrome (IAS) should be screened for drugs related to autoimmunity to endogenous insulin.
