Case 32: Not sweet enough
Monday, October 3rd, 2011Author: Dr Ngozi Chukwudi
A 27 year old Asian female with a background of congenital hyperinsulinism presented to A&E after what was thought to be a syncopal episode. Her boyfriend said she had been fit and well, and was walking across the road after lunch at a nearby restaurant when she passed out. He mentioned that prior to lunch her last meal was about 12 hours previously, as she had missed breakfastHer GCS on arrival was 11/15 and her blood glucose (by finger prick test) was 6.5 mmol/l. Over a 2 hour a period, her blood glucose gradually fell to 4.9, at this point IV glucose was given and almost immediately her GCS returned to 15/15. She was discharged the same day, at which time her blood sugar was 8.9.
1. What is congenital hyperinsulinism?
Click to see the answerCongenital hyperinsulinism is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. Congenital forms of hyperinsulinemic hypoglycemia can be transient or persistent, mild or severe, and these result from many genetic mutations. This disease tends to present in infancy with symptoms of jitteriness, lethargy and unresponsiveness, but in the milder adult forms, they may simply have a decreased tolerance for prolonged fasting as in this patient missing her breakfast.
2. What level of glucose is defined as hypoglycaemia?
Click to see the answerFor men, this is defined as a glucose level of 2.8mmol/L (<50mg/dL).
For women - 2.5mmol/L(<45mg/dL), and for children 2.2mmol/L (<40mg/dL).
This patient’s BM was found to be much higher than this, despite her being obtunded. This is a common feature with congenital hyperinsulism patients, and when they are given iv glucose replacement, they need much higher rates of glucose infusion to maintain normal homeostasis.
3. Who needs to be admitted with hypoglycaemia?
Click to see the answerAnyone who has an unexplained reason for their hypoglycaemia will require an admission to hospital.
Any patient who’s hypoglycaemia is secondary to oral hypoglycaemic drugs or after using a long acting insulin will need to be admitted, whether this is due to accidental or deliberate overdose, or whether the drugs were taken with an intended therapeutic benefit as there may be little correlation between dose taken and coma length.
Any child will need admission, as there is little evidence to predict the natural history of hypoglycaemia in this population.
If the hypoglycaemia was due to an identifiable cause and was rapidly reversed, and there is a competant adult at home, then the patient may be considered for discharge.