12 - LFTs and Jaundice Flashcards Preview

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Flashcards in 12 - LFTs and Jaundice Deck (25)
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1
Q

What is the definition of jaundice?

A

Can be divided into prehepatic, hepatic and post hepatic

2
Q

Where does bilirubin come from and how is it excreted?

A

- Breakdown product of haem

  • Initially unconjugated and bound to albumin
  • Conjugated in the liver so it is water soluble
  • Excreted in urine and faeces
3
Q

Within each category of jaundice, e.g prehaptic, what is the cause of the raised bilirubin?

A
4
Q

What are some common causes of pre-hepatic jaundice?

A
  • Increased degradation of Hb so increased demand on liver so raised levels of unconjugated bilirubin
5
Q

Why does neonate jaundice need to be corrected?

A
  • Raised levels of unconjugated bilirubin can pass BBB and damage brain
6
Q

What are some common causes of hepatic jaundice?

A

Reduced conjugating ability of liver due to damaged hepatocytes so mixture of conjugated/unconjugated bilirubin

7
Q

What are some common causes of post hepatic jaundice?

A
  • Obstruction of excretory pathway so raised conjugated bilirubin
  • Gall stones, biliary stricture, pathology of pancreatic head (e.g pancreatic carcinoma)
8
Q

What are some symptoms of post hepatic jaundice?

A
  • Pale stools and dark urine as more excreted in kidneys
9
Q

What are some intrahepatic pathologies that can be classed as both hepatic and post hepatic jaundice?

A
  • Oedema
  • Primary or metastatic malignancy
  • Scarring/Cirrhosis

All can compress the intrahepatic ducts

10
Q

How is pancreatic carcinoma a cause of post hepatic jaundice?

A
  • Growth of the head can lead to obstruction of duct
  • Weight loss and jaundice
11
Q

What are some tests we can look at to assess liver function?

A
  • Conjugated/Unconjugated bilirubin
  • Albumin
  • ALT
  • AST
  • ALP
12
Q

What blood tests can tell you about the synthetic function of the liver?

A

- Albumin: low in liver disease as synthesised here. can lead to ascites

- INR for clotting factors

13
Q

What are markers of hepatocyte damage?

A
  • Raised ALT and AST in the blood
  • AST less specific as found in cardiac, skeletal and RBC
  • ALT > AST in liver damage
  • AST > ALT in cirrhosis and alcoholic hepatitis
14
Q

What is ALP (alkaline phosphatase) a marker of and how can you distinguish between the two?

A
  • Bone turnover
  • Damage to biliary tree, e.g cholestasis, as found in cells lining the bile duct
  • Use Gamma GT, if both this and ALP raised it is bile duct pathology, if gamma GT not raised other cause likely
15
Q

What are the patterns LFTs can show?

A

- Obstructive

- Hepatocellular damage

- Mixed

  • LFTs can be deranged and no jaundice and if jaundice LFTs can help identify the cause
16
Q

What would be LFTs in each of the three types of jaundice?

A
17
Q

Describe two features of Crohn’s disease that could be visualised during a colonoscopy?

A
  • Hyperaemia and oedema of the mucosa
  • Skip lesions

Cobblestone appearance (linear ulcers crossing each other with areas of normal or oedematous in between)

  • Strictures
  • Openings of fistula
18
Q

What are some perianal pathologies that might be present in Crohn’s disease?

A
  • Anal fissure
  • Haemorrhoids
  • Skin tags
  • Perianal abscess
  • Opening of a fistula
19
Q

Why does weight loss occur in Crohn’s disease?

A
  • Commonly affects the small intestine which is the site of nutrient absorption in the gut
  • Inflammatory processes in the small intestine will reduce absorption of nutrients which will result in weight loss
20
Q

In pre-hepatic jaundice the raised plasma bilirubin levels tend to be unconjugated despite normal liver function.
Briefly explain why.

A
21
Q

In post hepatic jaundice patients will often notice they have dark urine, why is this? (remember conjugated bilirubin excreted into bile)

A

In post-hepatic jaundice the liver is able to process the conjugation of bilirubin so bilirubin is soluble

However there is a blockage of flow of bile into the gut so plasma (conjugated) bilirubin levels rise.

As the bilirubin is soluble it can be excreted by the kidneys and the bilirubin gives the urine a dark colour.

22
Q

What LFT is indicative of post hepatic jaundice?

A

ALP with gamma GT

23
Q

How does saliva become hypotonic?

A
  • More ions reabsorbed from saliva than secreted into saliva
  • Ductal cells relatively impermeable to water
  • Overall effect is more ions removed from saliva than water= hypotonic
24
Q

What are the main features and processes that occur in the pharyngeal phase of swallowing?

A
25
Q

What is a suitable investigation for dysphagia to solid foods?

A
  • Barium swallow
  • OGD