What is D+?
excessive fecal water:
• +/- increased frequency
• +/- increased fluidity
• +/- increased volume
Can you have severe SI dz without D+?
- yes, since the colon has the ability to resorb a lot of water → still able to cope
- often when we see D+, the colon's ability to do so has been overwhelmed
What are pathophysiological causes of D+?
• Osmotic
• Secretory
• Increased permeability
• Motility disorder
*** can have a mix of the first 3
What are usual causes of acute D+?
1. diet → check diet
2. parasites → fecal exam
3. infectious diseases → history (i.e., evidence of contagion or exposure), CBC, fecal enzyme-linked immunosorbent assay for canine parvoviral antigen, and the exclusion of other causes.
What should you first examine patients with chronic D+ for?
- parasites → multiple fecal examinations looking for nematodes, Giardia, and Tritrichomonas are indicated
What is the most reliable indication that an animal has large bowel dz?
What might be an exception?
What other CS/hx would you expect if an animal has lost wgt due to chronic D+?
- failure to loose wgt
- However, animals with colonic histoplasmosis, pythiosis, lymphoma, or similar infiltrative diseases may have weight loss despite large bowel involvement
- usually obvious signs of colonic involvement (i.e., fecal mucus, marked tenesmus, hemato- chezia)
WHy must you be careful with using the presence of tenesmus for differentiating LB from SB?
- ask when it was first noted??
- if did not begin until late in the course, it may be due simply to perineal scalding or anal soreness resulting from chronic irritation
What are categories for chronic SI D+?
What are two forms of malabsporptive dz's?
1. maldigestion
2. nonprotein-losing malabsorptive disease
3. protein-losing malabsorptive disease.
What is maldigestion primarily caused by?
- exocrine pancreatic insufficiency (EPI)
- rarely causes significant hypoalbuminemia
What is the most sensitive and specific test for EPI in dogs? cats?
serum trypsin-like immunoreactivity (TLI)
**indicated in dogs with chronic small intestinal diarrhea
EPI is rare in cats, but if suspected, an fTLI (feline TLI) is recommended
What are other possible test for EPI?
- Film digestion tests for fecal trypsin activity
- Sudan staining of feces for undigested fats
- fat absorption tests
*** many false-negative and false-positive results.
Is it recommended to treat an animal for EPI if suscpected and monitor response to tx? Why?
no
- up to 15% of dogs with EPI do not respond when enzymes are added to their diet → If EPI is incorrectly ruled out in such a case, then unnecessary endoscopies or operations often result.
Why is it important to definitively diagnose or rule out EPI before proceeding with other diagnostic tests or treatments?
false-positive diagnosis of EPI results in the unnecessary supplementation of expensive enzymes
What should you do if the animal has apparently responded to pancreatic enzyme supplementa- tion?
enzymes should be repeatedly withheld and then readministered to ensure that the enzymes are responsible for resolution of the diarrhea
When does D+ occur usually in malabsorptive dz?
Can an animal have wgt loss but no D+?
- if the absorptive capacity of the colon is exceeded
- Therefore a dog or cat can be losing weight because of small intestinal malabsorption and not have diarrhea (see the section on weight loss)
What are R/o's for hypoproteinemia?
1. protein-losing nephropathy
2. hepatic insufficiency
3. skin lesions,
What might be some additional tests done for nonprotein-losing malabsorptive disease?
- intestinal biopsy
- design therapeutic trials depending on how ill the patient is.
For what conditions are therapeutic trials often used to dx?
- antibiotic responsive enteropathy (ARE)
- dietary responsive disease.
**must be done properly, long enough, correct dose
Why might you do an US and biopsy first If the patient seems particularly ill (e.g., substantial weight loss) or if PLE is suspected?
spending 2 to 3 weeks waiting to see if a therapeutic trial will work can be disasterous if the therapy is incorrect and dz progresses
Why are diagnostic tests such as, abdominal imaging (especially ultrasonography) followed by gastroduodenoscopy or colonoscopy typically next steps ?
can help determine the cause of PLE and nonpro- tein-losing enteropathies in patients that do not have ARE or dietary responsive disease
What might US show?
lymphadenopathy or intestinal infiltrates that can be aspirated percutaneously.
What are some advantages of a scope to laparotomy?
quicker and safer than laparotomy and may allow the clinician to biopsy lesions not seen from the serosal surface
What should you ensure if the patient is hypoproteinemic and you plan a laparotomy?
use nonabsorbable suture material and/or perform intes- tinal serosal patch grafting.
What is suggestive of lymphangiectasia?
presence of distended intestinal lymphatics or lipogranulomas
What are some main possible reasons for an intestinal biopsy not showing a cause to the intestinal dz?
1. specimens were inadequate (e.g., notdeep enough, from the wrong place, toomuch artifact)
2. the animal has occult giardiasis
3. the animal has ARE
4. has dietary intolerance
5. there is localized lymphangiectasia or inflammation at a site other than the one biopsied
What is osmotic D+?
• due to increase in undigested solutes in bowel
• Unabsorbed solute retains water
• Overwhelms absorptive capacity of colon
• Bacterial degradation of unabsorbed substances
What are some reasons for the presence of the undigested soluted?
- EPI → malabsporption
- paper eating
Is osmotic D+ life threatening?
- no
- little acid base electrolyte changes
- other types of D, loose stuff
What are tx options for osmotic D+
1. NPO 24 hours → nice because responds to fasting
2. change diet (helps control)
3. enzymes
Why would it be better to give a solution of water with glucose then water alone for rehydration?
- glucose → facilitated water transport
- so get more absorption of water then if used water alone
What are causes of acute osmotic D+?
o Damage to villus tips → corona, inappropriate food ie: bones
o Ingestion of poorly absorbed substance
o Ingestion of large meal
o Abrubt dietary change
What are causes of chronic osmotic D+?
o EPI
o Diffuse small intestinal mucosal disease
*** this will need more testing
What is secretory D+?
What does it result in?
- Increased intestinal secretion → Active electrolyte loss
- loose water and electrolyte imbalances/losses
What are examples of causes of secretory D+?
• E. coli toxin increased Na dependent Cl secretion
• Campylobacter and Salmonella
• Hydroxyfatty acids and bile salts
Why are we a bit more concerned about disorders of permeability?
- likely to loose electrolytes and proteins
- more likley to get systemically ill as bacteria can translocate
What might we see if there are structural damage to the barrier?
What might be causes? 3
- hemorrhagic exudates and compromise of barrier function
- hookworm (very severe form of D+can loos puppies), HGE, parvo
What does parvo do to the GI tract?
- denudesd the entire GI tract
- transport of material from the body into the GI and translocation of bacteria into the body
What are concerns about HGE?
- V+, ± blood
- barrier issues because of blood in stool
- think about possibility of translocation
- regarding AM, no concrete answer of when to use
- signs of systemic illness
What is HGE?
- not sure what causes it, can be a lot of things
- a set of CS with:
• N blood proteins
• usually do not become anemic
Small vs. Large Bowel diarrhea:
• Frequency
• Volume
• Urgency/tenesmus
• Mucus
• Blood
• Food
• Weight loss
• Steatorrhea
What are some major causes of acute D+?
• diet
• parasites → usually not, unless whip
• infections (viral, bacteria)
*cause is rarely diagnosed because most affected animals spontaneously improve, although supportive therapy may be needed.
What are categories of Acute D+? 3
1. non-fatal, self limiting
2. secondary to other disease
3. severe, life threatening → if systemically ill, be concerned
What are some non fatal, self limiting causes for acute D+?
1. intestinal parasites
2. dietary
3. drugs
4. toxins
What are some dietary related causes for acute D+?
o intolerance, hypersensitivity
o indiscretion
o rapid change
o bacterial toxins, poor quality
What are some severe, life threatening causes for Acute D+?
• Viral → parvo, corona
• Bacterial → Salmonella, Campylobacter, Clostridium, etc.
• Misc.
• HGE
For which viral infection should you always hospitalize?
- parvo, even if they look good now, won't later!
Describe minimum workup for acute D+?
Minimum data base
o History
o Physical examination
o Fecal exam
o PCV/TP
What are possible additional tests you can do in more sever and persistant cases of acute D+?
o CBC
o Chemistry screen w/electrolytes
o amylase/lipase
o radiographs
o ultrasound
o fecal culture
o Parvo elisa or EM
o FeLV/FIV
What particular test would you want to do in cases of persistant D+?
- biopsies → especially if treating for awhile
What is the therapy for acute D+?
1. Dietary modification → consider fasting
2. Maintain hydration (oral, SC, IV)
3. Correct electrolytes, acid-base or biochemical abnormalities
4. +/- antibacterials
5. Antiparasitics
Are antidiarrheals needed in acute D+ cases?
• Seldom necessary
• Ideal motility modifier
o increase segmental contractions
o decrease peristalsis
What drug is the most effective at motility control? Why?
Opiods → affect motility and water/electrolyte transport
What might be part of you tx plan for Acute D+?
1. diet
2. Maintain hydration → Correct electrolytes, acid-base or biochemical abnormalities
3. +/- antibacterials
4. Antiparasitics
5. antidiarrheals
6. GI protectants
How are GI protectants hepful in case of acute D+?
• Act locally in intestine
• Absorb bacteria and toxins
• Protective coating on mucosa