PGIMER MCQs for MD MS Preparations | Hypernatremic dehydration

Hypernatremic dehydration is characterized by 

A. S. Sodium> 150 mmol/L 
B. Signs of dehydration are minimal 
C. ECF volume ↓ed 
D. Rapid correction is required 
E. Shift of water from ECF to ICF

Ans. A. Sodium Na>150meq/L ; (B) Signs of dehydration are minimal; (C) ECF volume is decreased. 

• Hypernatremia is defined as serum Na>150meq/L. Hypenatremic dehydration occurs in condition where there are water deficit and water and salt deficits if water deficits exceeds salt 

deficit. 

• The normal 2:1 ratio of ICF to ECF is also changed but quantitatively a two fold greater 

absolute reduction in ICF volume than ECF. Here the movement of water from ICF to ECF 

space maintains the intravascular volume. This maintains blood pressure and urine output and 

thus less symptomatic initially and the patient potentially becomes more dehydrated before 

seeking medical advice. 

• Treatment is replacement of water deficit, which should be corrected slowly (at least over 48- 

72 hrs.) to avoid the risk of rapid shift of water into brain cells resulting in seizure or permanent 

neurological damage. Plasma Na should be corrected by 0.5 mmol/L /hr and by no more 

than 12 mmol/L/day.