Colonic Dz's Flashcards
The mucosa of the LI does not have what?
NO villi!
The colon lacks large villi which are invaginations of surface epithelium to form intestinal crypts. What DOES The LI have ?
Crypts of Lieberkuhn; tubular crypts which extend the entire thickness of mucosa. They have mucous producing cells = Goblet cells = MANY MORE THAN IN SI
Cell turnover is slower than in SI: 4-7 days
What does the LI secrete?
Mucos and bicarb
What does LI absorb?
Water, Na, Cl,
What 5 clinical signs are colonic dz are UNIQUE to colonic dz?
- blood on or in stool
- mucus on stool
- tenesmus
- dyschezia
- urgency
T/F Weight loss and vomiting are signs of colonic disease.
FALSE
NO wt loss unless SI also involved OR advanced dz= inappetence . .. so they’re losing weight bc NOT eating as opposed to losing weight bc of malabsorption . . . makes sense bc LI doesn’t do absorbing of nutrients anyways
NO vomiting
Blue box: T/F Not uncommon for mixed bowel diarrhea to occur.
True!
Mixed bowel meaning SI + LI bowel components and thus, lots of testing recommendations overlap
We’re basically gonna do a shit ton of tests for everything always but what are some reasons why we do rads with large bowel dz?
Obstruction Constipation Megacolon Extraluminal masses +/- intraluminal Negative contrast colonogram: inflate air into empty colon- may highlight intraluminal masses Enlarged sublumbar LNs
CT is favorable for large colon dz bc it evaluates what?
Evaluates intrapelvic structures-distal colon, rectum, anal canal
T/F The ileocolic jxn, cecum and colon are thin walled structures.
True- about 1-2 mm so if seeing thickened layers on US, loss of layers etc then we’ll want to aspirate
When are colonoscopies useful?
When non GI dz ruled out, evidence of gross dz present on imaging and need biopsy, no abnormal findings on imaging and clinical signs support LI dz
What is the preparation an process involved in colonoscopies?
24-36 hour fast with preparation
Enemas before and under GA
Oral polyethylene glycol which is an OSMOTIC LAXATIVE
Blue box: Describe what should normally be seen on a colonoscopy and what we should be looking for.
Normal: pink, smooth, “glistening” (graphic), w frequent peristalsis
Biopsy abnormal tissues & normal tissues!
Evaluate for foreign material and parasites
What 6 parasitic infections can we see in large bowel (just to keep ourselves organized)?
- Whipworms: Trichuris vulpis
- Heterobilharzia americana
- Tritrichomonas fetus
- Giardia: Protozoal (seen and discussed in SI)
- Hisoplasmosis: Fungal (seen and discussed in SI)
- Pythium: Fungal/ algae (seen and discussed in SI)
Trichuris vulpis is a whipworm that can cause acute or chronic large bowel diarrhea. Dog > cat (tropical bc all bad things happen in the tropics). Fecal organ contamination so eating all the bad eggs (as opposed to dating all the bad eggs). Eggs hatch in SI and large eventually migrate to cecum +/- colon. What clinical signs do we see?
Asymptomatic Hematochezia Mucoid diarrhea Tenesmus Worse w worm burden- fucking obviously
Blue Arrows: T/F You can see Trichuris vulpis dz before you see eggs in their feces.
True. Eggs in feces 74-90 days AFTER infection.
Blue Arrows: T/F T. vulpis is v persistent.
True! Larvae develops inside egg in topsoil (taking 9-26 days to become infective) and infective eggs may persist for YEARS in the environment.
What are some important clin path changes we see with T. vulpis?
Can see HYPERK and HYPONa: PSEUDO-ADDISON’S DZ (ACTH stim results are NORMAL): pathogenesis not well understood –> may include metabolic acidosis and decreased renal excretion with dehydration
Blue arrow: How do we tx T. Vulpis?
ONCE A MONTH FOR 3 MONTHS!!!
Fenbendazole 3 days
DRONTAL PLUS
Heterobilharzia americana is a ‘schistosomiasis.’ Trematode= flukes. It is found predominately in Gulf coast US states so TX and LO. Acute or chronic LI diarrhea. Their reservoirs are mice, rabbit, RACCOONS. How does the process work through their IH?
Snail releases cercariae –> cercariae penetrates skin of dogs and migrates from lung to liver –> portal vein –> mesenteric veins where they lay eggs which secrete proteolytic enzymes –> intestinal mucosa and eggs are shed
Migrate into bowel wall= granulomatous inflammation
Eggs in circulation = disseminated dz
What clinical signs are associated with H. americanum?
V & large bowel diarrhea +/- small bowel
Wt loss
Inappetence
These pets are SICK
H. americanum affects other organs- not just large bowel. Because of this, we can expect to see what on our clin path?
HYPOAlb
HYPERGlob
Increased liver enzymes
HYPERCa
How do we dx and tx H. americanum?
Fecal sediment analysis w saline = BEST yield for eggs!!
Fecal float = POOR FOR EGG ID!!
Tx: Fenbendazole
Entamoeva histolytica is an uncommon cause of dz in cats and dogs but we do see it in YOUNG and IMMUNOCOMPROMISED animals. It prefers the cecum and colon BUT can move to other organs such as liver, lungs, brain and genitalia.
T/F E. histolytica is zoonotic.
True. Human –> pet transmission
Fecal oral
How do we tx E. histolytica?
Metronidazole or Furazolidone
Tritrichomonas foetus is an important mofo. We will see this protozoa frequently. It lives in the descending colon and cecum and causes chronic diarrhea. What species and age do we see it in a lot?
YOUNG CATS. It loves those young pussies.
Usually less then 1 YO, up to 2 yrs
Crowded housing –> shared litter boxes and mutual grooming
Survives in “moist” (her word, not mine) environment for hours to days
NOT zoonotic
What clinical signs do we see w T. foetus?
Waxing and waning LI diarrhea Tenesmus *Painful edematous rectum* Fecal incontinence *Common history: do well on antibiotics then reoccurs and is eventually self limiting*
**When diagnosing T. foetus, don’t fuck up and confuse it with what other parasite?
Giardia!!
T. foetus= progressive, forward movement, rolling motility, undulating membrane vs. Giardia ‘falling leaf’
**What diagnostic method should we use for T. foetus and why?
PCR bc most sensitive and specific !!
**How do we tx T. foetus? They’ve got burning butts so we gotta help them, right?
Nah, it typically resolves on its own in 9 months without therapy bc it’s self limiting BUT we can give them Ronidazole if we dx them . . . only problem w this drug is neuro signs possible
Prototheca is a toxic algae species found in soil and sewage. Blue green algal bloom. Clinical signs are V & D, ataxia and rapid death. Where do we see lesions occur?
Cats: cutaneous
Dogs: CNS, ocular and large bowel signs; chronic disease –> disseminated dz
How do we dx prototheca?
Rectal scraping