Constipation

Question 1

What is the difference between constipation, obstipation and megacolon

Answer 1

Constipation is the infrequent and difficult evacuation of feces with retention of feces within the colon and rectum

Obstipation is applied when prolonged constipation results in stool becoming harder and drier and feces can no longer be passed

Megacolon is the result of dysfunction of the colonic smooth muscle which can be idiopathic or secondary to chronic distension
- megacolon can also be defined as dilation of the colon to more than 1.5 times the length of the fifth lumbar vertebra in a cat that is also refractory to medical and dietary management

Question 2

What would be your main differentials for constipation

Answer 2

Drugs
- opiates
- anticholinergics
- sucralfate

Behavioral
- stressors (e.g., changes in the home)
- litter box aversion

Difficulty defecating
- pain in rectal or perineal area
- orthopedic problems
- neurologic problems

Fecal factors
- excessive fecal bulk

Colon factors
- mass: intra- or extra-luminal
- obstruction due to narrowed pelvic canal (e.g. from previous trauma)

Miscellaneous
- dehydration (e.g., due to CKD)
- idiopathic megacolon

Question 3

What radiographic finding is very suggestive of megacolon

Answer 3

Enlargement of the colon beyond 1.5 times the length of the body of L5 indicates chronic dysfunction and megacolon

Question 4

Explain why sodium phosphate containing enemas must not be used in cats

Answer 4

Because they can induce severe hypernatremia, hyperphosphatemia and hypocalcemia in cats