Acute diarrhea

- a self-limitng condition resulting from al alteration in bowel habit with an increase in frequency and decrease in consistency of stool.

- associated with increased stool weight (> 200g/day - Normal, 50-150 g/day)

- our GI gets about 10L of fluid a day, and we absorb 80% in the small intestine and 20% in the colon.

- fluids are secreted into the intestines via crypt cells.

- Intestinal water absorption and secretion are passive, and follow an osmotic gradient created by the active transport of Na.

What are the 2 main types of diarrhea? Describe Secretory.

What are the 2 main types of diarrhea? Describe osmotic. OH wait there's actually 5.

There are 5 main types (not 2!) of diarrhea. Describe Inflammatory.

*Note that this means that the other ones are not inflammatory, although I guess the one due to penetrating organisms probably is.

Inflammatory: caused by destruction of the bowel mucosa leading to impaired absorption and associated with an outpouring of blood and mucous. Small, frequent stools with blood and pus. Fever. Ex; enteroinvasice pathogens such as Entamoeba histolytica (amebiasis), Shigella dysenteriae (Shigellosis) and ulcerative colitis.

There are 5 main types of diarrhea, describe decreased absorptive surface type

There are 5 types of diarrhea, describe diarrhea due to motility disorders

What is diarrhea of generalized malabsorption?

They describe one specific mechanism of how a bacteral toxin and a virus could cause diarrhea. If you can remember it name it if not just read.

Bacterial toxin: changes the way that the epithelial cell secretes electrolytes (CL- for example) into the lumen. Some will activate adenyl cyclase receptors, which then activate cyclic AMP, and then that stimulates the secretion of ions into the lumen where water will follow. This is thus a secretory diarrhea.

Viral or bacterial enteroinvasion: you loose mature absorptive surfaces resulting in immature secretory surfaces.

What are some of the factors that will affect a host's ability to fight off invasion?

- gastric acid, intestinal motility, normal bowel microflora and Ig secretion.

- personal hygiene and sanitation (mostly the infectious agents are fecal-oral)

- PPis and other ant-acid meds make it harder for the stomach to eat up bacteria

- drugs like opiates and anti-cholinergics slow down the gut

What types of organisms will infect kids and cause diarrhea but not so much adults?

We often think of bacteria, viruses, protozoa and parasites as the cause of diarrhea, what else could cause it?

Name some bacteria that cause enterotoxins

- Aeromonas Hydrophila

- Bacillus cereus

- C. diff

- C. perfringens

- E. coli

- Shigella dysenteriae

- Staph aureus

- Vibrio cholerae

- Yersinia enterocolitica

Name some organisms that destroy intestinal mucosa

Viruses: Norwalk, Rotavirus

Bacteria: Campylobacter fetus (subspecies jejuni), E. coli, Salmonella, Shigella, Yersinea entercolitica

Protozoa: Cryptosporidium, Entamoebas, Giardia lamblia

Some helminths and intestinal nematodes.

Describe some factors that will affect the morbitity and mortality of infectious diarrhea

Host factors: malnutrition, immunosupression

Therapeutic factors: failure to recieve oral rehydration therapy and/or antimicrobial therapy

Microbial factors: Rotavirus infection in children, invasive organism (esp Shigella spp), Enterotoxigenic bacteria (esp Vibrio cholorae)

What is mucosal adherence?

Describe neurotoxin production in enteropathic organisms.

Neurotoxins:

- Most common is Staphylococcal enterotoxin b which leads to food poisoning (violent nausea, comiting and diarrhea with rapid convalescence, incubation 1-8 hrs).

- Bacillus cereus can make 2 diff types of toxin mediated food poisoning. Emetic type associated with rice dishes. Diarrhea type associated with meat and sauce and incubates 1-24 hrs.

- Clostridium botulinum

Toxins causing neuro symptoms (numbness, weakness, tingling and resp paralysis)

- tetrodotoxin from puffer fish (blocks neural Na+ channels)

- Botulinum toxin (blocks Ach release)

- Ciguatoxin from snapper fish (opens neural Na+ channels)

Describe the pathological factor "mucosal invasiveness"

- the ability of the bacteria to penetrate the intestinal mucosa and destroy the epithelial cells causing a dysentery-like-syndrome.

- Shigella spp, Campulobacter spp, Yersinia spp. (Sisters Shigella and Yersinia both with the last name spp are camping in your gut! Little sisters camping trip!)

What do enterotoxins do to the gut?

- they promote fluid secretion but do not damage the intestinal mucosa.

- Vibrio Cholera, ETEC, Salmonella, C. diff, Camplyobacter spp, Toxin A Clostridium perfringens type A. *We just saw that campylobacter can destroy mucosal cell, but let's suppose it doesn't always have to

- so you get water diarheaa but not bloody.

What do cytotoxins do to the gut?

- they destroy the intestinal mucosa which causes inflammatory colitis and dysentery.

- Shigella dysenteriae, E coli 0157:H7, C. diff, Salmonella spp, Campylobacter spp. (*C diff also appeared in the enterotoxin category)

What should you think of when you see watery diarrhea?

- here you have a non-inflammatory process (no fecal leukocytes). N/V occur frequently but cramping, abdominal pain, arthralgias, myalgias, chills and fever are rare. This is due to bacterial enterotoxins that alter fluid and electrolyte transport. Prototype is V. cholerae.

- Other organisns are rotavirus (most common in children.. a "norwalk agent...) and Giardia lamblia (the protozoan which causes Beaver fever)

What would a pt with Cholera look like?

- it's one of the watery non-inflammatory diarrhea types

- mediated by toxins

- incubation of a few hours to 5 days, onset of profuse, watery diarrhea or anorexia and abdominal discomfort followed by diarrhea. "Rice water" stool may have a mild fishy odor.

- tenesmus (feeling like you have to poop all the time) is rare, vomitting may occur sevral hours after the diarrhea.

- some proceed quickly to hypovolemic shock.

- Fever is ABSENT

- muscle cramps may come on because of electrolyte imbalance.

What is Dysenteric Syndrome?

Acute dysentry: involves colon and sometimes distal small bowel. Lots of leukocytes in teh feces, so diffuse colonic inflammation or invasion of the colonic mucosa.

- Culprits: Shigella spp, EPEC, Salmonella spp., Yersinia entercolotiica, C jejuni, V parahaemolyticus, E coli 0157:H7.

- That last one can cause HUS! Others can cause that and other complications as well.

What is pseudomembranous colitis?

- you get it when you take Abios, esp clindamycin, amoxicillin and the beta lactams. (This can come on during or long after tx), presentation variable in severity

- overgrowth of C diff is the major point here. C diff makes Toxin A-enterotoxin and Toxin B-cytotoxin, resulting in colonic membrane damage.

- sigmoidoscopy shows small, raised pseudomembranous nodules or plaque.

- Complications: severe diarrhea, hypovolemic shock, toxic megacolon, peritonitis, cecal perforation, hemorrhage and sepsis.

What is enteric fever?

- it's an acute systemic illlness characterized by fever, headache and abdominal discomfort. Usually caused by Salmonella typhi and is referred to as Typhoid fever, however, other Salmonella spp. may cause similar but less severe clinical syndromes. (spp means species)

- S. Typhi is a water and food borne microorg for which humans are the only natural host. Oral ingestion then they must traverse the acid barrier as well as various pancreatic enzymes, bile, and intestinal secreation and secretory IgA, which are effective antimicrobial facors. In a post-gastrecomy state, hypochlorohydria, altered intestinal motility and prior abios can predispose.

- Incubation is 5-21 days. They move to the small bowel and replicate in the Peyer's atches. Go into the blood through the lymph and replicate in RE cells in lymph nodes, liver, bone marrow and spleen.

- Onset of symptoms is gradual, non-specific symptoms like fever, headache and abdominal pain. Diarrhea occurs in bout 50%.

- Abdominal tenderness, hepatosplenomegally, evanescent maculopapular rash in the upper abdomen and lower thorax (Rose spots), bradycardia and mental confusion.

- Complications may be related to recurrent bacteremia with dissemination of the microorganisms. Could cause GI bleed.

What is travelers diarhea?

- the passage of 3 or more unformed stools per day in a resident from an industrialized country traveling in or returning from a developing nation. Usually happens within the first 2 weeks.

- Enterotoxigenic E coli is the most common isolated organism.

- almost always self limiting, rarely lasts more than 5 days.

- pain and cramping, a minority develop fever.

Name some diagnostic evaluations we can use for someone with diarrhea

- fecal leukocyte test

- stool culture and O and P

- Toxin analysis (for C diff as well as others)

- Direct visualization (proctosigmoidoscopy or colonoscopy) - would show plaques of pseudomembranous colitis or ulcerations comaptible with amebiasis.

- Upper endoscopy

How do you manage C diff?

First episode: Metronidazole 500 mg po tid for 10 days.

Second episode: same

Thrid episode: Vancomycin 125 mg po qid and rifampin 600 po bid for 7 days.

Describe Ascaris lumbricoides

- aka Ascariasis (nematodes, round worm)

- fecal oral (cough up worm)

- gives transient pneumonia type syndrome, GI obstruction, malabsortion, diarrhea

- tx with albendazole or mebendazole

* This is the grossest thing in the world. I couldn't ASK for anything grosser, I'm about do BENDazole over and barf.

Describe Ancylostoma duodenale, necator americanus

- aka Anculostomiasis (subclass: hookworm) *these are both types of hookworms

- skin penetration (walking on beaches, soil)

- cause Fe- deficiency anemia

- tx: Albendazole, mebendazole

*These guys look like fuckin mosters. Necator really hooks on to you! I still gotta bend-ova to barf!

Strongyloides stercoralis

-aka strongyloidiasis (subclass: threadworm) (nematodes, round worm)

- skin, gut penetration

- walking in mud

- causes immunocompromization, Hyper-infection syndrome where you can get gram negative sepsis. The strongoloides penetrates gut and meninges, then the gut bacteria can enter blood and CSF.

tx: ivermectin or albendazole.

*looks smaller and a tiny bit less gross, but it seems it's more dangerous than the others!

Enterobius vermicularis

- subclass: pinworm - nematodes (round worm)

- fecal-oral, kid with itchy bum at night. Can do scotch tape test over anus.

- mebendazole

* I'll still have to bend over a barf.

Giardia lamblia

- aka giardiasis or beaver fever.

- oral *enteroadhesive with suckers, causes malabsorption

- bloating, cramping, large volume greasy diarrhea

- tx: metronidazole

*You get Beaver Fever when you're far from the metro. Looks like a little cartoon character.

Entamoeba histolytica

- aka amebiasis, protozoa

- fecal-oral, enteroinvasive

- flask shaped colon ulcer, bloody diarrhea and pain, liver abcess "anchovy paste"

- With cysts: paromomycin

- diarrhea only: metronidazole

- hepatic abcess, metronidazole and iodoquinol

Cryptosporidium parvum

- Cryptosporidiosis, protozoa

- fecal-oral, swimming pools,

- this is a thing that immunocompromized ppl get!

- watery diarrhea, immunocompromized, fulminant diarrhea

- if healthy, it self resoved, if immunocompromized, give paromomycin

*Crypt like you're going to die of AIDS. You want your mom.

Microsporidia

Potential: inhale or oral

- biliary tract inf. in HIV pts.

- albendazole

Cyclospora spp

- fecal oral

- Guatemalan strawberries

- watery diarrhea around with around 1 mo non-specific GI

- albendazole

- Protozoa

Isospora spp

-rare, oral

- watery diarrhea

- healthy: self limiting

- immunocomp: TMP/SMX

Do the sample questions of the coop of GI045

What could you treat a kid with bloody diarrhea with before you knew what it was?