Often when we think of hypoglycemia, our first thought is diabetes. Often times, we are right. Most people that present to the emergency department with hypoglycemia are diabetics and the derangement in their blood glucose is related to medication mismanagement. However, hypoglycemia can occur for other reasons and we should be able to consider a wider differential diagnosis in a patient when an etiology is unclear.

Hypoglycemia is usually considered a blood glucose below 70 mg/dl, however some patients (mainly diabetics) can have symptoms of hypoglycemia above this level because their bodies are used to higher baseline blood glucose levels. This is important to recognize because relative hypoglycemia may be a sign of another pathology and requires treatment and workup depending on the clinical scenario.

We always start out with a thorough history and physical exam. Special attention should be paid to timing of the hypoglycemia related to meals and when medications are taken. In addition, past medical history, medication lists, social history, daily nutrition, and other concurrent symptoms should be obtained to attempt to find the cause.

The differential diagnosis for hypoglycemia in the non-diabetic patient is extensive but includes medications other than those taken by diabetics (fluoroquinolones, beta blockers, pentamidine, valproic acid, and ethanol among others), renal failure, infection/sepsis, starvation, hypothyroidism, pituitary insufficiency, islet and non-islet cell tumors. This is not an exhaustive list and a more complete list can be found on the Life in the Fast Lane website below as well as a mnemonic to help remember this differential.

As far as evaluation of this patient population, it depends on the clinical scenario. If a cause is identified and the patient is safe to have further evaluation by an endocrinologist or primary care physician as an outpatient, then discharge is appropriate. But, if the hypoglycemia is unpredictable or continues to occur despite treatment, the patient requires inpatient admission. Work-up is directed toward the differential diagnosis discussed above with addition of other testing including insulin levels, c-peptide levels, BHOB, and pro-insulin levels which can be undertaken as an outpatient or by the inpatient team. For further information, some resources/ sources for the information above can be found below.

Resources:

https://lifeinthefastlane.com/resources/hypoglycemia-ddx/

https://www.uptodate.com/contents/hypoglycemia-in-adults-without-diabetes-mellitus-diagnostic-approach?search=hypoglycemia&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1