Sunday, January 9, 2011

Cholera and death

I stressed several times last week that Cholera is a VERY treatable disease and once you have reached a clinic and been diagnosed your prognosis is very good. Yet I have seen several statistics giving data from countries where the cholera death rate in hospitals is ~5% amongst those that are admitted to the hospital. This made me curious about what was actually causing these deaths.

I found an interesting paper from the year 2000 that examined this very question in Bangladesh where Cholera is endemic: Mortality, morbidity, and microbiology of endemic cholera among hospitalized patients in Dhaka, Bangladesh.

The prevalence of Cholera in the area meant that the sample sizes were very large - 174,000 cases over 10 years! In the last year of the study for example 19,100 cholera patients were treated, 887 (4.6%) were admitted, and 33 of the admitted patients died (mortality rate 3.7% of cholera inpatients or 0.14% of all cholera patients). Why did these 33 patients die?

The main finding of our study is that concomitant infection accounted for the majority of deaths in hospitalized patients with cholera cared for in this endemic area. Concomitant infection was the cause of four of every five deaths in cholera patients in this study, and accounted for almost all deaths in children twelve months of age or younger. Although concomitant infection has previously been recognized as contributing to the morbidity and mortality associated with cholera, its role as a leading cause of death has not previously been reported. This finding is in large part due to the success of rehydration therapy programs and the virtual elimination of hypovolemia as a cause of death among hospitalized patients with cholera in this setting. The number of individuals with cholera who die before reaching medical attention in this modern urban area endemic for cholera, however, is not presently known. Two concomitant infections predominated in cholera patients in this study: respiratory infections and enteric coinfections. Mortality was primarily associated with the former.

Concomitant infections are other infections (apart from cholera) which the patients had upon admission.
Hypovolemia is loss of blood volume (due to dehydration in this case) which can be very dangerous.

Figure 2 at the end of the paper is interesting because it shows that ALL of the six cases in 1996 who died of Cholera died within a few hours of entering the hospital - ie they had probably arrived too late to be helped, four of them were noted to be pulseless and unconscious upon arrival.

So the bottom line is very clear. If you arrive at a clinic before you are unconscious and provided you do not have another infection (particularly a respiratory infection) that might be able to take advantage of your weakened state, cholera will not kill you. Cholera deaths are truly a failure of healthcare.

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