Gastroenterology Flashcards
What is alpha-1-antitrypsin?
A protease inhibitor
What is the pathophysiology of alpha-1-antitrypsin deficiency?
The neutrophil elastase enzyme digests connective tissues - A1AT is produced in the liver and inhibits this enzyme, protecting tissue. In the liver the mutant A1AT protein is trapped, builds up and causes liver damage. In the lungs, it allows an excess of protease enzymes.
Where is the A1AT gene coded for?
Chromosome 14
What is the inheritance pattern for A1AT?
Autosomal recessive
What are the two main organs affected by A1AT deficiency?
Liver and lungs (liver cirrhosis after age 50 and bronchiectasis and emphysema after age 30)
What are the investigations for A1AT deficiency?
Serum A1AT
Liver biopsy: cirrhosis and acid-Shciff-positive staining globules
Genetic testing
CT thorax
What is the management for A1AT?
Stop smoking
Symptomatic
Organ transplant
What are the two types of primary liver cancer?
Hepatocellular carcinoma
Cholangiocarcinoma
What is cholangiocarcinoma associated with?
Primary sclerosing cholangitis
How does cholangiocarcinoma present?
Painless jaundice
What is a tumour marker for hepatocellular carcinoma?
Alpha-fetoprotein
What is a tumour marker for cholangiocarcinoma?
CA19-9
What is a haemangioma?
Benign tumour of liver.
What is focal nodular hyperplasia?
Benign liver tumour. Often related to oestrogen and those on the COCP
Where is the mutation for Wilson’s disease?
Chromosome 13
What is the inheritance pattern for Wilson’s disease?
Autosomal recessive
What are the features of Wilsons disease?
Chronic hepatitis -> liver cirrhosis
Neurological and psychiatric problems: usually asymmetrical,
Haemolytic anaemia
Renal tubular damage leading to renal tubular acidosis
Osteopenia
What is the investigation for Wilson’s
Serum caeruloplasmin: low is suggestive of Wilson (this is the proteins hat carries copper in the blood)
Gold standard is liver biopsy
24-hr urine copper assay
What is the management for Wilson’s?
Copper chelation:
Penicillamine
Trientene
What is the pathophysiology of primary biliary cirrhosis?
Immune system attacks small bile ducts in the liver: first the intralobar ducts (‘Canals of Herin’), causing obstruction and cholestasis. The back pressure leads to fibrosis and cirrhosis
What is the presentation of primary biliary cirrhosis?
Fatigue
Pruritus
GI disturbance and abdo pain
Jaundice
Pale stools
Xanthoma and xanthelasma
Signs of cirrhosis and failure
What risk factors in epidemiology?
Middle aged women
Other autoimmune conditions
Rheumatoid conditions
What are the investigations for PBC?
LFT: ALP is raised due to obstruction - others can be raised later
Autoantibodies: particularly anti-mitochondrial antibodies, but also anti-nuclear antibodies
ESR - raised
IgM - raised
What is the management for PBC?
Ursodeoxycholic acid = reduces the intenstinal absorption of cholesterol
Cholestryamine = bile acid sequestrate, preventing absorption of bile acids in gut
Liver transplant
Immunosuppression?
What is the pathophysiology for Primary sclerosing cholangitis
Intrahepatic or extra hepatic ducts become strictured and fibrotic: obstruction in bile flow causes fibrosis.
Unclear cause but established association with ulcerative colitis
What are the risk factors for PSC?
Male
Ages 30-40
Ulcerative colitis
Family history
What is the presentation of PSC?
Jaundice
Chronic RUQ pain
Pruritus
Fatigue
Hepatomegaly
What are the investigations for PSC?
LFT: raised ALP. Autoantibodies aren’t always helpful.
Gold standard: MRCP (MRI scan of liver, bile ducts and pancreas)
What are the complications of PSC?
Acute bacterial cholangitis
Cholangiocarcinoma
Colorectal cancer
Cirrhosis and liver failure
Biliary strictures
Fat soluble vitamin deficiences
What is the management for PSC?
Liver transplant
ERCP - dilate and stent
Colestyramine to prevent bile acid absorption
