OBSTRUCTION LOGIC
A dog presents with vomiting and abdominal distension. Imaging shows intraluminal blockage with intact blood supply.
What classification best describes this obstruction?
Non-strangulating mechanical obstruction
What is the FIRST step after luminal obstruction?
Luminal distension
A cat with a needle lodged in intestines is unstable.
What is the BEST next step?
Surgical intervention
(sharp foreign body + instability)
A horse presents with gastric distension but no vomiting.
Why is vomiting absent?
Anatomical inability due to esophageal angle
A cow has multifocal necrotic lesions scattered throughout the liver.
What route of infection is MOST likely?
Hematogenous spread
A cat has chronic constipation progressing to obstipation. What underlying pathophysiologic change MOST directly leads to this progression?
Progressive colonic dehydration and reduced motility leading to fecal impaction
What vascular change occurs before ischemia?
Venous congestion (leads to edema and pressure buildup)
List ONE clinical sign that suggests surgical colic in horses.
Severe pain unresponsive to analgesics (or shock, distension, etc.)
A horse presents with colic. Rectal exam suggests firm ingesta at a narrowing.
Most likely location?
Pelvic flexure
A toxin causes necrosis around the central vein.
What zone is affected?
Zone 3 (centrilobular)
A dog with intestinal obstruction develops systemic shock.
What is the MOST likely mechanism driving this?
Endotoxemia secondary to mucosal damage and bacterial translocation
In intussusception, what structure becomes trapped and worsens disease severity?
Mesentery → vascular compression → ischemia
A 6-year-old Quarter Horse presents for colic. The owner reports intermittent pawing and flank watching over the past 6 hours. On exam:
Continue medical management and monitor
A large breed dog presents with restlessness, distended abdomen, and nonproductive retching after eating.
What is the MOST likely diagnosis?
GDV
A drug is metabolized into a toxic compound in hepatocytes.
Why is Zone 3 most affected?
High cytochrome P450 enzyme activity
A bowel obstruction is classified as “extramural.”
Give one likely cause.
Hernia or external mass compressing intestine
What initiates intussusception at the physiologic level?
Hyperperistalsis causing telescoping of intestine
A 7-year-old Thoroughbred presents with acute severe colic. Findings include:
What is the MOST appropriate next step?
surgery!!!
Explain what predisposed animals to GDV (what animal charateristics would lead to this being more common in them, give an example of one breed)
A pig presents with liver damage consistent with aflatoxin exposure.
What pattern of necrosis is expected?
Midzonal necrosis
A 6-year-old cat presents with chronic weight loss, intermittent vomiting, and occasional diarrhea. Imaging reveals a thickened intestinal wall with a mass.
What category of obstruction is MOST consistent with this presentation?
Intramural obstruction (neoplasia)
A dog with obstruction becomes hypotensive and febrile.
Trace the FULL pathogenesis leading to shock.
Obstruction → distension → ischemia → mucosal breakdown → bacterial translocation → endotoxemia → septic shock
A 3-year-old mixed breed dog presents with vomiting for 24 hours. The owner reports ingestion of a sock. On exam:
After 12 hours of IV fluids and antiemetics, the dog continues vomiting and becomes febrile.
What is the MOST appropriate next step?
Perform exploratory laparotomy
A dairy cow 3 weeks postpartum presents with decreased milk production, anorexia, and a “ping” on the left side.
Diagnosis?
Left displaced abomasum
A chronic liver injury case progresses over months.
What are the three major responses the liver undergoes?
Regeneration, fibrosis, bile duct hyperplasia