Hypernatremic dehydration is characterised by –a) Serum sodium > 150 mmol/Lb) Signs of dehydration are minimalc) ECF volume ↓edd) Rapid carrection is requirede) Shift of water from ECF to ICF
High-Yield Explanation
Hypernatremic dehydration
In about 5% of diarrhoea cases (especially if the child has been given fluids with more salt), serum sodium level may be elevated to more than 150 mEq/L. In this patient, the osmotic pressure of ECF is relatively higher. Therefore water comes from inside the cells to the extracellular fluids and therefore partially masks the loss of skin turgor.
The skin may appear soggy, doughy or leathery.
Such patient is in severe hypernatremic dehydration and is underestimated as mild dehydration.
Severe hypernatremia may result in cerebral haemorrhage, thrombosis and subdural effusion. The cerebral injury (due to cerebral cellular dehydration) leads to the permanent neurological deficit, if not corrected timely.
Thus hypernatremic dehydration is more dangerous than hyponatremic dehydration.