Colonic Dz's Flashcards by Sydney Randall

The mucosa of the LI does not have what?

NO villi!

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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

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What does the LI secrete?

Mucos and bicarb

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What does LI absorb?

Water, Na, Cl,

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What 5 clinical signs are colonic dz are UNIQUE to colonic dz?

blood on or in stool
mucus on stool
tenesmus
dyschezia
urgency

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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

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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

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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

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CT is favorable for large colon dz bc it evaluates what?

Evaluates intrapelvic structures-distal colon, rectum, anal canal

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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

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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

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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

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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

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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)

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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

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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.

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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.

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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

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Blue arrow: How do we tx T. Vulpis?

ONCE A MONTH FOR 3 MONTHS!!!
Fenbendazole 3 days
DRONTAL PLUS

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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

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What clinical signs are associated with H. americanum?

V & large bowel diarrhea +/- small bowel
Wt loss
Inappetence
These pets are SICK

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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

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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

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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

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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

How do we tx prototheca and what's our prognosis?

Amphotericin B + Itraconazole Prognosis: grace for disseminated Guarded for cutaneous

Campylobacter and Clostridium are both what?

They 're both pathogenic bacteria of the LI.

Campylobacter jejuni is gram -, spiral shaped bacteria. Enteroinvasive in animals and is obviously especially bad in stressed or immunocompromised animals bc everything is worse in them. But at least it's not zoonotic, right?

False! It IS zoonotic.

C. jejuni causes acute or chronic colitis (large bowel signs), pyrexia and anorexia. When we do a direct fecal smear for diagnosis, what are these guys gonna look like?

Slender seagull shaped bacteria

T/F C. jejuni is part of normal flora so we don't tx healthy carrier.

True. We would give Erythromcin and Tylosin to ill pets

Clostridium difficile is gram +, anaerobic rod. Toxin ___ & ____ are associated with the clinical disease.

Toxin A & B A: secretory diarrhea and tissue damage B: inflammation and necrosis of tissue

T/F We should consider C. difficile to be zoonotic.

Si, consider it to be zoonotic.

In what species is C. difficile a big problem in?

Humans

How do we dx C. difficile?

Pinshaped spores on fecal smear PCR and ELISA for toxins

What is our tx and prognosis of C. difficile?

Metronidazole Good prog

What is the trigger for stress colitis?

The name gives it away. It's associated with a stressful event like boarding, dr visit, moving to London etc Results in ACUTE large bowel diarrhea that is often self limiting so we don't really worry about tx

What is inflammatory colonic disease?

The same motha fuckin thing as in SI. You have intestinal signs and don't know what's going on. ****Affected animals fail response to parasiticides, antibiotics and diet**** On histopath --> mucosal changes include inflammatory infiltrates Can involve stomach +/- SI +/- LI

What diet trial for we try for colitis cases?

``` Hydrolyzed Novel antigen Low residue diets- prolonged time in gut High fiber diets Addition of fiber to meal- bind those babies up Prebiotics (psyllium) ```

What is the following describing? Addition of fermentable fiber is VERY helpful for some pets with colitis These fibers are fermented to short chain FA's by large intestinal flora They are a useful energy source for healthy flora and great beneficial environment for development of normal enterocytes

PREbiotics

What are some examples of PREbiotics?

Beet pulp Psyllium husks- Konsyl powder Fructooligosaccharides (resist fermentation in SI)

Chronic diarrhea without apparent pathogens, infection, inflammation or neoplasia. Patient responds to highly digestible diet with a soluble fiber or fiber supplement. That description is for what disease?

Fiber Responsive Dz Similar to Minimal Change Enteropathy but FIBER responsive

Blue box: What are the antibiotics we use for LI?

Metronidazole and Tylosin IF RESPONSIVE, USE FOR ONE MONTH THEN TRIAL OFF Caviate- if suspicious of HUC (Histiocytic Ulcerative Colitis) then get biopsy first

The following clinical summary describes what group of disease? Middle aged to older patients Large bowel diarrhea w occasional wt loss Good general body condition Palpation --> usually normal unless thickening or intussusception Rectal exam --> mass lesions (including polyps), pain, stricture Negative fecal and dewormed w no or minimal response *Lymphoplasmacytic predominates* When deworming, diet and antibiotics fail --> consider immune suppressant therapy

Inflammatory bowel diseases !

What is the numero uno breed that we see with Histiocytic Ulcerative Colitis (HUC)?

#1 Breed = BOXERS! . . . usually young animals

What will the US of an HUC patient show us?

Diffusely or segmentally thickened colonic wall . . can also be normal

**What will the histopath of HUC show us?

Multiple inflammatory cells including macrophages = GRANULOMATOUS INFLAM **PAS positive macrophages**: PAS stains intracytoplasmic phagocytized bacteria

When diagnosing HUC, we biopsy AND culture using what?

FISH- fluorescent in situ hybridization (not an actual fish bc fish are friends, not food) FISH is a technique used in molecular biology to ID bacteria within formalin fixed tissues

T/F Immunosuppression is an important aspect to managing HUC.

FALSE. DO NOT IMMUNE SUPPRESS THESE PATIENTS!!! ***Baytril for at least 8 weeks or longer pending resolution of clinical signs LONG TERM REMISSION HIGHLY POSSIBLE Stopping early will breed resistance = terrible prognosis So give the goddamn medicine every day like you're supposed to for the full 8 weeks.

Most neoplasias found in the colon and rectum are malignant. Which neoplasias are over represented in cats and dogs?

Adenocarcinoma and lymphosarcoma = C & D Mast cell = C

T/F Surgical biopsy is the best dx method for neoplasia.

False ***Avoid cutting into colon whenever you can!!***

This is the most common cause of extraluminal obstruction in the colon.

What is enterocolic intussusception.

Where is the #1 location for intussusceptions?

#1 = ileocolic

Intussusceptum = ______ part and intussuscipiens = ______ part.

``` Intussusceptum = INSIDE part Intussuscipiens = OUTSIDE part ```

**How do we differentiate a true intussusception from a rectal prolapse?

You're gonna do some anal fingering. An examining finger CAN be passed btwn the prolapse and the anus in patients with intussusception but NOT in patients with rectal prolapse.

Which species is more likely to have constipation problems?

Cats > Dogs

Megacolon is often seen in what age and species?

Middle aged male cats but can happen to any species or age

Blue box: T/F The majority of constipation, obstipation and megacolon cases are idiopathic. NO underlying dz and normal biopsy in up to 96% of cases.

True

What are the presenting complaints for animals with megacolon?

"Only pooping once every 4 days" "Spends 5-10 mins in litter box" "Vocalizing" "Vomiting" bc straining so hard Reduced, painful or absent fecal production- multiple unproductive attempts are defecation, vocalization

What does the PE of an animal w megacolon look like?

Normal appearance, weak, dehydrated, abdominal palpation-YOU CAN FEEL IT! Rectal: +/- lymphadenopathy, mass lesions, strictures, pelvic narrowing

Blue box: Do NOT consider sx on megacolon until non-responsive to _______ and ______.

Non responsive to diet and medical therapy !!

How do we tx megacolon?

Medications, diet modification, enemas (may need initial hospitalization for hydration and initiation of medical management), sx (recurrent obstipation)

What is the MOA for laxatives?

Stimulate fluid and electrolyte transport and can increase propulsive motility.

How does emollient laxatives work and give an example.

Increases lipid absorption and impairs water absorption. | Dicotyl sodium sulfosuccinate

Plz give examples of bulk forming laxatives.

Psyllium, wheat bran, pumpkin

How do lubes work as a laxative?

Prevent water reabsorption; useful in mild cases; mineral oil or white petroleum; not good for depressed cats d/t aspirate risk

How do hyper osmotics work as a laxative?

``` Poorly absorbed polysaccharides Lactulose Stimulate colonic secretion and propulsive motility Magnesium salts Polyethylene glycol ```

How do stimulant laxatives work?

Propulsive motility | Bisacodyl

Cisapride is an example of what kinda drug?

Prokinetic! Cisapride is also used for vomiting. | Stimulates colonic smooth m

Okay, so what are the 3 rectal suppositories that actually help us get the poop out?

1. Glycerine (lubricant) 2. DSS (emolient) 3. Bisacodyl (stimulant)

What kind of enema should you never give?

Fleet enema or any with sodium phosphate - severe electrolyte disturbances

Mixalaxx can also be used instead of ______

Lactulose

T/F Fluid overload is possible with enemas.

True

Clicker question: A french bulldog presents to you for chronic colitis signs. You determine via biopsy that he has granulomatous colitis. Your FISH stains are pending. Tx should include: A. Steroids until signs resolve then taper B. Diet change C. Enrofloxacin until results received and if positive, give for at least 8 weeks D. Deworming for 5 days

C. Enrofloxacin until results received and if positive, give for at least 8 weeks bc if doing a FISH test then that means that we've already done a diet change and deworming.