Gastroenterology, Pt. 5 Flashcards
Diarrhea; what is it? general properties
- Abnormal fluidity and/or frequency of fecal discharges
- Increased fecal water content
> Amount of fluid delivered by ileum > colonic absorptive capacity
> Increases fecal fluidity and/or volume (also from non-digestive content) - Increased frequency of defecation
> Due to increased fluidity and/or volume
> And/or primary alterations of motility - Enterosystemic cycle of fluid absorption and secretion
>- >98% of all fluid absorbed, most in jejunum, best in colon
MECHANISMS OF DIARRHEA (4)
1) Osmotic (villi)
2) Secretory (crypts)
3) Increased permeability (exudative)
4) Altered motility
- Disruption of enterosystemic cycle
- More than one mechanism often involved
osmotic diarrhea - how does it occur?
(villi)
* Unabsorbed nutrients (dietary overload, maldigestion, malabsorption), bacterial products
Secretory diarrhea - how does it occur?
(crypts)
* Bacterial enterotoxins, prostaglandins (inflammation), fatty acids
Increased permeability - how does it occur?
(exudative)
* Ulceration, inflammation, or neoplastic infiltration lead to leakage of fluid and ions ± proteins and red cells
Altered motility diarrhea - how does it occur?
- Increased peristalsis (primary rare), may occur as a consequence of increased fecal volume
- Decreased segmental contractions (common)
SMALL VS LARGE BOWEL DIARRHEA - why differentiaite?
- Severity of illness
> Takes less disease to cause large bowel diarrhea - Differential diagnoses
- Where to biopsy
small vs large bowel diarrhea:
frequency
small: N to slight up
large: up to super up
small vs large bowel diarrhea:
volume
small: N to slight up
large: down
small vs large bowel diarrhea:
mucous
small: no
large: likely
small vs large bowel diarrhea:
fecal blood
small: melena
large: hematochezia
small vs large bowel diarrhea:
steatorrhea
small: possible
large: no
small vs large bowel diarrhea:
borborygmus
small: possible
large: unlikely
small vs large bowel diarrhea:
tenesmus/dyschezia
small: no
large: common
small vs large bowel diarrhea:
attitude
small: more depressed
large: less depressed
small vs large bowel diarrhea:
hydration
small: more dehydrated
large: less dehydrated
small vs large bowel diarrhea:
weight loss (if chronic)
small: probable
large: uncommon
small vs large bowel diarrhea:
appetite (if chronic)
small: increased or decreased
large: often normal
bristol stool chart: what does it tell us
way of scoring poop based on texture
- 1 super hard balls, 7 liquid
- 4 is best
purina fecal score - what does it tell us
1 is hard lumps, 7 is liquid
- 2 is best
ACUTE COLITIS
¡ Differential diagnoses:
¡ Dietary change
> May also cause acute enteritis (small bowel)
¡ Clostridium perfringens, C. difficile?
¡ Giardia, Whipworms (Trichuris)
¡ Idiopathic (often recurrent)
> Irritable bowel syndrome (IBS)
> “stress-induced colitis”
¡ Acute pancreatitic colitis
ACUTE COLITIS: TREATMENT
- Same decision criteria as with acute vomiting, but hematochezia is not as much of a concern as melena or hematemesis
- Treatment of acute diarrhea: 3 “S”
> Supportive, symptomatic, specific - Fluid therapy
> Fluid losses occur via osmosis, secretion, exudation
> if dog is still drinking and normally hydrated no treatment given - Dietary restriction/change
- Do not routinely use “typical antibiotics [e.g. amoxicillin]” with simple acute diarrhea
- Motility modifiers
- Adsorbents
- Anti-inflammatory agents
- consider deworming if history of colitis without dietary change
what type of dietary change would we recommend for colitis treatment
- “Bland diet” – no spices
- Highly digestible – max number of nutrients absorbed in small intestine
- Absorptive surface disturbed, so want to reduce osmotic effect
- Want to decrease secretion from bacterial action on nutrients
- Proteins with high biological value
- Fats often reduced although highly digestible
- Complex carbohydrates – cooked white rice highly digestible
- Low fibre
- Commercial GI foods
- Home-made: rice, cottage-cheese, boiled chicken
do we usually use antibiotics to treat acute colitis? which ones? why? drawbacks?
¡ Do not routinely use “typical antibiotics [e.g. amoxicillin]” with simple acute diarrhea > Metronidazole or tylosin
- Metronidazole and tylosin have been frequently used in the management of chronic & recurrent idiopathic colitis
> Effect on GI microbial flora (treatment for dysbiosis)
> Effect on specific pathogens (Clostridium spp.)
> Local anti-inflammatory and immunosuppressive effects
> However, can promote dysbiosis and reductions of essential bacteria* - Some animals receive long-term therapy
are antibiotics for acute colitis encouraged? why?
- Short-term use may actually cause long-term dysbiosis
- Routine use being discouraged
- Most acute diarrhea resolves without use of antibiotics
- If compelled to give a treatment, consider a probiotic
what is normal gut motility? in most cases of diarrhea how is this altered? what drug is not reccomended and what is sometimes used?
¡ Normal motility is rhythmic segmentation and peristalsis
¡ In most cases of diarrhea the bowel is hypomotile
¡ Anticholinergics not usually recommended
¡ Loperamide (Imodium) increases segmentation and decreases peristalsis
* Used most to relieve discomfort of acute colitis
Adsorbents used for acute colitis? what do they do?
¡ Kaolin (Kao-Pectate), bismuth (Pepto-Bismol), barium
¡ Bulk up feces
¡ Some protectant and bacterial toxin adsorbing effects
Anti-inflammatory agents used to treat acute colitis? what can we use and what else does it do? what should we avoid?
¡ Bismuth subsalicylate (Pepto-Bismol): anti-inflammatory, anti-secretory, and antibacterial effects
¡ Other NSAIDS not recommended
Stools liquid, red, strong odour, frequent
> what kind of disease?
acute bloody enteritis
viral causes of acute bloody enteritis
- Parvovirus
- Coronavirus
bacterial causes of acute bloody enteritis
- Campylobacter (zoonotic concern)
- Salmonella (zoonotic concern)
- Salmon poisoning [Neorickettsia helminthoeca] (West coast)
what is bacterial acute bloody enteritis also called?
- Acute Hemorrhagic Diarrhea Syndrome (AHDS) (previously
Hemorrhagic Gastro-Enteritis [HGE]) - Peracute bloody diarrhea
what breeds are overrepresented when it comes to bacterial acute bloody enteritis?
Small breeds over-represented
vEspecially Yorkie, Min Pinscher, Min Schauzer, Maltese
PCV in bacterial acute bloody enteritis
- PCV > 57%, low total protein
> In other disorders of volume loss and dehydration PCV and TP move in same direction
bacterium implicated in bacterial acute bloody enteritis, and why
Caused by Clostridium perfringens?
* Type A toxins NET E & NET F cause ulceration (bleeding) and vascular permeability
helminths that can cause acute bloody enteritis
- Ancylostoma (hookworms)
- Strongyloides stercoralis
poisonings that can cause acute bloody enteritis
¡ NSAIDS
¡ Lead
Extra-GI disease that can cause acute bloody enteritis
¡ Extra-GI disease (acute GI ulceration, coagulopathy)
¡ Acute kidney injury, acute liver failure, acute pancreatitis, hypoadrenocorticism
¡ DIC
can foreign body cause acute bloody enteritis?
yes
should we always do a work up for acute bloody enteritis?
yes
¡ Work-up always indicated*
what should our workup for acute bloody enteritis be?
¡ Blood-work (CBC, biochemistry, testing for hypoadrenocorticism)
¡ Fecal testing:
> Fecal flotation
> Parvovirus testing (if applicable)
> Giardia ELISA
¡ Abdominal imaging
if we run a parvo test for acute bloody enteritis and its negative, what should we condier?
¡ Consider fecal culture for pathogens if Parvo negative
what type of test can we use for parvovirus?
SNAP Parvo Antigen Test (IDEXX)
- Detects all genotypes CPV-2
> CPV-2a, CPV-2b, CPV-2c
> Negative up to day 3 post-exposure
- Detects feline parvovirus
> Negative up to day 5 post-exposure
DIAGNOSTIC IMAGING for acute bloody enteritis? is it often done, when and why? main value?
- Abdominal imaging often unrewarding if main problem is acute diarrhea
- Not routinely performed if straightforward diagnosis of parvoviral enteritis
- The more severe the diarrhea, sicker the animal, and the more open the diagnosis, the more likely imaging is performed
- Main value is to:
> Investigate/characterize extra-GI problems > Rule out heavy metal
> Rule out foreign body or intussusception
radiographic Findings consistent with enteritis
- Functional ileus – gas and fluid
distention - Contrast – delayed GI transit
- Ultrasound – functional ileus, ± intestinal thickening, ± speckling of mucosa (necrosis)
TREATMENT for acute bloody enteritis?
- Fluid therapy
- Antiemetics
- Diet
> As with pancreatitis, fasting replaced with aggressive antiemetic therapy and early feeding to promote more rapid intestinal recovery - IV dextrose if hypoglycemic
- antibiotics, usually indicated
use of antibiotics for acute bloody enteritis?
- Usually indicated with hemorrhagic enteritis
- Severe small intestinal mucosal damage
> Hemorrhagic exudate indicates an ~10,000X increase in permeability - Provide prophylaxis against bacteremia and bacterial translocation
> Ex β-lactam and/or fluoroquinolone, cefoxitin - Colorado State University trial for parvo where major cost restrictions
> Convenia (cefovecin), Cerenia (maropitant), SC fluids - If primary bacterial, base on culture and sensitivity
