Antenatal Care: Cholestasis of Pregnancy & Acute Fatty Liver of Pregnancy Flashcards
What is obstetric cholestasis?
Obstetric cholestasis is characterised by the reduced outflow of bile acids from the liver during pregnancy. The condition resolves after delivery of the baby.
Relatively common complication of pregnancy (1%).
When does obstetric cholestasis typically occur?
It usually develops later in pregnancy (i.e. after 28 weeks)
What is obstetric cholestasis thought to be the result of?
Increased oestrogen & progesterone
What ethnicity is obstetric cholestasis more common in?
South Asian
Describe journey of bile from liver to intestines
1) Bile acids are produced in the liver from the breakdown of cholesterol.
2) Bile acids flow from liver to the hepatic ducts, past the gallbladder
3) Bile acids flow out of the bile duct to the intestines
What are bile acids made from?
Breakdown of cholesterol
What happens in obstetric cholestasis?
In obstetric cholestasis, the outflow of bile acids is reduced, causing them to build up in the blood, resulting in the classic symptoms of itching (pruritis).
What complication is obstetric cholestasis associated with?
an increased risk of stillbirth.
What is the key symptom of obstetric cholestasis?
Itching (pruritus) - particularly affecting the palms of the hands and soles of the feet.
Symptoms of obstetric cholestasis?
1) Pruritus
2) Fatigue
3) Dark urine
4) Pale, greasy stools
5) Jaundice
Is there a rash associated with obstetric cholestasis?
No - if a rash is present, an alternative diagnosis should be considered, such as polymorphic eruption of pregnancy or pemphigoid gestationis.
Classic LFT feature in most obstetric cholestasis cases?
raised bilirubin is seen in > 90% of cases
Where is itching tyically worse in obstetric cholestasis?
palms, soles and abdomen
Differentials of obstetric cholestasis (i.e. other causes of pruritus and deranged LFTs)?
1) Gallstones
2) Acute fatty liver
3) Autoimmune hepatitis
4) Viral hepatitis
What 2 investigation should be done in women presenting with pruritus?
1) LFTs: abnormal liver function tests (LFTs), mainly ALT, AST and GGT
2) Bile acids: raised
What is a normal LFT change in pregnancy?
It is normal for alkaline phosphatase (ALP) to increase in pregnancy.
A rise in ALP without other abnormal LFT results is usually due to placental production of ALP, rather than liver pathology.
Why does ALP rise in pregnancy?
Placenta produces ALP
1st line treatment of obstetric cholestasis?
Ursodeoxycholic acid: it improves LFTs, bile acids and symptoms.
How can symptoms of itching be managed in obstetric cholestasis?
1) Emollients (i.e. calamine lotion) to soothe the skin
2) Antihistamines (e.g. chlorphenamine) can help sleeping (but does not improve itching)
What can be given in clotting (prothrombin) time is deranged in obstetric cholestasis?
Water-soluble vitamin K
How can a lack of bile salts in obstetric cholestasis lead to vitamin K deficiency?
What can this lead to?
1) Bile acids are important in the absorption of fat-soluble vitamins in the intestines.
2) A lack of bile acids can lead to vitamin K deficiency.
3) Vitamin K is an important part of the clotting system, and deficiency can lead to impaired clotting of blood.
Monitoring of obstetric cholestasis?
Monitor of LFTs is required during pregnancy (weekly) and after delivery (after at least ten days).
When does sobstetric cholestasis typically resolve?
After birth
Potential management of obstetric cholestasis when LFTs and bile acids are severely deranged.?
Planned delivery after 37 weeks may be considered
Overview of management of obsetric cholestasis:
1) ursodeoxycholic acid
2) vitamin K supplementation
3) induction of labour at 37 weeks is common practice
What is acute fatty liver of pregnancy?
Acute fatty liver of pregnancy is rare complication which may occur in the third trimester or the period immediately following delivery.
There is a rapid accumulation of fat within the liver cells (hepatocytes), causing acute hepatitis.
When does acute fatty liver of pregnancy typically occur?
3rd trimester or period immediately following delivery.
Complications of acute fatty liver of pregnancy?
There is a high risk of liver failure and mortality, for both the mother and fetus.
Pathophysiology of acute fatty liver of pregnancy?
1) Acute fatty liver of pregnancy results from impaired processing of fatty acids in the placenta.
2) This is the result of a genetic condition in the fetus that impairs fatty acid metabolism: most common cause is long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency in the fetus.
3) This is an autosomal recessive condition: this mode of inheritance means the mother will also have one defective copy of the gene.
4) The LCHAD enzyme is important in fatty acid oxidation, breaking down fatty acids to be used as fuel.
5) The fetus and placenta are unable to break down fatty acids.
6) These fatty acids enter the maternal circulation, and accumulate in the liver.
7) The accumulation of fatty acids in the mother’s liver leads to inflammation and liver failure.
What is most common genetic condition in the foetus that leads to acute fatty liver in pregnancy?
Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency in the fetus