Chronic Diarrhea

Question 1

What are the main differences between the diarrhea due to small bowel disease vs large bowel disease?

Answer 1

Small bowel:
- large volume of feces
- normal or increased frequency of defecation
- flatulence, steatorrhea
- melena (tarry, black)
- weight loss
- vomiting may occur

Large bowel
- small volume of feces
- increased frequency of defecation
- mucous in the feces
- hematochezia (frank, red)
- tenesmus
- pain or urgency to defecate

Question 2

What are the main differentials for chronic small bowel diarrhea in dogs?

Answer 2

Primary Gastrointestinal:
- IBD (food or steroid responsive or antibiotic responsive/dysbiosis)
-lymphangiectasia (primary or secondary)
-parasites (giardia, roundworms, hookworms)
-histoplasmosis
-dietary indiscretion
- neoplasia

Systemic (extra GI):
- Addison’s
- Exocrine pancreatic insufficiency
- hepatobiliary disease
- chronic renal failure

Question 3

What is lymphangiectasia?

Answer 3

Lymphatic lacteals in the small intestine are present in the small intestine to help absorb fat from the diet
- with lymphangiectasia they do not empty correctly and become distended (can rupture and cause irritation of intestinal lining)
-also leads to lack of protein absorption and protein loss
-most common in yorkies (primary)
-can also be secondary to neoplasia (lymphoma), food allergies, steroid responsive IBD, etc

Question 4

What would increase suspicion of histoplasmosis in a chronic small bowel diarrhea case?

Answer 4

Fever, skin lesions, ocular lesions, lung signs

Question 5

If you are very worried about parasites in a small bowel diarrhea case, what steps should you take?

Answer 5

Should run 3 separate zinc sulfate tests or send out fecal for PCR
- it is also ok to empirically deworm

Question 6

What are the normal protein findings with antibiotic responsive IBD?

Answer 6

Often do not become hypoproteinemic

Question 7

What is the best test for ruling out Addison’s disease?

Answer 7

Basal cortisol
- needs to be 2 or lower to rule out addisons

Question 8

How can you rule out EPI?

Answer 8

Run a TLI test

Question 9

What is the only food on the market that is both hydrolyzed and low fat?

Answer 9

Purina HA

Question 10

When should a diet trial not be opted for in small bowel diarrhea cases?

Answer 10

In patients with moderate to severe hypoalbuminemia
- they are at risk for severe effusions
- in these cases imaging should be performed + maybe biopsy

Question 11

How can you diagnose lymphangiectasia?

Answer 11

Endoscopy
- can grossly see dilated lacteals
- should also take biopsies for histopath for confirmation (lymphoplasmacytic inflammation)

Question 12

What are the breeds that are predisposed to Primary intestinal lymphangiectasia?

Answer 12

Soft coated wheaten terriers, norwegian lundehunds, yorkies, maltese, shar pei

Question 13

What are the main consequences of PLE?

Answer 13

• Thromboembolic disease
• vitamin deficiencies and malnutrition (can become vitamin D deficient and subsequently hypocalcemic- check ionized)
• poor oncotic pressure leading to pleural effusion, pulmonary edema, abdominal effusion and limb edema

Question 14

What are some options for pulmonary edema due to a PLE?

Answer 14

Plasma, human albumin

Question 15

What is the treatment for primary intestinal lymphangiectasia?

Answer 15

Strict prescription low fat diet long term (royal canin GI low fat, Hills i/d low fat, Purina HA)
- if mild inflammation is present on histopath but primary lymphangiectasia is still suspected, anti-inflammatory prednisone may be considered if not readily responding to treatment

Question 16

What is the treatment for secondary intestinal lymphangiectasia?

Answer 16

Treatment focuses on underlying cause (such as steroids for IBD)
- low fat diet is used concurrently
- may consider hypoallergenic low-fat diet if food allergies have not been ruled out

Question 17

If a patient has lost a lot of weight from lymphangiectasia and is not gaining it back, what is an option to supplement calories/fat which is not absorbed through the lacteals?

Answer 17

Medium chain triglycerides

Question 18

If you suspect lymphangiectasia but cannot get definitive diagnosis through biopsies, what should be your plan of action?

Answer 18

Start with low fat diet (ideally hypoallergenic as well) for 3 weeks
- if not or only partial response start on prednisone 1 mg/kg/day for potential inflammation associated with primary lymphangiectasia
- if no response to that increase to 2 mg/kg per day for potential steroid responsive IBD

Question 19

What test can you run to rule out histoplasmosis?

Answer 19

Urine antigen test

Question 20

What are the main differentials for large bowel diarrhea?

Answer 20

• Histiocytic/ulcerative colitis (most common in young boxers and frenchies)
• inflammatory bowel disease (food responsive, antibiotic responsive or steroid responsive)
• parasites (whipworm, giardia)
• fiber responsive
• histoplasmosis
• prototheca (more common in southeast)
  -clostridium perfringes
• neoplasia (adenocarcinoma)
• irritable bowel syndrome

*Much less likely to be due to a secondary disease

Question 21

What is the treatment for histiocytic/ulcerative colitis?

Answer 21

Enrofloxacin as it is due to invasive Ecoli species
- will NOT respond to steroids