Diagnosis and Treatment > Signs and Symptoms
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Summary
Hypoglycemia is induced by many causes, especially over-dose of insulin or oral hypoglycemic agents in diabetic subjects. In such a case, hyperinsulinemic hypoglycemia is usually observed. On the other hand, it is important to classify secondary hypoglycemia and hypoinsulinemic hypoglycemia. Liver injury-induced hypoglycemia is one of the causes of hypoinsulinemic hypoglycemia but rarely observed in clinical practice. Herein, we experienced similar 2 cases of non-diabetic hypoinsulinemic hypoglycemia. Both of them were elderly subjects with low body weight. Furthermore, it is likely that hypoinsulinemic hypoglycemia in both subjects was triggered by severe liver injury, at least in part, due to possible limited liver glycogen store. In elderly subjects with low body weight and/or malnutrition, metabolism in the liver is reduced and glycogen accumulation is decreased. Such alteration brings out acute and marked liver injury, which finally leads to the onset of severe hypoglycemia. It is known that not only liver injury but also multiple organ failure could be induced due to extreme emaciation in subjects. It is likely that in elderly subjects with low body weight and/or malnutrition, multiple organ failure including liver failure could be induced due to the similar reason. Therefore, we should be very careful of such subjects in order to avoid the development of multiple organ failure which leads to life-threatening situations. In conclusion, we should keep in mind the possibility of hypoinsulinemic hypoglycemia when we examine severe liver injury, especially in elderly or starving subjects with low body weight and limited liver glycogen stores.
Learning points:
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It is important to classify secondary hypoglycemia and hypoinsulinemic hypoglycemia.
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Liver injury-induced hypoglycemia is one of the causes of hypoinsulinemic hypoglycemia but rarely observed in everyday clinical practice.
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Herein, we reported similar 2 cases of hypoinsulinemic hypoglycemia without diabetes presumably triggered by severe liver injury.
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In both cases, hypoglycemia was improved by glucose infusion, although their liver injury was not improved.
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We should keep in mind the possibility of hypoinsulinemic hypoglycemia when we examine severe liver injury, especially in elderly subjects with low body weight.
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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.
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Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, Melbourne, Victoria, Australia
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Department of Medicine, University of Melbourne, Parkville, Melbourne, Victoria, Australia
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Summary
This paper details the case of a 77-year-old male with refractory hypoglycaemia due to inoperable metastatic pancreatic neuroendocrine tumour (pNET) co-secreting insulin and gastrin. Multiple medical therapies were trialled with limited success, and we describe the complications experienced by our patient. Somatostatin analogues can ameliorate hypoglycaemia and may have tumour-stabilising effects; however, in our case resulted in paradoxical worsening of hypoglycaemia. This rendered our patient hospital dependent for glycaemic support including continuous dextrose infusion. Although this is a reported adverse effect with initiation of therapy, we describe successful initiation of short-acting octreotide as an inpatient followed by commencement of long-acting octreotide. Hypoglycaemic collapse occurred only after dose titration of long-acting octreotide. We outline the pitfalls of somatostatin analogue therapy and the mechanisms that may contribute to worsening hypoglycaemia. This rare side effect cannot be reliably predicted, necessitating close supervision and glucose monitoring during therapy. Our patient achieved disease stabilisation and gradual resolution of hypoglycaemia with peptide receptor radionuclide therapy (PRRT), an emerging therapeutic option for metastatic neuroendocrine tumours with high efficacy and low toxicity. We present a brief but comprehensive discussion of currently available and novel therapies for insulin secreting pNETs.
Learning points
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Hypoglycaemia due to malignant insulin secreting pNET is frequently severe and may be life-threatening despite supportive therapies.
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Octreotide can ameliorate hypoglycaemia, and may have anti-proliferative and tumour-stabilising effects in malignant pNETs that are surgically unresectable.
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Paradoxical worsening of hypoglycaemia may occur with octreotide initiation and dose titration, necessitating close supervision and glucose monitoring.
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PRRT is emerging as a therapeutic option with high efficacy and low toxicity.
