Treatment of Cholera

Rehydration is essential and must be instituted as soon as possible. Two phases are distinguished. First it is important to replenish what has been lost in the previous hours or days. Then one must compensate the persistent fluid loss (e.g. the amount of fluid that is lost every hour). In mild cholera without vomiting oral rehydration may suffice. In severe forms IV fluids should be administered.

There are several possible compositions of rehydration fluids. Solutions containing salt, sugar, potassium and bicarbonate are recommended. Acetate is also used. Lactate is also good because it is converted in the body to bicarbonate. In cholera it is preferable to use Ringer’s lactate ( = Hartmann’s solution). Normal physiological saline is second choice because it does not correct the acidosis nor does it contain potassium. Severe hypokalaemia may occur, with cardiac arrhythmias, kidney damage, paralytic ileus and significant muscle weakness with reduced or absent tendon reflexes. Dextrose (= glucose) 5 % without electrolytes is not advised as a rehydration fluid. A reminder: 1 gr KCl = 13 mEq KCl.

In severe cholera (fluid loss > 10 % of weight) the missing fluids should be administered quickly, e.g. 6 litres over 4 hours for a patient weighing 60 kg. The first 3 litres may each be administered in 10 minutes (total therefore 30 minutes). After administration of the lost volume, the losses are compensated for further IV and/or PO fluids (faeces volume + urine volume + 500 ml). Vomiting may make oral administration of fluids difficult. Generally a total of 6 to 10 litres per patient is necessary. When patients start to drink and do not vomit anymore, it is best to leave their IV lines in place for a while until one is sure that rehydration will not pose any more problems.

Special cholera beds are useful: they have a central opening to allow the liquid faeces to pass through, and they can be collected in a bucket. This makes it possible to quickly determine the amount of fluid loss. During an epidemic people who can still hold themselves upright can simply sit on a bucket and try to drink as much ORS [oral rehydration solution] as possible. Children quickly develop convulsions and coma. It is important that hypoglycaemia should be considered. For an adult 50 ml of a 50% glucose solution is given IV, for a child 2-4 ml/kg 25% glucose or 10 ml/kg of a 10% glucose solution.

Antibiotics are useful because they reduce the duration and thus the total volume of the diarrhoea. They are not essential, however, and resistance often occurs. Classic V. cholerae is usually sensitive to tetracyclines. The dose of tetracycline is 500 mg x 4 daily PO for 2 to 3 days. Parenteral antibiotics are of no value (the bacteria are not invasive). Alternatives are doxycycline 300 mg once or erythromycin, cotrimoxazole and chloramphenicol. Single-dose ciprofloxacin is also effective. V. cholerae O139 is often resistant to cotrimoxazole (sulphamethoxazole-trimethoprim) but sensitive to tetracyclines. This resistance to cotrimoxazole is determined by a certain genetic element (the SXT [sulphamethoxazole] element). Antiperistaltic drugs such as loperamide may cause accumulation of fluid in the intestinal lumen with unfavourable consequences.

Category: Medical Subject Notes , Microbiology Notes