Liver 5 (test 1) Flashcards
What is the definition of cirrhosis?
Adiffuse process characterized by: -
fibrosis and conversion of normal lobular architecture into structurally abnormal nodules (regeneration) - ↓ liver size (from scarring)
What is the result of chronic hepatitis resulting from a number of chronic, progressive disorders?
End stage liver failure
What is portal hypertension, and what are some of the causes?
Portal hypertension ↑ resistance to hepatic blood flow, due to - –Fibrosis (compression of sinusoids and central veins by scar tissue) –Abnormal lobular architecture –Development of arteriovenous anastomoses within the scars –etc.
What are come consequence of portal hypertension?
a] Ascites -may also be due, in part, to: •decreased plasma oncotic pressure •liver’s secondary effects on renal function (fluid retention)
b] ACQUIRED portosystemic shunts → Hepatic Encephalopathy
c) Splenomegaly (diffuse, symmetrical) = SPLENIC CONGESTION: secondary to decreased blood flow through the liver & portal hypertension
What is Hepatic Encephalopathy?
(HE) is a disorder of mental activity, neuromuscular function and consciousness that occurs as a result of either chronic or acute liver failure. This complex neuropsychiatric syndrome is primarily caused by metabolic abnormalities.
What is the pathogenesis of an acuired portosystemic shunt?
Fibrosis impedes hepatic blood flow and produces portal hypertension •Due to this increase in portal blood pressure, blood seeks the path of least resistance and –may shunt around the liver or –move directly through the liver via shared capillary beds Typically, many small shunts, not a single large vessel
What is the primary cause of cirrhosis?
Chronic persistent stumuli - chronic toxins / drugs (aflatoxin, alcohol, barbiturates) - chronic canine hepatitis -persistent viral infections (Human hepatitis virus) -Autoimmune and drug therapy are most common causes in dogs
What are some causes of passive congestion, and the pathogenesis to hepatic problems?
Passive congestion CAUSE: Right sided heart failure e.g. cardiomyopathy, heartworms, … ↓ cardiac output, ↓ venous pressure producing CONGESTION of – central veins & centrilobular sinusoids
What is caval syndrome?
This is a Dz caused by Dirofiliara Immitis (heartworm), where it deposits in the vena cava causing hypertension and inflammation of the liver.
How would you describe centrilobular fibrosis, and is the main cause?
↑ fibrous connective tisue around central veins CHF specifically RHF
Although centrilobular necrosis is generally caused by RHF, what are some other causes for this, and why?
overt hepatocyte necrosis
hemorrhage anemia shock
pathogenesis is centrilobular hypoxia
What are the two types of portosystemic shunts?
Congenital and acquired
What are the two options for a congenital portosystemic shunt?
Congenital = A congenital anomalous connection between the portal vein and a systemic vein
Portal blood is:
a] diverted around liver (Extrahepatic shunt) Small breed dogs
OR
b] shunted through liver (Intrahepatic shunt) Large breed dogs
Result is - BYPASS OF LIVER Toxins absorbed from the GI have direct access to the systemic circulation (e.g. ammonia) Usually a SINGLE relatively large caliber vessel
What is the signalment for a dog with portosystemic shunt?
- stunting
- high blood ammonia •hepatic encephalopathy
- +/- PU/PD
- Microhepatica = small liver = hepatic atrophy - due to a lack of hepatotropic factors •+/- ammonium biurate crystals in urine (this is a key one)
What abnormalities would you see in a PSS on blood profiles?
Abnormalities include:
- Elevated serum bile acids (especially postprandial) •Hyperammonemia
- +/- ammonium biurate crystals formation in alkaline urine Usually also:
- Hypoalbuminemia
- Decreased BUN
- +/- hypoglycemia
- +/- hypocholesterolemia
- +/- hypoglobulinemia Liver enzymes are often normal or only mildly increased! Hematology: Microcytosis (small RBCs)
What lab results can help to distinguish congenital from acquired shunts?
need pic
