Table.

Comparison of variables in a seven year old boy with hypernatraemia caused by salt poisoning (case 1) and in a boy aged eight months with dehydration (case 2)

Variable	Case 1			Case 2
Time after admission (hours)	0	24		0	1.8	17	48
Body temperature (°C)	36.8			39.2
Body weight (kg)	20.5	19.6		4.63		5.30	5.01
Change from stable weight (%)	+4.6	0		−7.6		+5.8	0
Plasma concentration:
Sodium (mmol/l)	155	132		156	162	144	139
Bicarbonate (mmol/l)	21	24		12	15	18	23
Urea (mmol/l)	2.0	4.5		10.6	10.9	4.9	4.1
Creatinine (μmol/l)	40	45		57	54	39	42
Urinary concentration:
Osmolality (mmol/kg)				961	1003	480
Sodium (mmol/l)	172	30		152	80	94	36
Creatinine (mmol/l)	2.2	1.8		5.5	6.3	2.0	1.52
Fractional excretion (%):
Water	1.81	2.50		1.04	0.86	1.95	2.76
Sodium	2.01	0.57		1.01	0.42	1.20	0.72
Estimated excretion rate:
Water (ml/kg/day)	84	103		28	12	76	98
Sodium (mmol/kg/day)	14.6	3.1		4.3	1.9	5.7	3.6