patient with diarrhea
Diarrhea- Excessive loss of fluid & electrolyte in the stool.

  • Passage of 3 or more loose or watery stool in a 24 hour period.
  • Loose stool- That would take the shape of a container.
  • For practical purpose, the recent change in consistency & character of the stool & its water content.

Types of Diarrhea

  • Acute watery diarrhea- lasts < 14 days.
  • Dysentery- Diarrhea with visible blood & mucus.
  • Persistent Diarrhea- Duration >14 days. Cause- infectious.
  • Chronic diarrhea-Duration >14 days. Cause- noninfectious.


  • Viruses (e.g., adenovirus, rotavirus, Norwalk virus)
  • Escherichia coli, Clostridium difficile and Campylobacter, Salmonella, and Shigella are common bacterial causes
  • Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, Salmonella, and others cause food poisoning
  • Entamoeba histolytica and Giardia, Cryptosporidium, and Cyclospora are parasitic or protozoal agents that cause diarrhea.

Causative agents

Causative agent Incubation period Duration of illness
1.Rotavirus 1-4 days 4-8 days
2.Norovirus 12-48 hrs 12-60 hrs
3.ETEC 1-3 days 3->7days
4.EHEC 1-8 days 5-10 days
5.Salmonella spp. 1-3 days 4-7 days
6.Shigella spp. 24-48 hrs 4-7 days
7.Bacillus cereus 1-6 hrs 24 hrs
8.Clostridium perfringens 8-16hrs 24-48 hrs
9.Staph aureus. 1-6hrs 24-48 hrs
10.Vibrio cholera 24-72 hrs 3-7 days
11.Entamoeba histolytica 2-3d to 1-4 Wks Several wks to mths
12.Giardia lamblia 1-2 Wks Days to wks
13.Cryptosporidium 2-10days Remitting/ relapsing


  • Dehydration
  • Dyselectrolytemia
  • Malnutrition
  • Acute renal failure
  • Septicemia & septic shock
  • Hemolysis, renal failure & hemorrhage
  • Hemolytic uremic syndrome

Assessment of hydration status

Symptom Minimal/ no dehydration (<3% wt loss) Mild to moderate dehydration 3-9% wt loss) Severe dehydration (>9% wt loss)
1.Mental status Well alert Normal, fatigue or restless, irritable Apathetic, lethargic, unconsciousness
2.Thirst Drinks normally Thirsty, eager to drink Drinks poorly, unable to drink
3.Heart Rate Normal Normal to increased Tachycardia, bradycardia.
4.Quality of pulses Normal Normal to decreased Weak, thready
5.Breathing Normal Normal, fast Deep
6.Eyes Normal Slightly sunken Deeply sunken
7.Tears Present Decreased Absent
8.Mouth & tongue Moist Dry Parched
9.Skinfold Instant recoil Recoil in < 2sec Recoil in >2 sec
10.Capillary refill Normal Prolonged Prolonged
11.Extremities Warm Cool Cold, mottled
12.Urine output Normal to decrease Decreased Minimal

Assessment of hydration status (IMCI Protocol)

Clinical signs General condition Eyes 
Skin Pinch
Well alert
Drinks normally
Go back quickly
Drinks eagerly, thirsty Goes back slowly
Drinks poorly
Goes back very slowly
Decide No signs of dehydration If the patient has 2 or more signs, there is “some signs of dehydration” If the patient has 2 or more signs, there is “severe dehydration”
Plan Plan A Plan B Plan C

* infant < 2mths of age, thirst is not assessed & decision regarding ‘some’ or ‘severe’ dehydration is made if 2 of the 3 signs are present

Guidelines for replacement of Fluid & Electrolytes

Plan A

  • < 6 months- quarter glass or cup( 50ml)
  • 7 months- 2 years- quarter to ½ glass or cup(50-100ml)
  • 2-5 yrs ½ to 1 glass or cup(100-200ml)
  • Older children- as much as the child can take.

Plan B

  • Correction of dehydration- ORS @ 75ml/kg over a period of 4 hours.
  • Reassess after 4 hours-if still dehydrated, repeat deficit therapy. If rehydrated, treat as “no dehydration” with Plan A
  • If ORT is not successful, treat as “ severe dehydration” with intravenous fluids as in Plan C.

Plan C

 Infant (<1 year) Older child (>1 year)
Volume of Ringers lactate 30ml/kg body wt within first 1 hour followed by 70 ml/kg body wt over next 5 hours 30ml/kg body wt within ½ hour followed by 70ml/kg body wt over the next 2.5 hours

Monitoring – Access for improvement every 1-2 hours
If not improving, give iv infusion more rapidly
Encourage oral feeding by giving ORS @ 5ml/kg/hr along with iv fluid as soon as the child is able to drink.
Reassess hydration status- After 6 hrs/3 hrs assess hydration status & choose an appropriate plan(A, B or C)

Clinical evaluation of dehydration

  • Mild dehydration (<5% in infant,<3% in an older child or adult)- normal or increased pulse, decreased urine output, thirsty, normal physical finding
  • Moderate dehydration (5-10% in an infant, 3-6% in older child or adult)- tachycardia, little or no urine output, irritable/lethargic, sunken eyes & fontanelle, decreased tears, dry mucus membranes, mild delay in elasticity (skin turgor), delayed capillary refill (>1.5 sec) cool & pale

Clinical evaluation of dehydration

  • Severe dehydration (>10% in an infant; >6% in older child or adult)- rapid & weak or absent peripheral pulses, decreased blood pressure, no urine output, very sunken eyes & fontanelle, no tears, parched mucus membrane, delayed elasticity (poor skin turgor), very delayed CRT (>3 sec), cold & mottled, limp, depressed consciousness

Fluid management of dehydration

  • Restore intravascular volume- 20ml/kg NS over 20 min. Repeat as needed.
  • Calculate 24 hrs fluid needs- maintenance + deficit volume
  • Subtract isotonic fluid already

administered from 24 hrs fluid needs

Fluid management of dehydration

  • Administer remaining volume over 24 hrs using ½ NS + 5% Dextrose & 20meq/l KCl
  • Replace ongoing loss as they occur
  • In a child with a known or probable metabolic alkalosis (child with isolated vomiting), RL should not be used as lactate will worsen the alkalosis.
  • Because dehydration can be associated with acute renal failure & hyperkalemia, potassium is

withheld from IV fluid until the patient has voided.

Summary of treatment

Degree of dehydration Rehydration therapy Replacement of losses Nutrition
Minimal or no dehydration Not applicable <10 kg: 60-120 ml >10 kg:120-240 ml ORS for each diarrheal episode/vomiting Breast feeding + age appropriate normal diet with adequate calorie intake
Mild to moderate dehydration ORS, 50-100 ml/kg body wt over 3-4 hrs Same Same
Severe dehydration RL or NS in 20ml/kg body wt IV until perfusion & mental status improve, then 100ml/kg body wt ORS over 4 hr, or ½ NS & 5% D IV at 2* maintenance dose Same, if unable to drink, administer through NG tube or administer 5% Dextrose with1/2 NS with 20 meq/l KCL IV Same

Oral rehydration salts (ORS) solutions

  • Preservation of the facilitated glucose-sodium cotransport system in the small-bowel mucosa is the rationale of oral rehydration therapy.
  • Greater net absorption of an isotonic salt solution with glucose than of one without it.
  • Potassium replacement during acute diarrhea prevents below-normal serum concentrations of potassium
  • Bicarbonate and citrate are equally effective in correcting the metabolic acidosis caused by diarrhea and dehydration

Oral Rehydration Salt

ORS Gm/liters ORS Mmol/liters
Sodium chloride 2.6 Sodium 75
Glucose, anhydrous 13.5 Chloride 65
Potassium chloride 1.5 Glucose, anhydrous 75
Trisodium citrate dihydrate 2.9 Potassium 20
Citrate 10
Total osmolarity 245

Advantages of this new reduced osmolarity ORS solution

  • It reduces stool output or stool volume by about 25% when compared to the original WHO-UNICEF ORS solution
  • It reduces vomiting by almost 30%
  • It reduces the need for unscheduled IV therapy by more than 30%.
  • According to the MOHP and 2001 NDHS, nearly all mothers of children under 5 years old in Nepal know about ORS packets (97.8 percent); however, only 32 percent of mothers administered ORS during a recent bout of diarrhea

Fluids to avoid

  • Fluids causing hypernatremia -most soft drinks
    -sweetened fruit drinks
    -sweetened tea
  • Fluids with stimulant, diuretic or purgative effect -coffee
    -some medicinal teas

Clinical approach to diagnosis

  • Access in the examination- physical signs of dehydration, nutritional status of a child, presence of other infections & signs of shock.
  • Rotavirus diarrhea- vomiting is early feature & diarrhea is more severe.
  • Large & watery stool in secretory diarrhea- ETEC or Vibrio cholerae (rice watery)
  • Fever, abdominal cramps & tenesmus with the passing of blood & mucus in dysentery (colitis)

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