Clinical features

When assessing for dehydration, look for ^a

• sunken eyes
• dry axillae
• dry nose or mouth mucous membranes
• longitudinal furrows on the tongue

Why?

Sunken eyes, dry axillae, dry mucous membranes and tongue furrows make dehydration more likely

Patient a	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
suspected hypovolaemia ot due to blood loss (pre-test probability: 15%)	hypovolaemia not due to blood loss (biochemistry)	sunken eyes	3.4 (1.0 to 12)	38%	0.5 (0.3 to 0.7)	8%
		dry axillae	2.8 (1.4 to 5.4)	33%	0.6 (0.4 to 1.0)	10%
		dry mouth and mucous membranes	2.0 (1.0 to 4.0)	26%	0.3 (0.1 to 0.6)	5%
		longitudinal furrows on tongue	2.0 (1.0 to 4.0)	26%	0.3 (0.1 to 0.6)	5

Note:

• The following are not very helpful at diagnosing dehydration ^b
  • postural changes in pulse or blood pressure
  • neurological signs or symptoms (including confusion and slurred speech)