Hypoglycaemia (revision 2)
Old revision·03:47, 10 Aug 2024·RegainRomilly
| Hypoglycaemia | |
|---|---|
| Common threshold | Below 3.9 mmol/L (70 mg/dL) |
| Level 2 | Below 3.0 mmol/L (54 mg/dL) |
| Level 3 | Severe: requires assistance |
| Risk with incretin monotherapy | Low |
| Topic infobox · conventions | |
Hypoglycaemia is abnormally low blood glucose. It is classified by level: below 3.9 mmol/L as an alert value, below 3.0 mmol/L as clinically significant, and any episode requiring assistance as severe regardless of the measured value.[1]
Incretin agonists carry a low intrinsic risk because their action on insulin secretion is glucose-dependent: they amplify a response that glucose has initiated rather than initiating one. Below the glucose threshold for triggering, there is nothing to amplify.[2]
Why glucose dependence matters
[edit]The beta cell distinguishes a triggering signal from an amplifying one. Glucose metabolism raises the ATP:ADP ratio, closes potassium channels and admits calcium — the trigger. Incretin signalling raises cAMP, which increases the amount of insulin released per unit of calcium — the amplifier.[2]
Sulfonylureas act on the trigger, closing the potassium channel pharmacologically regardless of glucose, which is why they cause hypoglycaemia. Injected insulin bypasses the beta cell entirely.