<s>[INST] context: Serum bile acid levels Obstetric cholestasis (also known as intrahepatic cholestasis of pregnancy or cholestasis of pregancy) is a liver disease unique to pregnancy which presents with pruritus. Clinical features Obstetric cholestasis most commonly presents in the third trimester (80% develop symptoms after 1st week). The pruritus is often severe and typically the palms of the hands and the soles of the feet are involved but the legs, thighs arms, backs, breasts and abdomen are also repoed. The diseaes tends to recur in every pregnancy and so a pa history of the condition is impoant. The disease is more common among multiple gestations. Other signs and symptoms of liver disease are not observed. Additional symptoms which may be repoed in common with other forms of cholestasis are right upper quadrant pain, pale stools and dark urine. Changes in liver function in obstetric cholestasis The most common abnormalities in liver function are - Increase in ALT (seen in 100% cases) - Increase in AST (seen in 99% cases) - Increase in bile acids (seen in 92% cases) - Elevated bilirubin (22% of cases) - Increased GGT (39% cases) Elevations in alkaline phosphatase are seen in cholestatic disease such as obstetric cholestasis as it is released from the damaged liver but because the enzyme is also released from the placenta in normal pregnancies, measurements are less helpful than outside the pregnancy. Serum bile acid test is the most accurate determinant of cholestasis of pregnancy. The problem with the bile acid test is that only a small number of labs around the world have the equipment necessary to perform it which can result in a considerable delay for women experiencing symptoms of the conditions. Liver biopsy in a case of obstetric cholestasis: ? Liver biopsy demonstrates: ? - Acinar cholestasis with centrilobular bile staining and bile plugs in the canaliculi. Liver biopsy is the definitive diagnostic test of the disease. Postnatal course in obstetric cholestasis - Biochemical abnormalities and pruritius in obsetric cholestasis persists until delivery following which resolution occurs. - Pruritus is typically absent within 48 hour after delivery usually improved within 1 week. - Liver function tests becomes normal within 6 weeks. Complications of obstetric cholestasis - Meconium stained liquor - Premature delivery - Fetal distress - Post paum hemorrhage Treatment of obstetric cholestasis : - i) Antihistamines - Chlorpheniramine can provide symptomatic relief in pruritus. ii) Topical treatments - If the skin is well moistured pruritus may be relieved. iii) Ursodeoxycholic acid iv) S-Adenosyl methiomine v) Dexamethasone - Dexamethasone in high dose results in resolution of all pruritus cases and significant reduction in total bile acids and ALT. vi) Vitamin K - In obstetric cholestasis there is malabsorption and subsequent deficiency of vitamin K. This will increase the risk of postpaum hemorrhage. - Vitamin K injection is given to reduce the risk of PPH. [/INST] question: Investigation of choice in cholestasis of pregnancy | options: A: Serum biliruhin levels B: Serum bile acids levels C: Serum alkaline phosphatase levels D: Serum glutathiones transferase levels | answer: B </s>