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Acutely Ill Patient > Jaundice- Initial Approach to identify cause > Flashcards

Jaundice- Initial Approach to identify cause Flashcards

1
Q

What is jaundice?

A

Jaundice is a yellow pigmentation to the skin, sclera and mucoussa that occurs when bilirubin levels are increased

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2
Q

Beyond what level of serum bilirubin do the clinical manifestations of jaundice appear?

A

> 60umol/L

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3
Q

How can you divide the causes of jaundice?

A

Pre Hepatic
Hepatic
Post Hepatic

Or whether there is a predominantly raised conjugated or unconjugated bilirubin

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4
Q

Why is a split bilirubin useful for determining the cause of jaundice?

A

The hepatocytes are responsible for the conjugation of bilirubin. Depending upon the location of the issue unconjugated or conjugated bilirubin will be raised, it therefore helps to localise the problem

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5
Q

Where does bilirubin come from?

A

The breakdown of red cells releases haemoglobin- a breakdown product of this is bilirubin

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6
Q

What is heme broken down into within the macrophages?

A

Protoporphyrin and Iron

Protoporphyrin is then converted to unconjugated bilirubin

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7
Q

What is protoporphyrin converted to? Where does it come from?

A

Unconjugated bilirubin

It comes from the breakdown of haeme (from haemoglobin)

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8
Q

Where does bilirubin conjugation take place?

A

The liver

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9
Q

What enzyme is responsible for the conjugation of bilirubin?

A

UGT

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10
Q

Which form of bilirubin is water soluble, and so will appear in the urine?

A

Conjugated bilirubin is water soluble

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11
Q

What happens to conjugated bilirubin in the small intestine?

A

Converted to urobilinogen

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12
Q

What is the fate of urobilinogen within the GI tract?

A

Some is converted to stercobilin- causes stools to appear brown

Some is reabsorbed and is oxidised to urobilin. Some of this goes to the kidneys and some to the liver. That which travels to the kidneys appears in the urine and causes the urine to appear yellow.

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13
Q

What type of jaundice is associated with a raised unconjugated bilirubin?

A

Pre-Hepatic

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14
Q

What are some causes of pre-hepatic jaundice?

A 
Haemolytic Anaemias
Ineffective Haematopoeisis 
Gilberts (defective UGT)
Crigler Najar (deficient in UGT)
Increased erythropoiesis
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15
Q

Why is unconjugated bilirubin raised most in pre-hepatic causes?

A

Level of unconjugated bilirubin exceeds the capacity of the hepatocytes to conjugate it, causing increased serum levels

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16
Q

Why does urine appear darker for pre-hepatic causes of jaundice?

A

Conjugated bilirubin (converted to urobilinogen) levels increase when there is an increased haem load, this causes increased levels of urobilinogen in the GI tract which is reabsorbed, oxidised to urobilin and some is excreted in the urine- causing it to appear darker

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17
Q

If suspecting a pre-hepatic cause what investigations should be requested to check for increased red cell breakdown?

A

FBC
Hb
Haptoglobin- decreases with increased red cell turnover
LDH- increases with cell breakdown
Reticulocyte count- increases with increased red cell breakdown
Blood smear
Direct Coombs Test (DCT) - to check for presence of antibodies against the red cells

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18
Q

What is the underlying process in physiological jaundice of the newborn?

A

Low UGT levels and breakdown of fetal red Hb causes jaundice, treatment with phototherapy to prevent levels exceeding dangerous amounts

Unconjugated bilirubin is fat soluble and can collect in the basal ganglia to cause Kernicterus

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19
Q

What is the complication that can occur with prolonged periods of raised unconjugated bilirubin?

A

Kernicterus- the fat soluble unconjugated bilirubin deposits in the basal ganglia

20
Q

What is the main treatment for physiological jaundice of the newborn?

A

Phototherapy

21
Q

What genetic disorders can cause increased levels of unconjugated bilirubin?

A

Gilberts- defective UGT

Crigler Najjar- deficient UGT

22
Q

What triggers jaundice to develop in patients with Gilbert’s?

A

Stress on the body- infection, stress, starvation due to increased haemolysis exceeding the conguating capacity of the defective UGT

23
Q

Why are you unlikely so see a case of Crigler Najjar Syndrome?

A

They don’t live very long as they develop fatal kernicterus

24
Q

What blood tests should be requested to localise the cause of jaundice?

A 
Total Bilirubin
Conjugated and Unconjugated Bilirubin
ALT
AST
GGT
ALP
Albumin
INR, PT, PTT
25
Q

What enzymes are markers of liver injury?

A

ALT

AST

26
Q

What blood tests are markers of hepatocellular function?

A

Albumin
INR
PT
PTT

27
Q

What are the two main causes of prehepatic jaundice?

A

Haemolytic Anaemia

Dyserythropoiesis

28
Q

What are some causes of dyserythropoiesis? Why does it cause a raised unconjugated bilirubin?

A

Hereditary Spherocytosis
Hereditary Elliptocytosis
Sickle Cell
G6PD Deficiency- inability to handle oxidative stress

The damaged or dysfunctional cells are more degraded by the reticuloendothelial system to produce haem which is broken down to unconjugated bilirubin

29
Q

How can the causes of haemolytic anaemia be divided?

A

Autoimmune
Alloimmune- transfusion reactions, haemolytic disease of the newborn
Drug induced (which triggers an immune reaction)

30
Q

What blood tests would you request if suspecting a haemolytic cause? Describe how they would change if there was a haemolytic process

A 
FBC- Low Hb
LDH- Increased
Haptoglobin- Decreased
Reticulocyte Count- Increased
Blood Smear- For structural problems
DCT- For autoimmune causes
31
Q

What genetic conditions can cause a raised conjugated bilirubin with no evidence of hepatocellular dysfunction?

A

Dubin Johnson Syndrome and Rotor Syndrome

Protein (MRP2 for DBS) that normally transports conjugated bilirubin into the bile is defective in both. The conjugated bilirubin then ends up on the blood stream- excreted in urine causing very dark urine

32
Q

What test is used to investigate for Dubin Johnsons Syndrome?

A

Urinary Coproporphyrins- normal in quantity but different quality due to altered levels of different forms

CP 1 normally excreted in the bile but is found in the urine in DBS

33
Q

What is test is use to investigate for Rotor Syndrome?

A

Urinary Coproporphyrins- normal in quality and quantity

34
Q

What blood tests results suggest a hepatic cause for jaundice?

A

Raised total bilirubin
Raised conjugated bilirubin (think of damage to hepatocytes causing it to leak out into the blood)
Raised ALT/AST

May be: (If liver dysfunction)
Decreased Albumin
Deranged clotting

35
Q

What are some hepatic causes of jaundice?

A 
Viral hepatitis- Hep B, C
Autoimmune Hepatitis
Alcoholic Hepatitis
NAFLD
Cirrhosis
Haemochromatosis
Wilson Disease
Primary Biliary Cholangitis
Hepatic Malignancy
36
Q

What blood results suggest a post-hepatic cause of jaundice?

A

Raised conjugated bilirubin
Highly raised ALP/GGT
Mildly raised or normal AST/ALT

37
Q

What are some causes of post-hepatic jaundice?

A

Painful- Gallstones

Painless- Pancreatic cancer, PBC, PSC, Cholangiocarcinoma (Tumour of Bile Duct)

38
Q

What tumour markers may be elevated for cholangiocarcinomas?

A

C19-9

CEA

39
Q

What is normally the first line investigation for a suspected obstructive jaundice?

A

Abdominal USS

40
Q

What investigation allows for detailed assessment of the structure of the biliary tree?

A

MRI/ MRCP- This will show any blockages or strictures within the biliary tree

41
Q

How is the prognosis for cholangiocarcinomas?

A

Poor as they are often metastatic at diagnosis

42
Q

Why does PSC cause a cholestatic picture?

A

Autoimmune disease that targets the intra and extrahepatic bile ducts causing strictures and fibrosis

43
Q

What investigation can be done to investigate for PSC?

A

MRCP to show if there are structures in the biliary tree

44
Q

What are some symptoms of pancreatic cancer?

A

Epigastric abdominal pain
Weight loss
Jaundice (Painless)

45
Q

What blood tests can be raised in pancreatic cancer?

A

Serum lipase

Ca 19.9

46
Q

What is the name of the surgical procedure carried out to manage pancreatic cancer?

A

Whipple’s Procedure

47
Q

What simple imaging test can be used to investigate for obstruction of the biliary tree?

A

Abdominal USS

Acutely Ill Patient (4 decks)

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