In the WHO-reduced osmolarity oral rehydration solution recommended for cholera and other acute watery diarrhoea, the sodium concentration and total osmolarity respectively are:

• A 90 mmol/L and 311 mOsm/L
• B 60 mmol/L and 200 mOsm/L
• C 111 mmol/L and 310 mOsm/L
• D 75 mmol/L and 245 mOsm/L ✓

Explanation

The reduced osmolarity ORS contains sodium 75 mmol/L, chloride 65, potassium 20, citrate 10 and glucose 75, giving a total osmolarity of 245 mOsm/L. It replaced the older full-strength WHO ORS of sodium 90 mmol/L and osmolarity 311 mOsm/L after trials showed less stool output, less vomiting and less need for unscheduled intravenous fluids. The 311 option describes the old formulation, which is the classic distractor here.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.