Obstetric Cholestasis & Acute Fatty Liver Flashcards
What is obstetric cholestasis?
- reduced outflow of bile acids from the liver
- resolves after delivery of the baby
- thought to be due to a rise in oestrogen + progesterone
When does obstetric cholestasis typically present?
- it occurs later in pregnancy (after 28 weeks)
- this is within the third trimester
Who is more at risk?
women of South Asian ethnicity
What is the pathophysiology involved in obstetric cholestasis?
- bile acids are produced in the liver from the breakdown of cholesterol
- they flow past the gallbladder and out of the bile duct into the intestines
- in OC, this outflow is reduced
- this causes the bile acids to build up in the blood
What severe risk is increased in OC?
increased risk of stillbirth
What is the main symptom of OC?
severe pruritus
- this particularly affects the palms of the hands + soles of the feet
What other symptoms may occur due to outflow obstruction in the bile ducts?
- fatigue
- dark urine
- pale, greasy stools
- jaundice
What is “cholestasis”?
- reduced or stopped bile flow
- instead of entering the duodenum, the bile builds up in the liver
- eventually, this results in bile acids entering the bloodstream
What rash is associated with obstetric cholestasis?
- there is NOT a rash associated with this condition
- if a rash is present, consider another condition:
- pemphigoid gestationis
- polymorphic eruption of pregnancy
What is polymorphic eruption of pregnancy?
- an itchy, bumpy rash that starts in the stretch marks of the abdomen
- occurs in the last 3 months of pregnancy
- more common in a first pregnancy
What is pemphigoid gestationitis?
- a rare pregnancy-associated autoimmune blistering skin condition
- tends to develop in the second or third trimester (13-40th week)
- starts as an itchy rash** that then **develops into blisters
What other causes of pruritus should be excluded?
- gallstones
- acute fatty liver
- autoimmune hepatitis
- viral hepatitis
What are the initial investigations for women presenting with pruritus?
- LFTs
- bile acids
How will OC present when LFTs / bile acids are checked?
Bile acids:
- will be raised
LFTs:
- ALT, AST & GGT will be deranged
Why is ALP not assessed during pregnancy?
- the placenta produces ALP
- it is NORMAL for ALP to be raised in pregnancy
- a rise in ALP without other abnormal LFT results is due to placental production, rather than liver pathology*
What is the main treatment for obstetric cholestasis?
ursodeoxycholic acid
!! this does not improve the itching !!
What treatments can be given to improve itching?
emollients such as calamine lotion
What other medication may be given in OC?
- antihistamines such as chlorphenamine
- these can improve sleeping
- they DO NOT improve itching
What can be given in OC if clotting is deranged?
water-soluble vitamin K
Why can vitamin K deficiency occur in cholestasis?
What can this lead to?
- vitamin K is a fat-soluble vitamin
- a lack of bile in the intestines reduces fat absorption, and hence, absorption of vitamin K
- vit K is involved in the clotting system
- deficiency can result in impaired clotting of the blood
What is involved in the monitoring of OC during pregnancy?
- LFTs should be monitored weekly
AND
- at least 10 days after delivery
When might planned delivery be considered in OC?
- planned delivery after 37 weeks is considered when LFTs / bile acids are severely deranged
- stillbirth in OC is difficult to predict
- early delivery can reduce this risk
What is acute fatty liver of pregnancy?
- rapid accumulation of fat within the hepatocytes
- this causes an acute hepatitis
- there is risk of liver failure / mortality for the mother + foetus
When does acute fatty liver occur?
third trimester
Why does acute fatty liver occur?
- there is impaired processing of fatty acids in the placenta
- this is due to a genetic condition in the fetus that impairs fatty acid metabolism
What is the most common genetic cause of impaired fatty acid metabolism?
LCHAD deficiency
- (long-chain 3-hydroxyacyl-CoA dehydrogenase)*
- this is an autosomal recessive condition
- the mother also possesses one defective copy of the gene
How can LCHAD deficiency result in acute fatty liver of pregnancy?
- LCHAD is important in fatty acid oxidation
- this allows them to be broken down + used for energy
- the fetus + placenta cannot break down fatty acids
- the fatty acids enter maternal circulation and accumulate in the liver
- accumulation of fatty acids leads to inflammation + liver failure
How does acute fatty liver present?
vague symptoms associated with hepatitis:
- N&V
- jaundice
- generalised fatigue
- abdominal pain
- lack of appetite (anorexia)
- ascites
- hypertension
What investigations are performed in acute fatty liver?
LFTs show raised liver enzymes (ALT / AST)
What other blood tests may be deranged in acute fatty liver?
- raised bilirubin
- raised WCC
- deranged clotting (raised PTT + INR)
- low platelets
What other condition can present with similar blood results to acute fatty liver?
HELLP syndrome
- they both present with low platelets + elevated liver enzymes
- HELLP syndrome is much more common
What is the management for acute fatty liver of pregnancy?
- it is an OBSTETRIC EMERGENCY
- it requires prompt delivery of the baby
- treatment for acute liver failure +/- transplant may also be considered
