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
