Hypoglycaemia: response to 50% glucose may help diagnose hypoglycaemia.

Clinical bottom line (level 4)

  1. Few patients with altered mental state responded to 50% glucose.
  2. Patients with an altered mental state who responded to 50% glucose were more likely to be hypoglycaemic (LR+43) , and patients who fail to respond were less likely to be hypoglycaemic (LR-0.20) .
  3. A partial response was unhelpful at diagnosing hypoglycaemia.
Hoffman et al: Annals of Emergency Medicine 1992; 21 (1): 20-24
Expires September 2003

The study

Setting: six paramedic units, urban community, USA

340 patients (aged ?, ?% male) with altered mental consciousness, given D50W as part of prehospital treatment
All patients received 50% glucose intravenously.
Non-independent ?blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • serum glucose obtained before administration of 50% glucose, or diagnosis based on clinical findings of emergency physicians
Diagnostic test: response to 50% glucose: complete awakening, partial or questionable response or absence of response

The evidence

pre-test probability of hypoglycaemia: 8.5%, (95% CI: 5.5% to 11%)

diagnostic test hypoglycaemia no hypoglycaemia or unknown LR
(95% CI)		 post-test probability
complete response to 50% glucose 20 5 43
(18 to 110) 		80%
partial response to 50% glucose 4 35 1.2
(0.47 to 3.2) 		10%
no response to 50% glucose 5 271 0.20
(0.089 to 0.44) 		1.8%
total 29 311

Comments

  1. Hypoglycaemia is an uncommon cause of altered mental status.

Citation

  1. Hoffman JR, Schriger DL, Votey SR, et al: The empiric use of hypertonic dextrose in patients with altered mental status: a reappraisal. Annals of Emergency Medicine 1992; 21 (1): 20-24
Contributor: Chris Ball and Clare Wotton, September 1999
Reviewer: Wai-Lam Chan

Clinical Question.
Patient altered mental consciousness
Intervention or Exposure complete recovery following 50% glucose
Outcome hypoglycaemia complete recovery