Acute Gastroenteritis is a major cause of morbidity and hospitalization in children. It is commonly caused by viruses like rotavirus in infants and norovirus in older children. Rotavirus causes severe dehydrating diarrhea primarily in children 6 months to 2 years of age during winter months. Diagnosis involves detection of virus or antigens in stool samples. Treatment focuses on rehydration and preventing complications through oral rehydration solutions and zinc supplementation in young children. Antibiotics are generally not needed unless a specific bacterial cause is identified. Vaccines have proven effective in preventing rotavirus infections.

1. Acute Gastroenteritis
Dr. Juhi Hussain

2. CDC:
• Major cause of morbidity and hospitalization
• >1.5 million outpatient visits
• 200,000 hospitalizations
• ~ 300 deaths/year
In resource-limited countries:
-infants experience a median of six episodes annually
-children experience a median of three episodes annually

3. HOW DO YOU DEFINE IT???
Definition:
• Clinical: > 3 loose stools/day +/- vomiting, fever, or abdominal pain.
• Objective definition : Infants and toddlers (<10 kg), : stool volume of more
than 20 grams/kg/day . Older children or teenagers >200 grams/day
Diarrhea classification:
• Acute – Bloody (Dysentery- Invasive) or Non bloody (secretory)
• Chronic/persistent: >14 days

5. CAUSES ????
1. Infectious gastroenteritis — causes differ by age group, geographical region, and type of
diarrhea.
- Viruses, Bacteria, Protozoa
• Travelers Diarrhea
• Food Borne Diarrhea
2. Non infectious :
1. Heavy metals
2. Antibiotic associated
3. Secondary to systemic infection (pneumonia, UTI,sepsis), Immunodeficiency (HIV), surgery
(intussusception)
4. Allergies ( allergic eosinophilic GE)
5. Rare causes of acute diarrhea in infancy: Primary disaccharides deficiency, Hirsch sprung toxic
colitis, Adrenogenital syndrome, Neonatal opiate withdrawal
Note: Constipation with overflow incontinence can be mislabeled as Diarrhea

7. Watery diarrhea :
• infants: most often due to rotavirus
• older children: it is most often due to E. coli (pathogenic/toxigenic- travelers)
Invasive (bloody) diarrhea
• Shigellosis is the most common etiology of invasive, or bloody, diarrhea in resource-
limited countries .
• Other etiologies : Salmonella enterica , Campylobacter spp, enterohemorrhagic E.
coli, enteroinvasive E. coli, & protozoan parasite: Entamoeba histolytica.

8. Rotavirus
• Six months and two years of age
• Spread via feco-oral route
• Common in Winter months
• Primary infection is severe & does not give immunity against re-infection,
BUT protects against development of clinically severe disease

9. Diagnosis
• Detection of virus/antigen in stools (peaks at day 3-4 of disease)
• ELISA – DAKO/IDEIA(assays)
• Latex Agglutination
• Electron microscopy (labor intensive)
• RT-PCR (reverse transcriptase PCR)

10. Rotavirus vaccines
Two vaccines introduced into National Immunisation schedule – 1st July 2007.
- oral, live attenuated vaccines.
• GSK (Rotarix)
monovalent human strain given orally at 2 and 4 months.
• Merck (RotaTeq)
Bovine-human reassortants (5 strains). Given orally at 2, 4 and 6 months.
Minimum age for receiving Rotavirus vaccine: 6 weeks.
Interval between dose 1 & 2: 4 weeks
Interval between Dose 2 & 3 :4 weeks
maximum age recommended for the last dose of RotaTeq is 8 months; it is 6 months for Rotarix.
Side Effect: Slightly increased risk of intussusception shortly after first dose.
Contraindication: allergy, SCID, acute/mod/sever GE, latex allergy (with RV1).
Prevention:

11. Norovirus
• Affects all age groups.
• Many outbreaks occur in institutions such as nursing homes, hospital wards,
and schools, restaurants and cruise ships.
• Transmission: contaminated food or water.
• Very Contagious: Low infectious dose, Strain diversity.

12. Food/Water-borne
Nontyphoidal Salmonella, Campylobacter, Shigella, Escherichia
coli O157:H7, Yersinia, Listeria monocytogenes, and Vibrio cholerae.
• Result from ingestion of:
Preformed enterotoxins produced by bacteria, such as Staphylococcus
aureus and Bacillus cereus, which multiply in contaminated foods
Nonbacterial toxins such as from fish, shellfish, and mushrooms.
• Heavy metals that leach into canned food or drinks causing gastric irritation and
emetic syndromes may mimic symptoms of acute infectious enteritis.

13. Nontyphoidal Salmonella : (Most common in US)
• Invasion the intestinal mucosa.
• Transmitted through contact with infected animals (chickens, iguanas, other
reptiles, turtles) or from contaminated food products, such as dairy products, eggs,
and poultry.
• A large inoculum of organisms is required for disease because Salmonella is killed by
gastric acidity.
• The incubation period ranges from 6 - 72 hours but is usually <24 hours.

14. Shigella Dysenteriae :
4 Species: Shigella dysenteriae, Shigella flexneri, Shigella boydii, and Shigella
sonnei. S. flexneri is the predominant species in children.
• Production of Shiga toxin .
• Incubation period is 1-7 days.
• person-to-person contact/ contaminated food with 10-100 organisms.
• The colon is selectively affected.
• High fever and febrile seizures may occur in addition to diarrhea.

15. E. coli
• Enter toxigenic (ETEC) : heat-labile (cholera-like) enterotoxin, heat-stable enterotoxin, .ETEC is a
frequent cause of traveler's diarrhea. (secretory Diarrhea)
• Enter hemorrhagic (EHEC) or Especially the E. coli O157:H7, produces a (Shiga-like toxin) that causes
hemorrhagic colitis and most cases of diarrhea associated with Hemolytic uremic syndrome (HUS) (
microangiopathic hemolytic anemia, thrombocytopenia, and renal failure )
• Shiga toxin–producing (STEC) -contaminated food, including unpasteurized fruit juice, undercooked beef, and
can present with nonbloody diarrhea that then becomes bloody
• Enter invasive (EIEC): invades the colonic mucosa, producing widespread mucosal damage with acute
inflammation similar to Shigella. (watery diarrhea, associated with fever)
• Enter pathogenic (EPEC) (watery diarrhea) , causes severe dehydration in young children in resource-poor
countries in sporadic or epidemic patterns.
• Enter aggregative (EAEC)

16. • Campylobacter jejuni - person-to-person contact, Contaminated water
and food, especially poultry, raw milk, and cheese. (bloody diarrhea)
• Yersinia enterocolitica is transmitted by pets, contaminated food,
especially chitterlings (pig intestine). Infants and young children
characteristically have a diarrheal disease, whereas older children usually have
acute lesions of the terminal ileum or acute mesenteric lymphadenitis
mimicking appendicitis or Crohn disease. Post infectious arthritis, rash, and
spondylopathy may develop.

17. Clostridium difficile - associated with prior antibiotic exposure.
• The organism produces spores that spread from person to person and also as fomites on
surfaces.
• Infection is generally hospital-acquired
• Diagnosis is made by detection of toxin in the stool.
• Infants <12 months of age should not be tested for C. difficile as they are frequently
asymptomatically colonized with the organism in their stool, possibly due to a lack of the
receptor required for infection.
• ( patients on antibiotics often experience diarrhea related to alterations in their intestinal
flora that are unrelated to C. difficile infection.)

18. Cholera: Vibrio Cholera (RICE WATER Diarrhea)
Travelers arriving from countries where the disease is still common, such as Africa,
Central Europe, Latin America and Asia.
• Incubation: A few hours to 5 days, usually 2 to 3 days.
spread by:
• drinking contaminated water
• eating food contaminated by dirty water, soiled hands or flies
• eating fish or shellfish from contaminated waters.

19. • Amebiasis (E. histolytica ) infects the colon; amebae may pass through the bowel
wall and invade the liver, lung, and brain. Diarrhea is of acute onset, is bloody,
and contains leukocytes.
• G. lamblia is transmitted through ingestion of cysts, either from contact with an
infected individual, from food or freshwater or well water contaminated with
infected feces
Insidious onset of progressive anorexia, nausea, gaseousness, abdominal distention,
watery diarrhea, secondary lactose intolerance, and weight loss is characteristic of
giardiasis.
• (

20. History
• Fever
• Cough /Cold (systemic infection)
• Myalgia/Joint pain/Rashes
• Abdominal pain – location, quality, radiation, severity, timing.
• Vomiting – Duration, amount, Content, Non projectile, non bilious , non bloody
• Change in Urinary frequency, output, colour.
• Stool- Duration, frequency, Quality , Bloody/Non bloody, Pus +/-
• Contaminated food
• Travel to Endemic areas
• Recent Illness requiring antibiotics
• Change in Appearance or behavior (weight loss)
• Vaccination status : Rota Vaccine
• Past Hx: immune deficiencies. Allergies, Chronic illnesses, constipation
• Feeding : Recent Change in feeding, poor feeding

21. O/E
• General appearance: Weight, ill looking, alertness, lethargy, irritability
• HENT: URTI, Fontanelle, tears, mucous membranes , sunken
• CVS : HR, Quality of Pulse
• Resp: Rate, quality(deep/acidotic)
• Abdomen: tenderness, guarding, bowel sounds, Rebound tenderness,
• Back: CVA: tenderness: indicate Pyelonephritis
• Rectal: Quality/colour stool. Gross blood/mucus.
• Extremities: CR time, warm/cold
• Skin: Abdominal rash (typhoid) , doughy feel (hypernatremia)

22. Look for Red Flags:
• Short gut syndrome
• Ileostomy
• Complex/cyanotic congenital heart disease
• Renal transplants or renal insufficiency
• Very young ( <6 months)
• Poor growth
• Fortified feeds (concentrated feeds or caloric additives)
• Recent use of potentially hypertonic fluids (eg Lucozade)
• chronic diseases
• Repeated presentations for same/similar symptoms

23. Differentials of Infectious GE:
• Gastrointestinal allergy (including allergy to milk or soy proteins)
• malabsorption defects, inflammatory bowel disease, celiac disease, or any
injury to enterocytes.
• Surgical Emergencies: intussusception and acute appendicitis

24. Investigation & Management:
Baseline Labs:
• CBC & Blood culture - If suspected systemic illness
• Electrolytes: Bedside CBG, U/E
• BUN
• Creatinine
• Urine Specific Gravity
• Stool Routine and culture (for giardia require 3 stool samples-trophozoites /cysts)
(Criteria for Stool analysis – LH guideline)  < 5 years, Blood in stool, Travel Hx

25. Asses for dehydration

26. NEED FLUIDS?
• Mild dehydration , tolerating orally – GIVE ORS (10ml/kg)
• Moderate – severe dehydration : GIVE FLUIDS

27. WHAT FLUID???USUALLY:
0.9% NS (usually given as bolus)
 0.45% NS in D5% (usually given as maintenance /deficit)

28. HOW MUCH???
• Bolus of Normal saline 0.9% (crystalloid) if in hypovolemic shock: 20ml/kg
(May repeat up to 3 boluses based on patient response)
• Maintenance:
D5% in 0.45%NaCL:
for mild dehydration -
not tolerating orally
or moderate dehydration -severe dehydration after bolus

29. Correction of Hyponatremia/Hypernatremia (covered)

30. ORS (Neolyte)
• 6 gram & 30g sachets

31. Pharmacological Management
Note: antibiotics generally not needed as most cases due to viral causes.
Pharmacotherapy only indicated to reduce morbidity and prevent complications.
• Probiotics: (lactobacillus GG) can be used in treatment and prevention of acute
diarrhea. Especially in C.diff associated diarrhea in children receiving Antibiotics.
• Zinc supplements: < 5years of age as per WHO- 10-20mg/day for 10 days
(developing countries)
• Vaccines- prevent 74-78 % of Rota Virus infections.

32. Antidiarrheal ??
• Kaolin-Pectin
• Loperamide
(CONTRAINDICATED IN ACUTE DIARRHEA)
lack of benefit / Increased side effects : Ileus, drowsiness, nausea.

33. Anti-emetics
• Ondansetron (Zofran) – 5HT3 receptor antagonist. Off label.
(Q-T prolongation with high dose)
Oral Dose: <4 years- according to BSA, >4-11y  4mg TID PRN , >11y  8mg TID
BSA: < 0.3m2 1mg TID PRN
0.3-0.6 m2 2mg TID PRN
0.6 – 1 m2 3mg TID PRN
1m2  4-8mg TID PRN
IV dose – 0.15mg/kg/dose (mx dose 8mg/dose)
• Metoclopramide – Dopamine receptor block. Off label.
(tardive dyskinesia)
0.1-0.2 mg/kg/dose up to QID IV/IM/PO (max: 0.8mg/kg/day)
• Dimenhydrinate- Ethanolamine H1 antagonist
(anticholinergic, antiemetic, antihistaminic, local anesthetic effect)

34. ANTIBIOTICS ???
- May prolong carrier state of Salmonella, or increase risk of HUS
- If suspected C.Diff (Stop offending antibiotic immediately). Start Metronidazole
(30mg/kg/day QID 7days) . Vancomycin in resistant cases.
• Cholera: Tetracyclin, Doxycycline (6mg/kg Single dose), < 8 years: Azithromycin
(erythromycin and Ciproflloxacillin alternative ttt)
• Giardia: Metronidazole (35-50mg/kg/d divided q8qh) . Alt: Nitazoxanide – also
covers cryptosporidium & G.lamblia trophozoites.
• Tetracycline: Gram Positive/Gram negative coverage , mycoplasma , Chlamydial,
rickettsia infections

36. LH
GUIDELINES

38. MCQ’s
Direct person-to-person contact outbreaks of gastroenteritis are usually
caused by
• Shigella
• Salmonella
• Rotavirus
• Giardia
• Clostridium difficile wpo

39. Most common cause of metabolic acidosis in children is:
• a) Vomiting
• b) Renal tubular acidosis
• c) Kidney failure
• d) Sepsis
• e) Diarrhea

40. The MOST common cause of hypokalemia in children is
• A. alkalemia
• distal rental tubular acidosis
• gastroenteritis
• diabetic ketoacidosis
• loop diuretic

41. Acute diarrhea in infancy is commonly caused by
• primary disaccharides deficiency
• overfeeding
• Hirsch sprung toxic colitis
• adrenogenital syndrome
• neonatal opiate withdrawal

42. Secretory diarrhea can be caused by
• Neuroblastoma
• laxative abuse
• lactase deficiency
• irritable bowel syndrome
• E. thyrotoxicosis

43. A 3-year-old boy appeared in the ER with pallor, lethargy, irritability, dehydration, and oliguria. These
symptoms and signs are preceded by acute gastroenteritis (e.g., vomiting, diarrhea with bloody stools) for the
last 5 days. Physical examination reveals hepatosplenomegaly, edema, and petechie.
The following statements are true about this clinical condition except:
• a) Renal failure does occur.
• b) Enter pathogenic E. coli is the most common organism
• c) Endothelial cell injury is the primary event in the pathogenesis.
• d) Peritoneal dialysis is indicated.
• e) Coombs test is positive.

44. A 12-month-old female child appears with alternate normal and watery stools for the last 14 days. She has
brown, watery stools more in the afternoon and evening. She likes to drink fruit juice. Physical examination
reveals weight (50th percentile), height (25th percentile), and normal soft abdomen. Most likely diagnosis:
• a) Viral gastroenteritis
• b) Gastrocolic reflex
• c) Toddler diarrhea
• d) Rotavirus infection
• e) Food poisoning

45. A 2-year-old girl was brought to the ER with history of vomiting and diarrhea for the last 24 hours. The mother
denies any history of fever. The girl was admitted 4 times in the last 6 months for gastroenteritis. The girl is
admitted to the pediatric floor. She vomited once after admission. Mother notified the nurse. She stayed with
her the whole night. She vomited again after several hours. She had no more episodes of diarrhea. The next day,
mother went home. The girl had no more vomiting and diarrhea. Mother returned in the evening. A few hours
later, the girl started to vomit again. Most likely diagnosis:
• a) Child abuse
• b) Viral gastroenteritis
• c) Munchausen by proxy syndrome
• d) Gastroesophageal reflux
• e) Intestinal obstruction

46. A child appears with history of vomiting, diarrhea, and abdominal pain. He also complains of
hot and cold sensations of the extremities, itching, and myalgias. His family went to the
seafood restaurant for dinner and the symptoms started within 2 hours after dinner. The
physical examination reveals rash on the palms and soles, tachycardia, and low BP. The most
likely diagnosis is:
• a) Scombroid fish poisoning
• b) Paralytic shellfish poisoning
• c) Amnesic shellfish poisoning
• d) Diarrhetic shellfish poisoning
• e) Ciguatera fish poisoning

47. A child who has diabetes mellitus appears with an abdominal distension, vomiting,
diarrhea, and bloody stools. He ate undercooked pork chitterlings. The most likely
organism causing this manifestation is:
• a) Shigella
• b) Salmonella
• c) E. coli
• d) Rotavirus
• e) Clostridium perfringens

48. A child appears with diarrhea, dermatitis, and dementia. The most likely
diagnosis is:
• a) Niacin deficiency
• b) Vitamin B12 deficiency
• c) Vitamin B1 deficiency
• d) Vitamin A deficiency
• e) Folic acid deficiency

49. The carrier state of cystic fibrosis is resistant to the following infection:
• a) Enteropathogenic E. coli
• b) Malaria
• c) Salmonella
• d) Shigella
• e) Pneumococcal

50. The most common organism in patients with hemolytic uremic syndrome
(HUS) is:
• a) S. pneumoniae
• b) Shigella
• c) Campylobacter
• d) Bartonella
• e) E. coli

51. • The most common organism in patients with a Gullain-Barre syndrome is:
• a) Yersinia enterocolitica
• b) Shigella
• c) Salmonella
• d) E. coli
• e) Campylobacter jejuni

52. A child appears with a severe abdominal pain, vomiting, painful defecation, urgency, and high fever for the last 2
days. She ate a
regular food at home. However, she went to the party with a group of children and ate salads. Two other
children have the similar symptoms. A physical examination reveals a toxic looking child, abdominal distension,
abdominal tenderness, hyperactive intestinal sounds, and tender rectum. The most likely diagnosis is:
• a) Shigella sonnei infection
• b) E. coli infection
• c) Vibrio cholerae infection
• d) Campylobacter jejuni infection
• e) Yersinia enterocolitica infection