Gastroenteritis

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Gastroenteritis Microchapters
Patient Information
Overview
Classification
Differential Diagnosis
Prevention

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

Overview

Acute gastroenteritis and diarrhea are among the leading causes of seeking medical care. Approximately, 48 million cases occur annually that cost about $150 million for the U.S. health care system. Gastroenteritis is defined as inflammation of the stomach or intestinal mucosa. It typically presents with acute diarrhea, fever, nausea and vomiting, anorexia and crampy abdominal pain and is defined as passage of loose stool for at least 3 times per day for less than 14 days. It may be cause by viruses, bacteria or parasites. Most cases of acute gastroenteritis are caused by viruses and among them, Norovirus is the most common etiology for adults. Other common viral causes include, Rotavirus, Adenovirus and Astrovirus. Common bacterial causes of gastroenteritis include, Escherichia coli sp, Salmonella sp, Yersinia enterocolitica and Vibrio sp that can cause watery diarrhea and Shigella sp and Campylobacter sp that can cause dysenteric diarrhea. Parasites are other causes of gastroenteritis especially in developing countries which Giardia lamblia and Entamoeba histolytica are the most frequent causes. First step in management of this patients is to evaluate the hydration status and vital signs. Once the patient is stabilized proceed to diagnostic evaluation. There are some principles to decrease the risk of acquiring infection which include, using safe water and foods, avoid unsafe foods during traveling and hand washing.

Classification

Abbreviations: ETEC: Enterotoxigenic Escherichia coli, EPEC: Enteropathogenic Escherichia coli, EHEC: Enterohemorrhagic Escherichia coli, EAEC: Enteroaggregative Escherichia coli, EIEC: Enteroinvasive Escherichia coli, SARS: severe acute respiratory syndrome

Gastroenteritis

Viral

Bacterial

Parasites

Common

Less Common

Common

Less Common

Helminthic

Protozoal

❑Rotavirus ❑Norovirus ❑Enteric Adenovirus ❑Astroviruses

❑Kobuviruses ❑Enterovirus ❑Orthoreovirus ❑Torovirus ❑Coronavirus (including SARS) ❑Parvovirus

Gram Positive

Gram Negative

Gram Positive

Gram Negative

❑Trichinella spiralis ❑Trichuris trichiura ❑Strongyloides stercoralis ❑Taenia solium ❑Taenia saginata ❑Diphyllobothrium latum ❑Schistosoma mansoni

❑Giardia lamblia ❑Entamoeba histolytica‡ ❑Cryptosporidium parvum ❑Cyclospora cayetanensis

❑Clostridium perfringens ❑Clostridium difficile

Dysenteric diarreha

Watery diarrhea

❑ Bacillus cereus ❑Listeria monocytogenes

❑Bacteroides fragilis ❑Aeromonas hydrophila

❑Shigella sp., ❑Campylobacter sp.

❑Escherichia coli (ETEC, EPEC, EHEC, EAEC, EIEC)§ ❑Salmonella sp.† ❑Yersinia enterocolitica† ❑Vibrio cholerae ❑Vibrio parahemolyticus

§ EHEC, EIEC, EPEC and EAEC may cause bloody diarrhea, but they are classically associated with watery diarrhea.
† Either Salmonella and Yersinia can cause dysentery.
‡ Entamoeba histolytica may cause dysentery

Differential Diagnosis

Organism			Age predilection	Travel History	Incubation Size (cell)	Incubation Time	History and Symptoms			Diarrhea type∞				Food source	Specific consideration
							Fever	N/V	Cramping Abd Pain	Small Bowel	Large Bowel	Inflammatory	Non-inflammatory
Viral	Rotavirus		<2 y	-	<102	<48 h	✔	✔	-	✔			✔	-	Mostly in day cares, most common in winter.
	Norovirus		Any age	-	10 -103	24-48 h	✔	✔	✔	✔			✔	-	Most common cause of gastroenteritis, abdominal tenderness,
	Adenovirus		<2 y	-	105 -106	8-10 d	✔	✔	✔	✔			✔	-	No seasonality
	Astrovirus		<5 y	-		72-96 h	✔	✔	✔	✔			✔	Seafood	Mostly during winter
Bacterial	Escherichia coli	ETEC	Any age	✔	108 -1010	24 h	-	✔	✔	✔			✔	-	Causes travelers diarrhea, contains heat-labile toxins (LT) and heat-stable toxins (ST)
		EPEC	<1 y	-	10†	6-12 h	-	✔	✔	✔			✔	Raw beef and chicken	-
		EIEC	Any ages	-	10†	24 h	✔	✔	✔		✔		✔	Hamburger meat and unpasteurized milk	Similar to shigellosis, can cause bloody diarrhea
		EHEC	Any ages	-	10	3-4 d	-	✔	✔		✔	✔		Undercooked or raw hamburger (ground beef)	Known as E. coli O157:H7, can cause HUS/TTP.
		EAEC	Any ages	✔	1010	8-18 h	-	-	✔		✔		✔	-	May cause prolonged or persistent diarrhea in children
	Salmonella sp.		Any ages	✔	1	6 to 72 h	✔	✔	✔		✔	✔		Meats, poultry, eggs, milk and dairy products, fish, shrimp, spices, yeast, coconut, sauces, freshly prepared salad.	Can cause salmonellosis or typhoid fever.
	Shigella sp.		Any ages	-	10 - 200	8-48 h	✔	✔	✔		✔	✔		Raw foods, for example, lettuce, salads (potato, tuna, shrimp, macaroni, and chicken)	Some strains produce enterotoxin and Shiga toxin similar to those produced by E. coli O157:H7
	Campylobacter sp.		<5 y, 15-29 y	-	104	2-5 d	✔	✔	✔		✔	✔		Undercooked poultry products, unpasteurized milk and cheeses made from unpasteurized milk, vegetables, seafood and contaminated water.	May cause bacteremia, Guillain-Barré syndrome (GBS), hemolytic uremic syndrome (HUS) and recurrent colitis
	Yersinia enterocolitica		<10 y	-	104 -106	1-11 d	✔	✔	✔		✔	✔		Meats (pork, beef, lamb, etc.), oysters, fish, crabs, and raw milk.	May cause reactive arthritis; glomerulonephritis; endocarditis; erythema nodosum. can mimic appendicitis and mesenteric lymphadenitis.
	Clostridium perfringens		Any ages		> 106	16 h	-	-	✔		✔		✔	Meats (especially beef and poultry), meat-containing products (e.g., gravies and stews), and Mexican foods.	Can survive high heat,
	Vibrio cholerae		Any ages	-	106-1010	24-48 h	-	✔	✔	✔			✔	Seafoods, including molluscan shellfish (oysters, mussels, and clams), crab, lobster, shrimp, squid, and finfish.	Hypotension, tachycardia, decreased skin turgor. Rice-water stools
Parasites	Protozoa	Giardia lamblia	2-5 y	✔	1 cyst	1-2 we	-	-	✔	✔			✔	Contaminated water	May cause malabsorption syndrome and severe weight loss
		Entamoeba histolytica	4-11 y	✔	<10 cysts	2-4 we	-	✔	✔		✔	✔		Contaminated water and raw foods	May cause intestinal amebiasis and amebic liver abscess
		Cryptosporidium parvum	Any ages	-	10-100 oocysts	7-10 d	✔	✔	✔	✔			✔	Juices and milk	May cause copious diarrhea and dehydration in patients with AIDS especially with 180 > CD4
		Cyclospora cayetanensis	Any ages	✔	10-100 oocysts	7-10 d	-	✔	✔	✔			✔	Fresh produce, such as raspberries, basil, and several varieties of lettuce.	More common in rainy areas
	Helminths	Trichinella spp	Any ages	-	Two viable larvae (male and female)	1-4 we	-	✔	✔		✔		✔	Undercooked meats	More common in hunters or people who eat traditionally uncooked meats
		Taenia spp	Any ages	-	1 larva or egg	2-4 m	-	✔	✔	✔			✔	Undercooked beef and pork	Neurocysticercosis: Cysts located in the brain may be asymptomatic or seizures, increased intracranial pressure, headache.
		Diphyllobothrium latum	Any ages	-	1 larva	15 d	-	-	-	✔			✔	Raw or undercooked fish.	May cause vitamin B12 deficiency

∞Small bowel diarrhea: watery, voluminous with less than 5 WBC/high power field

Large bowel diarrhea: Mucousy and/or bloody with less volume and more than 10 WBC/high power field
† It could be as high as 1000 based on patient's immunity system.

Prevention

Non travel setting

• Contaminated foods are major causes of foodborne illness in the United states.
• To prevent food preparation chain from contamination, every steps of this process including, products in the farms, packaging industries, stores, restaurants and individuals in the home who are buying and preparing food must be take in to consideration.
• Proper maintaining the filtration systems at water plants is also essential.
• Avoid consuming unpasteurized milk or soft cheeses.
• Frequent and effective hand washing and alcohol-based hand sanitizers.
• Rotavirus vaccination is recommended for all infants unless there is a contraindication for it.

Travel setting

• A simple rule is, boil it, cook it, peel it, or forget it!
• Use bottled water or boil all drinking water while on outdoor adventures.
• Frequent and effective hand washing and alcohol-based hand sanitizers especially for cruise travelers.
• Chemoprophylaxis with Bismuth subsalicylate (BSS) has been shown to reduce the frequency of TD when used during period of risk for 3 weeks. The recommended dose of BSS for TD prevention is two tablets four daily doses at mealtimes and at bedtime. BSS could be used for trips up to 2 weeks.
• Offer the typhoid vaccine to travelers going to countries with high prevalence of typhoid fever.