Download Diarrhea and Dehydration: A Case

Diarrhea and Dehydration: A Case - Based Approach
Pharmacy 456 October 21, 2004
Allison Dekker, BSP, RPh
A dad and his 18 month old son, Joshua, arrive in your pharmacy. Dad tells you they have just been to
Joshua's pediatrician regarding the diarrhea Joshua has been having for the last three days. The
pediatrician recommended "ORS" and suggested Dad pick it up at your pharmacy. Dad is unsure what
this "ORS stuff" is and certainly doesn't know which product to choose or how to use it. He has come to
you for assistance.
Assess Urgency
- undesirable symptom is diarrhea, but the most important issue is the potential for dehydration
- infants and children with diarrhea are at higher risk for the development of dehydration than adults
because they have a greater percentage of body water and smaller body mass
- assess urgency by determining the degree of dehydration
Clinical Signs of Dehydration in Children
• increased thirst
• slightly dry mucous membranes
Mild
potentially serious;
can be treated as
outpatient
Moderate
requires MD
assessment
Severe
medical emergency
requires IV rehydration
• thirst, restlessness, lethargy
• tachycardia, normal blood pressure
• decreased skin turgor, dry mucous membranes, sunken eyes and
fontanelle
• decreased urine output
• lack of tears
the above signs and:
• looks sick, circulatory collapse, cold extremities
decreased skin turgor, very dry mucous membranes
• no urine output
• apathy, somnolence
• shock, acidosis, death
- the most accurate way of assessing dehydration is to determine the amount of weight the child has lost
mild dehydration: < 5% weight loss
moderate dehydration: > or = 5 but < 10% weight loss
severe dehydration: > or = 10% weight loss
Joshua did weigh 11 kg. Now he weighs 10.5 kg
(11 kg - 10.5 kg) ÷ 11 kg x 100 = 4.5
Joshua has lost 4.5% of his body weight. He is mildly dehydrated.
Causes of Diarrhea in Children
a) infectious
i) viruses
- 70 - 80% of cases
- rotavirus (most common ~ 50%), adenovirus, astrovirus, torovirus, Norwalk
ii) bacteria
- 10 - 20% of cases
- commonly presents with a high fever; may have bloody stools
- Clostridium difficile, Escherichia coli, Salmonella sp., Campylobacter sp., Shigella sp.,
Yersinia
iii) parasites
- <10% of cases
- Giardia lamblia, Cryptosporidium parvum, Entamoeba histolytica
b) non-infectious
- dietary
- drugs (laxatives, magnesium-containing antacids, antibiotics)
- diseases (IBD, malabsorption, bowel surgery)
Joshua hasn't been to daycare nor has he traveled. Dad did not note a high fever or bloody stools.
Joshua has not received any drugs recently. He likely has an infectious diarrhea caused by a virus.
Mechanisms for normal water absorption
- passive absorption of water occurs through paracellular channels; small molecules such as electrolytes
are dissolved in the water and move with it.
- active absorption of sodium occurs via the glucose - sodium co-transporter, a protein found in the brush
border. Glucose is carried into the enterocyte by the transporter against a very high concentration
gradient. Each molecule of glucose can take a molecule of sodium with it. A high osmotic gradient is
created and there is passive absorption of water and chloride by osmosis.
**The amount of fluid absorbed depends on: sodium and carbohydrate (glucose) concentrations of
ingested fluids and osmolality of the luminal contents.
What happens in infectious diarrhea?
- patchy damage to brush border results in impaired digestion and absorption with fewer glucose-sodium
co-transporters.
fewer co-transporters = decreasedsodium/glucose absorption = decreasedwater absorption
- increased osmolality of intestinal contents causes more water to move into the gut lumen from the blood
- disaccharidases (located in the brush border and break down lactose) may become temporarily
deficient and a transient lactose intolerance may result.
- increased gut motility
Rationale for ORS (oral rehydration solution)
- there are fewer co-transporters available; however, those remaining can be used to effectively
rehydrate a child
- the basic elements of fluid therapy are: rehydration, replacement of losses, and provision of
maintenance fluid requirements
Oral Rehydration Solutions (ORS)
Product
CHO (g/L)
Na
(mmol/L)
K (mmol/L)
Cl
(mmol/L)
Base
(mmol/L)
Glucose:
Na
Rehydration
•
WHO
20
90
20
80
30
1.2
•
Lytren
25
75
20
65
30
20 - 25
75 - 90
20
Ideal
Maintenance*
•
Lytren
20
50
25
45
30 (citrate) 2.2
•
Gastrolyte
20
60
20
60
30 (citrate) 1.8
•
Pedialyte
25
45
20
35
30 (citrate) 3.1
•
Pharmascience 20 - 25
45
20
35
30 (citrate) 2.8 - 3.1
brand
•
Ideal
20 - 25
45 - 60
20
< or = 2
Sports Drinks
•
Gatorade
46 + 18
23
3
17
3
11.1
•
Powerade
40 + 40
5
4
•
All Sport
87
10
5
Home Remedy
•
apple juice
120
3.5
28
30
0
•
cola
70 - 120
3
0.01
2
3
•
ginger ale
90
3
1
2
4
•
tea
0
0
5
0
0
•
chicken broth
0
250
8
250
0
* Gastrolyte and Pedialyte are available in pharmacies. Lytren is available in hospitals only.
Osmolality
310
250
290
330
700
550
540
5
450
Available ORS products
Prioritization Criteria
Efficacy
Time to Effect
ADR
Contraindications
Convenience
• accurate mixing
required
• requires safe water
supply
• portable
• stability
• flavours
Drug Interactions
Cost
Pedialyte®
similar
similar
none
none
Gastrolyte®
similar
similar
yes, if improperly mixed
PKU (contains aspartame)
no
yes
no
yes
no (heavy)
48 hr once opened (fridge)
liquid: plain, fruit, grape, bubble
gum, apple, cherry
freezer pops: grape, cherry,
orange, blue raspberry
none known
$10.49 (1L brand)
$8.49 (1L generic)
$13.99 (4 x 200 mL “singles”)
$2.79 (237 mL generic)
$10.49 (16 x 62.5 mL freezer
pops)
yes
24 hr once mixed (fridge)
plain, fruit
none known
$12.49 (10 pkt/ 200 mL ea.)
covered by Ontario Drug Benefits
most covered by Ontario Drug
Benefits (not freezer pops)
Administration of ORS
For rehydration
1. If you know how much weight the child has lost: 1g body weight lost = 1mL water
example: if the child has lost 500g = 500mL water to replace over 4 hours
(125mL per hour)
2. If you only know the child’s usual weight:
a. weight x estimated % dehydration = estimated kg lost
example: 11kg child estimated to be 5% dehydrated
11kg x 0.05 = 0.55kg = 550g = 550mL to replace over 4 hours
(138mL per hour)
b. Canadian Paediatric Society recommendations for mild dehydration:
(www.cps.ca/english/statements/N/n94-03.htm)
Give 20mL/kg usual body weight for first hour, then 10mL/kg/h for next 6-8 hours.
example: for an 11kg child
20mL x 11kg = 220mL over 1 hour, then
10mL x 11kg = 110mL/h for next 6-8 hours
c. American Academy of Pediatrics recommendations for mild dehydration:
(www.aap.org/policy/gastro.htm)
During a 4 hour period, give 50mL/kg usual body weight + replacement of losses
For replacement of losses: 10mL/kg body weight/stool
2mL/kg body weight/emesis
example: for an 11kg child
50mL x 11kg = 550mL over 4 hours = 138mL per hour
+ 10mL x 11kg = 110mL per watery stool
3. If the child’s weight is unknown:
Canadian Paediatric Society and Hospital for Sick Children recommendations based on the child’s
age:
For the first 6 hours:
< 6mo
6 – 24mo
> 2 years
30 – 90mL every hour (CPS)
60 – 90mL every hour (HSC)
90 – 125mL every hour
125 – 250mL every hour
B. For maintenance fluids (after rehydration is complete)
a. Replace losses from diarrhea using ORS (see calculation above) if diarrhea
continues. Give electrolyte solution as dictated by thirst (child may refuse to
drink it once dehydration has resolved).
b. Calculate maintenance requirement for 24 hours:
100mL/kg for 1st 10kg body weight
50mL/kg for 2nd 10kg body weight
20mL/kg thereafter
example: for an 11kg child
100mL x 10kg = 1000mL
50mL x 1kg = 50mL
1000mL + 50mL = 1050mL per day (44mL/h)
DRP #2: Joshua is dehydrated and requires rehydration. He will also require maintenance
hydration while he continues to have diarrhea.
Clinical Outcome: correct dehydration; maintain hydration
Pharmacotherapeutic Outcome: ensure Joshua receives appropriate ORS
Pharmacotherapeutic Endpoints: increase weight to 11 kg in 4 hours (range = 4 - 6 hr).
Assessment: consider products above
Therapeutic Plan: Since products are basically equal, discuss with Dad and determine his preference
Dad chooses Pedialyte because he doesn’t need to prepare it. Joshua is picky but will take fruit flavoured
medicines. Dad isn’t walking so the bulkiness isn’t a problem. Dad expresses concern that he may not
be able to afford the more expensive product because the family is receiving family benefits. You check
your ODB formulary, realize it can be covered, and call the paediatrician for a prescription by phone.
Monitoring Plan
- increase weight to 11 kg in 4 hours
- no thirst in 4 hours
- diarrhea resolved in 48 hours
Implementation Plan
- give a verbal and written treatment plan re: mixing instructions (if any), how much to give, how to store,
and what to monitor (see signs of dehydration)
ORS should be given slowly; the hourly volume required should be divided into q 5 min. doses
over the hour. This volume can be increased (given less often over the hour) as the child
tolerates it. An oral syringe or medicine cup should be used. The solution does not taste great,
but it should not be diluted with a flavoured drink to make it more acceptable. Younger children
may not be as taste discriminating as older children. Water may also be given for thirst.
- follow up at the end of the rehydration period (4-6 hours) to ensure endpoints are met
- if the solution was not tolerated, the doctor should be contacted for reassessment
- if the child is vomiting, ORS may still be given at frequent intervals
Feeding a child with diarrhea
- breastfeeding should continue (including throughout the rehydration period)
- for older children, resume feeding after rehydration period is complete (not more than 6 hours); early
refeeding may actually shorten the duration of the diarrhea
- good foods: starchy foods, cereals, lean meats, fruits and vegetables
- foods to avoid: high fat or high sugar foods, spicy foods
OTC Medications and Childhood Diarrhea
- many parents want to use something for the diarrhea
- discourage use of these products in children
- a brief summary of the commonly used products follows:
Drug
activated attapulgite
(Kaopectate®)
Action
alters stool consistency
Efficacy
• unproven
• stool may be better
formed and easier to
clean up
• may adsorb toxins and
water, but volume of
loss is the same
ADR's
loperamide
(Imodium®,
generics)
antimotility
• increases intestinal
transit time; diminishes
cramping
- decreases stool
volume
• inhibits the protective effect of
diarrhea, therefore, is contrary to
basic diarrhea management
• may worsen bacterial diarrhea
• toxic megacolon
• not recommended for childhood
diarrhea
bismuth
subsalicylate
(Pepto - Bismol ®)
unclear
anti-inflammatory salicylate
antimicrobial - bismuth
• useful in traveller's
diarrhea; not for
childhood diarrhea
• gastrointestinal bleeding
• black tongue, black stools
• allergic reactions
• salicylate toxicity, concerns of
Reye's syndrome
inhibits intestinal
secretion
• possible Na+, K+ imbalances
• adsorption of nutrients, enzymes,
antibiotics