Vomiting Flashcards
The following describes what?
A reflex
Forceful expulsion of stomach contents through the mouth
One of the most common presentations of illness in our patients
Self limiting vs. debilitating
Vomiting!
What are the 3 phases of vomiting?
Nausea
Retching
Expulsion
What clinical signs are associated with the first phase of vomiting (nausea aka prodromal phase)?
Ptyalism
- Hiding*
- Seeking attention*
- Yawning*
- Shivering*
- Tachycardia*
- Pallor*
What clinical signs are associated with the second phase of vomiting (retching)?
Abdominal mm, chest wall and diaphragm all contract without any expulsion of gastric contents
Retrograde contraction –> duodenal contents into stomach
Deep inspiratory movements
Respiratory center is inhibited
What clinical signs are associated with the third phase of vomiting (forceful expulsion)?
Stomach DOES NOT actively expel!!
**Stomach, esophagus, and sphincters relaxed during vomiting!!
Force that expels arise from the contraction of the diaphragm and abdominal mm
What is the pathway for vomiting?
Stimuli –> afferent pathways (sensory and central); higher brain; vestibular apparatus (motion sickness); CRTZ –> emetic center –> efferent motor signals = VOMIT TME!
Explain the physiology of vomiting.
Activation of chemoreceptors and mechanoreceptors
Stimulation of visceral afferent receptors (5-HT3; NK-1)
Direct stimulation of the cerebral cortex and limbic system -fear, stress, trauma
Vestibular system stimulation (M-1 cholinergic; H1-histaminergic)
CRTZ (Chemoreceptor Trigger Zone)
-stimulated by vestibular system
-many receptors
-free nerve endings bathed in CSF -lacks BBB –> stimulated by ‘emetogens’
How does motion sickness (“kinetosis”) induce vomiting?
inner ear/labyrinth stimulation –> dopamine and serotonin released from CRTZ activation –> Ach released from emetic center
How do drugs such as chemo agents induce vomiting?
5-HT3 serotonergic receptors and CRTZ
How does intestinal inflammation induce vomiting?
- direct afferent input to vomiting center
- many causes of GI dz; pancreatitis
How do opioids induce vomiting?
-stimulation of CRTZ, increased vestibular sensitivity, gastric stasis, or impaired intestinal motility and constipation
How do toxins induce vomiting?
-CRTZ permeable and initiates NT cascade
How does uremia induce vomiting?
- decreased gastric clearance –> ulcers and gastritis (PPI, H2-antag)
- toxins cross BBB –> stimulate central and peripheral receptors
- activates CRTZ via D2-dopaminergic receptors
T/F When a client tells you their pet never eats anything that they shouldn’t you should believe them bc they know their pets best.
False. People don’t know shit.
What clinical signs do we see with vomiting?
vomiting lethargy inappetence \+/- diarrhea \+/- wt loss systemic signs of illness respiration changes if aspiration has occurred
There are some major things to note when performing physical exam with a dog that’s vomiting. What are they?
- dehydration- skin, eyes
- abdominal pain
- abdominal distension
- palpable foreign material
- thickened intestines
- constipation (bc straining so much in litter box they make themselves vomit)
- normal
- ptyalism
- mental status (toxins, CNS dz)
- respiratory status-can change
- diarrhea (do a rectal!)
- **look under the tongue!!
- wt loss
- signs of systemic illness
Diagnostics are sorta the same as always but what’s something additional that’s unique with regards to vomiting?
Baseline cortisol is an extra aspect of diagnostic workup to look into as well as coagulation profile (i.e. if hematemesis or protein losing nephropathy)
T/F DO NOT make initial recommendations based on owner finances.
True
What is your protocol when patient is NOT systemically ill and is acutely vomiting?
Symptomatic therapy; few days of diet and medications then wean onto normal diet
What is your protocol when patient IS systemically ill and is acutely vomiting?
Symptomatic therapy; lab evaluation and imaging
What is your protocol when patient is NOT systemically ill and is chronically vomiting?
Symptomatic therapy; food trial at least 2 -3 wks; +/- Medication trials
What is your protocol when patient IS systemically ill and is chronically vomiting?
Symptomatic therapy; lab evaluation and imaging; +/- biopsy
What are the basics to know about PCV/TS?
PCV= estimate of RBC decreased= anemia increased= dehydration
TS= total solids= serum proteins- mostly Alb and globulins, as well as fibrinogen and other proteins decreased= low protein increased= dehydration, some advanced inflammatory dz and neoplasia
What are some basics to know about Blood glucose?
BG= blood glucose decreased= hypoglycemia from various cause increased= possibly DM
On many glucometers –> affected red cell count
decreased= artificially w polycythemia
increased= dehydration
Serum chemistry rules out what ?
kidney, liver and electrolyte concerns
Urinalysis helps rule out what?
UTI and UTO; indicators of other systemic dz
Fecal tests help rule out what?
Parasites
Coags help rule out what?
if hematemesis or other signs of bleeding are present
When would we perform a baseline cortisol?
to rule out Addison’s or support pursuing ACTH stim
When would we perform a PLI?
To check for pancreatitis
T/F It is fine to just take abdominal ultrasound and not perform x rays.
False! US does not take the place of X rays!
How do we treat patients with acute vomiting but “not ill”?
medical management: antacid +/- fluid therapy and time . . . anti nausea can suppress normal vomiting response to expel FB - SO DONT MASK WITH MEDS! Let dem vomit
T/F In patients that are acute vomiting but “not ill,” water should be withheld for 6-8 hours with small, frequent amounts working back to normal over 24-48 hours. If not vomiting, small meals should be given every 4-6 hours for day 1 with bland diet or prescription diet.
True. Bland diet= chicken and rice or beef and rice or prescription diet
How do we administer outpatient fluids?
SQ or IV bolus
When giving an outpatient treatment fluids, the volume will depend on the hydration status. Typically, the hydration status is mild which means we give what fraction of their daily maintenance?
1/3- 1/2 daily maintenance
If a 10 kg dog is being given outpatient fluids, how many mLs would he be given if his maintenance is 60 mLs/kg/day?
200-300 mLs because 10 x 60= 600 and then we give 1/3-1/2 of daily maintenance
What is the shock dose needed for rehydration?
60-90 mLs/kg; start w 1/4-1/3 then reassess
What are the risks of fluid therapy?
History of heart failure (volume overload so consider enteral water via nasogastric tube) and severe hypoproteinemia (can easily induce edema, effusions)
Normosol, Plasmalyte, LRS and Sodium Chloride 0.9% are all considered maintenance fluids. How are they administered?
SQ/IV
Explain the MOS of H2 Receptor Antagonists.
Affects gastric parietal cell receptors. Limits acid secretion (antacid) with mild to little affect on pH.
Famotidine, Ranitidine and Cimetidine are al examples of wut?
H2 Receptor Antagonists
Cimetidine has more Rx interactions than the other 2
Explain the MOS of PPIs (Proton Pump Inhibitors).
- gastric proton pump inhibitor antacid
- inhibits transport of hydrogen ions into the stomach
- inhibits the hepatic cytochrome P-450 mixed fxn oxidase system
- MUST check for drug interactions
Pantoprazole and Omeprazole are examples of what?
PPIs
Explain the MOS of Antiemetic medications.
Block/compete with neurotransmission at the RECEPTOR SITES associated with emesis
Anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, phenothiazines and NK-1 receptor inhibitors are all examples of what?
Antiemetic medications
M1- Cholinergic Receptor Antagonists (Scopalamine, Phenothiazines, Propantheline and isopropamide) are not used very often. Why?
They cause sedation and hypotension
T/F Histamine antagonists can be safely used on cats.
False. Not helpful for cats bc no histamine receptors on CRTZ.
Diphenhydramine, Meclizine and Cyproheptadine are all examples of what?
Histamine antagonists.
Metoclopramide is an example of what?
D2-dopaminergic antagonist . . . know this mother fucker!
Explain the MOS of Metoclopramide.
Stimulus on movement of distal esophagus. Cats» dogs.
Antiemetic: Dogs»_space; cats (few CNS dopamine receptors)
Multiple drug interactions
5-HT3 antagonist & 5-HT4 agonist
What are the SE’s of Metoclopramide?
Constipation, mentation change
Where do 5-HT3- Serotoin antagonist work?
Work in GI tract & CRTZ
What are the SEs oF 5-HT3- Serotoin antagonist?
constipation (she sees this a lot), fatigue, dry mouth
Anzemet and Zofran are examples of what?
5-HT-Serotoin Antagonists
How do NK-1 Receptor Antagonists work?
Competes with Substance P peripherally and centrally
Cerenia is an example of what?
NK-1 Receptor Antagonists. . . she looooves her some Cerenia
What are the SE’s of Cerenia?
ataxia, anorexia, diarrhea, injection soreness, bradycardia w high dose
Cerenia is used to tx vomiting and what else?
Motion sickness! Need higher dose when tx motion sickness.
Carafate is a what?
Gastric mucosal protectant
How does Carafate work?
Stimulates PG E2 & I1- cytoprotective
Reacts w HCl to form paste which sticks to ulcers
Inactivates pepsin and binds bile acids
Binds GI phosphorous
Weak antacid
When should Carafate be given?
2 hours before or after other meds and food
Metoclopramide, Cisapride, Ranitidine and Erythromycin are all what?
Prokinetics!
How do 5-HT4 Receptor Activators work?
Gastric emptying and GI motility
Stimulate release of Ach into the enteric NS
LES, stomach, colon
Cisapride and Metoclopramide are examples of what?
5-HT4 Receptor Activators
Cisapride works really well for constipation tx in what species?
Cats!
Cisapride, Constipation, Cats.
C’s get degrees.
How do macrolide antibiotics work?
Stimulates Motilin
Promotes intestinal motility
Initiates phase III of migrating myoelectric complex which propels ingesta
What’s an example of a macrolide antibiotic?
Erythromycin
T/F Withholding food is appropriate with chronic vomiting.
False. Withholding food is NOT appropriate with chronic vomiting.
T/F You should not perform a food trial if animal is systemically ill.
True. Why try and fuck with them when they’re sick? Leave them alone. Deal with food changes later.
Cyproheptadine is an H1 receptor blocker and serotonin antagonist. Why do we utilize it in vomiting?
It’s a appetite stimulant!
How does Tetracyclic antidepressants work as appetite stimulants?
They increase NE and thus appetite
Mirtazapine is an example of what?
Tetracyclic antidepressant
What are some SE’s of Mirtazapine?
Polyphagia, sedation or excitement
Clicker Q: Cerenia works by which mechanism?
A. Serotonin receptor (5-HT3) antagonist
B. Substance P competitor at NK-1 receptor
C. Magic
D. PPI
B! Substance P competitor at NK-1 receptor
