Hypoglycaemia: clinical features were not very helpful at diagnosing hypoglycaemia.

Clinical bottom line (level 4)

  1. Patients with altered mental conscious who were tachycardic, sweating or have a history of diabetes mellitus were slightly more likely to be hypoglycaemic, but further testing was required.
  2. Likewise patients with none of these were slightly less likely to be hypoglycaemia but further testing was required.
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, who were 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: 9.0%, (95% CI: 5.9% to 12%)

diagnostic test hypoglycaemia no hypoglycaemia or unknown LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
any of tachycardia, sweating or available history of diabetes mellitus 22 134 1.7
(1.3 to 2.1) 		14% 0.45
(0.23 to 0.86) 		4%
total 29 292

  • 7.4% of patients had a complete response to 50% glucose.

Comments

  1. The paramedics who obtained details about the patients medical histories (including diabetes) were also the ones who administered D50W and determined the degree of response to D50W. This unblinded assessment can skew the results, favouring those with a history of diabetes.
  2. Probably easier to measure a fingerprick blood glucose to diagnose hypoglycaemia!

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