Vomiting Flashcards
Is vomiting a reflex?
Yes
What is vomiting?
Forceful expulsion of stomach contents through the mouth
Very common presentation of illness
What are the three phases of vomiting?
Nausea
Retching
Expulsion
What is the nausea phase also known as?
Prodromal phase
What are the clinical signs of the prodromal/nausea phase?
Ptyalism, hiding/attention seeking, yawning, shivering, tachycardia, pallor
What is the retching phase characterized by?
Contraction of the abdominal muscles, chest wall, and diaphragm without any expulsion of gastric content
What is retrograde contraction?
Duodenal contents pushed back into the stomach
What is inhibited during the retching phase of vomiting?
Respiratory center- lessen chances of aspiration
Does the stomach actually contract during forceful expulsion?
No- the sphincters are relaxed and abdominal muscles and diaphragm contract
What is the pathway from stimulation to vomiting?
Stimuli
Afferent pathways, higher brain, vestibular apparatus, CRTZ
Emetic center
Effenent motor signals–> Vomiting
What are some things that will lead to vomiting?
- Activation of chemo or machanoreceptors
- Stimulation of visceral afferent receptors
- Direct stimulation of the cerebral cortex and limbic system
- Vestibular stimulation
- CRTZ stimulation
What are the things that stimulate the cerebral cortex and limbic systems which case vomiting?
Fear, stress, or trauma
What are some Ddxs for vomiting?
- Metabolic disease
- Toxins
- Dietary indescretion or foreign body
- Drug induced
- Primary GI disease
- Environmental, motion sickness
- Organ failure
- Pancreatitis
- Urinary or repro disease
- Neoplasia
- Pain
What are some emetogens?
- Medications
- Infections
- Metabolic disease
- Uremia
- Radiation
What is the mechanism for vomiting due to motion sickness?
aka Kinetosis
Inner ear/labyrinth stimulation–> dopamine and serotinin released from CRTZ–> Ach released from emetic center
What is the mechanism for vomiting due to drugs such as chemo-agents?
5-HT3 serotonergic receptors and CRTZ
What is the mechanism for vomiting due to intestinal inflammation?
Direct afferent input to vomiting center
What is the mechanism for vomiting due to opioids?
Stimulation of CRTZ, increased vestibular sensitivity, gastric stasis, or impaired intestinal motility and constipation
What is the mechanism for vomiting due to toxins?
CRTZ permeable and initiates neurotransmitter cascade
What is the mechanism for vomiting due to uremia?
- Decreased gastric clearance–> ulcers and gastritis
- Toxins crossing BBB–> stimulation central and peripheral receptors
- Activation of CRTZ via D2- dopaminergic receptors
What are the clinical signs/presenting concerns for a vomiting patient?
- Vomiting…..
- Lethary and inappetence
- May have diarrhea and weight loss
- Systemic signs of illness
- Respiration changes if aspiration
What are some questions you should ask concerning the vomiting?
- Quantity and quality
- Duration
- Relationship to food and diet change
- Current feeding and environment
- Medical history
What are some common physical exam findings for a vomiting patient?
Dehydration, abdominal pain and distention, palpable foreign material?, Thickened intestines, constipation, ptyalism, altered mental and respiratory status, Diarrhea, weight loss, systemic illness
MAY BE TOTALLY NORMAL
What are some diagnostics that are useful in the vomiting patient?
Labwork, rads/US, coritsol, GI panel, fecal, coag profile, endoscopy
What is the time frame used to describe acute versus chronic vomiting?
Acute = 1 week
What are some of the top differentials for acute vomiting?
- Toxins/medications
- Diet change
- Foreign body
- Acute organ disease, pancreatitis
- Dietary indiscretion
- Addisonian crisis
What are some of the top differentials for chronic vomiting?
- Intermittent foreign body
- Organ failure/dysfunction
- Chronic pancreatitis
- Primary gastric or intestinal disease
- Atypical addisonian or hyperthyroid
What are the general guidelines for therapy for an acute vomiting patient that is not systemically ill?
Symptomatic therapy and a few days of a bland diet and medications then wean off
What are the general guidelines for therapy for a chronic vomiting patient that is not systemically ill?
Symptomatic therapy and a food trial of at least 2-3 weeks +/- medication trials
What are the general guidelines for therapy for an acute vomiting patient that is systemically ill?
Symptomatic therapy and laboratory evaluation with imaging
What are the general guidelines for therapy for a chronic vomiting patient that is systemically ill?
Symptomatic therapy and laboratory evaluation with imaging +/- biopsy
What are the “Big 4” of a diagnostic work up?
PCV, TS, Glucose, AZO stick
Why is abdominal imaging useful?
Rule out GDV, obstruction, foreign body, constipation, masses, urinary obstruction, pyometra
Why is thoracic imagining useful?
- aspiration pneumonia
- dilated esophagus
- Diaphragmatic hernia
What is abdominal ultrasound useful for determining??
- Obstruction
- Mass size and evaluation
- Alterations in the lining or layering
- Pancreatitis
- Other organ issues
- Acquire peritoneal fluid or organ aspirates
Why is endoscopy useful?
- Visualize esophagus, sphincters, stomach, and duodenum
- Remove foreign bodies
- Biopsy tissue of interest
T/F: It is common to find hypochloremia in vomiting patients.
True- selective chloride loss in vomitus
How do you medically manage an acutely vomiting patient with no signs of systemic illness?
Antacid +/- fluid therapy and weight
Are anti-nausea medications recommended for acute vomiting, non-ill patients?
No since they can suppress normal vomiting response to expel FB
What is the feeding protocol for an acutely vomiting non-ill patient?
No water for 6-8hr then small frequent amounts working back to normal
If no vomiting then feed small meals every 4-6 hours with a bland or prescription diet
Why is important to administer fluids to vomiting patients?
Ongoing dehydration issues that cause debilitating issues
What kinds of animals should you be cautious about giving fluids to?
Heart failure or severely hypoproteinemic patients
What are the types of fluids we typically give to vomiting patients?
Maintenance fluids SQ/IV
Normosol, plasmalyte, LRS, isotonic saline
What do H2 receptor antagonists do?
Affect the gastric parietal cell receptors that limit the acid secretion with little effect on pH
What drugs are H2 receptor antagonists?
Famotidine, ranitidine, cimetitidine
What do proton pump inhibitors do?
Inhibit gastric proton pumps and hepatic cytochrome P-450 to limit acidity in the stomach
What drugs are proton pump inhibitors?
Pantoprazole and omeprazole
What is the MOA of antiemetic medications??
Block or compete with neurotransmission at receptor sites associated with emesis
T/F: Many antiemetic drugs are used off label in veterinary medicine.
True
What is scopalamine?
A M1 cholinergic receptor antagonist
May cause excitement in cats but typically not used due to sedation and hypotension
T/F: Histamine antagonists work really well in cats.
False- cats do not hav histamine receptors in CRTZ
What are some histamine antagonist drugs?
Diphenhydramine, meclizine, cyproheptadine
What is metoclopramine?
A D2 dopaminergic antagonist that stimulates movement of distal esophagus in cats and works as an antiemetic in dogs
Has multiple drug interactions
What are dolasetron and ondansetron?
5-HT3 serotoin antagonists- work in the GIT and CRTZ
What is maropitant?
Substance P competetor peripherally and centrally
Labeled for vomiting and for motion sickness but need higher doses for motion sickness
What drug is a gastric mucosal protectant?
Sucralfate
Stimulates PG and reacts with HCl to form a paste which helps protect ulcers and is a weak antacid
What two drugs are used to treat advanced gastric disease?
Misoprotol- prostaglandin analog
Octretide- somatostatin analog
What is misoprotol used to treat?
Used to treat and prevent gastric ulcers and enhances mucosal degense system
What is octretide used to treat?
Insulinomas and gastrinomas
What drugs are prokinetics?
Metoclopramide, cisapride, ranitidine, erythromycin
What drug is a 5-HT4 receptor activator and how does it work?
Cisapride and metoclopramide
Improves gastric emptying and GI motility
How does erythromycin increase motility?
Stimulates production of motilin which promotes intestinal motility
What is cyproheptadine?
H1 receptor blocker and serotonin antagonist that stimulates appetite
How do tetracyclic antidepressants work to improve appetite?
Increase NE secretion
ie Mirtazapine
