5.1.1 Triage and admission
Diagnosis of cholera
Individuals presenting with clinical features corresponding to the clinical case definition are considered (and registered) as cholera cases.
Individuals presenting with clinical features not corresponding to this definition (no diarrhoea, bloody diarrhoea, etc.) are referred to the appropriate health facility.
Initial assessment of hydration status
The objective of the clinical evaluation is to determine whether dehydration is present and if so, its severity1
. After this rapid evaluation, patients are placed into one of the following three categories:
– Severe dehydration (including shock)
– Some dehydration
– No dehydration
Hydration status on admission determines the initial treatment (oral or IV, volumes to be administered, etc.).
5.1.2 Elements of therapy
1. The first priority is to correct or prevent dehydration with the appropriate rehydration fluids.
2. Complementary therapies (antibiotic, zinc sulfate) are useful in reducing the duration and severity of diarrhoea but do not replace fluid therapy, which remains indispensable.
3. Cholera is associated with some degree of emesis, anorexia and malabsorption which can all impact on nutritional status, especially in children. Once the patient is capable of oral intake, feeding should resume (usually 3 to 4 hours after starting rehydration).
5.1.3 Fluid therapy
Treatment consists of two phases: a rehydration phase and a maintenance phase.
– The rehydration phase is aimed at correcting the estimated initial fluid deficit over a defined time period.
• Severe dehydration: a volume of Ringer lactate (RL) corresponding to 10% of the patient’s body weight (i.e. 100 ml/kg), is administered by IV route. This corresponds to "Treatment Plan C".
• Some dehydration: the patient receives a volume of oral rehydration solution (ORS) corresponding to 5-9% of their body weight. By convention, 7.5% is used (i.e. 75 ml/kg). This corresponds to "Treatment Plan B".
During the oral or IV rehydration phase, fluid losses will continue due to significant ongoing diarrhoea2 . If these losses are not compensated by an additional volume of ORS or RL, dehydration will persist, even if the volume initially required has been administered.
Once dehydration has been corrected, i.e. when there are no longer signs of dehydration, the patient enters the maintenance phase.
– The maintenance phase is aimed at preventing a relapse of dehydration. It is directed at continuing the systematic oral replacement of ongoing fluid losses as they occur until diarrhoea ceases. This corresponds to "Treatment Plan A".
Patients with no dehydration do not need rehydration by definition, so they begin directly with the maintenance phase (Treatment Plan A) to prevent dehydration. Some of these patients can be treated at home depending on the context and their ability to drink ORS. In these cases, patients and/or attendants must be given clear instructions on treatment administration and the signs requiring medical attention.
5.1.4 Clinical evolution and impact of therapy
The initial treatment protocol prescribed (Treatment Plan C, B, or A) corresponds to the dehydration level at the moment of admission.
– In patients with severe dehydration, treatment should rapidly correct danger signs and progressively reduce signs of dehydration. A favourable clinical evolution allows a reduction in the intensity of treatment: at the end of Plan C, the patient can pass to Plan B (if only signs of some dehydration remain) or even Plan A (if there are no remaining signs of dehydration).
– In patients with some dehydration, treatment should eliminate signs of dehydration. At the end of Plan B, the patient can pass to Plan A.
– In non-dehydrated patients, treatment Plan A should avoid the appearance of signs of dehydration.
However, the initial clinical state can rapidly deteriorate (or not improve) if:
– The volume of fluid prescribed on admission is insufficient: degree of dehydration underestimated or error in calculation.
– The volume is not administered within the correct time frame: rehydration too slow or too fast, interruptions in treatment (empty IV bags or ORS cups).
– On-going fluid losses (continued diarrhoea) are not adequately compensated by additional ORS or RL.
– Frequent vomiting persists: IV therapy may be needed for those who systematically vomit all ORS, even in patients with some dehydration.
If the patient’s state deteriorates during therapy, a change in protocol must be rapidly considered (switching from Plan A to Plan B; from Plan B to Plan C or re-administering a bolus if necessary) without waiting for the completion of a failing therapy.
5.1.5 Patient surveillance
To evaluate the efficacy of treatment, to react when a patient’s condition deteriorates or does not improve, to change treatment plan or make a decision on patient discharge, surveillance is indispensable. Surveillance is based on observation of:
1) Clinical evolution:
– Improvement or the (re-)appearance of signs of dehydration or danger signs.
– Ability to drink ORS (frequency of vomiting, level of consciousness, etc.).
– Appearance of complications (symptomatic hypokalaemia, fluid overload, etc.).
– Patient-specific surveillance (e.g. blood pressure in pregnant women).
– Resumption of food intake after 3-4 hours of admission.
2) Intake (“Ins”, fluid received) and output (“Outs”, diarrhoea and vomiting):
• Count and record the volume (in ml or litres) of RL infused or cups of ORS drunk.
• Verify that fluids are given in the prescribed quantity and time frame (e.g. X litres of RL in 3 hours, X ml of ORS in 4 hours).
• Record the number of stools (so as to be able to replace this lost volume).
• Record the number of emesis (so as to be able to evaluate the capacity to drink and retain ORS).
Surveillance of patient fluid loss has the following objectives:
– Reinforce surveillance in the event of profuse diarrhoea or repeated vomiting (i.e. identify patients whose rehydration therapy will be longer or more complex).
– Determine if fluid replacement compensates the on-going losses (is the patient receiving sufficient, too much or not enough additional fluid to replace losses?) and to adjust therapy if necessary.
– Monitor the evolution of the patient’s illness (the number of stools should decrease over time).
While all cholera patients need regular surveillance, certain patients require closer observation:
– Patients with severe dehydration or hypovolaemic shock until they are stabilized.
– Infants, the elderly, pregnant women, malnourished children, as the risk of complications is higher.
– Patients with co-morbidities.
– Patients receiving oral therapy who have difficulty drinking or who vomit repeatedly, as their condition can rapidly deteriorate.
5.1.6 Complementary therapy
Antibiotics can reduce the volume and duration of diarrhoea and decrease the period of Vibrio shedding3 . They are indicated in patients with some or severe dehydration and should be administered in the first 4 hours.
The choice of antibiotic should be based on drug-resistance patterns from cholera cultures performed early in an outbreak. While awaiting results of drug sensitivity testing, patients can be given doxycycline. If drug sensitivity testing shows doxycycline resistance, these patients do not need to be retreated with a different antibiotic.
In the context of a cholera epidemic, the usual contraindications for certain antibiotics (e.g. doxycycline in children and pregnant women) are relative, particularly in light of their use in single dose. In any cases, follow national recommendations.
In children under 5 years, diarrhoea causes a significant loss of zinc which must be replaced. Zinc sulfate shortens the duration and severity of diarrhoea, and if taken for 10 days, may prevent other diarrheal illnesses for up to 2 to 3 months.
Zinc is indicated for children under 5 years presenting with diarrhoea, regardless of dehydration status.
It can be given when the child is able to tolerate oral intake (usually on the first day).
Children and adults should resume an unrestricted normal diet as soon as possible.
For breast-fed infants, breast-feeding should continue, even during the rehydration phase.
5.1.8 Management of specific populations
In pregnant women, young children, children with severe malnutrition (defined by anthropometric or clinical criteria) or severe anaemia, the case management principles remain the same. However, the clinical assessment and/or treatment protocols may or must be adapted.
5.1.9 Unnecessary treatments
Antispasmodics, antidiarrhoeals, antiemetics, plasma expanders and IV fluid containing only glucose (e.g. 5% glucose) are not indicated in the treatment of cholera and should not be used.
5.1.10 Patient discharge
Patients admitted with severe dehydration can be discharged once the following 3 criteria have been achieved:
– No signs of dehydration.
– 3 or less liquid stools and no vomiting in the last 4 to 6 hours.
– The patient (or the person taking care of her/him) has demonstrated that maintenance therapy can be taken at home without supervision.
Patients admitted with some dehydration can be discharged once the following 3 criteria have been achieved:
– No signs of dehydration.
– No vomiting in the last 4 hours.
– The patient (or the person taking care of him) has demonstrated that maintenance therapy can be taken at home without supervision.
Patients with no dehydration on admission need not remain under observation for 4 to 6 hours and can be discharged within 1 to 2 hours if they are able to drink sufficient ORS after each stool, do not vomit, and are easily able to return if their condition deteriorates.
Dehydration is expressed as a percentage of lost body weight. An absence of signs of dehydration corresponds to a deficit of < 5% of body weight. Clinical signs of “some dehydration” appear when fluid loss is 5-9% of body weight and signs of "severe dehydration" occur when losses equal 10% or more.
The volume of diarrhoea is around 10-15 ml/kg/hour during the first 4-6 hours, diminishing progressively over time as the illness revolves and with effective complementary therapy (antibiotic and zinc).
Antibiotics begin to decrease stool volume within 12-24 hours and can reduce the duration of significant diarrhoea down to 48-72 hours. Stool culture for Vibrio cholerae typically becomes negative over 2-3 days compared to 5-7 days without antibiotics.