Chemical Pathology/ Abnormal Liver Function Tests Flashcards
What are the most common causes of transaminase elevation?
- viral hepatitis
- alcohol-induced liver damage
- nonalcoholic steatohepatitis (NASH)
- hepatotoxic medications/herbs
Name some physical signs that may indicate that elevated transaminase elevations are due to chronic liver disease or cirrhosis. (8)
- gynecomastia
- testicular atrophy
- spider nevi
- asterixis
- finger nail clubbing
- ascites
- organomegaly
- palmar erythema
What liver function test is most specific for hepatocyte injury?
Alanine transaminase (ALT)
What causes of transaminase elevation result in an AST/ALT ratio >2?
Alcoholism and Wilson disease
What liver function tests are markers of cholestasis?
- ALP
- GGT
- serum bilirubin
What tests are markers of liver function and protein synthesis?
Serum albumin and prothrombin time
The following lab result would suggest that a patient’s elevated transaminases are due to what disease?
- High ferritin, high serum iron, and low TIBC
Hemochromatosis
The following lab result would suggest that a patient’s elevated transaminases are due to what disease?
-Low ceruloplasmin
Wilson Disease
The following lab result would suggest that a patient’s elevated transaminases are due to what disease?
High antinuclear antibody and anti-smooth muscle antibody
Autoimmune hepatitis
The following lab result would suggest that a patient’s elevated transaminases are due to what disease?
Low Alpha-1-antitrypsin
Alpha-1-antitrypsin deficiency
What patient characteristics and/or comorbid diseases would make you suspect NASH?
- obesity
- hyperlipidemia (especially hypertriglyceridemia)
- diabetes mellitus
If a workup for elevated transaminases yields no specific cause and the patient profile does not fit a diagnosis of NASH, what is the next step in management?
Referral to gastroenterologist for liver biopsy
In the United States, what over-the-counter medication is the most common cause of drug-related acute liver failure?
Acetaminophen
For most adults, what is the maximum safe dose (g/day) of acetaminophen?
4 g/day
What antibiotic is the most common drug cause of acute hepatitis?
Amoxicillin-clavulanic acid (Augmentin)
What medications (or classes of medications) used to treat diabetes may cause hepatotoxicity?
- Acarbose
- Pioglitazone
- Sulfonylureas
What medications (or classes of medications) used to treat hyperlipidemia may cause hepatotoxicity?
Statins, nicotinic acid
Lab values showing an AST to ALT ratio greater than 2:1, hypoalbuminemia, markedly elevated GGT, elevated alkaline phosphatase, and macrocytic anemia are suggestive of what type of liver disease?
Alcoholic hepatitis
What vitamin supplements should be given to patients who consume alcohol regularly?
Folate and thiamine
What are the symptoms of hepatitis A?
Early signs: fever, malaise, headache, decreased appetite, nausea and vomiting, abdominal pain, diarrhea
Later signs: jaundice, tender hepatosplenomegaly, pale stool
What is the mode of transmission of hepatitis A?
- Fecal-oral (affected person may shed virus in stool for months, even when asymptomatic)
- food and water sources may be contaminated and produce epidemics
What is the incubation period of hepatitis A?
15-45 days
Children with hepatitis A are more often asymptomatic while adults are more often symptomatic. True or false?
True
It is possible for a hepatitis A infection to last several months; however, there is no chronic carrier state. True or false?
True
How can hepatitis A be prevented?
- Meticulous hygiene
- hepatitis A vaccine
- hepatitis A immunoglobulin (only for travelers to endemic areas and for those with known close contact to an infected individual)
How is hepatitis B virus (HBV) transmitted?
- Through infected blood (eg, drug use, tattoos, healthcare accidents)
- saliva
- semen, and vaginal secretions (Note: while sexual transmission is common, perinatal exposure can infect infants.)
What is the incubation period of hepatitis B?
60-90 days
What percent of those infected with HBV will develop chronic liver disease?
10%
Chronic hepatitis B infection can lead to what complications?
Cirrhosis and hepatocellular carcinoma
Which virological marker is the first to emerge after infection with HBV?
Hepatitis B surface antigen (HBsAg)
Which virological marker correlates with the infectivity of HBV?
Hepatitis B e antigen (HBeAg)
Which virological marker allows you to distinguish between recent and chronic infection with HBV?
Hepatitis B core antibody (HBcAb)
Is HBcAb IgM positive in recent or chronic infection?
Recent infection
Is HBcAb IgG positive in recent or chronic infection?
Chronic infection
Interpret these Hepatitis B virological marker panels. HBsAg negative, anti-HBsAb positive, and anti-HBc IgG positive
Past HBV exposure
Interpret: HBsAg negative and anti-HBsAb positive
Prior immunization
Interpret: HBsAg positive, anti-HBsAb negative, and anti-HBc IgM positive
Acute hepatitis
Intepret: HBsAg positive and anti-HBc IgG positive
Chronic hepatitis
How does an acute infection with HBV present?
- Viral prodrome 4-12 weeks after infection
- then with jaundice
- scleral icterus
- enlarged liver
- right upper quadrant pain
Which laboratory tests may appear elevated during acute infection with HBV?
- aspartate transaminase (AST)
- alanine transaminase (ALT)
- bilirubin
- alkaline phosphatase
- lymphocytes (especially atypical)
- prothrombin time (PT)
in the United States, what disease is the most common cause of liver transplant?
Chronic hepatitis C
What is the average incubation period of hepatitis C?
7-8 weeks
What is the mode of transmission of hepatitis C?
- Most commonly through exposure of infected blood (IV drug use
- blood transfusion
- tattooing
- organ transplant, etc)
- although exposure by other body fluids is possible
What percent of adults with acute hepatitis C develop chronic hepatitis C infection?
70% (even more develop persistent infection)
What is the initial test for diagnosis of hepatitis C?
Enzyme immunoassay (EIA) for anti-HCV
Why should patients with hepatitis C avoid alcohol? (2)
- Alcohol consumption increases the severity and rate of progression of liver disease.
- Alcohol also decreases the response to treatment (interferon therapy).
What complications may arise from chronic hepatitis C infection?
Cirrhosis and hepatocellular carcinoma
About what fraction of US patients have nonalcoholic steatohepatitis (NASH)?
Almost 1 in 4
Although NASH is usually asymptomatic, with what signs may it present?
- Fatigue
- malaise
- right upper quadrant pain
What percentage of patients with NASH has hepatomegaly?
50%
How much do transaminase levels increase when a patient has NASH?
About 2-3 times normal levels (alkaline phosphates and GGT may also be elevated)
What is the preferred first-line and most cost-effective imaging modality for diagnosing NASH?
Right upper quadrant ultrasound (shows fatty infiltrates although does not determine severity of disease)
How is NASH managed?(4)
- Weight reduction, alcohol restriction, lipid and glucose control
