Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (192 page)

   
Core laboratory
: Pattern of abnormal liver function tests is variable depending on severity of heart failure; the mildest show only slightly increased ALP and slightly decreased serum albumin; moderately severe also show slightly increased serum bilirubin and GGT; one fourth to three fourths of the most severe will also show increased AST and ALT (≤200 U/L) and LD (≤400 U/L). All return to normal when heart failure responds to treatment. Serum ALP is usually the last to become normal, and this may be weeks to months later. AST and ALT may be increased 2–3× normal in less than one third of cases but much higher in severe acute heart failure. Serum albumin is slightly decreased in <50% of patients but is rarely. Serum bilirubin is increased in ≤70% of cases (unconjugated more than conjugated); usually <3 mg/dL but may be >20 mg/dL. It usually represents combined right- and left-sided failure with hepatic engorgement and pulmonary infarcts. Serum bilirubin may suddenly rise rapidly if superimposed myocardial infarction occurs. Serum cholesterol and esters may be decreased. Serum ammonia may be increased. Urine urobilinogen is increased. Urine bilirubin is increased in the presence of jaundice.

   
Hematology
: PT may be slightly increased in 80% of cases, with increased sensitivity to anticoagulant drugs. Fails to correct with vitamin K.

PORTAL HYPERTENSION

   This condition may be

   Prehepatic (e.g., portal vein thrombosis, splenic arteriovenous fistula)

   Intrahepatic

   Presinusoidal (e.g., metastatic tumor, granulomas such as sarcoid, schistosomiasis)

   Sinusoidal (e.g., cirrhosis)

   Postsinusoidal (e.g., hepatic vein thrombosis, alcoholic hepatitis)

   Posthepatic (e.g., pericarditis, tricuspid insufficiency, inferior vena cava web)

BILIARY EXTRAHEPATIC OBSTRUCTION, COMPLETE

DISEASES OF THE GALLBLADDER AND BILIARY TREE (INTRAHEPATIC OR EXTRAHEPATIC) (SEE ABDOMINAL PAIN)

   Laboratory Findings

   
Liver enzymes
: AST is increased (≤300 U/L), and ALT is increased (≤200 U/L); they usually return to normal within 1 week after relief of obstruction. In
acute
biliary duct obstruction (e.g., due to common bile duct stones or acute pancreatitis), AST and ALT are increased >300 U/L (and often >2,000 U/L) and decline 58–76% in 72 hours without treatment; simultaneous serum total bilirubin shows less marked elevation and decline, and ALP changes are inconsistent and unpredictable. Typical pattern of extrahepatic obstruction includes increased serum ALP (>2–3× normal), AST <300 U/L, and conjugated serum bilirubin. In extrahepatic type, the increased ALP is related to the completeness of obstruction. Normal ALP is extremely rare in extrahepatic obstruction. Very high levels may also occur in cases of intrahepatic cholestasis.