GI infections and toxins

secretory diarrhea

-increase in secretion or inhibition of absorptiom

-large volume without inflammation

-common cause = infection, pancreatic insufficiency

inflammatory diarrhea

-bloody diarrhea with fever

-common cause = invasive organisms

-pathogens invade and penetrate the intestinal epithelium and invade deeper tissues

osmotic

-excess water drawn into bowel lumen

-common cause = malabsorption, maldigestion, consumption

stool culture

-obtaining a sample of patients stool and sending it to lab for culture

fecal lactoferrin and stool leukocyte stains

-indicate presence of WBC in stool and signify inflammation

-distinguish inflammatory from secretory or osmotic

-can be seen in IDB, TB, amebic infection, bacterial infection

Ova and parasite testing

-stool sample examined by lab for ova and parasites

NAAT testing

-PCR

-detect presence or absence of bacteria in stool

toxin assay

-test for presence of toxin released by certain bacterial strains

invasive diarrhea (Gram -)

Bloody +/- mucous, fever, tenesmus, pain

-enterohemorrhagic E coli

-shigella

-salmonella

-campylobacter jejuni

-yersinia enterocolitica

enterohemorrhagic E coli diarrhea

-cause: E coli O157:H7

-shiga toxin

-5-10 days

-undercooked ground beef

Sx: severe cramps, bloody diarrhea, fever, potential for HUS

Dx: PCR or EIA

Tx: supportive care

-avoid abx

shigella

-cause: shigella species, gram - rod

-1-7 days

-fecal oral transmission, contaminated food/water, common daycare setting

Sx: bloody diarrhea, cramping, pain, fever, tenesmus

Dx: PCR

Tx: replace fluids

-azithromycin or cipro if severe

salmonella

-cause: salmonella species, gram - rod

-4-7 days

-contaminated poultry, egg shells

-Sx: watery diarrhea, cramps, fever, septicemia common

Tx: supportive care

-cipro or ceftriaxone for severe

campylobacter

-cause: campylobacter jejuni, gram - curved rod

-2-5 days

-undercooked poultry, unpasteurized milk, contaminated water

Sx: watery or bloody diarrhea, cramps, fever, potential for Guillain Barre

Tx: supportive care

-azithromycin and cipro in severe case

yersinia

-cause: yersinia enterocolitica, gram - coccobacillus

-unpasteurized milk, contaminated water, puppy or big exposure

Sx: fever, pain, diarrhea, mesenteric adenitis, mimic appendicitis

-erythema nodosum, reactive arthritis

Dx: stool culutre on CIN agar

Tx: supportive care

-cipro or TMP-SMX for severe

non-invasive diarrhea (Gram -)

-Watery, cramping, nausea, vomiting

-enterotoxigenic E coli diarrhea

enterotoxigenic E coli diarrhea

-cause: E coli

-travelers diarrhea

-1-5 days

-contaminated food or water

Sx: watery diarrhea, cramps, nausea, low grade fever

Dx: PCR or EIA

Tx: supportive care

-azithromycin or cipro if severe

cholera

-cause: vibrio cholerae, gram - curved shaped rod

-2-3 days

-contaminated water, unsanitary conditions, poor hygiene, travel to epidemic areas

Sx: profuse, watery diarrhea, (high volume)

-rapid dehydration

Dx: stool culture

Tx: aggressive hydration

-doxycycline = first line for adults

-azithromycin = pregnant or child

helicobacter

-helicobacter pylori is a gram -, curved/spiral, microaerophilic bacillus

-multiple flagella, urease +, catalase +, oxidase +

Sx: epigastric pain, N/V, bloating, weight loss, IDA, B12 deficiency

-chronic gastritis, peptic ulcer disease gastric adenocarcinoma, MALT lymphoma

Dx: urea breathe test

-endoscopy

Tx: omeprazole + clarithromycin + amoxicillin or metro for 14 days

bacterial GI illness (Gram +)

-clostridium difficile

-listeria

clostridium difficile

-colonize the gut after normal flora disruption > produces toxin A and B

Etiology: after abx use (clindamycin), PPI use

Sx: watery diarrhea, abdominal pain, fever, nausea, loss of appetite

Dx: NAAT, EIA for toxin A and B

-colonoscopy: pseudomembranous colitis

Tx: discontinue offending agent

-oral vancomycin or fidaxomicin

listeria

-listeria monocytogenes, gram + bacilli

-severe infection in neonates, immunocomp, elderly

Etiology: in soil, water, decaying vegetation, raw sprouts

Sx: fever, neck stiffness, headache, altered mental, neuro deficits, signs of meningitis

-healthy people will have flu like sx

Dx: blood culture, CSF, placental fluid

Tx: IV ampicillin or penicillin G

-TMP-SMX

nonbacterial infectious diarrhea

-giardia

-norovirus

-rotovirus

giardia

-most common intestinal parasite in US

-cause: giardia duodenalis

-high risk for hikers who drink unfiltered water

Sx: foul smelling fatty stool

Dx: stool culture

Tx: tinidazole

norovirus

-12-48 incubation period

-contaminated food/water, person to person, common in closed setting

Sx: sudden onset of vomiting, watery diarrhea, abdominal cramping

-1-2 days

Dx: clinical

Tx: supportive care (BRAT diet)

rotovirus

-2 day incubation

-fecal oral, most common cause in infants

Sx: rapid onset of dehydration in young children, watery diarrhea, vomiting, fever

-5-8 days

Dx: fecal EIA testing

Tx: supportive

toxin mediated disease

-clostridium botulinum

-corynebacterium

-bacillus anthracis

botulism

-cause: clostridium botulinum , gram + bacilli

-ingestion of contaminated home canned foods, ingestion of honey <1 yo

-block release of acetylcholine > flaccid paralysis

Sx: sudden onset, fluctuating severe weakness, preserved sensation, progressive, blurred vision, dryness, nasal speech, weakness

Dx: EMG studies, notify local health authority

Tx: heptavalent anti toxin

diptheria

-cause: corynebacterium diphtheriae, gram + bacillus

-spread by respiratory secretion

Sx: tenacious gray membrane covers the tonsils and pharynx

Dx: bacterial culture

Tx: remove membrane surgically

-diptheria anti-toxin

-oral penicillin or erythromycin x 14 days

-Dtap vaccine

anthrax

-cause: bacillus anthracis, gram + encapsulated spore forming bacilli

-fatal when inhaled

-contact via infected animals through butchering, ingestion of raw meat

Sx: stage 1 = flu like sx

-stage 2 = mediastinitis, respiratory failure

Dx: PCR, serologic testing, immunohistochemistry

-blood culture, lesion swabs

-chest x ray, CT

Tx: cutaneous: ciprofloxacin 500 mg IV or doxy and + antrasil, raxibacumab, obiltoxaximab

-GI antrax: IV cipro + clindamycin + antitoxin

-postexposure: doxy or cipro + vaccine

tetanus

-cause: clostridium tetani

-found in soil > produces an exotoxin called tetanospasmin

Tx: -human tetanus immunoglobulin

-tetanus toxoid vaccine

-IV metronidazole

-benzos and pancuronium

-short acting BB, IV mag sulfate, vasopressor

-intubation and tracheostomy

Prevention: Tdap/Td vaccine every 10 years

-booster in cases of potentially contaminated wound 5 or more years after regular visit