Approach to Vomiting Flashcards
describe vomiting
- active expulsion of contents from the stomach
- to get contents to move backwards (from stomach out the mouth)
-LES relaxes
-stomach contracts
-UES relaxes
-food is propelled out the esophagus and mouth - in a conscious animal: the airway is protected by the epiglottis
- in an unconscious animal, the airway is NOT protected so there is a risk of aspiration pneumonia!
- vomiting evolved as a protective mechanism against toxic substances ingested
what animals can and cannot vomit?
can: dogs, cats, ferrets
cannot: rodents, lagomorphs (rabbits)
what causes vomiting?
substances circulating in the blood trigger the brain to initiate vomiting
5 triggers:
1. we induce it
2. opioids
3. vestibular disease: motion sickness or true neuro disease
4. circulating toxins: uremic, hepatic, enterotoxin, endotoxin, inflammatory cytokines, drugs, toxins
5. GI disease: direct triggers to the brain
describe the complex interrelationship of all the brain centers that cause vomiting
emetic center is the king of vomiting in the brain
- chemoreceptor trigger zone (CRTZ): brain senses circulating trigger and tells emetic center to vomit
-via dopamine receptors in dogs and alpha 2 receptors in cats - oculovestibular center: senses that the world is spinning and tells the emetic center to vomit
-via NMDA, H1, and M1 receptors - the cerebral cortex perceives nausea and tells the emetic center to vomit
-via omega2 and other receptors - the GI tract gets so many signals when GI disease is present and via NK, 5-HT, motilin, and other receptors, tells the emetic center to release the vomit
describe how we can use drugs to make and animal vomit, or not vomit
vomit:
1. apomorphine: dopamine agonist, will make DOGS vomit but not cats (fewer dopamine receptors in their CRTZ)
- dexmedetomidine, xylazine: alpha 2 agonist, will make CATS vomit
-reversal: antesedam, yohimbine (alpha 2 antagonists)
-if give dexmed IM in cats, can make vomit so be careful with sedation/protect airway! - hydromorphone (opioids): ENKdelta agonist
-will make dogs vomit 50-60% of the time!
-giving maropitant 30-45 min prior to injection can eliminate vomiting - vestibular disease/motion sickness: oculovestibular center to CRTZ
- circulating toxins: CRTZ senses and trigger vomiting
- GI disease: 5-HT3 (serotonin) released from CRTZ
anti-vomit:
1. maropitant/cerenia: NK1 antagonist to block CRTZ vomit trigger; can take away nausea if use apomorphine to induce vomiting
- meclezine/dramamine (NK1 antag, CRTZ), diphenhydramine/benadryl (H1 antag, oculovestib): better for motion sickness!
how can you truly distinguish vomiting from regurgitation?
you need to witness/hear it!
describe possible PE abnormalities with vomiting, then signs of concern with vomiting
possible PE abnorm:
-dehydrated
-decreased BCS or MCS (chronic)
-nausea, hypersalivation
-pale or icteric MM
-tachypnea, crackles, coughing
-abdominal pain, crouched
-enlarged LNs
-skin tumors
-vulvar discharge, intact female dogs ALWAYS CAN BE PYOMETRA
concerning:
-very frequent or large volumes
-chronicity (>3-4 weeks)
-marked weight loss
-marked abdominal pain or swelling
-marked malaise, lethargy, weakness
-fever
-PU/PD
-bradycardia, arrhythmias
-icteric or pale MM
-neuro signs
-persistent vomiting despite symptomatic treatment
what are the 2 big disease categories for vomiting?
- GI causes:
-triggers from GIT
-reverse flow: obstruction
-disruption of the GI barrier: triggers emetic center - Not GI: circulating triggers
HELP TAKEN
-hyperthyroid
-endotoxin
-liver disease
-pancreatitis
-toxin
-addison’s
-kidney disease
-electrolyte/acid base
-neurologic
describe reverse flow GI causes for vomiting
- mechanical obstruction: things can’t go forwards because something is blocking them
-FB, GDV, mesenteric torsion, neoplastic mass, pyloric stenosis - functional obstruction/decreased motility so things can’t go forwards
-gastric ileus, intestinal ileus, constipation, bilious vomiting syndrome
MUST rule out mechanical obstruction before you can diagnose functional obstruction!!
describe foreign bodies (reverse flow, mech obstruct)
- chronic or acute
-gastric can be acute or chronic: if gorilla glue is expansile and requires surgery immediately!
-intestinal: always acute - clinical signs:
-vomiting
- +/- regurgitation - diagnosis:
-abd rads
-abd ultrasound
describe GD, GDV, and mesenteric torsion (reverse flow, mech obstruct)
GDV: dogs and guinea pigs, see other lectures
GD: most commonly food bloat
mesenteric torsion:
-acute, rapid decompensation, cardiovascular instability
-GSD/working dogs
-dx: history, clin signs, PE, abd rads
describe solitary or multiple masses (reverse flow, mech obstruct)
- most common: lymphoma, carcinoma
- clin signs:
-vomiting: often progressive
-weight loss
- +/- diarrhea - dx:
-abd ultrasound is best tool
- +/- FNA, biopsies
describe pyloric stenosis (reverse flow, mechanical obstruct)
also called hypertrophic pyloric gastropathy
- congenital: abnormally thick pylorus at birth that gets thicker over the next 4-12 months
-boston terrier, boxer, english bulldog, etc. - clin signs:
-chronic, intermittent vomiting within a few hours of eating
-may progress to gastric obstruction - diagnosis:
-abd ultrasound
-endoscopic visualization
describe gastric ileus (reverse flow, functional obstruction)
- decreased motility:
-secondary to gastritis, pancreatitis, neoplasia, intestinal ileus - clin signs:
-vomiting initially
-then regurgitation
-anorexia - dx:
-POCUS abdomen: markedly dilated stomach
-abd rads
-abd US
describe intestinal ileus (reverse flow, functional obstruct)
- decreased intestinal motility; secondary to
-cats: chronic enteropathy or pancreatitis
-dogs: severe pancreatitis or gastroenterocolitis - clin signs:
-vomiting
- +/- regurg
-anorexia - dx:
-abd US preferred
- +/- abd rads
-fin d underlying disease
regurgitation is always associated with disease in one of which two places?
- esophagus
- LES
describe constipation (reverse flow; functional obstruct)
- decreased colonic motility secondary to dehydration or GI disease
- clin signs:
-vomiting: esp after attempting to defecate (increased vagal tone)
-tenesmus - diagnosis:
-abd rads
- +/- abd US
describe bilious vomiting syndrome (reverse flow, functional obstruct)
- decreased intestinal motility when fasting causes reflux of duodenal contents (bile) into the stomach
- clin signs: early morning vomiting before breakfast
- dx:
-clin signs/timing
-ruling out other causes of vomiting
-response to treatment
describe disruption of the GI barrier as a GI cause for vomiting
cells slough off, toxins, gaps between cells, influx of inflam cells due to
- inflammation:
-acute: gastritis, enteritis, colitis
-chronic: chronic enteropathy, IBD, PLE
-ulcerations - infectious: all the lil guys
- neoplasia: diffuse
-small cell lymphoma
-mast cell neoplasia
describe acute inflammation (disruption of the GI barrier)
- gastritis, enteritis, or colitis due to:
-ingestion: dietary indiscretion or changes, drugs, toxins
-allergy: dietary intolerance
-adjacent: pancreatitis or peritonitis - clin signs:
-vomiting
-anorexia
- +/- diarrhea
-NO evidence of chronic disease - dx:
-hx, clin signs, rule out other causes
describe chronic inflammation (disruption of GI barrier)
- underlying chronic disease
-food, fiber, or probiotic responsive enteropathy
-autoimmune enteropathy (IBD)
-PLE: IBD, lymphangiectasia, neoplasia - clin signs:
-chronic vomiting
- +/- weight loss, diarrhea, anorexia/hyporexia - dx:
-rule out non-GI causes: bloodwork, abd rads
-abd US!!
- +/- GI panel (TLI, PLI, folate, B12)
- +/- dysbiosis index
-response to tx: food, fiber, probiotic
-endoscopic biopsies: rec for PLE to differentiate chronic diseases
describe gastric and intestinal ulcerations as a disruption of the GI barrier
- secondary to
-acute or chronic inflammation
-toxins, drugs (NSAIDs, steroids)
-caustic substances
-gastrinoma (gastrin producing tumor in the pancreas)
-helicobacter spp in guinea pigs and ferrets (NOT dogs and cats - clinical signs:
-vomiting
-hematemesis
-melena - diagnosis
-clinical signs
-rule out other hemostatic disorders (TCP, coagulopathy)
-CBC and chemistry: anemia, hypoproteinemia, +/- thrombocytosis, +/- elevated BUN
-abdominal ultrasound: not sensitive or specific
-endoscopy: gold standard for ID ulcerations
-response to treatment
describe viral causes of disruption of the GI barrier in dogs
most viral infections will also cause diarrhea
- parvovirus:
-clinical signs:
–vomiting and diarrhea in a puppy or unvx young dog
-dx:
–point of care test (SNAP test, witness test)
–fecal PCR - distemper virus:
-clinical signs:
–starts with resp signs, progresses to GI signs (vomiting, diarrhea)
–neurologic signs
-dx:
–conjunctival swab for inclusion bodies
–respiratory disease for PCR panel
describe viral causes of disruption of the GI barrier in cats
most viral infections will also cause diarrhea
- feline panleukopenia virus:
-clinical signs: vomiting and diarrhea in KITTENS
-dx:
–point of care test: SNAP
–fecal PCR
- systemic virulent feline calicivirus:
-clinical signs:
–oral ulcerations
– +/- oculonasal signs
–vomiting, anorexia
–diarrhea
–fever
dx: PCR n swabs from nose, throat, conjunctiva, or feces
describe bacterial causes of disruption of the GI barrier
- enterotoxins: cause inflammation and circulate
- enteroinvasive bacteria: cause direct damage to the mucosa
- types:
-E. coli
-salmonella spp.
-shigella
-yersinia
-helicobacteria spp. = only stomach specific bacteria; rarely cause primary disease in dogs and cats, but can cause primary disease in guinea pigs and ferrets - clinical signs:
-vomiting (+/- blood)
-often diarrhea, unless helicobacter
-anorexia
- +/- weight loss - diagnosis:
-fecal PCR panel: also looks for toxins
-gastric biopsies for helicobacter spp.
-FECAL CULTURES ARE NOT HELPFUL IN DOGS AND CATS
describe fungal causes of disruption of the GI barrier
- histoplasmosis: disseminated or primary GI
-cats: most commonly get from potted house plants
-dogs: inhalation of spores from soil - southern US most common (Texas)
- clinical signs:
-chronic wasting!
-fever, anorexia
- +/- vomiting, diarrhea - diagnosis:
-abd ultrasound: thickened intestines, mass, enlarged LNs
-org ID on cytology: rectal scrape, US guided FNA
-endoscopic biopsy
-blastomyces urine antigen test (mira vista): cross reacts with histoplasmosis
-serum immunoassay: cats
describe oomycetes disrupting the GI barrier
- pythium inisidiosum: focal large masses (esophagus, stomach, SI, colon
- common in california: large breed dogs, less so in cats
- clin signs:
-vomiting
-weight loss
- +/-diarrhea - dx:
-abd US: stomach, intestinal mass
-CT scan
-serology for antibodies
-ID organisms on biopsies: sx or endoscopic
-PCR on tissue biopsies
describe protozoal causes of disruption of the GI barrier
- cats: toxoplasma gondii
-often self limiting diarrhea but once they have it they always have it - clinical signs:
-vomiting
-diarrhea
-weight loss
-neuromuscular disease
-hepatobiliary disease - dx:
-PCR on fluid/tissue
-IgG and IgM antibody testing
any protozoal disease that causes diarrhea can also cause vomiting!
describe physaloptera spp, a parasitic cause of disrupting the GI barrier in dogs and cats
- stomach parasites, transmitted by ingesting invertebrate insects
- adult worm develop in the stomach
- clin signs: chronic vomiting
- dx:
-ID worm in vomit or in the stomach
-fecal smear (NOT float)
describe ollulanis tricuspis, a parasitic cause of disrupting the GI barrier in cats
- direct transmission by ingesting another infected cat’s vomit
- adult worms develop in the stomach
- clin signs: chronic vomiting
- dx:
-Baermann sedimentation on stomach fluid or vomit (NOT stool)
-ID adult worms, cannot be found in feces
describe heterobilharzia americanum, a parasitic cause of disrupting the GI barrier in dogs
- transmission by ingesting contaminated meat/water
-larvae migrate across intestinal wall causing granulomatous inflammation - clin signs:
-vomiting +/- hematemesis
-diarrhea +/- hematochezia
-anorexia
-PU/PD
-weight loss - dx:
-fecal PCR
-fecal saline sedimentation (NOT float)
-abd US
describe intestinal parasites as a general cause of disrupting the GI barrier in dogs and cats
- any intestinal parasite that causes diarrhea can also cause vomiting
- dogs and cats with large worm burdens can vomit intestinal worms
- roundworm and tapeworm burdens most common!
describe diffuse neoplasia as disrupting the GI barrier
- small cell lymphoma or mast cell neoplasia
-more common in cats - clin signs:
-vomiting
-weight loss
- +/- diarrhea - dx:
-abd US: bacon or swiss roll
- +/- FNA of LNs or spleen
-endoscopy is needed to differentiate lymphoma from IBD - scale:
-mild IBD to moderate IBD to severe IBD up to small cell lymphoma
-tx often the same for IBD and lymphoma: start with steroids and add chlorambucil depending on response
-biopsies: hard time differentiating (esp endoscopic)
-prognosis: small cell lymphoma has very good prog!
describe hyperthyroidism, a non-GI cause of vomiting
- thyroid hormones directly trigger CRTZ
- GI dysfunction
- increased metabolic rate leads to GI stasis
-vomiting/weight loss are the number 1 sign of hyperthyroidism in cats!
describe endotoxins, a non-GI cause of vomiting
- gram negative bacteria from any infection in any organ can release
-pyometra = most common
-pyelonephritis
-prostatis
-discospondylitis
-cholangitis
-hepatic abscess/hepatitis
-endocarditis
- or sepsis
describe liver disease, a non-GI cause of vomiting
- bilirubin and hepatotoxins are direct CRTZ triggers
- portal hypertension leads to edematous stomach and intestines and GI barrier disruption
describe acute pancreatitis, a non-GI cause of vomiting
- severe inflammation leads to circulating triggers for CRTZ
- adjacent acute inflammation disturbs the GI barrier
- possible sequelae:
-chronic pancreatitis: difficult to differentiate from acute pancreatitis without ultrasound
-pancreatic abscess
-pancreatic pseudocyst
-exocrine pancreatic insufficiency
-diabetes mellitus
describe toxins as a non-GI cause of vomiting
SO SO MANY, love to mess with the GI tract
describe addison’s/hypoadrenocorticism as a non-GI cause of vomiting
- typical and atypical
- missing cortisol (stress hormone) which is needed for GI health
-more later so probs FYI for now
describe kidney disease as a non-GI cause of vomiting
AKI or CKD results in uremic toxins that trigger the CRTZ
describe electrolyte and acid-base abnormalities as non-GI causes of vomiting
- hypercalcemia
- hyponatremia
- hypokalemia
- acidosis: DKA, lactic acidosis
all are direct CRTZ triggers!
describe neurologic non-GI causes of vomiting
- vestibular disease
-old dog vestib disease
-thromboembolic disease
-hypertension - oculovestibular center triggers CRTZ and emetic center
list antinausea (6) and vomiting inducing (3) meds
anti-nausea:
1. cerenia
2. ondansetron
3. metoclopramide
4. acepromazine, chlorpromazine
5. meclizine
6. diuphenhydramine
vomit-inducing:
1. apomorphine (dogs)
2. dexmedetomidine (cats; reversal is atipamezole/antisedan)
3. hydrogen peroxide (dogs, not cats)
