SAM Exam 3 - GI

Pathophysiology of vomiting

• CNS reflex → medulla 

  • CRTZ, vestibular, vagal, pain, stress

• Receptors:

  • Dogs: dopamine, histamine

  • Cats: α2, serotonin

• Metabolic Alkalosis: Pyloric Obx → Vomit → loss HCl = ↑ HCO₃ + ↓ Cl

  • Tx: 0.9 % NaCl + KCl

Vomiting

• Et: GIT dz, renal dz, hepatic dz, pancreatitis, toxins, pain

• Cs: abdominal contractions, salivation, digested food + bile

  • Active forceful expulsion GI and intestinal contents

• Dt: metabolic alkalosis, ↓ Cl + K, Min database, endoscopy

  • Acute < 24h & BAR = symp Tx

  • Chronic > 3w = workup

• Tx: withhold food 24h, small bland meals, oral fluids, antiemetics, maropitant + ondansetron (refractory)

Stepwise Diagnostics for Upper GIT

1. Severity:

   • Test: >3w, ADR, FB

   • Symptomatic Tx: <24hrs, hydrated, BAR, No Bld/FB

2. Anatomy: history, video, observe eating, oropharyngeal exam (awake + sedated), rads of skull + pharynx + thorax

   • Rule out non-GIT before GIT related

3. Fxn: fluoroscopy, endoscopy, neuromuscular evaluation

   • Exclude mechanical obx

Vomiting Syndromes

• Gastrointestinal Bleeding

  • Et: Sepsis, Ulcers

  • Cs: Hematemesis, melena, pale MM, anemia, iron deficiency(chronic) : (acid makes blood brown)

    • Sepsis/DIC: petechiae, fever, systemic illness, abnormal coagulation tests

    • Ulcer: localized GI signs, normal coagulation, anemia

  • Dt: Rads, Contrast GI studies, Fluoroscopy, US

• Delayed Gastric Emptying

  • Et: Outflow obx, opioids, anesthetics, Post-surgical vagal nerve damage, Parvo

  • Cs: Food in vomitus >10h post eating, projectile vomiting, bloating after eating, burping, metabolic alkalosis (acid loss from body)

  • Dt: Normal Rads(chest/abd.), Contrast GI studies(thickening), Fluoroscopy(funct. dysphagia), US(mass/hernia)

    • Exclude mechanical obx by imaging and endoscopy

Regurgitation

• Et: Megaesophagus, MG, PRAA, reflux, FB, hiatal hernia

• Where:

  • With dysphagia: Oropharynx + prox esophagus

  •  Normal swallowing: Lower esophagus

• Sig: GSD, Shar Pei, Golden, Bulldog

• Cs: No warning, no abdominal effort, tubular foamy material, undigested food

  • Passive expulsion undigested post eating + No bile

• Dt: Imaging endoscopy, MG test (AChR Ab), Oral exam (awake + sedated)

• Comp: Aspiration pneumonia, malnutrition, weight loss

Endoscopy vs Gastric Surgery

• Endoscopy & biopsy

  • What: Non-invasive, atraumatic diagnostic tool

    • Upper and Lower

  • Why: Direct visualization of mucosa

    • Pro: No Sx incision, Quick recovery, Immediate

      • Takes 10-15 biopsies in area of interest

    • Con: Cannot access submucosa or muscularis, Cannot diagnose mural or extra-luminal dz

• Surgery

  • Why: full-thickness biopsies, large or mural masses, large obx FB removal, when limited endoscopic access

    • Pro: Allows evaluation of entire abdominal cavity, correct mechanical obx directly

Dysphagia

• Et: Dental dz, oropharynx dz

• Where: 

  • Only Dysphagia: Oropharynx

  • With Regerg: Oropharynx + prox upper esophagus

• Cs: Difficulty chewing + swallowing

• Dt: Oral exam (awake + sedated), imaging, endoscopy

• Comp: Aspiration pneumonia, malnutrition, weight loss

Localizing Vomiting, Regurgitation and regurg w/ dysphagia

Sildenafil

• MOA: relax GES, ↑ emptying, ↓ regurg

• Use: canine esophagitis

  • canine esophagus is skeletal muscle

    • Cisapride + Metoclopramide is not effective

Famotidine(pepcid) + Cimetidine

• MOA: H2-blocker

  • ↓ gastric acid, gastroprotective

    • No promotility effect

• Use: short-term acid suppression (2-3 d)

  • Adjust dose in renal disease

Omeprazole (prilosec)

• Proton Pump Inhibitor

• MOA: inhibits parietal cell ATPase

  • ↓ gastric acid, gastroprotective

    • Better than H2-blockers

• Use: 30 mins before food, taper if used >3-4w(prevent rebound acid hypersecretion), dosed q 12h

Sucralfate

• Rx: Aluminum salt of sucrose sulfate

  • Local effects

• MOA: Binds to ulcer base, inactivates pepsin, adsorbs BA, ↑ PG

  • Site gastroprotective

• Use: Separate from oral drugs by >1h

Metoclopramide

• Promotility Drugs

• MOA: ↑ACh, D2 antagonist, 5-HT4 agonist, 5-HT3 antagonist

  • ↑ prox GIT motility, antiemetic

    • No colon effect

• Use: parvo 

  • not canine esophagitis, not effective centrally in cats, not obx

    • canine esophagus = skeletal muscle

Cisapride

• Promotility Drugs / constipation 

• MOA: 5-HT4 agonist

  • Full GIT promotility drug

    • No antiemetic action

• Use: Compounded drug

  • esophagitis: cats, may worsen regerg, not cardiac dz

    • canine esophagus = skeletal muscle

Azithromycin + Erythromycin

• MOA: Motilin agonist

  • ↑ motility in GES, stomach, SI, colon

• Use: Azithromycin cheaper

Ranitidine(no good) + Nizatidine

• MOA: Inhibit AChE, ↑ ACh, H2 blocker

  • ↑ motility in stomach, SI, colon

• Use: Short-term gastric acid + hypomotility Tx

Apomorphine + Ropinirole

• MOA: D2 agonists 

  • CRTZ stim

• Use: Induce emesis in dogs

  • not cats they have ↓ D2 receptors in CRTZ

Xylazine + Dexmedetomidine + Mirtazapine

• MOA: α2 agonists

• Use: Induce emesis in cats, appetite stim

  • Good for anorexic cats

Maropitant

• MOA: NK1 antagonist

  • block Substance P in vomiting center, CRTZ, vagal afferents

• Use: Anti emetic 

  • Pancreatitis (#1), Obx, parvo, vestibular vomiting, motion sickness, chemo, refractory

Ondansetron

• MOA: 5-HT3 antagonist

• Use: antiemetic + anti-nausea

  • Chemo, Pancreatitis, Obx, vestibular vomiting (#1), refractory

Phenothiazine tranquilizers

• Rx: Chlorpromazine or prochlorperazine 

• MOA: D2, H1, M1 blockade

• Use: sedating, antiemetic 

  • contraindicated in dehydration/hypotension

Diphenhydramine

• MOA: H1 antihistamine

• Use: antiemetic

  • vestibular vomiting, motion sickness

Esophageal Foreign Body

• Et: located at cervical, thoracic inlet, base of heart, diaphragm

• Sig: young

• Cs: acute regurg, dysphagia, gagging, salivation

• Dt: rads, endoscopy

• Tx: urgent endoscopic removal or surgery

• Comp: perforation, esophagitis, stricture, aspiration pneumonia

Esophageal Perforation

• Et: Air in mediastinum or pleural space

• Cs: peri-esophageal swelling, pain, resp distress 

• Dt: Serial rads

• Tx: NG tube feeding, Antibiotics, fluids: heals w/ symptomatic therapy

  • Sx if Large

Esophagitis

• Et: anesthesia: reflux, caustic injury(chemical), FB,  Doxycycline (C), hiatal hernia, bulldogs

  • Endogenous: Gastroesophageal reflux(gastric acid)

• Sig: Young, GSD/Shar Pei

• Cs: regurg 1-3d post GA

• Dt: endoscopy w/ erythema, erosions, ulcers

• Tx: Omeprazole, Sucralfate, Metoclopramide (C), Cisapride (C), Corticosteroid, tube feed, sildenafil (D)

  • Prevention w/ pre-op omeprazole (12h + 3h pre-op)

• Comp: stricture

  • multi balloon dilations over 5d

  • ↑ recurrence, guarded px

Esophageal Stricture

• Abnormal narrowing of the esophageal lumen d/t fibrous tissue

• Common causes:

  • Gastroesophageal reflux during anesthesia

  • 2º to esophageal foreign body

  • Oral doxycycline, clindamycin tabs (cats)

  • Other (caustic agents, esophageal surgery)

• Strictures form when esophagitis involves deeper layers (submucosa/muscularis) which heal with fibrous tissue

• CS: regurgitation, ravenous appetite, weight loss 

  • Solid > liquid foods

  • occurs w/in 3-14 d after injury

• TX: balloon dilation, sx resection

  • Steroids, G tube : medical treatment

Persistent Right Aortic Arch

• Et: vascular ring traps esophagus, constriction near heart base

• Sig: Young <6m, onset at weaning

• Cs: regurg.

  • solids > liquids

• Dt: thoracic rads, contrast esophagram or CT

• Tx: Sx

• Comp: residual dilation when delayed

Esophageal Neoplasia

• Sarcoma: Spirocerca lupi

• Squamous cell carcinoma: old cats

• Leiomyoma/sarcoma: dilated esophagus of dogs

• CS: Asymptomatic (early)

  • Obstruction (advanced)

• TX: Surgical resection (distal leiomyoma)

  • prognosis guarded except: Leiomyoma

Megaesophagus

• Et: Congenital, Idiopathic (#1 dogs), MG, Hiatal hernia, Reflux esophagitis

  • R/O:  Esophageal Obstruction → cause diffusely dilated esophagus

• Sig: 

  • Congenital: kittens + GSD/Shar Pei puppies

  • Acquired: GSD, Golden

• Cs: Regurg after weaning, Diffuse dilation, weight loss

  • Cats: Uncommon, Hiatal hernia and reflux esophagitis underlaying causes

• Dt: lab work, Rads, barium esophagram, AchR antibody (MG 25%)**, cortisol, lead, thyroid

• Tx: upright feeding (Bailey chair), small soft meals, G tube feeding, pyridostigmine (MG), immunosuppressives (MG)

  • Avoid promotility agents

• Px: May improve but not normal

  • better w/ MG, recurrent pneumonia

Breed-related esophageal disorders

• Congenital idiopathic megaesophagus: GSD, Shar Pei

• Myasthenia gravis: GSD, Golden

  • Focal MG: Facial, pharyngeal, laryngeal, esophageal muscle involvement only (≥1)

• Cricopharyngeal achalasia: Golden

• Hiatal hernia or reflux esophagitis: Shar Pei, Bulldog

Achalasia-like Syndrome

• Et: Primary esophageal motor dz

  • degen of the myenteric plexus, poor GES relax, unorganized peristalsis

• Sig: megaesophagus in dogs

• Dt: “Beak sign” on distal esophagus contrast

• Tx: Sildenafil

  • Relaxes GES

Gastritis

• Inflammation of the gastric mucosa: requires biopsy

  • Lymphoplasmacytic most common

  • Cats = part of diffuse IBD

• Acute 

  • Et: idiopathic (#1), dietary indiscretion, NSAIDs, antibiotics, chemo

  • Cs: Sudden vomiting, healthy otherwise → spon. resolves

    • Diarrhea =  gastroenteritis

  • Dt: history + Cs

    • biopsy not done, no indepth Dt

  • Tx: self-limiting 24-48h, no food 24h, bland diet, fluids, antiemetics

• Chronic 

  • Et: idiopathic (#1), allergy, toxin, drugs, Helicobacter(G-), Parasitic (Physaloptera rara, Ollulanus tricuspis(vomit eating)), Bilious vomiting syndrome(dogs)→ am bile vomiting / feed b4 bed

    • Dog: Beef, dairy, wheat

      Cat: Beef, dairy, fish

  • Cs: vomiting food/bile for weeks/years, otherwise healthy

  • Dt: min database, biopsy, fecal, xrays

  • Tx: Therapeutic trials #1 → Novel diet 4-6w, Fenbendazole 2-3w, Omeprazole 2-3w, Biopsy(tx fail), Pred (post biopsy), diet therapy cont.

Helicobacter

• Et: normal flora

  • Infection ≠ dz

• Cs: Anorexia, nausea, vomiting

  • Pet: mild gastritis, no ulcers, asymptomatic 

  • Humans: ulcers, gastritis + gastric cancer

• Dt: gastric biopsy 

  • cannot culture

• Tx: Metronidazole, amoxicillin, clarithromycin, omeprazole (14-21d), Bismuth (pepto) 6 m (D)

  • Recurrence common w/in 6 m

Physaloptera rara

• Et: Nematode in stomach + proximal duo 

  • Insects, rodents, snakes

• Cs: gastritis, chronic vomiting 

• Dt: fecal float unreliable 

• Tx: Fenbendazole, Pyrantel, Ivermectin

Bilious vomiting syndrome

• Et: night-time duodeno-gastric reflux of bile

• Cs: Morning bile vomiting otherwise healthy, chronic gastritis 

• Tx: Sm meal at bed, Metoclopramide, Omeprazole

  • Avoid fasting

Gastroduodenal Ulcers

• Et: NSAID, Steroid, GDV, MCT, renal dz, hepatic dz, sepsis

  • NSAIDs block PG synthesis → ↓ mucus, bicarb, blood flow → mucosal erosion

  • NSAID + steroid = ulcer

• Cs: Hematemesis, melena, anemia, pale MM

• Dt: Endoscopy (#1), regen/ iron-deficiency anemia, ↓ protein, thick mucosa

  • Determine GI or systemic

• Tx: Fluids, (PPI) Omeprazole, Sucralfate

Gastric Foreign Bodies

• Et: Obx at pylorus or intestines, Metal toxicity (zinc or lead), pressure necrosis, perforation

  • Post-1983 pennies contain zinc

• Cs: acute vomiting, Obx

• Dt: metabolic alkalosis (pyloric outflow obx), repeat rads before endoscopy

  • LAB: Hypochloremic, hypokalemia metabolic alkalosis with obstruction

• Tx: Apomorphine (sm + smooth), endoscopic removal, Sx

  • Dont induce: Sharp, caustic, Obx, shock, airway compromise, corrosives

Hairballs

• Et: swallowing hair during grooming

  • all cats don’t vomit hairballs

    • excess grooming from fleas, skin dz, anxiety, GI motility dz

• Sig: long-haired cats

  • Nasopharynx: Vomited though nose

  • Esophagus: Obstruction, esophagitis, stricture

  • Intestine: Obstruction

• Tx: grooming(lion clip), ↑ fiber diet, Laxatone (NOT mineral oil), Metoclopramide, Cisapride

Delayed Gastric Emptying

• Et: Mechanical Obx, Extramural compression, Fxn Obx

• Sig: 

  • Young: congenital pyloric stenosis, FB 

  • Old: antral pyloric hypertrophy (D), neoplasia 

• Cs: acute or chonic vomit >10h after eating, projectile vomiting

• Dt: metabolic alkalosis, imaging

  • Hypochloremic, hypokalemic metabolic alkalosis

• Tx: Sx, fluids→0.9% NaCl w/ KCL(metabolic alkalosis), cisapride→ (post gastric antony or fxn delay ONLY), ↓ fat canned diet, Sm frequent meals

  • Promotility drugs are contraindicated if Obx

Gastric Dilatation-Volvulus (GDV)

• Et: Rapid distention of stomach with air + volvulus @ axis

  • Compression of caudal vena cava → ↓ venous return → hypovolemic shock

  • EMERGENCY

• Sig: Old, Lg, deep chest, rapid eating, aerophagia, raised food bowls, anxiety

• Cs: non-productive retching, salivation, distention, tympany, tachycardia, weak pulse, shock

• Dt: R-Lateral abdominal rads, double bubble, ↑ PCV, metabolic acidosis, coagulation defects

• Tx: 

  • Initial: LRS shock fluids, O2, Gastric decompression (NG tube or trocarization), Antibiotics

  • Sx: Emerg Gastropexy

  • Prevent: Prophylactic gastropexy, slow feeding, sm meals

Food Bloat

• Et: over - eating

• Cs: acute distention, panting, drooling, retching

• Dt: r/o GDV →R-Lateral abdominal rads w/ uniform food-filled stomach

  • No volvulus present, rule out GDV

• Tx: fluids, analgesics, gastric lavage

  • Supportive

  • resolves < 24-48hr, good Px

Gastric Neoplasia

• Malignant: Adenocarcinoma (dogs), Lymphoma (cats)

• Benign: Leiomyoma (dogs), Polyps (cats and dogs)

• CS: Chronic vomiting, weight loss, +/- hematemesis; +/- anemia

  • GI bleeding, delayed gastric emptying, vomiting, anorexia, weight loss

• Dx: gastroscopy, biopsy

• TX: Surgical resection, chemo(lymphona)

• Prognosis: poor w/ malignant

Diarrhea

• Et: Diet, Toxins, NSAIDs, antibiotics, Parasites, infectious dz, endocrine dz, IBD, EPI

• Cs: <3w = acute, >3w = chronic

• Dt: fecal float, CBC, biochem, rads

  • systemic signs or chronic→ req tests

    • Rule out non-GI causes before

  • Mild → tests optional 

• Tx:

  • Acute: self-limiting, deworm, Fenbendazole, Fluids, Probiotics, fiber, Loperamide, Bismuth subsalicylate

    • No empirical antibiotic

  • Chronic: cobalamin, steroids (post biopsy, entropathy + IBD), diet trial, fiber, antibiotics, probiotics 

    • Stepwise format

Protocol for treating chronic diarrhea

• Stepwise before biopsy

  • Anthelmintic: Fenbendazole (whipworms)

  • Fiber supp: psyllium or high-fiber diet

  • Diet trial: novel/hydrolyzed protein

  • Probiotics

  • Antibiotics: tylosin or metronidazole

  • If unresponsive → biopsy (confirm IBD)

• Corticosteroids: Chronic enteropathy, IBD

  • Steroids only after biopsy

Localizing Diarrhea

• Small Bowel 

  • Et: hyperthyroidism, dysbiosis, hypoadrenocorticism (Addison’s), EPI, Giardia, IBD, FeLV, allergies, dysbiosis, Lymphangiectasia, Neoplasia, Histoplasmosis

  • Cs: 2x daily, lg volume, watery, weightloss, gas, fatty stool, melena

    • Urgency, Mucus, Tenesmus rare

• Large Bowel 

  • Et: Whipworms (Trichuris vulpis), Tritrichomonas, IBS, Lymphocytic plasmacytic colitis, Neoplasia, Histoplasmosis

  • Cs: >3x daily, Sm volume, Urgency, tenesmus, fresh red blood (hematochezia), Mucus

    • No vomiting, weightloss, or gas

Serum biochemistry in a diarrhea patient

• ↓ albumin + globulin: PLE

• ↑ globulins: BD, FIP 

• ↓ Na + ↑ K: Addison’s disease, whip worms

• ↓ Cholesterol: small intestinal malabsorption, PLE

• ↑ ALT/ALP: liver disease, enteritis

  • Small Intestine Dihareha 

• ↑ T4: hyperthyrpoid cats

  • Chronic Small Intestine Dihareha 

• Cortisol/ACTH stim: hypoadrenocorticism (Addison’s)

  • Chronic Small Intestine Dihareha 

• Neutropenia: viral (parvo) or bacti 

• Low fasting serum TLI: EPI

Folate + cobalamin tests

• ↓ folate: proxl small intestinal dz, malabsorption

• ↑ folate: small intestinal bacti dysbiosis

• ↓ cobalamin (B12): EPI, ileal dz, dysbiosis, villus atrophy,  mucosal inflam

  • Normally absorbed in the ileum

  • Distal small intestinal malabsorption

Gastric Supplements

• Probiotic: 

  • MOA: Modulate immune response (↑ IgA, ↓ inflam), strengthen intestinal barrier, inhibit pathogen colonization

  • Ex: Enterococcus faecium, Lactobacillus, Bifidobacterium

    • Live microorganisms

• Prebiotic:

  • MOA: Promotes gut flora

  • Ex: FOS, Inulin, Pectin, Psyllium

    • Fiber

  • Use: Large bowel diarrhea, Fiber-responsive diarrhea, IBS, Acute diarrhea recovery

• Synbiotic: Combo prebiotic + probiotic

• Cobalamin:

  • MOA: Deficiency worsens intestinal dz

    • villus atrophy and mucosal inflam

    • Why: chronic enteropathy

Fecal Microbiota Transplantation

• MOA: intestinal flora modification 

• How: Stool from healthy donor transplanted

  • normalize microbiome

• Use: GI dz, parvo, Chronic enteropathy

Opioids

• Rx: Loperamide (Imodium), Lomotil (Diphenoxylate & atropine)

• MOA: ↑ absorption, ↓ secretion, ↓ motility, ↑ anal tone

  • First pass metabolism, does not pass BBB

• Use: acute diarrhea 

  • Control urgency, cramping, frequency

• Avoid: infectious/bacti diarrhea, MDR1-deficient dogs (Collies), cats

Anticholinergics

• Rx: Atropine, Aminopentamide (Centrine), Dicyclomine, propantheline

• MOA: ↓ all motor activity, ↓ secretion 

  • ↓ peristalsis + ↓ non-propulsive motility

• Use: Not recommended

• Risk: Ileus, worsen diarrhea, constipation, tachycardia

Pepto-Bismol

• MOA: GI protectant, Coat mucosa, inhibit bacti, Bind toxins, Anti-inflam

  • Remains in lumen

• Use: Avoid in cats (salicylates)

Gastric Diets

• Novel

  • What: one protein + carb source not previously eaten

  • Why: Food allergies or chronic enteropathies

• Hydrolyzed

  • What: Proteins broken into small peptides

  • Why: chronic or refractory diarrhea

    • Diet history unclear or “been on everything.”

• Highly digestible low-fat

  • What: Easily digestible, ↓ fat, ↑ fiber

  • Why: Acute diarrhea, dietary indiscretion, chronic small bowel diarrhea, fat intolerance

• High fiber diet

  • Why: Large bowel diarrhea, Fiber-responsive diarrhea, Constipation, IBD

Intestinal Dysbiosis

• Et: Flora imbalance, secondary to chronic dz

• Cs: diarrhea that respond to antibiotics

• Dt: ↑ Folate, ↓ cobalamin

• Tx: Metro, Tylosin

Chronic Enteropathy / IBD

• Et: Allergy, IM, genetics

  • Food/Antibiotic/steroid responsive or Non-responsive

  • Lymphocytic-plasmacytic (#1), Eosinophilic, Neutrophilic , Granulomatous

• Sig: Middle-aged, tradis in cats

  • Triaditis: IBD, pancreatitis, cholangitis

    • Breeds: GSD, Shar pei, boxers, basenji

• Cs: Chronic vomiting, diarrhea, weight loss, thickened intestines, enlarged LN, ascites/edema (alb < 1.5)

• Dt: CBC, chem, TLI, cobalamin, US, biopsy

  • FeLV/FIV, T4, Resting cortisol(addiosn’s)

    • Therapeutic diet trials before biopsy: Diet x2 → flora mods → steroids

    • Dysbiosis index:

      • <0 normal, 0-2 equivocal, >2 dysbiosis

• Tx: Diet, probiotics, pred (#1), Vit B12, Budesonide, Chlorambucil (C), Cyclosporine/atopica, Azathioprine (D)

  • 65% respond to diet alone

    • Novel protein, hydrolyzed 2-3w → rechallenge

  • Fiber: LG bowel signs

Canine Parvovirus

• Et: Incubation 4–7d, fecal-oral

  • Intestinal crypt cell necrosis → necrosis → vomiting + hemorrhagic diarrhea

  • BM → neutropenia

  • Lymphocytes → lymphopenia + immunosuppression

• Sig: puppies 6w-6m, Rottweilers, Dobermans, Pits, GSD, Labs

• Cs: Acute vomiting, bloody diarrhea, lethargy, anorexia, dehydration, fever, cardiac dz

• Dt: Marked neutropenia + lymphopenia,  ELISA SNAP test

• Tx: fluids, Convenia, antiemetic, pyrantel, famotidine, vax, isolate

• Px: 90% survival with ER care, outpatient possible

Panleukopenia

• Et: feline parvovirus 

• Sig: kittens 8-12 w

• Cs: Fever, anorexia, lethargic, vomiting, mild diarrhea, peracute death, cerebellar hypoplasia,

  • end stage = hypothermia, DIC

• Dt:  Marked neutropenia + lymphopenia, ELISA K9 SNAP test

• Tx: fluids, antiemetics, antibiotics, early nutrition,

  • Prevention: vaccines 

• Px: poor, high mortality

Minor Viral Diarrhea

• Enteric Coronavirus

  • Et: Fecal-oral, shed 6–9 days

    • may mutate to FIP in cats

  • Cs: mild malabsorptive diarrhea(occ. blood), Anorexia, lethargy, vomiting, fever(cats)

  • Dt: Fecal PCR

  • Tx: Supportive

    • Prevention: non-core vaccines

• Canine Rotavirus

  • Sig: uncommon, in puppies <3 months

  • Cs: Subclinical or mild gastroenteritis

  • DX: PCR

  • Tx: Supportive, no vaccines 

Clostridium

• C. difficile + C. perfringens(safety pins)

  • Dt: PCR + ELISA toxin test 

    • culture isolation ≠ disease, find strain + toxin

      • Toxin A + B

    • Found in healthy animals(C. perfringens): type A causes issues

  • CS: Fatal acute hemorrhagic diarrhea

    • Small, large, or diffuse bowel signs

  • Dx: culture, PCR, ELISA + ELISA toxin test

  • Tx: Metro(difficile), self limiting, symptomatic 

    • Antibiotics only if systemic dz

• Acute Hemorrhagic Diarrhea Syndrome (AHDS)

  • Et: C. perfringens in young small dogs

  • Cs:  Acute vomiting, hematemesis progressing to hemorrhagic diarrhea, Intestinal necrosis and inflammation

    •  “raspberry jam”/bloody

    • **** hemoconcentration → PCV > 60% ****

  • Dx: clinical dx, no test

  • Tx: fluids!*, symptomatic

    • No antibiotics unless fever, shock, abnormal WBC

      • Ampicillin 1st choice

  • Px: Excellent

Campylobacter

• ID: Motile slender curved rod (G-)

• Et: many healthy carriers, zoonotic

• Cs: diarrhea(young), fever, vomiting → “pet store puppies”

  • stress, over crowding, coccurrent dz

• Dt: Fecal smear (gull-wing), culture, PCR

• Tx: Erythromycin, azithromycin, enrofloxacin

Salmonella

• G- bacilli

  • Raw food diets higher risk, pig ears

• Et: healthy carriers, zoonotic 

• Cs: Vomiting, diarrhea, fever, lethargy

  • Acute 3-5 days post exposure 

• Dt: Fecal culture (x3), PCR

• Tx: self limiting, supportive care

  • Ampicillin + enrofloxacin only if systemic dz

E. coli Granulomatous Colitis

• AKA “ boxer colitis or  “Histiocytic Ulcerative Colitis”

• Et: invasive E. coli

• Sig: Young, Boxers, Bulldogs, Mastiffs.

• Cs: severe Chronic large bowel diarrhea, weight loss, inappetence

• Dt: Hypoalbuminemia, anemia(GI loss), Colon biopsy (inflammation, PAS+ macrophages, FISH: Fluorescence in situ hybridization)

  • culture: not helpful for dz, helpful in tx

• Tx: Enrofloxacin based on c/s from the biopsy

• Px: Good, improve 1w, full dose for remission 

Fungal Diharreah

• Histoplasmosis

  • Et: Soil-borne, Mississippi & Ohio River valleys

  • Cs: multisystemic (GI(colon), liver, spleen, lungs, eyes, bones)

    • LG/SM bowel diarrhea, wt loss, fever, thickened bowel loops

  • Dt: Cytology (rectal/liver/spleen FNA), biopsy, urine ag test

  • Tx: Itraconazole, fluconazole, amphotericin B (≥6 months).

• Pythium insidiosum

• Gulf coast southern US

  • Et: GI tract, granulomatous masses

    • Focal or multifocal segmental thickening

      • Stomach, SI, colon, ± esophagus

  • CS: vomiting, diarrhea, anorexia, wt loss

  • Dt: Cytology or biopsy, ELISA(antibody), PCR(antigen)

  • Tx: Sx, itraconazole + terbinafine,  pred

  • Px: poor

Giardia

• Et: Fecal-oral, cysts survive months, dogs + cats

  • Protozoal Diarrhea 

• Cs: young, small bowel diarrhea ± mucoid, weight loss(chronic)

• Dt: Fecal ZnSO₄ flotation, smear(floating leaf), ELISA, PCR

• Tx: Fenbendazole, Metro

  • Treat all animals, bathe, disinfect enviro

Tritrichomonas foetus

• Feline Trichomoniasis

  • Only trophozoite form unlike giardia

• Et: Colonizes colon/ileum

  • Protozoal Diarrhea 

• Sig: young cats

• Cs: Chronic large bowel diarrhea, blood, mucus, incontinence, cow pie, ± fecal incontinence - otherwise healthy cats!

  • “waxes and wanes” = Weeks to years

• Dt: Fecal PCR, fecal smear(jerky movement) 

  • fresh diarrheic feces (lima bean size) 

• Tx: Ronidazole, spontaneous resolution w/i 2y but remain PCR +

Cryptosporidiosis

• Et: C. parvum, Zoonotic

  • Protazoal Dihareah 

• Cs: small bowel diarrhea

  • Puppies or kittens with concurrent disease or immunocompromised

• Dt: fecal Immunoassay or PCR

• Px: poor, difficult to eliminate 

Coccidiosis

• Et: Protozoal Diarrhea 

• Sig: young animals

• Cs: Mild–severe diarrhea, sometimes blood

• Dt: Fecal flotation.

• Tx: Sulfadimethoxine, TMS,  Ponazuril.

• Px: Good

Whipworms

• Et: Trichuris vulpis

  • Dogs, rare in cats

• Cs: Large bowel diarrhea, hematochezia

• Dt: Fecal flotat (false neg common), colonoscopy

• Tx: Fenbendazole repeat in 3m

  • Consider therapeutic trial of fenbendazole!!

Roundworms

• puppies and kittens

• Et: Toxocara + Toxascaris

• Cs: Diarrhea, ± vomiting, poor growth/hair coat, “pot-belly”

• Dt: Fecal float

• Tx: Pyrantel, Fenbendazole

Hookworms

• Et: Ancylostoma + Uncinaria

• Sig: young 

  • subclinical in adults

• Cs: Anemia(pale MM), melena, diarrhea, Blood loss/iron-deficiency anemia, Failure to thrive

• Tx: Pyrantel, Fenbendazole

Tapeworms

• dogs and cats

• Et: Dipylidium, Taenia

  • Transmission by fleas

• Cs: Anal irritation, NOT diarrhea

• Tx: Praziquantel, Episprantel, control fleas

Strongyloides stercoralis

• Et: protazoa

• Sig: puppies → shelters/pet stores

• Cs: mucoid/hemorrhagic diarrhea, lethargy

• Dt: Fresh feces or Baermann

• Tx: Fenbendazole, thiabendazole, ivermectin. 

• Px: guarded with serve CS ± pneumonia

Prototheca zopfii

• Rare

• Et: Algal infection → tissue invading

  • colon, eyes, skin

• Cs: bloody diarrhea (LG bowel signs)

• Dt: Cytology, biopsy

• Tx: Amphotericin B

• Px: poor.

Intestinal Obstruction

• Et: FB (#1), intussusception, neoplasia

  • More Proximal obx = more severe vomiting

  • Linear: #1 cause of Obx

    • Cats young (#1)→ base of tongue

    • Dogs older→ pylorus

• Cs: Vomiting, dehydration, lyte imbalance, ± aneroxia, depression, abd. pain, ± shock/sepsis

• Dt: PE, Palpation,  survey Rads #1 ± contrast, US(more sensitive)

  • dilated loops, stacking, gas pattern

    • Comma-shaped gas bubbles

• Tx: pre anes. fluids, Sx once stable, cut string under tongue, 

  • monitor if simple: Healthy cat (present only 1-2 days) → sx in 12-24h if not better

Intussusception

• One intestinal segment (intussusceptum) into an adjacent segment (intussuscipiens)

  • “Sausage loop” on PE

• Young animals

• Et: idiopathic, enteritis, motility dz, parasites

  • intussusceptum into intussuscipiens common at ileocolic jxn 

• Cs: Vomiting, diarrhea, anorexia, lethargy, pain, “sausage-like” mass, hematochezia

• Dt: Palpation, rads, US

• Tx: Sx reduction or resect

Intestinal Adenocarcinoma

• Most common primary neoplasm of GI tract

  • Dogs

• CS: vomiting if causing obstruction; weight loss,

  diarrhea

  • diffuse thickening or focal, circumferential mass

    lesions

• Dt: contrast radiographs, explore sx

  • Apple core lesions w/ contrast = focal

• Tx: surgery, good prognosis if fully resected

Intestinal Lymphoma

• Both can be focal or diffuse

• Most common in cats

• Large cell (lymphoblastic) High grade

  • Most common in dogs, can occur in cats

  • CS: Acute (days to weeks): Weight loss, anorexia, vomiting, diarrhea, GI perforation

• Small cell (lymphocytic) Low grade T-cell

  • Most common in cats

    • LGITL

  • CS: chronic (weeks to months) GI signs indistinguishable from chronic inflammatory enteropathy

  • Mimics lymphocytic plasmacytic enteritis (LPE)

    • May need immunohistochemistry or PARR (PCR) to differentiate

• Dx: cytologic (lymphoblastic only) or histopathologic (both) or PCR antigen - PARR

  • Biopsy: gold standard

• Tx: Chemo → lymphoblastic lymphoma do not do as well

  • Pred + chlorambucil (cat SM cell)

Exocrine Pancreatic Insufficiency (EPI)

• Et: 90% loss of pancreatic enzyme secretion

  • Pancreatic acinar atrophy: hereditary GSD, young dogs1-4 y, Most common: DLA-88

    • exocrine function preserved: no diabetes

    • Inflammation and fibrosis absent: pancreas

  • 2ndary Chronic pancreatitis(acquired): cats, small dogs

    • older onset, may have diabetes

• Cs: dysbiosis, ravenous appetite + weight loss, yellow Cow-patty, greasy stool, fart

  • Cats less obvious clinical, mostly just weight loss 

  • Chronic small bowl diarrhea

• Dt: ↓ TLI (#1), Cobalamin ↓

  • Dogs: < 2.5

  • Cats: < 8

• Tx: Life long: Pancreatic enzyme supp, Cobalamin supp, digestible diet, Tylosin

• Px: excellent, lifelong therapy

Protein-Losing Enteropathy

• General: dogs > cats

  • Et: Chronic bowel dz, Hookworms, histoplasmosis

    • Loss of albumin and globulins into intestines

  • Cs: panhypoproteinemia, edema, ascites, effusion, diarrhea, vomiting, weight loss

    • Edema: Transudate fluid

  • Dt: ↓ Albumin**, ↓ Globulin-**, fecal α1-proteinase inhibitor, Imaging + biopsy

    • a1 test - not till others are r/o: UPC, bile acids

• Lymphangiectasia subtype

  • Et: Primary, Obx CHF, portal hypertension

    • Lacteals rupture with lymph loss and cholesterol

  • Sig: yorkies 

  • Cs: Weight loss, small bowel diarrhea, ascites, effusion

  • Dt: ↓ Albumin, ↓ Globulin, ↓ Cholesterol, ↓ Ca, lymphopenia, US w/ thick striations/speckling, Biopsy

  • Tx: ↓ fat diet #1, Cobalamin supp, Pred, Aspirin, clopidogrel, Octreotide

Small vs. Large bowel diarrhea

Chronic Colitis

• Inflammation limited to colon (cats +/- small bowel)

• CS: Dogs: Mucoid diarrhea, Hematochezia, Frequent defecation, Vomiting and weight loss (rare)

  • Large bowel signs

    • Cats: Hematochezia, diarrhea

• Dx: r/o other LG bowel dz 

• Tx: Therapeutic trials prior to biopsy

  • Modified fiber diet, probiotics, Pred, sulfa(risk KCS)

    • If diet fails: biopsy→ Lymphocytic-plasmacytic inflammation most common, idiopathic

Irritable Bowel Syndrome (IBD)

• Et: Stress**  

  • travel, boarding, separation, noise/storms

• Cs/Dt: Recurrent idiopathic large bowel diarrhea with normal biopsy

• Tx: Fiber, Probiotics, Metro, Anti-anxiety meds

Constipation

• Infrequent or difficult evacuation of dry, hard feces

• Et: Bones, Dirty litter box, Anal sac dz, Pelvic fracture, Arthritis, CKD, ↑ Ca

  • Large intestine dz

• Cs: ↓ defecation, dry feces, straining, Paradoxic Diarrhea (Liquid leaks during straining)

• Dt: rads, palpation

• Tx: Fulids, Lactulose, Miralax, Enemas (avoid in Sm animals), Manual deobstipation, fiber

  • Treat underlying issue!!

Megacolon

• Et: Over weight cats

  • Cats: primary dz, idiopathic smooth muscle dysfunction, perm dilation

  • Dogs: secondary to stricture or obx

• Cs: constipation, anorexia, lethargy, weight loss, paradoxical diarrhea

• Dt: enlarged colon & painful colon on PE, rectal exam, rads

  • dehydration, hypokalemia, pre-renal azotemia may be present

• Tx: Fluids 12-24h, Enemas, Lactulose, Miralax, Fiber, Cisapride, Subtotal colectomy (refractory)

  • NO Fleet enemas in cats → ↑P,  ↓Ca, death

    • Long term: Fiber-enriched diet, Metamucil, Oral laxative

Cholestasis**

• Et: Impaired bile flow**

  • Extrahepatic: gallbladder, common bile duct

    • mechanical

  • Intrahepatic: functional

• Cs: icterus, vit K malabsorption

• Dt: ↑ BA, ↑bilirubin, ↑ cholesterol

• Tx: parenteral Vit K1, Sx (extrahepatic)

Sulfasalazine

• MOA: acts locally in colon

• Use: for large bowel colitis only 

  • Ineffective for small intestinal IBD

  • Risks: KCS, monitor tear production

Anal Sac Disease

• Et: impaction, sacculitis, abscess

  • small breeds, obesity, diarrhea, allergic skin dz

• Sig: common in dogs, rare in cats

• Cs: scooting, licking, biting, tail chasing, blood on feces, dyschezia

• Tx: express sacs, antibiotic-steroid infusion, compresses, Sx, fiber, weight loss, manual expression, weight loss

Rectal diseases

• Anorectal Prolapse

  • Et: Secondary to diarrhea or straining

  • Dt: Differentiate from intussusception 

    • probe can pass deeper in intussusception

  • Tx: Replace + purse-string suture

• Anorectal Stricture

  • Et: Fibrous narrowing of lumen, congenital or post-inflammation

  • Cs: painful defecation

  • Dt: palpation ± imaging

  • Tx: dilation (balloon/tapered syringe dilation (mild), Sx (severe)

  • Comp: fecal incontinence

• Rectal Polyps

  • Sig: Older dogs

  • Cs: hematochezia, dyschezia, blood with normal stool

  • Dt: rectal palpation, colonoscopy

  • Tx: Sx

  • Px: good

Perineal diseases

• Hernia

  • Et: Weak pelvic diaphragm, rectal sacculation, constipation, perineal bulge

  • Sig: Older intact males

  • Cs: dyschezia, perineal swelling, bladder entrapment (emerg), depression, vomiting

  • Dt: rectal, imaging, Post-renal azotemia 

  • Tx: Sx

• Fistula

  • Et: Painful ulcers/sinus tracts around anus, IM (T-cell)

  • Sig: Mid age GSD

  • Cs: tenesmus, hematochezia, dyschezia, pain!!, discharge, anorexia, diarrhea, weight loss

  • Tx: Cyclosporine ± Ketoconazole, Tacrolimus 0.1% ointment, Novel diet

Exocrine Pancreatic Carcinoma

• Uncommon

• Older dogs and cats

  • High metastatic rate (liver, nodes) @ dx

• CS: Lethargy, anorexia, weight loss, vomiting

  • 7-day median duration of signs in dog

  • Palpable abdominal mass in cats; previous hx diabetes

    mellitus

• Dx: cytology, biopsy, necropsy; ↑ liver enzymes, bilirubin

  and pancreatic enzymes

  • mimic acute pancreatitis in dogs and increase cPL

• Tx: Chemo?

Acute Pancreatitis

• Premature activation of trypsinogen within the pancreas

• Et: Idiopathic (#1), Dietary indiscretion, DM, Cushing’s, Hypothyroidism, Schnauzers hypertriglyceridemia

• Sig: Old, obesity, dogs

• Cs: Acute vomiting, anorexia, lethargy, dehydration. inflammation, abd. pain → edematous: self limiting

  • Cats subclinical: Increased liver enzymes, bilirubin

    • Triaditis

• Dt: biopsy (#1), ↑ PL snap + US, ↑ bilirubin

  • Diagnosis of exclusion

  • Snap is NOT definitive also + with kidney failure

    • NEGATIVE test rules out pancreatitis

  • Rads have ↓ sensitivity + specificity

    • Soft tissue density in area of pancreas with displacement of duo to the right

• Tx: Fluids (LRS + K + Ca), analgesia, Maropitant, Ondansetron, ↓ fat diet, avoid table scraps 

  • Avoid NSAIDs

• Risks: Organ failure, DIC, SIRS, mortality 50%

  • necrotic > edematous

  • • Abscess*

    • Pseudocyst*

    • Biliary obstruction*

Chronic Pancreatitis

• Et: idiopathic (#1), IBD, Cholangitis, Biliary obx, DM, Hepatic lipidosis, drugs

• Sig: Older, cats

• Cs: subclinical Cats

  • Dogs: chronic intermitting GI signs

    • can cause EPI and DM

• Dt: Suspicion, low-grade inflammation

  • Lymphocytic-plasmacytic inflammation, fibrosis and

    atrophy most common

    • US + PL will look normal

    • Snap is NOT definitive, + w/ kidney failure

    • Rads have ↓ sensitivity + specificity

• Tx: ↓ fat diet, Steroids

Triaditis in Cats

• Pancreatitis 

• Cholangitis 

  • Cat pancreatic and bile ducts join → predisposed to triaditis

• Inflammatory Bowel Disease

Functional Categories of the Liver

• Metabolic: Carb + protein + fat metabolism, Detoxification 

  • gluconeogenesis, glycogenolysis, cholesterol, bile acids, lipoproteins, albumin, coagulation factors, urea synthesis

  • Avoid drugs needing hepatic activation

  • Reduce doses of those inactivated by liver

    • ↑ NH3, ↑coags, ↓ glucose, ↓ chloesterol, ↓ BUN, ↓ albumin, ↑ bile acids

• Circulatory: Receives portal and arterial blood, regulates blood flow

  • Liver has large reserve  → Cs at <30% fxn

  • R CHF → Venous congestion → backup of blood into liver → hepatic enlargement

  • Liver maintains low blood ammonia, normal BUN

  • NH₃ produced in colon → hepatocytes convert to urea

• MOST COMMON LIVER DISEASE IN DOGS THAT CAUSES PORTAL HYPERTENSION IS CIRRHOSIS

• Secretory + Excretory: Bile synthesis +secretion, Bilirubin excretion

Portosystemic Shunts

• Et: Portal Blood bypasses liver

  • Single congenital: no portal hypertension

  • Multiple acquired: secondary to portal hypertension

•  Sig: Yorkie, Cairn, Maltese, Schnauzer, Wolfhound, Lab

  • Extra: Small dogs, cats 

  • Intra: Large-breed

• Cs: Hepatic atrophy, Microcytosis, Ammonium biurate crystals, HE, PU/PD, stunted growth, urate uroliths, Hepatic encephalopathy: ammonia toxicity is key

• Dt: Nuclear scintigraphy ↓ BUN, ↓ albumin, ↓ cholesterol, ↓ glucose, ↑ BA → post prandial

• Tx: Protein-restricted diet, lactulose, antibiotics, ameroid constrictor Sx (extra), radiology coil embolization (intra).

  • Sx for congenital NOT acquired 

•  Px: Good with closure; cats ↑ post-op risk.

Hepatic Encephalopathy

• Et: congenital/acquired PSS, hepatic necrosis, cirrhosis, urea cycle enzyme defects

  • Ammonia + toxins affect CNS

• Cs: anorexia, lethargy, drool, head pressing, circling, ataxia, blind, seizures, coma

  • Can wax and wane

• Tx: PSS Sx, ↓ diet protein, lactulose

Portal Hypertension

• Et: 

  • Prehepatic: portal vein thrombus/mass

  • Intrahepatic: cirrhosis, congenital hypoplasia

  • Posthepatic: CVC obstruction, R heart failure, pericardial effusion

• Cs: Ascites, Acquired PSS (not post-hepatic), Hepatomegaly (post-hepatic), Gastric ulcers

  • ↑ hydrostatic pressure → ascites

Cholestasis

• Et: Impaired bile flow, ↑BA, bilirubin, cholesterol in blood

  • Extrahepatic: gallbladder, common and main bile duct

    • mechanical

  • Intrahepatic: functional

• Making this distinction is clinically important since

  mechanical causes may be corrected with surgery

• Cs: icterus, vit K malabsorption

• Tx: parenteral Vit K1, Sx for extrahepatic

Icterus

• Run PCV FIRST!

• Et: Pre-hepatic hemolysis, Hepatic dz, Post-hepatic biliary obx

• Cs: Bilirubinuria (orange urine), acholic feces (gray)

• Dt: serum bilirubin >2.5 mg/dl, PCV, US

  • Normal PCV = not pre-hepatic

  • US for post-hepatic obx

Ascites in Liver Disease

1. Portal hypertension: ↑ hydrostatic pressure

2. Hypoalbuminemia: ↓ oncotic pressure

3. Renal sodium and water retention: secondary effect