Issues and Controversies in the Evolution of Oral Rehydration Therapy (ORT)

Abstract

The original studies demonstrating the efficacy of oral glucose-electrolytes solutions in reducing or eliminating the need for intravenous therapy to correct dehydration caused by acute watery diarrheas (AWD) were focused chiefly on cholera patients. Later research adapted the oral therapy (ORT) methodology for treatment of non-cholera AWDs including for pediatric patients. These adaptations included the 2:1 regimen using 2 parts of the original WHO oral rehydration solution (ORS) formulation followed by 1 part additional plain water, and a "low sodium" packet formulation with similar average electrolyte and glucose concentrations when dissolved in the recommended volume of water. The programmatic desire for a single ORS packet formulation has led to controversy over use of the "low sodium" formulations to treat cholera patients. This is the subject of the current review, with the conclusion that use of the low-sodium ORS to treat cholera patients leads to negative sodium balance, leading to hyponatremia and, in severe cases, particularly in pediatric cholera, to seizures and other complications of sodium depletion. Therefore it is recommended that two separate ORS packet formulations be used, one for cholera therapy and the other for non-cholera pediatric AWD.

Keywords: ORS formulations; cholera; hyponatremia; hyponatremic seizures; hyponatremic sequelae; non-cholera acute watery diarrheas (AWDs); oral rehydration solutions (ORS); sodium balance.

Figure 1

Severely dehydrated child in Greentown, Lahore, Pakistan. Note deeply sunken eyes and obtunded appearance. Etiology unknown.

Figure 2

(a) Father pinches abdominal skin as instructed, (b) showing tenting indicating decreased elasticity after withdrawing hand.

Figure 3

Father begins to offer patient oral rehydration solution (ORS) (WHO 90 formulation) to drink.

Figure 4

Patient continues to drink, using hand to keep ORS coming.

Figure 5

Patient now more alert, eyes less sunken at 1 h after starting ORS.

Figure 6

Patient after recovery, with pretreatment appearance on right.

Figure 7

The ultimate goal: another child with acute watery diarrheas (AWD) starting ORS to prevent becoming dehydrated.

Figure 8

Relationship of diarrheal sodium and potassium losses (mEq/L) to stooling rate in 37 cholera patients during a period of maximum diarrhea 12–24 h after admission. At all ages, stool sodium tends to rise and potassium to fall at higher diarrhea rates. The numbers of patients were: 12 (0–4 yrs old), 10 (5–9 yrs), 6 (10–14 yrs), 2 (15–19 yrs), 7 (20 yrs and over). From Lancet, 30 October 1976, p. 957.