Basic Gastrointestinal SX Part 1 Flashcards
How long does it typically take a foriegn body to pass through the GI tract?
3-4 days
With sharp objects, what can you feed prior to induction of emesis?
cotton (not sure if effective)
What types of foreign bodies rarely pass through the GI tract and need immediately removal?
linear FB (strings)
abrasive FB (corn cobs)
Age, breed, an sex predispositon for GDV?
large/giant deep-chested breed dogs (Great Danes 10%> St. Bernards>weimaraner, GSH, Irish setter 7%>gordon setter)
mature/middle aged
males 2x as likely as females
Risk Factors of GDV
mutifactorial Disease:
- ingestion cereal-based diets + water then vigorous exercise
- Stretching of the hepatogastric or hepatoduodenal ligaments from chronic overeating
- FB pyloric gastric outlet obstruction in some cases (splenic torsion is secondary)
- Bacterial fermentation? (likely post-mortem cause)
- aerophagia
- gastric motility disorders
- hypergastrinemia
A young puppy presents with intermittent vomiting of undigested food. DDX?
Foreign body
Methods to DX a FB?
- normal rads for radiopaque FB
- contrast rads for radiolucent
- endoscopy
What will the biochemical profile be for a acute complete block of the pylorus from a FB?
hyponatremic, hypokalemic, hypochloremic metabolic alkalosis (loosing HCl and Na/K in projectile vomit)
What is the layer of strength for the gastrotomy closure?
submucosa (collagen rich and good blood supply)
Closure suture pattern for gastrotomy
1st layer submucosa Cushing
2nd layer submucosa and seromuscular lembert
absorbable suture (no catgut)
Where should you make your gastrotomy incision?
ventral incision equidistant between greater and lesser curvature
What is used to help hold the stomach up?
stay sutures
A dog presents with restless, uncomfortable, painful, hyper-salivation, non-productive vomiting (aka wretching), abdominal distention, hyperapnea >30 bpm, and shock (pale mm, prolonged CRT, eak femoral pulse). DDx?
GDV
For GDV gastric rotation:
dilatation alone?
volvulus?
dilatation: 90 degrees counterclockwise
volvulus: 270 clockwise rotation
With GDV, how does the stomach fundus and pylorus and spleen rotate?
stomach fundus: left dorsal to right ventral
Stomach pylorus: right ventral to left caudal & dorsal
spleen: ventral to dorsal (follows greater curvature to right)
What is the pathophysiology for GDV?
Which arteries tear as a result of the volvulus in GDV?
The gastrosplenic ligament and short gastric arteries are often torn during the volvulus.
What is the result of damage to Auerbach’s plexus in GDV?
Neurologic damage to the ganglion cells of Auerbach’s plexus may lead to decreased peristalsis, hypotonia and flaccidity of the dog’s stomach.
Why is septic shock observed with GDV?
Splanchnic visceral congestion and decreased venous return result in a decreased cardiac output (64%) and reduced mean aortic pressure (48%).
Portal venous congestion may initiate septic shock due to failure of the liver to detoxify endotoxins produced in the intestinal tract.
Hypotension and decreased rate of tissue perfusion may cause microvascular sludging and the development of DIC.
Of the 40% of dogs that develop DIC with GDV, what are the signs?
What percent of dogs with >1 abnormality have stomach necrosis?
Ability to pass the tube into the stomach does/does not mean that gastric volvulus is not present.
dose not
After decompression with a foal stomach tube, how much water should be used to lavage the stomach?
4-5 L H2O
What cardiac dysrhythmias are commonly seen with GDV?
Tx?
Paroxysmal ventricular tachycardia, and premature ventricular contractions are most commonly seen.
Lidocaine (CRI; toxicity=seizures, admin valium and stop drug)
Others: Procainamide and quinidine
What is the likelihood of recurrence of GVD if the patient is treated solely with decompression or repositioning alone?
80% **
What are the three commonly used techniques at the VMTH for fixing the stomach to the abdominal wall with a gastropexy?
circumcostal , tube and incisional
What are the three goals for SX for GDV?
- reposition the stomach
- evaluate GI tract
- prevent recurrence
Viable or not?
- black, grey, green
- blue & dark red
- not viable
- viable
If the stomach wall is thin, what is the viability?
likely not viable
What are the ways stomach tissue viability can be assessed?
What are the advantages of a tube gastrotomy?
- rapid, easy
- permanent adhesion
- allows for gastric decompression
- allows tube feeding
What are the advantages & disadvantages of an incisional gastrotomy?
Advantages: rapid, easy; stomach lumen not entered
Disadvantages: no good clinical follow-up (hard to know if effective); no access to stomach
What are the classifications of an intestinal obstruction?
Why do patients with an intestinal obstruction have an increased likelihood of becoming dehydrated?
increased secretion and decrease absorption in intestine proximal to the obstruction
vomiting
Diarrhea, tenesmus, and/or scanty amounts of bloodstained feces are also often seen in patients with what?
intussusception
Scanty stools often indicate a obstruction?
incomplete
A dog presents with sporadic vomiting, anorexia and weight loss which often progresses in severity over days or weeks.
Complete or incomplete obstruction?
incomplete (with complete the clinical signs do not wax and wane)
Why is absorption decreased and fluid build-up in the lumen common with a complete obstruction?
Absorption decreased b/c ischemia and devitalization of intestines.
Edema in intestinal wall leads to fluid accumulation (can enter lumen or peritoneal extravasation aka leaks into peritoneal space)
What type of luminal obstruction is present?
polypoid mass
What are the three classes of mechanical obstructions?
- luminal (FB or polypoid mass)
- intramural (neoplasia or fungal granuloma)
- extramural (adhesion or strangulated hernia)
What type of mechanical obstruction is this?
extraluminal (adhesions)
What type of obstruction is likely if the dog has:
Bilious vomitus
feculent vomitus
Bilious vomitus suggests that the lesion is distal to the bile duct
feculent vomitus suggests a distal bowel obstruction
A dog presents with unrelenting projectile vomit and rapid dehydration.
Proximal or distal obstruction?
Proximal obstruction (pylorus or duodenum)
A dog presents with anorexia and chronic signs of bowel obstruction. The dog did vomit initially but then the vomiting subsided.
Proximal or distal obstruction?
Distal (jejunum, ileum, colon)
Why do dogs with proximal intestinal obstructions become rapidly dehydrated?
Duodenal obstruction prevents large quantities of salivary, gastric, pancreatic, or duodenal secretions from contacting the jejunal and ileal mucosal surfaces for reabsorption, resulting in rapid dehydration. Obstruction of the distal ileum spares most of this absorptive surface.
What is the difference in the biochem electrolyte changes seen with a proximal obstruction vs. an obstruction after the pancreatic and bile ducts?
pylorus: gastric fluids rich in potassium (K+), sodium (Na+), hydrogen (H+), and chloride (Cl-) ions are vomited and a hypochloremic, hypokalemic, moderately hyponatremic, metabolic alkalosis
distal to the bile and pancreatic ducts: loss of highly alkaline (HCO3) duodenal, pancreatic, and biliary secretions→ Metabolic acidosis
How much of the gas accumulation proximal to the obstruction is swallowed air and diffusion from blood supply into bowel?
72% swallowed air
28% gas formed by body
If you are looking at a radiograph of a dog, cat, or ferret with a potential intestinal obstruction, what are the bowel sizes that would be of concern?
Dog: >1.6x height of L5 (>2x 80%+ chance of obstruction) or 4x rib
Cat: >12 mm
Ferrets: 5-7mm
Based on the pattern, type of FB?
linear (accordion pattern)
How do alterations to venous and arterial flow result in tissue necrosis?
Venous and lymphatic hydrostatic pressures are exceeded but arterial pressures are not which results in vascular congestion. Reduced capillary flow, diminished tissue perfusion, and an ultimate increase in vascular permeability result in extravasation of fluid into the interstitium. Mural edema further compromises blood flow causing hypoxia, tissue ischemia, and mucosal necrosis.
Why is systemic hypotension observed with septic shock?
Vasoactive properties of bacteria, endotoxins, and free peritoneal hemoglobin create systemic hypotension and septic shock.
T/F Sharp foreign bodies such as straight pins, safety pins, bones, nails, or glass will usually pass through the gastrointestinal tract without creating intestinal perforation.
True
How do lymphoma, adenocarcinoma, and intussusception look like on U/S?
What are the two mechanisms of strangulating obstruction and their subtypes?
- local pressure necrosis from FB
- Mesenteric vascular disruption
- volvulus
- intususseception
- hernia
- Thromoboembolism
What are the three parameters for establishing intestinal viability?
Which is the most reliable (***)?
- color
- arterial pulsations
- presence of peristalsis***
How can the viability of an intestinal segment be tested?
pinch test
How big of a non-fluorescent dye area is considered non-viable intestine with the IV vital dye test for intestinal viability?
3 mm
Experimental ways to test intestinal viability?
