Defined as inflammation of the mucous membrane of stomach and intestine usually causing nausea ,vomiting and diarrhea. Gastro-intestinal infections represent a major public health and clinical problem worldwide. Many species of bacteria, viruses and protozoa cause gastro-intestinal infection.

1. PUBLIC HEALTH
GASTROENTERITIS

2. GASTROENTERITIS
Defined as inflammation of the mucous membrane of stomach and
intestine usually causing nausea ,vomiting and diarrhea.
Gastro-intestinal infections represent a major public health and clinical
problem worldwide. Many species of bacteria, viruses and protozoa
cause gastro-intestinal infection.

3. two main clinical syndromes.
1-Non-invasive infection (Enterotoxic syndromes) The organism enters the mucosal cells,
destroys them, causing diarrhea usually with blood in the stool. Or The organisms do not
invade the mucosa, but produce enterotoxins of which act as chemical mediators causing
hypersecretion of the fluid. Little damage to the tissue is done that manifests clinically as
diarrhea and vomiting.
2- Invasive, causing systemic illness, often with few gastro-intestinal symptoms. like
Helicobacter pylori and its associated with gastritis , peptic ulceration and gastric carcinoma.
Gastro-intestinal infections can be transmitted by consumption of contaminated food
.

4. Gastroenteritis Causes:
Viral 50-70% Norwalk virus Caliciviruses ,Rotavirus Adenovirus Parvovirus
,Astrovirus.
Bacterial 15-20% Salmonella, Shigella, and Campylobacter species are the top 3
leading causes of bacterial diarrhea worldwide.
Parasitic 10-15% like Giardia Lambelia ,Entamoeba histolytica and Others.
Development of symptoms after ingestion of gastro-intestinal pathogens depends on
two factors.
Which are :sufficient organisms must be ingested and then survive host defense
mechanisms.

5. Gastroenteritis Key Symptoms:
Viral :Abdominal cramps, Vomiting ,Profuse watery stools, Myalgia ,Fever, Headaches,
Arthralgia
Bacterial Dysentery :Small volume stools ,Fever ,Bloody mucoid stools , stomach pain.

6. Laboratory Diagnosis:
Stool Culture , Hemoccult of stool , Fecal leukocytes,
CBC; If WBC count is elevated increased likelihood of bacterial infection. If eosinophils
present mean parasitic infection).
TREATMENT OPTIONS
Many gastro-intestinal infections are mild and self-limiting and never reach medical
attention.
Where treatment is required, there are three main therapeutic considerations:

7. 1- Fluid and electrolyte replacement is treatment of diarrheal disease.
Most patients can be managed with oral rehydration systems, but
severely dehydrated patients require rapid volume expansion with
intravenous fluids.
2 -Antiemetics and antimotility (antidiarrheal) agents is sometimes
used, especially as self-medication.
3 -Antimicrobial agents useful both in effecting symptomatic
improvement and eliminating of pathogens thus, reducing the risk of
transmitting infection to others.

8. Oral rehydration solutions
In 2004, WHO and UNICEF recommended the use of low-osmolarity
oral rehydration salts (ORS) in association with zinc tablets to treat
all types of diarrhea among all age groups ,The rationale for this was
that zinc supplementation may increase the uptake of ORS and reduce
the severity and duration of the diarrhea episode.
Oral rehydration solutions (glucose/electrolyte mixtures) increase
water absorption by stimulation of sodium-glucose transport in the
small intestine. They are highly effective for combating dehydration
and its serious consequences, and are the treatment of choice in infants
and young children and very elderly.

9. Antimotility agent
Loperamide may cause dangerous prolongation of illness in patients with some forms of
bloody or inflammatory diarrhea and, therefore, should be restricted to patients with non
bloody stool.
bismuth subsalicylate (Pepto-Bismol) is a safe alternative in patients with fever and
inflammatory diarrhea.

10. Probiotics
Defined as are live bacteria and yeasts that are good for your health, especially your
digestive system. useful in the treatment of diarrhea. Probiotics include various
Lactobacillus, Streptococcus.
Several pharmacological effects have been attributed to probiotics include:
1. increased disaccharidase activity
2. production of antibacterial substances
3. competition for bacterial adhesion
4. stimulation of various immune defense mechanisms

11. Antimicrobial agents
The requirement for antibiotic treatment in gastro-intestinal infection depends on;
• causative agent
• type and severity of symptoms
• presence of underlying disease .

12. Management
1-Mild to moderate diarrhea:
Metronidazole (oral or intravenous) or vancomycin (oral) for 10 days
2-Severe or complicated disease:
combined therapy with intravenous metronidazole and oral (or per rectum)
vancomycin may be considered .
3-Traveler’s Diarrhea: a digestive tract disorder that commonly causes loose
stools and abdominal cramps. It's caused by eating contaminated food or drinking
contaminated water.

13. ACUTE DIARRHEA
Diarrhea of < 2 weeks duration is most commonly caused by invasive or noninvasive
pathogens and their enterotoxins.
Acute noninflamatory diarrhea
• Watery, non-bloody (stool)
• Usually mild, self-limited
• Caused by virus or noninvasive bacteria
• Diagnostic evaluation is limited
Acute inflamatory diarrhea
• Blood or pus, (stool)
• Usually caused by an invasive or toxin producing bacterium
• Diagnostic evaluation requires routine stool bacterial culture.

14. CHOLERA
• People get cholera from eating fish that is not cooked
enough (contaminated water ).
• The toxin causes diarrheal disease.
• intestine with a risk of subsequent hypovolaemic shock and
renal failure and death.

15. CHOLERA
Cholera is an infection of the intestine by the bacterium Vibrio cholera.
Symptoms: may range from none, to mild, to severe. The classic symptom is
large amounts of watery diarrhea that continuous for few days. Vomiting and muscle
cramps may also occur. Diarrhea can be so severe that it leads within hours to severe
dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin,
decreased skin elasticity, and wrinkling of the hands and feet. The dehydration may
result in the skin turning bluish. Symptoms start two hours to five days after exposure.
Cholera affects an estimated 3–5 million people worldwide and causes 58,000–130,000
deaths a year as of 2010

16. TYPICAL "RICE WATER"
DIARRHEA

17. Cholera can be transmitted by water or by food contaminated with contaminated water.
cholera grows well in warm temperatures, causing marked seasonality in the incidence of
cholera .
Pathogenesis
cholera is a gram-negative becteria , pass through the stomach to small intestine and
produce toxin .The cholera toxin stimulates the intestinal epithelial cells producing
hypersecretion of water and chloride ion and a massive diarrhea.
Death results from hypovolemia.

18. Clinical pointers
1-Abruptly onset of watery diarrhea and vomiting .
2-Large volumes of rice-water stools The liquid stool is without fecal odor, blood, or
pus ("rice water stool") .
3-Dehydration may be severe. Patients suffering from severe dehydration owing to
rapid fluid loss are at risk for death within several hours of disease onset.
4-Metabolic acidosis .
Diagnosis
by Stool cultures .

19. Treatment
1-By replacement of fluids. oral rehydration Solution (ORS) usually is adequate .
2-Intravenous fluids are indicated for persons with signs of severe hypovolemia and those
who cannot take adequate fluids orally .
3- Severe hypokalemia can develop but will respond to potassium given either IV or orally.
4- Antimicrobials administered to patients with cholera decrease the volume of diarrheal
losses, shorten the duration of illness.

20. B- Salmonellae
Salmonellae are enteric gram-negative bacilli that are important because is transmit from
food to humans.
• Nontyphoidal salmonellae (e.g., Salmonella typhimurium and many others) cause the
clinical syndromes of Gastroenteritis.
• Typhoidal salmonellae (Salmonella typhi and Salmonella paratyphi A, B, and C) cause
the syndromes of enteric fever

21. 1-Salmonella Gastroenteritis
• Clinical feature and diagnosis.
Patients with Salmonella gastroenteritis present with an acute fever, diarrhea,
dehydration, and abdominal cramping within 6 to 72 hours of ingestion of
contaminated foods.
• Diagnosis stool culture.
• Treatment
Salmonella gastroenteritis is usually self-limited, and antibiotics have no
proven value. Patients respond well to ORT. Symptoms typically diminish in 3
to 7 days. Antimotility agents should not be used.

22. 2-Enteric Fever
Enteric fever caused by S. typhi is referred to as “typhoid fever,” whereas enteric fever caused
by S. paratyphi is referred to as “paratyphoid fever.”
Symptoms and Signs
1-During the first week, there is an increasing headache, cough, often with abdominal pain and
constipation, while the fever increased gradually.
2-In the second week, the rash (rose spots) but may be very difficult to see . And it disappears in
3–4 days .
3- In third week, intestinal perforation and intestinal hemorrhages may occur.
Not/ Paratyphoid a milder illness than typhoid fever

23. Diagnosis
by blood culture.
Complications:
Usually occurring in the third week . It include Intestinal hemorrhage (may lead to shock),
or intestinal perforation. Other complications such as: pneumonia , meningitis , cholecystitis
and osteomyelitis .
Some patients become chronic carrier ( the patient excrete salmonella from stool for more
than 1 year after infection)

24. Treatment :
1-Fluid uptake and good nutrition.
2-Several other antibiotics, including ampicillin, azithromycin effective for treatment of
enteric fever caused by drug-susceptible strains .
3-The 1–5% of patients who develop chronic carriage of Salmonella can be treated for 4–6
weeks with an appropriate oral antibiotic. Treatment with oral amoxicillin, trimethoprim-
sulfamethoxazole, ciprofloxacin ~80% effective in eradicating chronic carriage of
susceptible organisms.

25. D-Shigellosis
Shigella causes bacillary dysentery (dysentery: refers to a diarrheal stool containing pus and
blood).
Symptoms and Signs
The illness usually starts abruptly, with diarrhea and lower abdominal cramps. The diarrheal
stool often is mixed with blood and mucus. Systemic symptoms are fever, chills, anorexia
and malaise, and headache .
Laboratory Findings Stool culture is positive for shigellae in most cases .P

26. GIARDIASIS
microscopic parasite
E-Parasitic infections:
1-Giardiasis
• Transmitted by contaminated water or food (Symptoms normally begin 1 to 3 weeks after
becoming infected- incubation period )
• Diagnosed by microscopic examination of stool.
Symptoms
•Diarrhea •Gas or flatulence
•Greasy stool that can float
•Stomach or abdominal cramps
•nausea• Dehydration

27. Treatment
1-All symptomatic adults and children over the age of 8 years should be treated with
metronidazole 250 mg three times daily for 7 days, or tinidazole 2 g as a single dose.
2-The pediatric dose of metronidazole is 15 mg/kg per day three times daily for 7 days.
2-Amebiasis
Transmitted by contaminated water or food
Pathology
E. histolytica invades mucosal cells of colonic epithelium lead to tissue necrosis and ulceration .
Sometimes the organisms penetrate the bowel wall and enter the portal circulation, and then it
will be carried to the liver, where it produces abscess and fibrosis .

28. Symptom
1. Intestinal Disease
• Vague abdominal discomfort
• Symptoms may range from malaise to severe abdominal cramps, flatulence, and bloody
diarrhea with mucus . The stools often have an offensive odor .
2- Amebic Liver Abscess
• May present with high fever with significant leukocytosis , and elevated alanine
aminotransferase .
• Physical findings: hepatomegaly, and liver tenderness (a feel of pain when touched ) .
Diagnosis
•Intestinal amebiasis is diagnosed by stool culture.

29. Treatment
1-Metronidazole, diloxanide furoate and paromomycin.
A systemic or tissue-acting agent may be so well absorbed that the amounts of the drug
remaining in the bowel may be insufficient to have local effects .
2-Asymptomatic cyst passers (identified by stool examinations, and who may develop
invasive disease) should receive a luminal agent like diloxanide furoate 500 mg three times
daily for 10 days.
Paromomycin is the preferred agent in pregnant patients .

30. 3-Patients with symptomatic intestinal disease or liver abscess should
receive metronidazole 750 mg three times daily for 10 days, followed by the
luminal agents indicated above since metronidazole does not eradicate cysts
.
The pediatric dose of metronidazole is 50 mg/kg per day in divided doses,
which should be followed by a luminal agent.
Tinidazole administered in a dose of 2 g daily for 3 days is an alternative to
metronidazole. Patients who cannot tolerate oral doses of metronidazole
should receive metronidazole intravenously.

31. THANK YOU