Ch 48 Large intestine Flashcards
Which species has a distinct ileocolic and cecocolic valve?
canine
which is feline and which is canine?
A canine
B feline
What are the 4 theories of pneumatosis coli?
Bacterial, Mechanical, Mucosal damage, Pulmonary disease
Narrowing and irregularity of the descending colon are present immediately cranial to the air- inflated catheter cuff. This was due to spasm associated with insertion of the catheter. B, The spasm was transient based on a subsequent radiograph made several minutes later.
Dose for barium enema to fill entire colon
7-15 ml/kg
Which radiographic technique might help for subtle mucosal lesions of the colon?
double-contrast study performed by removing as much of the barium as possible and then inflating the colon with room air through the catheter
What should be differentiated from ulcers in the canine colon, and feline colon and cecum?
mucosal lymph follicles; they can appear as spicules (barium enema) or pinpoint radiopacities (double contrast)
Can you evaluate the colon after per os barium?
No, there is inadequate distension and there will be filling defects from ingesta/faeces
Which contrast is normally used for an enema study, and which if a colonic rupture is suspected?
Barium for a routine (barium) enema study
15-20% non-ionic aqueous iodine for suspected rupture
What is the downside of using aqueous iodine as contrast when colonic rupture is suspected?
Mucosal detail will be diminished compared to barium
What are the causes of transient colonic spasm?
- narcotic premedications
- cold contrast medium
- irritation of the wall by the catheter
meniscus sign > intussusception (in this case: ileocecocolic in a dog)
dog with a pelvic fibroleiomyoma that caused partial colonic obstruction and fecal accumulation
Generalized megacolon in a young dog due to Hirschsprung’s disease, which is a congenital deficiency in colonic innervation. Note the increased opacity of the fecal material due to inspissation
Normal canine colon diameter
< L7 length
Normal feline colon diameter
2.2x SI diameter
<1.3 L5 length
<2.8 L2 endplate
____________ is clinically defined as infrequent and reversible fecal retention,______________ as permanent but reversible loss of colonic function, and______________ as permanent and irreversible colonic distension.
Constipation;
obstipation;
megacolon
A ratio of _____ between colonic diameter and L5 length in cats, is suggestive of megacolon.
1.5
Which spinal anomalies can lead to megacolon?
Cauda equina syndrome
Sacrocaudal agenesis in Manx cats
Which metabolic disorders can cause megacolon?
hypokalemia
hypothyroidism
What are some mechanical causes of colonic obstruction?
pelvic narrowing (malunion fractures)
prostatomegaly
lymphadenomegaly
colonic masses
barium enema of a cat with an ileocolic intussusception. The intussusceptum creates a filling defect in the barium. Edema and swelling of the intussusceptum create a coiled-spring appearance to the filling defect; this is typical of the appearance of the intussusceptum in a barium enema.
what do A, BL C and D represent?
medial iliac lymphadenomegaly, secondary to anal sac adenocarcinoma in a dog
prostatomegaly
images a, b, c (not bottom right)
dog with a colonic volvulus. The large comma-shaped or C-shaped distended bowel segment in the cranial abdomen is typical of a colon torsion. Also, the cecum (C) is located dorsally and on the left, and the transverse colon (T) is in the mid-abdomen.
Barium enema in a dog with a colon torsion showing the twist in the descending colon.
dog with localized colitis, characterized by nondistensibility and mucosal irregularity of the distal portion of the descending colon
dog with a benign colonic stricture of unknown etiology.
dog with a mass (arrows) creating a polypoid filling defect in the mid-portion of the descending colon. The diagnosis was lymphoma.
Which segments are missing in feline short colon syndrome?
ascending and transverse colon; this leads to leftward displacement of the ileocolic junction.
What does a hyperechoic band in the colonic muscular layer represent?
fibrous tissue of the mesenteric plexus, separating the inner circular and outer longitudinal tunica muscularis (normal finding)
What do hypoechoic submucosal micronodules represent in canine colons and feline cecums and colons?
Enlarged lymphoid follicles; in the feline cecum, they can coalesce to form a follicular layer.
They can be found in asymptomatic patients, but some studies suggest it represents active inflammation or neoplasia if there is concurrent wall thickening or loss of layering.
In the dog, to which lymph node is the white arrow pointing?
right colic
Dorsal rectal wall thickening (between arrowheads) due to submucosal bleeding in a Labrador retriever that sustained trauma.
When measuring the colon to compare
with the length of L5 to determine
megacolon in cats with highest accuracy
(76.9% sensitivity, 84.6% specificity),
a) measure the colon at at the maximum
diameter (a)
b) measure the colon at the pelvic inlet (b)
c) measure the colon at the level below L5,
by drawing a perpendicular line (c)
d) measure
a) measure the colon at at the maximum
diameter (a)
Which of the following involves a mechanical etiology of megacolon?
a) Manx syndrome
b) Hirschprung’s disease
c) Hypothyroidism
d) Key-Gaskell Syndrome
e) Pelvic fracture malunion
e) Pelvic fracture malunion
