Constipation in Large Animals

Question 1

descrie meconium impaction

Answer 1

1. most neonates will pass meconium within 1-6 hours of nursing
   -passage can be delayed up to 12 hours without concern
2. many farms/practices will practice routine enema administration to assist with passage of meconium
3. meconium retention will ultimately result in impaction and clinical sigs of colic
4. most common in foals!

Question 2

describe clinical signs of meconium impaction

Answer 2

similar to adults:
1. restlessness
2. pawing
3. flank watching
4. repeatedly getting up and down
5. rolling

more specific in foals:
1. tail flagging and straining to defecate
2. dead bugging

Question 3

describe colic workup for meconium impaction

Answer 3

1. NGT
2. abdominal and thoracic ultrasound
3. digital rectal
4. +/- abdominal radiographs, abdominocentesis, gastroscopy

Question 4

describe diagnosis and prognosis of meconium impaction

Answer 4

diagnosis:
1. failure to produce meconium
2. palpation of feces in the rectum by digital palpation
3. demonstration of feces in the colon by ultrasound/radiography

prognosis:
-good with therapy (fluids, laxatives, enemas, and rarely surgery if needed

Question 5

describe atresia coli/recti/ani

Answer 5

1. congenital malformation where lumen of intestinal segment fails to develop appropriately
2. atresia coli: typically spiral colon affected, but can include transverse colon, or descending colon
3. atresia recti: rectum affected
4. atresia ani: anus affected
5. types:
   -membrane atresia: membranous diaphragm occludes lumen

-cord atresia: fibrous band/cordlike intestinal remnant connect blind ends

-blind end atresia: complete absence of a segment with disconnected blind ends and a gap in the mesentery

Question 6

describe clinical signs, diagnosis, treatment, and prognosis of atresia coli/recti/ani

Answer 6

clinical signs:
1. absent feces even after nursing
2. lethargy/dullness
3. decreased appetite
4. colic by 2-3 days old

diagnosis:
1. barium enema
2. barium swallow study

treatment:
1. surgery rarely successful
-lack of intestinal length for anastomosis
-intestinal health often compromised by time of surgery
-even if surgery is successful in short term, complications such a strictures, adhesions, etc are common long term

2. prognosis guarded to grave

Question 7

describe lethal white foal syndrome

Answer 7

1. genetic disorder in overo paint horses
   -mutations in endothelin receptor B gene
   -causes intestinal aganglionosis leading to a non functioning colon
2. clinical signs:
   -affected foals born entirely or mostly white
   -severe colic within first 24-48 hours of life
3. diagnosis:
   -clinical signs and genetic records (if available)
4. client education:
   -prognosis grave
   -avoid breeding two heterozygotes

Question 8

describe rectal prolapse

Answer 8

1. part of rectal wall or the entire rectum protrudes through the anal ring
2. more common in small ruminants and pigs but also occurs in cattle
   -rare in horses
3. mostly secondary to other conditions that cause:
   -tenesmus
   -increased abdominal pressure
   -loss of perianal muscle tone: sheep with tails docked too short can affect innervation of muscles around the anus

Question 9

describe the 4 types of rectal prolapse and prognosis in general

Answer 9

type 1: rectal mucosa and/or submucosa protrudes through anus

type 2: all layers of the rectum protrude through anus

type 3: rectal prolapse plus intussusception of the small colon

type 4: intussusception of the small colon through the anus

prognosis: variable dependent on type, duration, and requirement for medical vs surgical mgmt