UCONN Emergency Medicine Interest Group

Posts Tagged ‘endocrinology’

Pearl/Pitfall: Hypoglycemia

In PEARL/PITFALL on July 25, 2011 at 2:15 PM

Based on two discussions I had with Dr. Nowicki and Dr. Price:

Always check a blood glucose level in patients with altered mental status or neurologic deficits. The clinical presentations of hypoglycemia are protean; Dr. Nowicki told me about a case in which a patient presented with an isolated unilateral CN VII palsy in a patient with no prior neurologic history, which completely resolved after the hypoglycemia was corrected. It is both embarassing to the provider as well as potentially dangerous for the patient for delay in diagnosis of this condition. It is very simple and fast for this to be ruled out as a likely cause of the patient’s symptoms, and the stakes are high. However, there are several things that should be considered as pitfalls here.

First, the blood glucose level at which nondiabetic patients and diabetic patients display symptoms may differ considerably. In one study in NEJM (reference provided below), poorly controlled diabetics first developed symptoms at a mean glucose of 78 mg/dL, while nondiabetics developed symptoms at a mean glucose of 53 mg/dL. The implication is that a so-called “normal” glucose level, which may not be flagged as abnormal by the lab (which has no knowledge of the patient’s history) may actually be hypoglycemic in terms of their body’s altered metabolism.

Second, it is important not to undertreat hypoglycemia. The initial treatment, of course, is IV dextrose; adult patients typically require 0.5-1.0 g/kg D50. Since an amp of D50 has 25 g of dextrose, a single amp of D50 will usually not be sufficient to match this requirement (consider that the “standard” patient is 70 kg; this implies that they will need at minimum 35 g, and up to 70 g of dextrose, which implies they will need at least 2 and potentially 3 amps). Once the patient is able, this initial bolus of dextrose should then be followed by a meal; this provides sustained calories over time (if the patient cannot eat, dextrose infusions may be necessary). Otherwise, the patient may rebound back into hypoglycemia!

References:

Boyle PJ, Schwartz NS, Shah SD, et al. Plasma glucose concentrations at the onset of hypoglycemic symptoms in patients with poorly controlled diabetes and in nondiabetics. N Engl J Med. 1988;318:1487-1492.

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