Liver Failure Case Study Flashcards
1
Q
How many functions is the liver responsible for?
A
Over 400! Therefore any dysfunction to the liver will cause diffuse and serious complications
2
Q
What can liver failure result from?
A
- Viral hepatitis
- Cirrhosis
- Damage d/t drugs or alcohol
3
Q
Describe the blood supply of the liver:
A
- Liver made of two major lobes and then subdivided into smaller lobes
- Liver receives large amounts of blood via the hepatic artery (one to each lobe), supplying ~25% of blood to liver. Portal vein branches from stomach, spleen and intestines supply ~75% of blood for filtering.
- Hepatic vein returns filtered blood to inferior vena cava
4
Q
Describe the anatomy of the liver:
A
- Organized into lobules (hexagonal shapes)
- Each lobule contains several liver cells (hepatocytes), with a central vein in the middle of each lobule that branches off
- Branched veins connects to more bile ducts, hepatic veins and arteries on corners of hexagon
- Essentially the liver receives +++ blood supply for filtering this way!
5
Q
What are some of the physiological functions of the liver?
A
- Carbohydrate metabolism
- Maintenance of blood glucose (stores excess as glycogen; synthesize glucose from amino acids; release during fasting)
- Lipid metabolism (synthesis of cholesterol, lipoproteins; formation of triglycerides from carbs or proteins)
- Protein synthesis and degradation (plasma proteins, fibrinogen, coagulation factors, albumin, binding and transport of hormones and bilirubin)
- Conversion of ammonia to urea (the byproduct of metabolic liver reactions)
- Storing nutrients and vitamins (e.g. Vitamin A, D, K)
- Metabolism of drugs
- Production of bile salts and eliminating bilirubin
- Metabolism of steroid hormones
- Filtration of blood and removal of bacteria via Kupffer cells
6
Q
How does albumin work?
A
Contributes to plasma colloidal osmotic pressure
7
Q
What is ammonia? How is it made?
A
- By-product of metabolic reactions in the liver
- During deamination process (removal of amino groups from amino acids), conversion of amino acids to ketoacids and ammonia occurs
- Also in intestines d/t conversion of ammonia
8
Q
Why is ammonia harmful?
A
Toxic to tissues, especially neurons, so it requires quick removal from the body. typically removed from blood by liver and converted into urea, which is a safer form that can be easily excreted by the kidneys,
9
Q
What is alcoholic cirrhosis?
A
- Condition resulting from permanent damage or scarring to liver leading to blocked blood flow and prevention of normal metabolic and regulatory processes
- Diffuse fibrosis of liver into nodules that vary in size d/t imbalance regeneration and constrictive scarring
- Liver attempts to reorganize and repair itself after injury, but process is disorganized and leads to fibrosis
- Fibrosis is constrictive and disrupts flow of vascular and biliary duct systems
- Disorganization = poor cellular nutrition and hypoxia, causing further decreased liver functioning
10
Q
Why is alcohol a cause of cirrhosis?
A
- Liver responsible for metabolism of alcohol
- Metabolic end-products of conversion have multiple toxic effects to liver cells and their function; forces reorganization and functional changes
- Alcoholism can also cause malnutrition, which is bad for the liver
11
Q
What are common manifestations of cirrhosis?
A
- Weight loss, masked by ascites
- Weakness
- Anorexia
- Diarrhea
- Hepatomegaly (d/t structural changes)
- Abdominal pain d/t hepatomegaly and ascites - dull, aching, sensation of fullness
- Portal hypertension
- Splenomegaly (build up of blood d/t portal hypertension)
- Ascites **
- Bleeding d/t decreased clotting factors (thrombocytopenia)
- Anemia d/t splenomegaly
- Spider angiomas (increased circulation of estrogen makes more visible)
- Palmar erythema
- Improper drug action and increased sensitivity to adverse effects
- Endocrine disturbances (gynecomastia in men)
12
Q
What is the connection between liver failure and thrombocytopenia?
A
- Responsible for production of prothrombin and other factors essential for blood clotting
- Strongest indicator of cirrhosis *
13
Q
What happens when the liver fails to metabolize aldosterone?
A
- Aldosterone plays a role in water regulation
- Liver unable to metabolize, so high rates remain in the body
- Hyperaldosteronism with subsequent sodium retention = water retention and K+ loss = increased fluid retention
- Increased sodium re-absorption by renal tubules = increase in anti diuretic hormone = additional water retention = decreased blood flow and GFR
14
Q
What is portal hypertension?
A
- Increased resistance to flow in the portal venous system with increased pressure
- Can be d/t pre, post or intra origins
- Cirrhosis causes intrahepatic portal HTN d/t tissue changes and increased resistance in blood flow
- Increased pressure and dilation of venous channels behind obstruction = opening of collateral channels to connect portal circulation with systemic venous circulation = ascites, splenomegaly and esophageal varices
15
Q
What is ascites? What causes it?
A
- Late-stage manifestation of liver failure; an accumulation of fluid in the peritoneal cavity (evident ~500 cc of fluid)
- Increase in hydro-static pressure d/t portal hypertension
- Salt and water retention by kidneys
- Decreased osmotic pressure r/t impaired albumin syntehsis
- When portal pressure changes, proteins shifts from blood vessels to larger pores into lymph space = lymph unable to carry off such a high amount of fluid and proteins = leaking through liver capsule into cavity occurs = osmotic pressure of proteins pull fluid into cavity
