Hypoglycaemia Flashcards
Hypoglycaemia
Hypoglycaemia
Causes
insulinoma - increased ratio of proinsulin to insulin
self-administration of insulin/sulphonylureas
liver failure
Addison’s disease
alcohol
Other possible causes in children
nesidioblastosis - beta cell hyperplasia
Hypoglycaemia Diagnosis: Example Question
A 19-year-old pharmacy student is admitted to hospital after collapsing while at work. She denies biting her tongue or becoming incontinent during the collapse and was groggy but alert on coming around. At the time, a first aider measured her blood glucose to be 1.5 mmol/l. The patients mother reports that the patient has had 2 other episodes of collapse.
The students observations include a blood pressure of 127/77 mmHg, pulse of 81 bpm, and oxygen sats of 97%.
What is the best first-line investigation?
> Glucose, c-peptide and insulin Morning c-peptide Evening c-peptide Computed tomography (CT) scan of the abdomen Oral glucose tolerance test
Measuring blood glucose, insulin and c-peptide allows the differentiation between the causes of hypoglycaemic attacks, including insulinoma, insulin or sulphonylurea misuse.
Hypoglycaemia - Example Question
A 24-year-old nurse presents after collapsing on a night shift. His blood glucose is measured at being 1.4 mmol/l. His blood pressure at the time was noted to be 115/82 mmHg. He has no palpitations and had not bitten his tongue or become incontinent during the episodes. He was shaken afterwards, although did not have memory loss and stated he had not tripped over anything. He also said he has had five of these episodes over the last two weeks.
Blood tests are sent off and unremarkable except for a low-normal C-peptide level and markedly raised insulin level.
Which of the following is the most likely diagnosis of his multiple episodes of collapse?
Sulphonylurea misuse > Insulin misuse Alcohol misuse Retroperitoneal sarcoma Insulinoma
Hyperinsulinaemia in the absence of raised C-peptide points towards the diagnosis of insulin abuse. Elevation of C-peptide, when combined with hyperinsulinaemia suggests sulphonylurea abuse. To rule this out it may be appropriate to assay levels of commonly used sulphonylureas in urine. Insulinomas are a more rare cause of repeated hypoglycaemic episodes.
