This document provides an overview of acute gastroenteritis. It defines acute diarrhea and lists common causes in both adults and children, including viral, bacterial, and parasitic infections as well as some non-infectious conditions. The document outlines the clinical approach to a patient with acute diarrhea including taking a thorough history and physical exam. It notes key indications for testing stool or blood. The management section discusses rehydration therapy including oral rehydration solutions, diet, use of anti-diarrheal medications, antimicrobial therapy, and probiotics.

1. Acute Gastroenteritis
Presented by
Abdulaziz Bagasi – R2 Family Medicine NGH
Supervised by
Dr.Nisreen Asraf
22nd November 2018
1

2. Objectives
• Definitions
• Differential diagnosis
• Clinical approach(history ,physical examination, investigation)
• Management
• Indications of referral
• Prevention
• MCQs
2

3. Acute Gastroenteritis
Increased stool frequency with or without vomiting, fever, or
abdominal pain
3

4. Definition of acute diarrhea
The passage of :
• 3 or more loose or liquid stools per 24 hours
and/or
• Stools that are more frequent than what is normal for the
individual lasting <14 days
and/or
• Stool weight greater than 200 g/day.
4

5. Causes of acute diarrhea in adults: infections
Viral pathogens
• Norovirus (cause 50% of acute diarrheal illnesses in the United States)
• Rotavirus (mostly affects children ≤ 2 years old)
Bacterial pathogens
• Salmonella, Shigella, Campylobacter, E.coli, and Clostridium difficile.
Parasites
• Giardia lamblia and Entamoeba histolytica
5

6. Causes of acute diarrhea in adults: Noninfectious conditions
MedicationsEndocrine conditionsGastrointestinal conditions
Antibiotics (especially broad-
spectrum and clavulanic acid
containing)
Neuroendocrine tumorsInflammatory bowel disease
LaxativesHyperthyrodismIrritable bowel syndrome (IBS)
Magnesium antacidsLactose intolerance
ColchicineCeliac disease
Long-term steroidIschemic colitis
6

7. Non-inflammatory vs. Inflammatory
infectious diarrhea
7

8. Causes(DDs) of acute diarrhea in children:
infectious
• Gastrointestinal infection
• The most common cause of acute diarrhea in children
• Viral pathogens account for most cases of gastroenteritis in children
8

9. Causes(DDs) of acute diarrhea in children: Non-infectious
MedicationsEndocrine diseaseExtraintestinal
infection
Gastrointestinal
conditions
life-threatening
conditions
Antibiotics
(especially broad-
spectrum and
clavulanic acid
containing)
HyperthyroidismMeningitisInflammatory
bowel disease
Intussusception
LaxativesCarcinoid tumorsPneumoniaIBSHemolytic-uremic
syndrome
Magnesium
antacids
Urinary tract
infection
Lactose intoleranceClostridium difficile
(pseudomembrano
us colitis)
ColchicineAcute otitis mediaCeliac diseaseToxic shock
syndrome
long-term steroid
use
Appendicitis
(diarrhea may be
initial symptom in
some younger
children)
9

10. Approach to patient with acute diarrhea
10

11. Case
• A 6 years old boy
• Came complaining of diarrhea for 3 days
How to approach this patient ?
11

12. History
• Ask about symptom characteristics to assess severity
 Fever
 Diarrhea characteristics
• Onset
• Duration
• Frequency
• Severity
• Stool character - watery, bloody, mucus-filled
 Signs of dehydration
Thirst
Dizziness
Change in mental status
Decreased urine output
Decreased activity
Chief concern (CC)
12

13. History
• Ask about associated symptoms
 Fever
 Tenesmus
 Nausea and/or vomiting
 Severe abdominal pain and age ≥ 50 years
• Ask about stool characteristics
 Bloody stool bacterial infection with intestinal inflammation
 Rice-water stool Vibrio cholera
• Ask about timing of symptoms after suspected infectious exposure
 Onset 2-7 hours after possible exposure foodborne illness
 Onset 24-48 hours after possible exposure viral pathogen
• Ask about duration
 Diarrhea lasting > 7 days raises suspicion of parasitic infection, especially if weight loss.
History of present illness
13
bacterial infection, but does not exclude viral infection.
bacterial infection.
viral gastroenteritis or food poisoning
intra-abdominal condition which may require surgical
intervention

14. History
• Ask about past medical conditions that are associated with diarrhea
 Gastrointestinal conditions
 Endocrine conditions
• Some conditions raise suspicion of specific etiology
 Recent hospitalization or antibiotic use Clostridium difficile infection.
 Ask about medications associated with diarrhea
Past medical history
Medication history
14

15. History
• Fluid and food intake (including breast milk) since onset of diarrhea
• Ask about recent food consumption
 Untreated water raises suspicion of parasitic infection or cholera
 Fried rice raises suspicion of Bacillus cereus infection
• Dairy and eggs
 Raw milk raises suspicion of Salmonella , Campylobacter, Shiga toxin-producing E. coli
 Eggs raises suspicion of Salmonella infection
• Seafood (particularly raw or undercooked shellfish)
 V. cholerae, Salmonella, or norovirus infections
• Poultry
 raises suspicion of Campylobacter or Salmonella infection
Diet history
15

16. History
• Travel to a developing country raises suspicion of E. coli (most common)
• Exposure to animals (such as reptiles [may harbor Salmonella], or pets with diarrhea.
Social history
ICEE
16

17. Clues to the diagnosis of acute diarrhea
???
17

18. Clues to the diagnosis of acute diarrhea cont.
18
???

19. Physical exam
• Common findings on physical examination of patients with acute viral gastroenteritis
 Mild diffuse abdominal tenderness on palpation
 Fever
• Look for signs of dehydration to assess severity
• Abdominal examination (assess bowel sounds, palpate for localized pain and
rebound tenderness)
• Neck stiffness (bacterial meningitis)
19

20. Copyrights apply
Dehydration in
adult

21. Copyrights apply
Dehydration in
children
What are the most useful individual
signs for identifying dehydration in
children ?

22. • The most useful individual signs for identifying dehydration in
children are
Prolonged capillary refill time
 Abnormal skin turgor
Abnormal respiratory pattern
22

23. Back to the case
• A 6 years old boy
• Came complaining of diarrhea for 3 days
• fever 38
• Mild diffused abdominal pain
• Vomiting 2 times daily of food contents , no blood
• It was sudden in onset and occurred about 4 times per day
• The diarrhea was watery in nature, yellowish to brown in color with no blood
or mucus
• His mother said was appeared lethargic and less active than usual
• No recent history of taking outside food or travelling
• Other systemic review unremarkable
• Past medical/surgical history : negative
• Immunization up to his age23

24. Back to the case
On examination
• Awake ,alert, not ill looking
• Vital signs : fever and tachycardia , no hypotension
• Mild to mederate dehydrated : tongue and mucous
membranes were dry , reduced skin turgor, Capillary refill time
was less than 2 s ,no sunken eyes
• The abdomen appeared normal, on palpation his abdomen
was soft and non tender with no organomegaly.
24

25. What investigation will you order?
25

26. Investigation
• Testing usually not needed, particularly if symptoms are mild
with no red flags and usually of viral etiology.
26

27. Indications of acute diarrhea testing
1) Severe illness
 Profuse watery diarrhea with signs of dehydration
 Passage of >6 unformed stools per 24 hours
 Severe abdominal pain
2) Other signs or symptoms concerning for inflammatory diarrhea
 Bloody diarrhea
 Passage of many small volume stools containing blood and mucus
 Temperature ≥38.5ºC (101.3ºF)
3) High-risk host features
 Age ≥70 years
 Comorbidities, such as cardiac disease, which may be exacerbated by hypovolemia or rapid infusion of fluid
 Immunocompromising condition (HIV infection)
4) Inflammatory bowel disease
5) Pregnancy
6) Symptoms persisting for more than one week
7) Suspected infectious outbreak (e.g handlers large quantities of food)
27

28. Investigation : stool analysis
• Stool studies (such as culture, PCR, or immunoassays):
Occult blood (increase suspicion for inflammatory bacterial diarrhea)
Consider testing for fecal lactoferrin or fecal leukocytes to assess for
inflammation.
o Lactoferrin is marker for leukocytes released by damaged cells which increases in bacterial
infections
o Lactoferrin testing is the preferred method (over testing for leukocytes)
o sensitivity > 90% and specificity > 70%
Consider microbiological stool investigation (depend on the lab and the
pathogen suspected).
Parasitic infections: consider stool ova and parasite test
PCR can detect evidence of multiple pathogens and can distinguish
between them.
28

29. Investigation :Other tests
• Blood tests
CBC
Electrolytes
Blood cultures
• Urinalysis
29

30. Back to the case
• CBC and electrolytes are normal
• Stool studies : negative
• Urine analysis : negative
30

31. What imaging will you order?
31

32. Indications for imaging
• Abdominal imaging is not typically needed.
• For patients who have significant peritoneal signs or ileus
• Most typically CT to rule out other DD
32

33. So our diagnosis is acute viral gastroenteritis
with mild to moderate dehydration
33

34. Q1
You are seeing a 6-year-old boy with nausea and vomiting. His symptoms
began acutely last evening, starting with malaise, headache, low grade
fever, body aches, and diarrhea. On examination, he has dry mucous
membranes, but no orthostatic symptoms. He has diffuse mild abdominal
pain without rebound or involuntary guarding. Which of the following is
the best treatment for his condition?
a. Nothing by mouth until his symptoms improve
b. Oral rehydration with clear liquids, advancing the diet as tolerated
c. IV rehydration, advancing to oral as tolerated
d. Antiemetics, given intravenously or intramuscularly
e. Trimethoprim/sulfamethoxazole therapy
34

35. Management
35

36. 36

37. Management
1. Rehydration therapy
2. Diet
3. Antidiarrheal medications
4. Antimicrobial medications
5. Probiotics
37

38. 1.Rehydration therapy
• The most critical therapy in diarrheal illness.
• Preferably by the oral route, with solutions that contain water,
salt, and sugar.
• Consumption of fruit juices, sports drinks, soups, and saltine
crackers
38

39. Copyrights apply
Dehydration in
adult

40. Rehydration in children
• Acute GE (no or minimal signs of dehydration) managed at
home after educating parents about fluid management, proper
nutrition and how to identify signs of dehydration.
• If dehydration is present
Oral rehydration solution(e.g: Pedialyte) with mild to moderate
dehydration
IV rehydration with severe dehydration
40

41. Rehydration in children: Composed of two steps
1. The first is to emergently correct severe dehydration with IV
isotonic fluids
• Severe dehydration (more than 10%) :
Rapid infusion of 20 mL/kg of isotonic saline.
Then reassess during and after the saline bolus
 And similar isotonic fluid infusions should be repeated as needed until
adequate perfusion is restored.
• Mederate dehydration (6-9%) :
Bolus of 10 mL/kg is given over 30 to 60 minutes
Then reassess to decide on administration of a repeat IV bolus or change
to oral therapy.
41

42. Rehydration in children: Composed of two steps
2. The second step is to finish repletion of fluids and electrolytes
either with IV fluids or ORT (the preferred method unless can not
tolerating orally )
42

43. ORS preparation at home
• From Rehydration Project by UNICEF
1 L clean drinking water (or water that has been boiled and then
cooled)
one-half teaspoon salt
6 teaspoons sugar
consider adding one-half cup orange juice or some mashed banana
to provide potassium and improve taste
43

44. Q2
A 22-year-old healthy male sees you for “diarrhea.” He reports frequent
loose stools without bleeding. You determine that he likely has a
virally mediated process and recommend supportive care. Which of the
following dietary measures should you recommend?
a. The patient should fast until the diarrhea resolves.
b. The patient should not eat solids, but should drink an oral rehydrating
solution.
c. The patient should drink milk.
d. The patient should drink fruit juice.
e. The patient can eat rice and potatoes.
44

45. 2.Diet
• After dehydration resume feeding as soon as possible because
it reduces illness duration
• Limited or no evidence to support although they are
recommended :
Avoiding solid food or dairy
BRAT diet
45

46. Anti-diarrhea medications are they
recommended or not in acute GE ?
46

47. 3.Anti-diarrhea medications(in adult)
• May reduce stool volume and frequency.
• Specific symptomatic therapies for adults with acute viral
gastroenteritis with moderate to severe non-bloody diarrhea
or signs of dehydration ,and no fever
• Contraindicated if :
bloody stool
 fever
abdominal pain
• Due to concern about prolonging duration of inflammatory
infectious diarrhea.
47

48. 3.Anti-diarrhea medications (in children)
• In general, antidiarrheal medications should not be used in
children with acute gastroenteritis because they delay the
elimination of infectious agents from the intestines.
• May be considered after patient is adequately hydrated (Weak
recommendation)
48

49. 3.Anti-diarrhea medications
• Loperamide(anti-motility) (Imodium) monotherapy
Initial dose ≤ 4 mg, with additional doses ≤ 2 mg after each unformed
stool up to 8 mg/day (max 16 mg/day) for 2 days.
• Loperamide-simethicone combination
Such as chewable tablet containing loperamide 2 mg plus
simethicone 125 mg.
Recommended over monotherapy for faster and more complete
relief of acute nonspecific diarrhea and gas-related discomfort
• Racecadotril (anti-secretory)
may reduce acute diarrhea in adults by about 1 day or about 1 unformed stool
per day49

50. 4.Antimicrobial medications
• Antimicrobial use not recommended in most patients
• Empiric antibiotic therapy not recommended unless high
likelihood of traveler's diarrhea
50

51. 4.Antimicrobial medications
• Inappropriate use may lead to
Antimicrobial resistance
Prolonged duration (such as with Clostridium difficile infection)
Prolonged carrier state (such as with Salmonella infection)
Harmful eradication of normal flora
• Treating Shiga toxin-producing E.coli (STEC) O157 with
antimicrobials may increase risk of hemolytic-uremic syndrome
(HUS)
51

52. 4.Antimicrobial medications
• Consider antimicrobial therapy if
 Symptoms severe (such as passage ≥ 6 stools daily or duration without
improvement > 72 hours) or do not improve after rehydration
therapy or antidiarrheal medication
AND
Bacterial or parasitic pathogen strongly suspected such as with
Fever or bloody stool
Suspected hospital-associated or antibiotic therapy-associated diarrhea
Suspected traveler's diarrhea (characterized by ≥ 3 loose stools over 24-hour
period shortly after or during travel)
52

53. 5. probiotics
• Defined by WHO: live microorganisms that, when administered in
adequate amounts, confer a health benefit on the host.
• Example : Lactobacillus casei .
 Probiotics may reduce duration of acute infectious diarrhea (level 2
[mid-level] evidence)
 When used with an oral rehydration solution, probiotics can help reduce
the duration of diarrhea in children with gastroenteritis
 Probiotics associated with reduced duration of diarrhea and stool
frequency on day 2 of treatment in children < 5 years old with acute
diarrhea (level 2 [mid-level] evidence)
53

54. Probiotics in private pharmacy
54

55. Do you recommend Zinc supplements in
treatment of acute gastroenteritis?
55

56. Zinc supplementation
• The effect on adults
Has not been studied, and its use is not the standard of care.
• The effect on children
Reduces the severity and duration of acute diarrhea in children from
populations in which zinc deficiency is common
56

57. Indication of referral of GE (in adult)
• Signs of severe dehydration
• Persistent vomiting
• Abnormal electrolytes or renal function
• Excessive bloody stool or rectal bleeding
• Severe abdominal pain
• Prolonged symptoms (more than one week)
• Age 65 or older with signs of hypovolemia
• Comorbidities (eg, diabetes mellitus, immunocompromised)
• Pregnancy
Red
Flags
57

58. Indication of referral of GE (in children)
• Diarrhea lasting more than one week
• Severe dehydration
• Hypernatremia
• Clinical features suggesting extraintestinal involvement
or another etiology (eg, hemolytic uremia syndrome)
• Immune compromise
58

59. Prevention
• Non-vaccine prevention methods
Good hygiene practices such as hand washing
Safe practices in food preparation
Access to clean water
Probiotics
59

60. Probiotics in prevention
• Probiotics shown to reduce rate of antibiotic-associated diarrhea (level 1 [likely
reliable] evidence)
• Some probiotics appear effective in prevention of traveler's diarrhea (level 2 [mid-
level] evidence)
60

61. Prevention
• Prophylactic vaccines are available for
 Rotavirus (more common in children)
Typhoid fever
Cholera
61

62. Copyrights apply

63. Evaluation of acute diarrhea
63

64. MCQ
64

65. Q3
A 30-year-old man returned from a vacation in Mexico 1 day ago.
He spent the last 3 days of his trip with loose, more frequent bowel movements
that are continuing without resolution. He has not had bloody stool
or fever. His examination is normal, except for mildly diffuse lower abdominal
pain. Which of the following is the best empiric treatment option for
his condition?
a. Erythromycin
b. Ciprofloxacin
c. Metronidazole
d. Doxycycline
e. Vancomycin
65

66. Q4
You are seeing a 6-month-old boy whose mother reports that he has
had diarrhea for almost 2 weeks. He has had four to six bowel movements
a day, with a loose to liquid consistency. His mother stays at home with
him and the child is not in day care. His symptoms began after his young
cousins visited for Christmas. Which of the following is the most likely
cause of his diarrhea?
a. Rotavirus
b. Norwalk virus
c. Giardiasis
d. Salmonella
e. Enterotoxigenic Escherichia coli
66

67. Q5
You are performing a physical examination on a student traveling to
Mexico with her college Spanish class. She is concerned about traveler’s
diarrhea, and asks about antibiotic prophylaxis. Which of the following
best represents the current guideline from the Centers for Disease Control
and Prevention (CDC) for prevention of traveler’s diarrhea?
a. The CDC does not have an antibiotic guideline regarding antibiotic prophylaxis
for traveler’s diarrhea.
b. The traveler should take trimethoprim-sulfamethoxazole.
c. The traveler should take doxycycline.
d. The traveler should take ciprofloxacin.
e. The traveler should take metronidazole
67

68. Explanation Q5
The answer is a.
The CDC does not recommend antibiotic chemoprophylaxis for
traveler’s diarrhea because of the development of resistant
organisms. Most of the times, the condition is self-limited.
The CDC does recommend using common sense regarding food
and water,eating nothing unless it is boiled, peeled, or cooked.
68

69. Q6
An 18-month-old child presents to the emergency center having had
a brief, generalized tonic clonic seizure. He is now postictal and has a temperature
of 40°C (104°F). During the lumbar puncture (which proves to be
normal), he has a large, watery stool that has both blood and mucus in it.
The most likely diagnosis in this patient is
a. Salmonella
b. Enterovirus
c. Rotavirus
d. Campylobacter
e. Shigella
69

70. Explanation Q6
The answer is e.
Clinical manifestations of shigellosis range from watery stools for several days to severe infection, with
high fever , abdominal pain, and generalized seizures. In general, about 50% of these
children have emesis, greater than two-thirds have fever, 10 to 35% have
seizures, and 40% have blood in their stool. Often, the seizure precedes
diarrhea and is the complaint that brings the family to the physician. Fever
usually lasts about 72 h, and the diarrhea resolves within 1 week.
Presumptive diagnosis can be made on the clinical history; confirmation is through
stool culture. Supportive care, including adequate fluid and electrolyte support,
is the mainstay of therapy. Antibiotic treatment is problematic; resistance
to trimethoprim-sulfamethoxazole is common, necessitating therapy
with third-generation cephalosporins in many cases.
70

71. Q7
A 2-year-old boy develops bloody diarrhea shortly after eating in a
fast-food restaurant. A few days later, he develops pallor and lethargy; his
face looks swollen and his mother reports that he has been urinating very
little. Laboratory evaluation reveals low hematocrit and platelet count and
positive blood and protein in the urine. Which of the following diagnoses
is likely to explain these symptoms?
a. Henoch-Schonlein purpura
b. IgA nephropathy
c. Intussusception
d. Meckel diverticulum
e. Hemolytic-uremic syndrome
71

72. Explanation Q7
The answer is e.
Hemolytic-uremic syndrome is
characterized by an acute microangiopathic hemolytic anemia, thrombocytopenia from increased
platelet utilization, and renal insufficiency from vascularendothelial injury and local fibrin deposition.
Ischemic changes result in renal cortical necrosis and damage to other organs such as colon, liver, heart,
brain, and adrenal. Laboratory findings associated with hemolyticuremic
syndrome include low hemoglobin level, decreased platelet count, hypoalbuminemia, and evidence of
hemolysis on peripheral smear (burr cells, helmet cells, schistocytes). Urinalysis reveals hematuria and
proteinuria.
A marked reduction of renal function leads to oliguria and rising levels of blood urea nitrogen (BUN) and
creatinine. Gastrointestinal bleeding and obstruction, ascites, and central nervous system findings such
as somnolence, convulsions, and coma can occur. In the past decade, infection by the verotoxin-
producing Escherichia coli 0157:H7 has been implicated as a cause of hemolytic-uremic syndrome. This
organism is epizootic in cattle. Outbreaks associated with undercooked contaminated hamburgers have
been reported in several states. Roast beef, cow’s milk, and fresh apple cider have been implicated as
well. The Coombs test is not positive in this type of hemolytic anemia.
72

73. Q8
An awake, alert infant with a 2-day history of diarrhea presents
with a depressed fontanelle, tachycardia, sunken eyes, and the
loss of skin elasticity.
The appropriate percentage of dehydration is
a. Less than 1%
b. 1 to 5%
c. 5 to 9%
d. 10 to 15%
e. More than 20%
73

74. Explanation Q8
The answer is c.
A moribund state is characteristic of a loss of greater than 10%
of body weight from dehydration. The other findings are
characteristic of a loss of body weight of 5 to 9% when there is
no hypernatremia. Additional findings at this level of dehydration
can be restlessness, absent or reduced tears, weak radial pulses,
and, possibly, orthostatic hypotension.
74

75. 75

76. Any Questions?
76