DMN: practice questions (week 12)

PA abdominal surgery, pancreatic disease, CA/PA/equine liver disease, liver toxicities, hepatic fibrosis

What results would a venous blood gas of a cow with a displaced abomasum show?

Hypochloremia, hypokalemia, pH 7.45

What term is described by making a temporary opening into the gall bladder?

Cholecytotomy

What term is described by making a temporary opening into the common bile duct?

Choledochotomy

70% of blood flow in the horse is deoxygenated by what structure?

Portal vein

What are the “less specific” liver enzymes in horses & what do they tell us about?

AST → hepatocellular damage

ALP → cholestatic disease

What are the three methods of flank anesthesia in cattle?

Paravertebral, Inverted L, Line blocks

What are the risk factors for developing a displaced abomasum (most likely left)?

-Guernsey, Holstein-Friesian, Ayrshire breeds

-Low calcium (peripartum)

-Large abdominal cavity

-Springtime (North America)

-High grain/low roughage diet

-Reduced exercise

-Secondary disease (mastitis, RFM, ketosis, fatty liver)

A Holstein-Friesian cow presents in the spring with reduced milk production, anorexia, weight loss, reduced fecal output, & a left caudal rib “sprung”. You perform percussion & hear a ‘ping’ on the left side. What is your top differential diagnosis?

Left displaced abomasum

A right displaced abomasum presents similarly to a left displaced abomasum in cattle. If a right displaced abomasum becomes torsed, what additional abnormalities will you find?

Colic, Metabolic alkalosis, Hypochloremia + hypokalemia

What are the conservative treatment options for a displaced abomasum in cattle?

-Cast + roll (LDA) → cast on right, roll over back clockwise; recurrence is common

-Blind tack/toggle (abomasopexy) → higher success rate

Which conservative treatment method for displaced abomasum in cattle is contraindicated if respiratory compromise, no ‘ping’, or concurrent abdominal disease is present?

Abomasopexy (blind tack/toggle)

Which abomasal surgery options in cattle are performed using a standing left flank approach?

1. Abomasopexy for LDA

2. Rumenotomy

Which abomasal surgery options in cattle are performed using a standing right flank approach?

1. Abomasopexy for RDA or RTA

2. Omentopexy or pyloropexy (LDA/RDA)

3. Small intestinal conditions

4. Cecal dilation/displacement

5. Colon conditions

Which abomasal surgery options in cattle are performed in a recumbent position?

1. Paramedian LDA abomasopexy

2. Toggle + blind tack (LDA/RDA)

3. Maybe cecal/colon conditions if patient goes into shock or too painful

What treatments should be given pre-abomasal surgery in cattle?

-Analgesia → Flunixin IV

-Antimicrobials → broad spectrum

-IV fluids

-Sedation

When performing a flank laparotomy procedure, what layers do you extend a vertical incision through after your initial incision through the skin + subcutaneous tissues?

External + internal abdominal oblique muscles

What is the immediate risk of a left flank approach while making the incision in cattle?

Could hit the rumen

What are the pros vs. cons of a left flank abomasopexy approach for LDA in cattle?

-Pros: Abomasum in “natural” position, less rummaging in cow, adhesions + ulcerations can be directly visualized/treated, exploratory rumenotomy can be performed if indicated

-Cons: Need long arms (big cows), causes localized peritonitis, suture may ‘detach’ + abomasum float back up, be wary not to puncture milk vein when passing needle thru ventrum

How is a right flank abomasopexy approach better for correcting LDA than other surgical approaches?

-Better than ventral paramedian in severely compromised cow → easier to remove fluid w/o contamination, less risk to patient if standing, only option if abomasal volvulus

-No second person/long arm necessary like in omentopexy

-Less of anchoring procedure performed blindly like in abomasopexy

The ventral paramedian approach to a LDA abomasopexy is very similar to the roll & toggle method. What differentiates it?

Ensures that you actually anchor the abomasum + don’t trap gut (invasive)

What are the pros vs. cons of a ventral paramedian approach for LDA in cattle?

-Pros: Abomasum in ‘natural’ position, instantaneous repositioning, able to examine abomasum for ulceration, strong adhesion formation

-Cons: Casting requires man-power, risk of regurgitation, cannot explore rest of abdomen, incisional infection

What is the only method you can use to correct a right displaced or torsed abomasum in cattle?

Standing right flank → omentopexy/pyloropexy

What are some of the indications for performing a rumenotomy in cattle?

FB (TPR, obstruction), Rumen overload, Rumen impaction

What are the main differential diagnoses for a cow with a small intestinal condition, presenting with the reduced fecal output/ileus as well as a drop in milk production (occasionally acute abdomen)?

Intussusception + Volvulus → mainly in distal jejunum/ileum

How can we best diagnose small intestinal conditions in cattle?

Exploratory laparotomy

A milking cow presents with a drop in milk yield, reduced appetite, reduced fecal output, discrete colic signs, & distension of the right paralumbar fossa. You suspect a cecal dilation/torsion + confirm your suspicions with a ‘ping’ on percussion of the right paralumbar fossa as well as palpating the cecum upon rectal examination. What are the most likely possible causes of the cecal dilation/torsion in this cow?

Hypocalcemia or Elevated VFA production

For which conditions in cattle might we perform a Typhlotomy?

Cecal dilation, Cecal torsion, Cecal dislocation

How do we close after performing a Typhlotomy to correct cecal conditions in cattle?

In 2 layers → 2nd inverting Cushings or Lembert

Which part of the GI tract does atresia coli most frequently affect, often in Holstein-Friesian, appearing normal in the first 48 hours of life but quickly declining into bloat + distension of the abdomen with no fecal output?

Mid spiral colon

What nerves are blocked for the distal paravertebral block in cattle?

T13, L1, L2

The transverse processes of which vertebrae are used as landmarks for the distal paravertebral nerve in cattle?

L1, L2, L4

What is the first thing you see when entering via the right paralumbar fossa in a normal bovine?

Descending duodenum

What suture pattern & what direction is best used to close the transverse abdominis + peritoneum in cattle after a right or left paralumbar surgical approach?

Simple continuous, ventral to dorsal

What suture pattern is best used for skin closure in cattle after a right or left paralumbar surgical approach?

Ford interlocking

What exactly is pancreatitis in small animals?

Inflammation of the pancreas → pancreas tries to digest itself from activation of zymogens leading to local ± systemic inflammation

What are the primary clinical signs of pancreatitis in dogs?

ANOREXIA, VOMITING, LETHARGY, diarrhea, icterus, fever

What are the primary clinical signs of pancreatitis in cats?

LETHARGY, ANOREXIA, vomiting, diarrhea, dyspnea, icterus, fever

What is exocrine pancreatic insufficiency (EPI)?

Inadequate secretion of digestive enzymes leading to maldigestion + osmotic diarrhea

What are the clinical signs of pancreatic insufficiency?

Weight loss, greasy diarrhea (steatorrhea), polyphagia

What should be your diagnostic plan for a dog with acute abdomen + suspected pancreatitis?

-POCUS/AFAST → to check for free abdominal fluid

-Abdominal radiographs → to r/o FB obstruction

-CBC/Chem/UA → to look for extra GI or GI causes (toxins, kidney dz, etc.)

-Pancreatic lipase → SNAP or spec tests

What is the anatomical explanation for triaditis in cats (pancreatitis, IBD, cholangitis)?

Insertion of the common bile duct + major pancreatic duct into the duodenal papilla

What is the gold standard + only way to truly/definitely diagnose pancreatitis in small animals?

Biopsy

Pancreatic lipase immunoassays (Snap/Spec-PL) may be used when in a bind to aid in diagnosis of pancreatitis in small animals. What other diseases may cause false positives on these tests?

Acute abdomen, HAC, Pancreatic neoplasia

What does it mean for a patient with pancreatitis if they show >10mg/L on a C-Reactive protein test?

Increased risk for hospitalization + death

What are the general treatments for small animal patients with acute pancreatitis?

-IV fluids → provide perfusion to pancreas + replenish deficits

-Anti-emetics → maropitant or ondansetron (or both)

-Analgesia → opioids (fentanyl or buprenorphine), lidocaine, gabapentin

-Nutrition → low fat for canines, balanced or hydrolyzed protein (not low fat) for felines

What treatments should you try to avoid giving to small animal patients with acute pancreatitis?

NSAIDs/steroids, Antimicrobials (unless sepsis), Plasma (unless DIC), Surgery

Why are NSAIDs always contraindicated in the treatment of pancreatitis in small animals?

Decreased perfusion to pancreas + kidneys

What are the general treatments for cats with chronic pancreatitis (most likely triaditis)?

-Anti-inflammatory → prednisolone

-Diet trial → hydrolyzed or novel protein

-Treat concurrent diseases (CIE, cholangitis)

-Treat flare-ups like acute pancreatitis supportively (fluids, fentanyl, maropitant)

What is the test of choice + treatment for exocrine pancreas insufficiency (EPI) in small animals?

Test: TLI

Treatment: Pancreatic enzymes + B12 supplement

What are the main indications for surgery of the pancreas?

Pancreatic neoplasia (rare), abscess, pseudocyst, or trauma

What is the clinical relevance of the pancreas shared blood supply with the duodenum?

Don’t ligate the blood supply to the duodenum when performing pancreatic surgery

What is the main exocrine excretory duct of the pancreas in dogs?

Accessory pancreatic duct (minor duodenal papilla)

What is the main exocrine excretory duct of the pancreas in cats?

Pancreatic duct (major duodenal papilla)

What suture material should be used for ligation of the pancreatic ducts in small animals?

Non-absorbable (polypropylene or nylon)

-unless septic in pancreas → absorbable monofilament (PDS or monocryl)

What are some of the possible post-operative complications of performing surgery in the pancreas (biopsy, partial pancreatectomy)?

Pancreatitis, Iatrogenic exocrine pancreatic insufficiency (EPI or DM)

What diagnostic tool would be most helpful in identifying surgical pancreatic disease in dogs?

Abdominal ultrasound

When would you utilize the suture fraction technique for a partial pancreatectomy in small animals?

Focal lesions on the margin of the pancreas

What are the two approaches for pancreatic biopsy, with the patient in ventral recumbency + approaching from the right side for both?

1. Surgical

2. Laproscopic

In diffuse pancreatic disease, where do you want to take a biopsy sample from on the pancreas?

Caudal right lobe → away from main ductal system, accessible, vascular supply not shared with duodenum

What is the underlying cause of icterus in most cases of exocrine pancreatic adenocarcinoma, mainly seen in Boxers + Airedale Terriers?

Bile duct obstruction

How can we diagnose + treat exocrine pancreatic adenocarcinoma in small animals?

Diagnose: Cytology of peritoneal lavage fluid + Radiology/Ultrasonography

Treat: Partial or total pancreatectomy

-poor to grave prognosis → likely already mets to liver + LNs (MST <3mos)

What is the most common pancreatic tumor in dogs that is also common in ferrets?

Insulinoma

What enzyme mainly tells us that there is hepatocellular damage (leakage, hepatocytes) in small animals, especially if it is increased 2-fold over the reference interval?

ALT

What enzyme mainly tells us that there is cholestatic damage (inducible, biliary tree) in small animals, especially if it is increased 2-fold over the reference interval?

ALKP

Liver enzymes have longer half lives in dogs. Why does this matter to us when assessing lab values?

Enzyme elevations may persistent even after liver insult has ended

Liver enzymes have shorter half lives in cats. Why does this matter to us when assessing lab values?

Enzyme elevations will indicate an ongoing problem

On a chemistry panel, which parameters give you a clue that there is liver function failure, but are not specific?

Decreased Glu, BUN, Alb, Chol + Increased Tbili

What are the two main causes of hepatocellular patterns of inflammation + injury to the liver?

-Toxins → amanita mushrooms, sago palms

-Inflammatory liver diseases → copper-associated hepatopathy, breed-associated hepatopathies

What are the main causes of a cholestatic pattern of liver disease?

-Obstruction of biliary tree → mucocele

-Infection of inflammation of biliary tree → bacterial/inflammatory cholangitis, leptospirosis

-Metabolic → hepatic lipidosis, cushing’s

What are the three causes of a decreased function pattern of liver disease?

-Congenital PSS

-Hepatic lipidosis

-End-stage liver disease

What test(s) can help determine if the cause of icterus in a small animal patient is pre-hepatic (hemolysis)?

Blood smear + CBC

In a case of a 9yo cat with a hepatocellular enzyme pattern, what is the nest most logical step for diagnosis?

Diagnostic ultrasound

An anorexic, hospitalized patient is suspected of having an infectious liver disease. Considering the most common causes of infectious liver disease, what is a good empiric therapy plan to begin while waiting on test results?

IV ampicillin, IV ampi/sulbactam, IV metronidazole, or IV fluoroquinolone

In what cases would bile acids NOT be helpful in obtaining a diagnosis as it cannot differentiate hepatic vs. post-hepatic?

Icteric patients

What is ultrasound really useful for when assessing for liver disease?

Ruling out biliary obstruction

What is FNA helpful for diagnosing in suspected liver disease?

Hepatic lipidosis + Round cell tumors

What is the ideal test when assessing for leptospirosis in small animal patients with liver disease?

MAT (microscopic agglutination test) paired titers

-can also use PCR (blood or urine) or SNAP test

Why is it recommended to perform a PCR on both the blood + urine in patients with suspected leptospirosis?

-Bacteria is only in the blood for a short period (days) following infection

-Bacteria reaches urine after the blood; spirochetes shed inconsistently in urine so leptospiuria is intermittent

What treatments would you give to a small animal patient with a toxic liver injury?

Cholestyramine, antioxidant, silymarin, nutrition

What treatment would you give to a small animal patient with infectious liver disease?

Antibiotics

What treatments would you give to a small animal patient with Inflammatory liver disease?

Prednisolone, chelation

What treatments would you give to a small animal patient with biliary disease?

Ursodiol, low fat diet

What enzyme pattern will infection with leptospirosis + ascending infection (E. coli, Salmonella) of the liver show on bloodwork?

Cholestatic pattern

What enzyme pattern will a focal abscess in the liver show on bloodwork?

Hepatocellular pattern

What is the feline liver fluke that lives in the biliary ducts + gallbladder, leading to both cholestatic & hepatocellular patterns?

Platynosum fastosum (“lizard poisoning”)

-trx with praziquantel

Which diseases may lead to pyogranulomatous hepatitis in small animals?

FIP + Fungal liver disease

What enzyme pattern do most parasites cause in the liver of small animals?

Hepatocellular pattern

Which hepatotoxin in both dogs + ruminants leads to periodic episodes of persistent vomiting, excess salivation, increased water consumption, anorexia, & icterus from the seeds, leaves, & pulp of the plant due to methylazoxymethanol glycosides?

Sago palm (Cycas sp.)

Which hepatotoxin damages the bile duct canalicular membranes + microvilli, leading to blockage of bile flow (obstructive cholangitis) as well as signs such as general GI issues to start out, then leading to icterus & elevated liver enzymes?

Lantana sp. → Lantadenes (triterpenoid)

What will the liver look like upon pathology after an animal ingests Lantana sp.?

Swollen, orange colored due to bile staining

-GB will also be enlarged with edematous walls

-microscopic mild to moderate centrilobular necrosis

What is the recommended treatment for Lantana sp. hepatotoxicity?

Activated charcoal or bentonite + Fluids, glucose, electrolytes + Sodium thiosulfate IV

Which hepatotoxin, mainly found in open range sheep, leads to swelling of the head (bighead), photosensitization, elevation of liver enzymes (AST/ALT), & microscopic centrilobular necrosis due to hepatic biotransformation of the toxicant?

Tetradymia sp. (Horsebrush)

-Tetradymis to tetradymol

Which hepatotoxin in seeds within the bur + two-leaf seedling stage leads to an abrupt onset of non-specific signs & protein-rich fluid in the thorax/abdomen in large animals as well as spasmodic muscular activity & recumbency eventually leading to death due to inhibition of phosphorylation in mitochondria?

Xanthium sp. (cocklebur)

What is the recommended treatment for Xanthium sp. (cocklebur) hepatotoxicity in large/production animals?

Glucose IV + Milk/lard (protective in pigs)

Which hepatotoxin in large animals alters RNA + protein synthesis, impairing cell division & leading to hepatocytomegaly, karyomegaly, & ataxia/stupor as the cells now grow slowly but are unable to divide?

Crotalaria sp. (Rattlebox) → pyrrolizidine alkaloids (monocrotaline)

What does Crotalaria sp. (Rattlebox) notably cause in large animals on liver pathology?

Hepatocellular megalocytosis, karyomegaly, central vein fibrosis

What is the hepatotoxin that leads to poor BCS, icterus, head pressing, aimless pacing, ataxia, tenesmus, & yawning due to pyrrolizidine alkaloids (heliosupine)?

Cynoglossum sp. (Hound’s tongue)

What is the recommended treatment for hepatotoxicity caused by Crotalaria sp. (Rattlebox), Senecio sp. (Ragwort/groundsel), or Cynoglossum sp. (Hound’s tongue)?

Supportive care → sedation, IV fluids, feeds with good quality protein

How do pyrrolizidine alkaloids (Senecio, Crotalaria, & Cynoglossum sp.) become cumulative hepatotoxins?

Bioactivation (mixed function oxidases, hydrolysis, & dehydrogenation) in the liver → pyrrole metabolites

What is the prognosis of hepatotoxicity by chronic exposure to pyrrolizidine alkaloids leading to “hepatic cripples”?

Poor to grave