Disorders of the liver Flashcards
What are the functions of the liver
o Accessory digestive gland, produces bile (alkaline compound that aids in digestion of fat + absorption of vit K)
o Plays major role in carbohydrate metabolism and has numerous function
• Gluconeogenesis: synthesis of glucose from certain AAs (lactate, glycerol)
• Formation of glucose from protein + fat
• Glucogenolysis: breakdown of glycogen into glucose
• Glucogenesis: formation of glycogen from glucose
o Lipid metabolism
• Cholesterol synthesis
• Lipogenesis: production of triglycerides
o Produces coagulation factors
• Fibrinogen, prothrombin, protein C, protein S, antithrombin, clotting factors 5,7,8,9,10,11
o 1st trimester of the fetus:
• Liver is main site of RBC production
• By 32 wks: bone marrow has taken over to create RBCs
o Breakdown of insulin + other hormones
o Converts ammonia to urea (excreted by kidneys)
o Stores Vit A, Vit D, Vit b12, Vit K, Iron
o Detoxification of various metabolites
o Plasma protein synthesis
o The production of biochemicals necessary for digestion
o Regulation of glycogen storage
o Decomposition of red blood cells
o Hormone production
Glucogenolysis:
breakdown of glycogen into glucose
Glucogenesis:
formation of glycogen from glucose
What is viral hepatitis
liver inflammation d/t viral infection. Can be either acute, recent infection, rapid onset OR chronic. It is a systemmic viral disease primarily affecting liver. Types include: Hep A, B, C, D, E (and G but not common)
How are liver cells damages in viral hepatitis?
Liver cells can be damaged in TWO WAYS d/t:
• Direct action of virus
• Cell-mediated immune responses to virus
Cell injury leads to inflammation + necrosis of liver:
• Hepatocytes + liver appear swollen
• Diffuse necrosis present
• Severe inflammation: BILIARY may develop, causing backup of bile into blood
• Hepatic cells may regenerate or fibrous scar tissue forms in liver
• Scar tissue often obstructs blood + bile flow leading to further damage (interferes with unique organization of liver lobule, ischemia)
• Chronic inflammation in Hep B, C, D: persistent inflammation, necrosis of liver for MORE THAN 6 MONTHS
• Eventually causes permanent liver damage + cirrhosis
• Increased incidence of hepatocellular cancer assoc with chronic hepatitis
What is Hepatitis A
Hepatitis A: caused by small RNA virus (HAV)
o Hepatitis A can be found in the feces, bile, and sera of infected individuals
o Usually transmitted by the fecal-oral route (contaminated water, shell fish)
o Short incubation period (2-6 weeks)
o Causes acute, self-limiting infection; does NOT have carrier/chronic state
o Fecal shedding of virus occurs before onset of signs
• IgM HAV appear (1st group), IgG HAV (2nd group) (remain in serum for years, providing immunity against infection)
What are risk factors for Hep A
o Risk factors (spread by fecal oral route)
• Crowded, unsanitary conditions
• Food and water contamination
• Daycare centers
• Sexual transmission (in homosexual pop)
What is hepatitis B
Double stranded DNA virus; contains 3 antigens that each stimulates antibody production in the body
o Long incubation period: avg 2 mo
o Large amts of HBV surface antigen produces by infected liver cells early in course of infection
• Antigen in serum - High risk of continued active infection + damage to liver
o Common: carrier state – asymptomatic, but contagious
o Window/prolonged lag time occurs before serum markers, symptoms become present
• Virus cannot be detected but can be transmitted
• Long incubation period – harder to track sources and transmission
How is Hep B transmitted?
o Transmitted through contact with infected blood, body fluids, or contaminated needles • Body piercing • Tattooing • Blood Transfusion • Sexual transmission • Mother to fetus • Vertical transmission: breast feeding? • Maternal transmission can occur if the mother is infected during the third trimester
Hepatitis C
Single stranded RNA virus.
- Can exist in carrier state and be chronic (50%- 80% of hepatitis C cases result in chronic hepatitis)
- MOST COMMON hepatitis transmitted via blood transfusions
What are the causes of Hepatitis C
Causes:
• Blood transfusion
• Sharing of needles
• Mother to baby (Maternal transmission to fetus occurs in 5-10% of cases
• Body piercing/tattoos
• Unprotected sex w/ multiple partners
o Primary mode of transmission is IV drug use through sharing of needles
o Secondary risk is through high-risk sexual behavior.
What are complications of Hep B and C
o Complications
• Chronic hepatitis with cirrhosis
• End Stage Liver Failure
• Hepatocellular Carcinoma
What is hepatitis D?
An incomplete RNA virus that requires presence of HBV to replicate + produce active infection
o Increases severity of HBV infection o Same transmission route as HBV o Depends on HBV for replication o Transmitted by blood o High incidence of infection in IV drug users
Hepatitis E
Hep E is a single stranded RNA virus (SPREAD BY Fecal-oral transmission)
o Developing countries (Asia, Africa) – high mortality rate in pregnant women
o Similar to Hepatitis A in course
• Lacks chronic, carrier state
Overview of viral hepatitis
There is currently no method to destroy hepatitis in body
o Gamma-globulin helpful when given earlier in course of infection
o Rest, diet high in protein, carbs, vitamins (most useful)
o HBV, HCV may be treated with interferon + epivere to decrease viral replication (Effective in 30-40% of individuals)
o Slow-acting interferon + antiviral drug (vibovaren?) reduced rate of viral replication in 80% of HCV pts
o Gradual destruction of liver occurs leading to cirrhosis, hepatocellular cancer
