15 – GI Diagnostics and Vomiting

Question 1

Diagnostic approach

Answer 1

• History and physical exam
• Labs
• Imaging
• Biopsies

Question 2

What are some common presenting problems?

Answer 2

• Drooling
• Dysphagia
• Regurgitation (ex. chest rads)
• Vomiting
• Diarrhea (large (unlikely to be dehydrated) vs. small bowel)
• Weight loss

Question 3

Vomiting ‘signs’

Answer 3

• Actively
• *Bile (no bile does NOT necessarily mean no vomiting)
• Acidic
• Digested food
• Prodromal signs
  o Uncomfortable, pacing, drooling

Question 4

Regurgitation ‘signs’

Answer 4

• Passive act
• No bile
• Non-acidic
• Undigested food
• No prodromal signs

Question 5

Small vs. large bowel diarrhea

Answer 5

• Frequency: increased with large bowel
• Urge: more with large bowel
• Volume: small bowel=larger
• Mucous: large bowel
• Frank blood
• Melena: small bowel (can be anywhere above the large bowel)
• Weight loss: small bowel

Question 6

Physical examination

Answer 6

• Needs to be thorough
• Nose to tail
• *don’t just look at info on primary GI problems, but also make sure there isn’t concurrent illness

Question 7

Oropharyngeal exam

Answer 7

• Teeth
• Mucous membranes
• Tongue
• Palate
• Gag reflex
• Sedation to look at:
  o Tonsils, pharynx, larynx, epiglottis

Question 8

Head and neck

Answer 8

• Salivary glands
• Lymph nodes
• Muscles of mastication
• Esophagus
• Thyroid gland

Question 9

Abdominal palpation

Answer 9

• Liver (can elevate front of animal to make things ‘fall back’)
• Pancreatic region
• Stomach
• Intestines: thickness, consistency, mobility
• Colon, rectum

Question 10

Rectal examination

Answer 10

• Fecal sample
• Feel mucosa
• Sublumbar lymph nodes
• Anal glands
• Urethra
• Prostate

Question 11

Fecal examination

Answer 11

• Float (zinc sulfate, most common test)
• Sedimentation
• Direct smear
• Fecal fat, fecal occult blood
• Giardia ELISA
• Parvovirus ELISA
• Electron microscopy
• Culture (campy, salmonella)

Question 12

Standard lab evaluation

Answer 12

• CBC
  o Anemia, eosinophilia, stress
• Serum chemistries
  o Electrolytes, protein losing disease, secondary causes
• Urinalysis
  o Protein loss, bilirubin, urobilinogen

Question 13

Ancillary laboratory testing

Answer 13

• Amylase and lipase: not specific
• TLI: Trypsin and Trypsinogen
  o Dogs and cats EPI
  o PLI for pancreatitis
• Cobalamine: decreased in SIBO (SI bacterial overgrowth)
• Folate: increased in SIBO

Question 14

Radiology

Answer 14

• Plain radiographys
• Contrast studies
  o Barium swallow
  o Positive contrast gastrogram
  o Double contrast gastrogram
  o Barium series
  o BIPS
  o Barium enema

Question 15

Ultrasonography

Answer 15

• Visualize extraintestinal organs
• Assess mural thickness
• Assess lymph node size

Question 16

If blood in vomit, what might it be from?

Answer 16

• Ulcer: “coffee grounds”
• Tumor
• Hemostatic disorder

Question 17

What are the steps in vomiting?

Answer 17

• Prodromal nausea
  o Licking lips, drooling, restless, yawning
  o Hypersalivation-relaxes gastroesophageal sphincter
• Retrograde giant contraction
• Retching (contraction of abdomen with closed glottis)
• Flaccid stomach and relaxed sphincters

Question 18

What are the 2 pathways of vomiting?

Answer 18

1. Neural pathway
   a. Vagosympathetic
   b. CRTZ
   c. Vestibular
2. Humoral pathway

Question 19

Neural control of vomiting

Answer 19

• Vomiting center
  o Medulla
  o Final pathway
• Chemoreceptor trigger zone
  o No BBB
  o 4th ventricle
• *vestibular and peripheral receptors

Question 20

What are the consequences of vomiting?

Answer 20

• Aspiration pneumonia
• Dehydration
• Electrolyte and acid-base abnormalities
  o Hyponatremia
  o Hypochloremia
  o Hypokalemia
  o Acid base status often variable

Question 21

What are the causes of vomiting?

Answer 21

• Secondary to a variety of disease
• Primary GI disease

Question 22

Acute gastritis

Answer 22

• Diet
  o Intolerance, bacterial or fungal toxins, chemical toxin
• Infectious
  o Viruses, bacteria
• Drugs
  o NSAIDs, antibiotics

Question 23

GI foreign body

Answer 23

• Generally acute onset
• Possibly painful on palpation
• Cats more often linear
  o Hair scrunchies common?

Question 24

Therapeutic guidelines: vomiting and GI

Answer 24

• Supportive care
  o Supply fluids and electrolytes
• Antiemetics
• Specific therapy of problem

Question 25

Metoclopramide

Answer 25

• Dopamine antagonists at CRTZ and at peripheral receptors
• Antiemetic and stimulant for GI motility
• Short half-life
• *NOT great

Question 26

Antihistamines

Answer 26

• Weak antiemetics
• Usually used for motion sickness

Question 27

Maropitant

Answer 27

• Cerenia
• NK1 receptor antagonist
• Can be used in dogs and cats
• Good efficacy

Question 28

Ondansetron (5-HT3 antagonist)

Answer 28

• One of better ones
• Cost is high
  o Often used as an add on

Question 29

Mirtazapine (5-HT3 antagonist)

Answer 29

• Antidepressants
• Effective for vomiting and nausea
• Commonly recommended in cats with CRD (renal disease)

Question 30

GI protectants

Answer 30

• H2 receptor antagonists
• Omeprazole (causes vomiting and diarrhea, GI side effects, ONLY use when needed)
• Sucralfate
• Misoprostol