Exam 1 - Colonic Disease

Question 1

what is the function of the colon?

Answer 1

secretion & absorption of water & electrolytes - helps firm up feces

production of mucus

motility - segmentation, peristalsis, & mass transmit

immune surveillance & immune tolerance

Question 2

why is the ileocolic valve important?

Answer 2

stops back up from colon into ileum - could cause dysbiosis problem

Question 3

what is the longest part of the colon?

Answer 3

descending colon

Question 4

why does it take longer to see diarrhea from small bowel causes when compared to large bowel disease?

Answer 4

the large bowel compensates for the small bowel, but in large bowel disease, fairly mild disease can cause diarrhea very quickly

Question 5

what is the role of the colonic microbiome?

Answer 5

development of mucosal immune system

energy metabolism of epithelial cells - butyrate, need fermentation of butyrate for energy!!

vitamin synthesis (folate, vitamin K, & biotin)

absorption of complex macromolecules

Question 6

what are some common helminths that cause large bowel disease?

Answer 6

trichuris vulpis & heterobilharzia americanum

Question 7

what are some common protozoal causes of large bowel diarrhea in cats?

Answer 7

tritrichomonas fetus

giardia intestinalis (small bowel in dogs & large bowel in cats)

Question 8

what cats are commonly affected by t. fetus?

Answer 8

common in pure bred cats & shelter cats - typically young cats

Question 9

T/F: some cats infected with t. fetus can be apparently healthy with no clinical signs

Answer 9

true

Question 10

how is t. fetus diagnosed?

Answer 10

fecal direct smear - lacks sensitivity

in-house culture - sensitivity around ~55%

fecal PCR - most sensitive, gold standard!!

Question 11

what is the gold standard test for diagnosing t. fetus infection in cats?

Answer 11

fecal PCR

Question 12

T/F: t. fetus is resistant to metronidazole

Answer 12

true

Question 13

what is the treatment used for t. fetus infections causing large bowel diarrhea in cats?

Answer 13

ronidazole - 30mg/kg every 24 hours for 2 weeks

Question 14

what are the adverse effects associated with ronidazole?

Answer 14

neurotoxicity!!

Question 15

an owner brings in their bengal cat they recently adopted with large bowel diarrhea, this is seen on the fecal - what is it? how do you treat it?

Answer 15

tritrichomonas fetus

ronidazole

Question 16

what are some fungal/mold causes of large bowel diarrhea?

Answer 16

histoplasma capsulatum, phythium insidiosum, & prototheca zopffi

Question 17

what bacterial causes commonly cause large bowel diarrhea?

Answer 17

campylobacter, clostridium perfringens, & clostridium difficile

Question 18

what are the 3 main treatments used for chronic enteropathies of the colon listed in order?

Answer 18

diet trial - if they respond, fiber-responsive colitis

tylosin trial - antibiotic responsive colitis

biopsy then immunosuppressant trial (IBD)

Question 19

what are your main options for diet trials?

Answer 19

intestinal diets - moderately restricted fat content, omega-3 fatty acid supplementation, & high digestibility

exclusion diets - novel protein sources & hydrolyzed antigen

fiber supplementation - psyllium husk, fructooligosacchararides, & canned pumpkin

Question 20

what is a more practical term to use instead of dysbiosis?

Answer 20

antibiotic responsive diarrhea

Question 21

what is dysbiosis?

Answer 21

imbalance in the intestinal microbiota that may be a primary problem or can be secondary to another disease

Question 22

T/F: not every dog with antibiotic responsive diarrhea has dysbiosis & not every dog with dysbiosis has antibiotic responsive diarrhea but there is overlap

Answer 22

true

Question 23

what are the proposed mechanisms in which dysbiosis/antibiotic responsive diarrhea can lead to diarrhea & malabsorption?

Answer 23

competition for nutrients is increased

production of secretory stimulants (think e. coli)

decreased brush border enzyme activity

Question 24

what is the treatment recommended for dysbiosis?

Answer 24

abx - tylosin at 20mg/kg every 12 hours for 4-6 weeks, metro, but know that signs often relapse as soon as meds are stopped

prebiotics - fiber!!!

may try probiotics or potentially a fecal microbiota transplant

Question 25

T/F: IBD can affect any part of the intestinal tract

Answer 25

true

Question 26

T/F: it is unusual for IBD to just affect the colon in dogs

Answer 26

true

Question 27

what is the most common age of onset of IBD? what is the most common clinical sign?

Answer 27

6 years in dogs & cats diarrhea

Question 28

what clinical signs are seen in boxers with e. coli associated granulomatous colitis?

Answer 28

large bowel diarrhea +/- weight loss

Question 29

T/F: in e. coli associated granulomatous colitis, most dogs develop clinical signs prior to 2 years of age

Answer 29

true

Question 30

what is the treatment for large bowel signs in IBD?

Answer 30

intestinal or elimination diet +/- prebiotics anti-inflammatory/immunosuppressive drugs with prednisone/prednisolone being your top choice chlorambucil - add on agent in cats cyclosporine - add on agent in dogs sulfasalazine - for large bowel disease in dogs only!!!

Question 31

what breed of dog is commonly affected by e. coli associated granulomatous colitis?

Answer 31

boxer dogs

Question 32

what is granulomatous colitis?

Answer 32

granulomatous inflammation with PAS positive macrophages & intralesional bacteria that is caused by e. coli

Question 33

how is e. coli associated granulomatous colitis diagnosed?

Answer 33

fluorescence in situ hybridization (FISH) & culture

Question 34

how is e. coli associated granulomatous colitis treated?

Answer 34

enrofloxacin at 10mg/kg every 24 hours for at least 6 weeks

Question 35

why does enrofloxacin need to be prescribed for at least 6 weeks in dogs with e. coli associated granulomatous colitis?

Answer 35

if the medication is stopped, signs of e. coli associated granulomatous colitis will come back

Question 36

this biopsy shows a lesion that is caused by e. coli in the colon - what is it?

Answer 36

granulomatous colitis of boxers

Question 37

neoplasia in the colon is associated with what clinical signs? what finding is commonly detected during a physical exam?

Answer 37

tenesmus & dyschezia, large bowel diarrhea, hematochezia, obstruction, weight loss, & vomiting if the disease is diffus mass detected on rectal exam or abdominal palpation

Question 38

what are the most common tumor types seen in the colon of dogs?

Answer 38

adenocarcinoma, lymphoma, gi stromal tumors, & benign adenomas/polyps/leiomyomas (less common)

Question 39

T/F: large intestinal tumors are more common than gastric & small intestinal tumors

Answer 39

true

Question 40

what are the most common tumor types seen in the colon of cats? what is the general risk of metastasis?

Answer 40

adenocarcinoma, lymphoma, & mast cell tumors high rates of metastasis

Question 41

____________ intussusception accounts for 2/3 of intussusceptions in dogs & cats, & of these, _________ is the most common

Answer 41

enterocolic ileocolic

Question 42

what clinical signs are associated with intussusception?

Answer 42

vomiting, inappetence, diarrhea, +/- abdominal pain - can occur as a complication of acute gi disease

Question 43

what is seen on physical examination of a patient with an intussusception?

Answer 43

may feel a cylindrical mass in the abdomen, may protrude through the rectum

Question 44

how do you differentiate an intussusception from a rectal prolapse?

Answer 44

use a thermometer - if prolapsed rectum, you can't pass it between the prolapse and the anus in patients with intussusception you can pass it

Question 45

how is an intussusception diagnosed?

Answer 45

physical exam, target lesion on ultrasound, & surgical exploration

Question 46

what is the treatment for an intussusception?

Answer 46

surgery - reduce it or R&A

Question 47

what lesion is seen on this ultrasound image?

Answer 47

ileocolic intussusception

Question 48

how are some ways in which signalment helps you when creating your differential list for a patient with colonic disease?

Answer 48

patient age - neoplasia is less likely in young animals young animals are more likely to have infections & dietary intolerance/allergy breed predispositions - think boxers & the granulomatous colitis

Question 49

what are the main clinical signs associated with large bowel disease?

Answer 49

diarrhea & constipation

Question 50

how do you differentiate small & large bowel diarrhea?

Answer 50

small bowel - large volumes of watery diarrhea, normal to mildly increased frequency, no tenesmus or urgency, no mucus, may have melena, & weight loss large bowel - normal to mildly increased volumes, markedly increased frequency, tenesmus & urgency usually present, mucus frequently present, fresh blood can be present, & weight loss is uncommon

Question 51

T/F: a sick patient should have a stress leukogram, so the absence of one suggests addison's disease

Answer 51

true

Question 52

what diagnostic tests should be done for a patient with large bowel disease?

Answer 52

cbc - look for stress leukogram chemistry - evaluate patient for systemic disease that can cause diarrhea & also evaluate for consequences of gi disease ua

Question 53

what is a zinc sulfate fecal centrifugation useful for? how can you increase its sensitivity?

Answer 53

detecting helminths & other parasites pool 3 days worth of feces

Question 54

when is a direct fecal smear useful?

Answer 54

detecting protozoal trophozoites

Question 55

why is it difficult to interpret a positive bacterial culture for salmonella or campylobacter?

Answer 55

healthy dogs & cats can be colonized by these organisms!!! are they just there or are they actually causing an issue

Question 56

what is the best testing used for detecting giardia?

Answer 56

IFA antigen testing

Question 57

why is it hard to establish a causal relationship of clostridium & large bowel diarrhea?

Answer 57

enterotoxin producing strains of clostridium have been found in healthy dogs

Question 58

what clostridium species have been associated with large bowel diarrhea in dogs?

Answer 58

clostridium perfringens & clostridium difficile - both produce enterotoxins

Question 59

what aspect of clostridium actually causes the diarrhea?

Answer 59

the enterotoxins cause the diarrhea

Question 60

what diagnostic test is used for diagnosing phythium?

Answer 60

elisa tests

Question 61

what diagnostic tests are used for diagnosing heterobilharzia?

Answer 61

fecal sedimentation & fecal PCR

Question 62

what diagnostic tests are used for diagnosing histoplasmosis as a cause of large bowel diarrhea?

Answer 62

cytology & EIA for antigen in serum or urine

Question 63

when are survey abdominal rads most useful for patients with gi problems?

Answer 63

better used when the patient has vomiting as well as diarrhea

Question 64

when is rectal scraping especially useful as a diagnostic tool for animals with large bowel disease?

Answer 64

may be used to detect infectious agents such as histoplasmosis/prothecosis performed on conscious/mildly sedated dogs

Question 65

what is the stage 1 in approaching chronic large bowel diarrhea?

Answer 65

rule out parasitism using a fecal float/sedimentation & deworm with fenbendazole (50mg/kg by mouth every 24 hours for 3 days) do a diet trial with a highly digestible diet

Question 66

what is the stage 2a in approaching chronic large bowel diarrhea?

Answer 66

rule out systemic disease - not often seen with large bowel diarrhea - CBC, chem, UA, FeLV/FIV snap test in cats

Question 67

what is the stage 2b in approaching chronic large bowel diarrhea?

Answer 67

further fecal testing - look for t. fetus in cats, giardia antigen testing in cats, & may test for heterobilharzia may do diagnostic imaging - rads/ultrasound

Question 68

what is the stage 3 in approaching chronic large bowel diarrhea?

Answer 68

therapeutic trials - novel protein or hydrolyzed antigen diet, add soluble fiber to the diet, antibiotic trial with tylosin +/- probiotics & fecal transplant

Question 69

what is the stage 4 in approaching chronic large bowel diarrhea?

Answer 69

abdominal ultrasound +/- rads if they haven't been done yet intestinal biopsy for upper & lower gi tract or surgical biopsy (not commonly done on the colon)

Question 70

what is the stage 4 in approaching chronic large bowel diarrhea?

Answer 70

abdominal ultrasound +/- rads if they haven't been done yet intestinal biopsy for upper & lower gi tract or surgical biopsy (not commonly done on the colon)

Question 71

what is constipation?

Answer 71

infrequent or difficult evacuation of feces

Question 72

what is obstipation?

Answer 72

intractable constipation that is refractory to treatment

Question 73

what is megacolon?

Answer 73

abnormal dilation of the colon resulting from constipation or obstipation

Question 74

what is dilated megacolon?

Answer 74

end stage disease due to the loss of motility

Question 75

what is hypertrophic megacolon?

Answer 75

megacolon due to obstruction that is potentially reversible

Question 76

what are some obstructional causes of constipation?

Answer 76

luminal mass, mural mass, extra-mural issue

Question 77

T/F: painful defecation can be a cause of constipation

Answer 77

true - anal fistulas

Question 78

what are the 2 categories of neuromuscular causes of constipation?

Answer 78

primary & secondary

Question 79

what is the most common cause of constipation in cats?

Answer 79

idiopathic megacolon

Question 80

what is the general approach that should be taken for an animal that presents with constipation?

Answer 80

rule out drugs that reduce gi motility rule out metabolic disease - CBC, chem, urinalysis, & TT4 rule out obstruction - abdominal rads, +/- u/s, biopsies

Question 81

what medications are used for treatment for constipated patients?

Answer 81

hyperosmotic laxatives - lactulose or miralax colonic prokinetics - cisapride (need to have it compounded!!)

Question 82

what therapies are used for patients that are constipated?

Answer 82

removal of impacted feces - rectal suppositories, enemas, & manual extraction surgery

Question 83

what patients are colectomies reserved for?

Answer 83

cats that are refractory to medical management - try to preserve the ileocolic valve