Vomiting and Regurgitation Diagnostic Approach

Question 1

What is the basic diagnostic approach for vomiting?

Answer 1

Define the problem –> Define the system –> Define the location –> Define the lesion

Question 2

What kind of activity is vomiting?

Answer 2

Vomiting is a coordinated activity

Question 3

What are the 4 main components of the emetic reflex? Which of these components are usually targeted by treatments?

Answer 3

1. Visceral Receptors - targeted by treatments
2. Vagal and sympathetic afferent neurons
3. Chemoreceptor Trigger Zone (CRTZ)
4. Vomiting Center within reticular formation of the medulla oblongata

Question 4

Vomiting is almost always preceded by ________

Answer 4

Nausea

Question 5

How does the CRTZ trigger vomiting?

Answer 5

No BBB in this zone which means anything can get in to trigger vomiting response

Question 6

Where are visceral receptors located?

Answer 6

In the gut

Question 7

What is the function of vagal and sympathetic afferent neurons?

Answer 7

Take messages for vomiting

Question 8

What are the 3 Stages of Vomiting? Describes the steps which happen at each stage

Answer 8

1. Nausea
   - Reduced gastric tone
   - Duodenal and proximal jejunal tone is increased
   - Duodenal contents refluxed into the stomach
   - Depression, hypersalivation, repeated swallowing
2. Retching
   - Vomiting without bringing anything up
3. Vomiting
   - Glottis closed, soft palate pressed up against nasopharynx (protects against aspiration)
   - Abdominal muscles and diaphragm contract
   - Will not see diaphragm contracting, but will see abdomen contracting
   - Cardia opens, pylorus contracts (stomach)
   - Reverse peristalsis
   - Cardiac rhythm disturbances, changes in colonic motility
   - Some animals defecate at the time of vomiting (pressure)

Question 9

How does regurgitation differ from vomiting?

Answer 9

Regurgitation is a passive process while vomiting is an active process

Question 10

What can often induce/exacerbate or encourage regurgitation?

Answer 10

• Alterations in food consistency
• Exercise
• Facilitated by gravity when the head and neck are held down and extended

Question 11

What are the receptors in the vomiting center and which 2 drugs target this site?

Answer 11

a2, NK1, 5HT1a
NK1 antagonists, Phenothiazines

Question 12

What are the receptors in the CRTZ and which 4 drugs target this site?

Answer 12

D2, M1, H1/H2, 5HT3, NK1
NK1 antagonists, Phenothiazines, Antihistamines, Metclopramide

Question 13

What are the peripheral receptors and which 3 drugs target these receptors?

Answer 13

M2, D2, NK1, 5HT3, Motilin
NK1 antagonists, Metclopramide, Anticholinergics

Question 14

What is the receptor in the vestibular system and which 4 drugs target this site?

Answer 14

M1
Anticholinergics, NK1 antagonists, Phenothiazines, Antihistamines

Question 15

What can affect the vomiting center and what are these sites responsible for?

Answer 15

CRTS, Toxins, Vestibular system (motion sickness, inner ear infection), Nucleus tractus solitarius (integration), Peripheral receptors (gut, abdominal organs), Higher CNS (pain, fear smell)

Question 16

Which 2 systems responsible for vomiting can also communicate with each other?

Answer 16

CRTZ and vestibular system

Question 17

Where does the physical/observable action of vomiting vs. regurgitation originate from?

Answer 17

Vomiting - comes from the stomach
Regurgitation - comes from the shoulders

Question 18

What comes up from vomiting vs. regurgitation?

Answer 18

Vomiting - bile (or reflux) + stomach contents (no saliva)
Regurgitation - Undigested food + saliva

Question 19

Can vomiting/regurgitation be ruled out based on pH analysis of contents brought up?

Answer 19

No

Question 20

Can either vomiting or regurgitation be treated symptomatically?

Answer 20

Vomiting can usually be treated symptomatically, but regurgitation cannot.

Question 21

What is regurgitation usually a sign of if its a persistent condition?

Answer 21

Usually a sign of a “bad” disease

Question 22

How does investigation of vomiting vs. regurgitation differ?

Answer 22

Vomiting - investigation using biochemistry, hematology, UA, abdominal imaging, endoscopy, ex-lap
Regurgitation - investigate using imaging of esophagus or endoscopy. Doing hematology, biochem, and ex-lap is a waste of owner’s money and can be dangerous for patient.

Question 23

What is the best thing to do if you find a foreign body during endoscopy in a patient experiencing regurgitation?

Answer 23

Best to push FB into the stomach to allow passage/surgical retrieval rather than retrieve it/pull it out from esophagus or let it sit in esophagus for longer.

Question 24

What is primary vs secondary GI disease?

Answer 24

Primary GI disease - structural disease, stomach to colon
- Define as either surgical or medical
Secondary GI disease - functional disease
Accessory digestive organ (pancreas)
- Electrolyte imbalance (Na+, K+, Ca2+)
- Endogenous toxins (kidney, liver, ketoacidosis, infection)
- Exogenous toxins
- Primary CNS

Question 25

How does investigation of primary vs secondary GI disease differ?

Answer 25

Primary GI disease - IMAGING most useful (rads, U/S) - Labs might give info about clinical signs, but rarely about the cause of vomiting Secondary GI disease - Hematology, UA, imaging, ex-lap, endoscopy

Question 26

Is vomiting always related to eating? What is the exception?

Answer 26

Vomiting does often relate in time to eating, but the only exception is pancreatitis

Question 27

Does vomiting not related to eating rule out primary GI disease? Why?

Answer 27

No - Vomiting may be delayed for some hours in animals with non-inflammatory gastric disorders

Question 28

Give some examples of situations when an animal might vomiting despite not eating?

Answer 28

Foreign body Secretory disorders of the bowel

Question 29

How does vomiting usually occur in relation to eating in lower bowel disorders?

Answer 29

In lower bowel disorders vomiting usually occurs at variable times after eating

Question 30

When should primary GI disease be strongly suspected?

Answer 30

- An abnormality is palpable in the gut (FB, intussusception) - Vomiting is associated with significant diarrhea - Patient is clinically and historically normal in all other respects - The onset of vomiting significantly preceded any development of signs of malaise, depression and/or anorexia - Important to check if vomiting started earlier than presentation at the vet office - Vomiting is consistently related in time to eating

Question 31

How do you define the location in primary GI disease?

Answer 31

Anywhere from stomach to the colon Use barium meal, barium enema, endoscopy, proctoscopy, laparotomy

Question 32

How do you define the lesion in primary GI disease?

Answer 32

Split into diseases of the stomach vs diseases of the intestine

Question 33

What are the most common primary GI causes of vomiting?

Answer 33

Gastritis - spoiled food, dietary indiscretion, food intolerance Viral infection - Parvo, Corona, Rotavirus Foreign body GI neoplasm

Question 34

When should secondary GI disease be strongly suspected?

Answer 34

- Patients usually metabolically ill (Exceptions: Early pancreatitis, Hyperthyroid cats) - Vomiting occurred subsequent to the onset of other signs of malaise, inappetence and/or depression - Other clinical signs present (jaundice, PU/PD)

Question 35

What should you do if you can't tell if its primary vs secondary GI disease?

Answer 35

Define the location - define the organ involved --> Define the lesion

Question 36

What are some secondary GI causes of vomiting?

Answer 36

Pancreatitis Liver or Renal Disease Endocrine Disease (Ex. Diabetic ketoacidosis, Addison's, Hypercalcemia)

Question 37

What changes about the order of logical approach in regurgitation vs vomiting?

Answer 37

In regurgitation defining the location and lesion comes before defining the system that is responsible --> This will lead us to finding out that the problem is in the esophagus Most causes of regurgitation are primary structural problems with the esophagus and defining the system responsible only relates to the condition of megaesophagus

Question 38

Describe congenital vs acquired megaesophagus?

Answer 38

Congenital Acquired - Primary (idiopathic) vs Secondary (systemic causes) - Myasthenia gravis, Hypoadrenocorticism (reversible)

Question 39

What are some lesions that can cause esophageal disorders (defining the lesion) and regurgitation

Answer 39

Anatomic - cricopharyngeal disease, hiatal hernia, diverticulum Megaesophagus - congenital vs acquired External compression - persistent R aortic arch ie. vascular ring anomaly (congenital) - Mediastinal lymphoma - Thyroid tumors Internal obstruction - FB - Stricture Esophagitis - Trauma - Reflux of gastric acid - Irritation Intramural lesions - Neoplasms, Abscesses, Granulomas - Parasites (ex. Spiroserca lupi in endemic areas)

Question 40

When is symptomatic therapy appropriate for a vomiting patient?

Answer 40

Appropriate when primary GI disease has transient cause (dietary indiscretion, toxin) or Mild pancreatitis

Question 41

When is symptomatic therapy NOT appropraite for a vomiting/regurgitating patient?

Answer 41

Signs of secondary GI disease Patient is dehydrated, painful or depressed

Question 42

When do you need to go further and assess the metabolic effects of vomiting on a patient?

Answer 42

No response to symptomatic therapy Vomiting is present and severe Other clinical signs present suggesting secondary GI disease (PU/PD, Jaundice, Anemia)