Liver Function Tests
Download
Report
Transcript Liver Function Tests
Liver Function Tests
Steve Bradley
Chief Medical Resident, HMC
Inpatient Services
What are “Liver Function Tests”
Few are truly associated with function
– Albumin: protein synthetic function
– INR: clotting factor synthesis
Most are related to cell injury
– Patterns point to specific cell injury
Tests of Liver Injury
AST/ALT
– Cytoplasmic enzymes found in hepatocytes
– Very sensitive marker for hepatocyte injury
Specificity is poor (other sources, e.g. muscle)
– Mitochondrial isoenzyme
AST increased by ethanol (explains 2:1 ratio)
Alkaline Phosphatase/GGT
– Canicular enzymes
Gradual increase in plasma levels with obstruction
of canicular flow
Patterns of Enzyme Elevation
Hepatocellular injury
– AST/ALT
Cholestatic
– Bilirubin/alkaline phosphatase
Mixed
Isolated/predominant alkaline
phosphatase elevatioin
Caveats to Patterns
Hepatocellular injury
– Also results in release of bilirubin
– Alkaline phosphatase also found in hepatocyte
Cholestatic
– Biliary obstruction can lead to hepatocellular
injury
History and Physical guide your thinking!!
Patient #1: Suzie Duzie
Presents with two days of fever, abdominal pain,
yellow skin, nausea, vomiting.
Labs demonstrate the following:
–
–
–
–
–
–
AST 3210
ALT 3060
Alk phos 249
TBili 6.2 (Direct 4.3)
Albumin 3.1
INR 1.2
What targets the hepatocyte?
Toxins
– Alcohol
– Medications
– Severe hypotension
– Vasoconstriction
– Sepsis
Tylenol
– Mushrooms
Viral
– Hepatitis A/B/C
– EBV/HSV/CMV
Ischemia
Autoimmune
Wilson’s
Alpha-1 antitrypsin
deficiency
Degree of elevation points to
etiology
>1000 to 2000
– Ischemia
– Toxin
– Virus
>500 to 1000
– Acute biliary obstruction
<300
– Alcoholic liver disease, cirrhosis, chronic obstruction
– AST/ALT>2 and each <300 suggests EtOH or cirrhosis
If >500, unlikely EtOH
Back to our patient
Transaminases in the 1000s
– Suggests ischemia/toxin/viral
IVDU
– Risk of acute Hep B or acute Hep C
Cocaine
– Risk of ischemia
Recent infection
– Doxycycline
Patient #2: Ima Hurtin
40 year-old overweight woman presents with
right UQ abd pain, fever, chills. Previous
episodes after fatty meals.
Laboratory Studies
–
–
–
–
–
–
AST 67
ALT 57
Alk Phos 293
TBili 4.1 (Direct 2)
Albumin 4
INR 1
Increased Bilirubin
Sources
– Increased production
– Hemolysis, hematoma reabsorption
– Impaired uptake/conjugation
– Dubin-Johnson, Gilbert’s
– Impaired excretion
– Renal failure, biliary obstruction
Conjugated=direct=processed by liver
Unconjugated=indirect=not processed by liver
– Fractionation – helpful to assess for unconjugated
hyperbilirubinemia
< 20% direct AND indirect >1.2
Biliary Obstruction
Canicular cell injury
– Alkaline phosphatase
Liver and bone major sources
Increased synthesis and release in liver disease
– Up to 3x normal in variety of liver disease
– GGT
Sensitive indicator of canicular cell injury
Parallels alkaline phosphatase increase when of
liver origin
Causes of Biliary Obstruction
Extrahepatic
– Choledocholithiasis
– Malignancy
Cholangiocarcinoma
Pancreatic cancer
Gallbladder cancer
Ampullary cancer
– Primary sclerosing
cholangitis
– AIDS Cholangiopathy
Intrahepatic
– TPN
– Sepsis
– Primary sclerosing
cholangitis
– Primary biliary
cirrhosis
– Intrahepatic mass
How would you like to approach
this patient?
Finding the source of obstruction
– Ultrasound: good for extrahepatic cause
– CT/MRI/ERCP: for both intra or extrahepatic
cause
In our patient?
Patient #3: Biggie Smalls
46 yo man with history of IVDU and longstanding alcohol use following up in clinic.
Laboratory
– AST 68
– ALT 37
– Alk phos 194
– TBili 1.3
– Albumin 2.9
Mixed Patterns of Elevated Liver
Function
Chronic Liver disease
– Hepatitis B, Hepatitis C
– NASH
– Alcoholic liver disease
– Hemochromatosis
– Autoimmune hepatitis
Patient#4: Iva Fallen
72 yo man fell in bathroom. Found the
next day.
Laboratory
– AST 167
– ALT 58
– Alk phos 127
– TBili 1.8
– Albumin 3.9
What else do you want to know?
Where else is AST and ALT found?
How can you look for evidence of muscle
injury?
Additional Laboratory
CK 7260
Myoglobin 23390
UA – 2+ blood, microscopic no RBC
Diagnosis?
Isolated or Predominant Alk Phos
Chronic Biliary Disease
– Primary biliary cirrhosis
– Primary sclerosing cholangitis
Infiltrative disorder
– Amyloid
– Granulomatous diseases
– Metastatic carcinoma
– abscesses
Last Case: Sue Sadd
32 yo woman, depressed, “took some
pills” a few days ago
Laboratory
– AST 1450
– ALT 1620
– Alk phos 242
– TBili 8 (direct 4)
– Albumin 2.9
– INR 1.7
Fulminant Hepatic Failure
Rapid development of severe acute liver
injury with impaired synthetic function and
encephalopathy
– Previously had a normal liver or had wellcompensated liver disease
Causes
Treatment
Directed therapy
– Acetaminophen - mucomyst
– Acute fatty liver of pregnancy - delivery of
infant
– Amanita mushroom poisoning - penicillin and
silibinin
– Wilson's disease - D-penicillamine
– Herpes Simplex Infection – acyclovir
Liver transplant