Kapitel 96 - Hepatic Vascular anomalies

Question 1

List the tributes of the portal vein from caudal to cranial. Which one is the largest tributes?

Answer 1

a. Cranial mesenteric vein (drains small intestine) and caudal mesenteric vein (drains colon and proximal rectum)
b. Splenic vein (drains spleen and the stomach via the left gastric vein
c. in dogs, the gastroduodenal vein, which drains portions of the pancreas, duodenum, and stomach (does not exists in cats)

 The cranial mesenteric vein is the largest portal vein tributary.

Question 2

When does functional and structural closure of ductus venosus occur?

Answer 2

a. Functional: 2-6 days after birth

b. Structural: Within 3 weeks

Question 3

Name the three categories of liver vasculature disease

Answer 3

a. congenital PSS

b. Primary hypoplasia of the portal vein (PVH
i. PVH with portal hypertension and PVH without portal hypertension.

c. Disturbances in portal outflow.

Question 4

Name the shunts

Answer 4

A. Portal vein to caudal vena cava.
B. Portal vein to azygos vein.
C. Left gastric vein to caudal vena cava.
D. Splenic vein to caudal vena cava.
E. Left gastric, cranial mesenteric, caudal mesenteric, or gastroduodenal vein to caudal vena cava.
F. Combinations of the above

Question 5

What toxic impact does ammonia have in hepatic enchaphalopathy?

Answer 5

a. Increases brain tryptophan and glutamine
b. decreases ATP availability
c. increases neuronal and cellular excitability
d. increases glycolysis
e. can cause brain edema
f. decreases microsomal Na+,K+-ATPase in the brain

Question 6

List suggestive causes of coagulopathy in liver failure

Answer 6

a. decreased factor synthesis and increased factor utilization
b. increased fibrinolysis and tissue thromboplastin release
c. synthesis of abnormal coagulants (dysfibrinogenemia)
d. decreased platelet function and numbers
e. vitamin K deficiency (particularly in bile duct obstruction)
f. increased production of anticoagulants

Question 7

what type of urinary stone can be seen in patients with PSS? And why?

Answer 7

a. Urate urolithiasis
b. Decreased urea production, increased renal ammonia excretion, and decreased uric acid metabolism leads to formation of ammonium urate calculi and can be associated with secondary bacterial urinary tract infections.

Question 8

Are neurological signs more commonly seen in congenital PSS or acquired PSS?

Answer 8

Congenital

Question 9

What abnormalities could be seen in patients with PSS in a. Hematology,
b. biochemistry
c. urinalysis and
d. liver function tests?

Answer 9

a. Microcytosis with or without associated normochromic, nonregenerative anemia (microcytosis typically resolves after shunt attenuation), target cells in dogs and poikilocytes in cats. Leukocytosis may occur (associated with a poor prognosis).

b. Hypoalbuminemia (uncommon in cats), reduced BUN, hypocholesterolemia, and hypoglycemia. Mild to moderate increases in serum liver enzyme activities (two- to three-fold increases in alkaline phosphatase and alanine aminotransferase values, if more than 4-fold suspect concurrent liver disease–> take biopsy)

c. Decreased urine specific gravity and ammonium biurate crystalluria and sometimes proteinuria.

d. Increase in bile acid concentration (could be positive for other reasons) and increased ammonia concentration (not as sencitive as bile acid)

Question 10

What clotting factors are synthesised by the liver?

Answer 10

1, 2, 5, 9, 10, 11 and 12 as well as 9 via liver vascular endothelium

Question 11

List differentials to hepatic vascular anomalies.

Answer 11

a. toy-breed hypoglycemia
b. hydrocephalus
c. atlantoaxial subluxation
d. idiopathic epilepsy
e. gastrointestinal parasitism
f. hypoadrenocorticism
g. protein-losing enteropathy
h. other primary hepatopathies (e.g., dissecting lobar hepatitis, chronic hepatitis, leptospirosis)
i. toxicity
j. enzyme deficiencies associated with the urea cycle

Question 12

briefly outline the medical treatment for portosystemic shunts

Answer 12

a. Fluid therapy and slow correction of hypokalemia or metabolic acidosis. Addition of glucose, especially in puppies
b. Warm water enemas, oral or rectal lactulose to reduce ammonia uptake and decrease colonic bacterial number
c. Antibiotics to decrease urease producing bacteria
d. Seizure control – Levatiracetam
e. If bleeding, anemia or coagulopathies – blood products. Fresh wole blood is preferred because stored RBCs contain increased ammonia concentrations, which could worsen clinical signs in case of hepatic encephalopathy.
f. Nutritional management – moderate protein restricted
g. Gastrointestinal protection in case of gastric ulceration

Question 13

Where can you place catherers to measure the portal pressure?

Answer 13

Splenic, jejunal or portal vein

Question 14

For ameroid constrictors. How much is the internal diameter reduced and when is shunt attenuation most rapid?

Answer 14

a. 32%
b. During the first 3-14 days after implantation.

Question 15

What size of Ameroid constrictor should be used?

Answer 15

It depends on the size of the vessel and the constrictors internal diameter should be larger than the vessel.

Question 16

What are visual signs of portal hypertension after attenuation of PSS?

Answer 16

a. pallor or cyanosis of the intestines
b. increased intestinal peristalsis
c. cyanosis or edema of the pancreas
d. increased mesenteric vascular pulsations.

Question 17

What are the recommended portal pressure post attenuation?

Answer 17

a. a maximum portal pressure of 17 to 24 cm H2O (12.5 to 17.6 mm Hg)
b. maximal change in portal pressure of 9 to 10 cm H2O (6.6 to 7.35 mm Hg),
c. maximal decrease in central venous pressure of 1 cm H2O (0.74 mm Hg)

Question 18

for how long can the liver tolerate temporary blood occlusion?

Answer 18

Up to 20 min but should be limited to 10-15 min to avoid intestinal ischemia.

Question 19

What is the post-op treatment after shunt attenuation?

Answer 19

a. Fluid therapy and pain management
b. Continuation on lactulose for about 4-6 weeks
c. Contuniation of protein restricted diet
d. Recheck of bile acids and biochem after 2-3 month.
e. The animals is typically slowly weaned of medical treatment over a 2-3 month period, starting with antibiotics, then lactulose then diet.
f. If bile acid continues to be moderately increased medical treatment is continued and the animal is rechecked every 5-6 month

Question 20

list possible complications associated with surgical shunt attenuation

Answer 20

a. hypoglycemia
b. hemorrhage
c. coagulopathy
d. anemia
e. portal hypertension
f. thrombus formation
g. seizures
h. arrhythmias
i. peritonitis
j. bacterial hepatitis
k. sepsis
l. sudden death
m. recurrence of clinical signs

Question 21

what is the primary surgical treatment for hepatic arteriovenous malformation?

Answer 21

Liver lobectomy of affected lobe.

Question 22

Give examples of interventional techniques for shunt attenuation

Answer 22

a. Percutaneous transjugular coil embolization
b. Cyanoacrylate gule embolization