Liver Diseases Flashcards
What is jaundice?
Accumulation of bilirubin in the skin
* Pigmentation yellow/orange
* Significant Itch
Where is jaundice most noticeable?
sclera of the eye
What is the pathway for haem breakdown?
erythrocytes > heme > biliverdin > bilirubin > conjugated bilirubin
What will happen if the bilirubin is not conjugated?
it will not be excreted and therefore it will accumulate
What is bilirubin excreted as in urine?
urobilin
What is bilirubin excreted as in stool?
stercobilin
What are the 3 classifications of jaundice?
pre-hepatic
hepatic
post-hepatic
Why would there be excess bilirubin due to pre-hepatic causes?
increased haem load (excess breakdown of RBCs)
due to
autoimmune
spleen issues
abnormal RBCs
Why would there be excess bilirubin due to hepatic causes?
liver cell failure
due to
cirrhosis
hepatitis
Why would there be excess bilirubin due to post-hepatic causes?
biliary, gall bladder and pancreatic disease causing obstruction
What are the reasons there may be excessive quantities of RBC breakdown products?
- Haemolytic anaemia
- Post transfusion (bad match)
- Neonatal (maternal RBC induced)
Why does hepatic failure cause jaundice?
Prevents metabolism of RBC breakdown products - no conjugation
What colour is the stool/urine in hepatic jaundice?
pale stool/urine
What can cause a obstruction to the intrahepatic biliary system?
primary biliary cirrhosis
What can cause a obstruction to the extrahepatic biliary system? (gall bladder and common bile duct)
Gall bladder
- Gall stones
Common bile duct
- Pancreatic carcinoma
- Cholangiocarcinoma
What can gall stones do?
- Can block biliary tree - obstructive jaundice
- Can cause inflammation
- Can move out to biliary tree
What is inflammation of the gall bladder called?
cholecystitis
What are symptoms of gall bladder diseases?
- Pain in SHOULDER tip - due to relation with diaphragm and C 3,4,5 nerves
- Abdominal Pain Right side
- Pain brought on by eating Fatty food
- Stimulates bile release by contraction of the gall bladder.
What is gall bladder disease usually caused by?
- Usually Gall stones
- Rarely Cholangiocarcinoma (bile duct cancer)
How can jaundice be imaged? And what does it show?
- Ultrasound - Detects dilated bile channels WITHIN the
liver, also dilated biliary tree - Plain Radiographs - Show RADIOPAQUE gall stones
- ERCP -Endoscopic Retrograde Cholangio Pancreatography - Contrast radiograph of biliary tree
How is a ERCP carried out?
using an endoscope to put a cannula into the biliary tree from duodenum
Where is a cholangiocarcinoma tumour most severe?
extra hepatic
What are the two causes of pancreatitis?
role of alcohol in chronic pancreatitis
role of mumps virus – usually temporary
What common disease is usually a consequence of chronic pancreatic disease?
diabetes
What do patients with cystic fibrosis require?
oral pancreatic enzyme supplements
How is jaundice managed at pre-hepatic?
identify and treat the cause - spleen, anaemia, autoimmune
How is jaundice managed at post-hepatic?
Remove obstruction
* Gall stones via ERCP
* Gall Stones via lithotripsy (ultrasound to break stones)
* Force open channel with a stent (biliary tree stent)
* Prevention of Gall stone recurrence - remove gall bladder (cholecystectomy)
How can build up of bile acid be prevented?
- Ursodeoxycholic Acid tablets
- Low calorie & low cholesterol diet
How can bile acid resorption form the GIT be prevented?
cholestyramine sachets
What is neonatal jaundice due to?
- Increased Haem breakdown - Birth trauma
- ABO & Rhesus incompatibility
- Poor liver function in neonate
What is the risk of neonatal jaundice?
kernicterus
brain damage from bilirubin as brain-blood barrier not fully developed
What is the treatment for neonatal jaundice?
phototherapy
- blue light cause bilirubin to breakdown and get excreted
What is acute liver failure and what can it cause?
Sudden loss of liver function
Rapid death from:
* Bleeding
* Encephalopathy
What is the cause of acute liver failure?
paracetamol poisoning
free radical damage to hepatocytes caused by processing paracetamol through alternative pathway due to blockage/overloading of normal pathway
What is the treatment for acute liver failure?
liver will usually recover given time if patient can be kept alive
transplant often the only option
What are the causes of chronic liver failure?
- Cirrhosis
- Primary liver cancer
- Secondary liver cancer (metastases from bowel tumours)
What is cirrhosis?
damage, fibrosis & regeneration of liver structure
standard triad may be damaged
What are the causes of cirrhosis?
- Alcohol
- Primary Biliary Cirrhosis
- viral disease - chronic active hepatitis
- autoimmune chronic hepatitis
- Haemachromatosis (too much iron irratites the liver)
- Cystic fibrosis
What does a small liver mean and what does a large liver mean?
small = shrunken and fibrinoid
large = inflammation
What are the signs and symptoms of cirrhosis?
- Acute bleed - portal hypertension and oesophageal varices
- Jaundice
- Oedema & ascites (abdominal fluid from portal vein to peritoneum)
- Encephalopathy (toxic materials reach brain as liver can’t remove them)
- Spider naevi, palmar erythema due to high oestrogen levels from reduced metabolism
Why does ascites occur?
- High portal venous pressure
- Low plasma protein synthesis
- Lower oncotic pressure
Fluid leaks out
How do oseophageal varices occur?
Disordered portal triads in liver cirrhosis cause portal hypertension
- Blood engorges as passes through vessels at the end of the embryological gut – lower oesophagus – getting from left gasric vein to portal vein to the systemic circulation
- Veins dilated and fragile – thin walled
- Protrude into oesophageal lumen – easy to rupture and can lead to catastrophic bleed
What synthesis functions are lost in liver failure?
- plasma proteins
- Transporting proteins
- Gamma globulin
- clotting factors (rupture of varices can be fatal)
- hormones
What metabolic functions are lost in liver failure?
- drug metabolism (esp. 1st pass)
- detoxification
- conjugation of RBC breakdown products
What enzymes escape liver cells if they are damaged or inflamed?
ALT
GGT
What tests are done for liver function?
hepatic cell enzyme levels (raised in liver inflammation)
INR
What does the INR measure?
Measures PROTHROMBIN time against a control (lab worker!)
* Prothrombin > Thrombin
Why is the INR measured in liver disease?
prothrombin and vitamin K (essential in blood clotting) are produced in the liver
What is the normal INR value?
1
What is the range of INR id on warfarin?
2-4
What does it mean if the INR is not 1?
SIGNIFICANT liver synthetic dysfunction
What are the effects of liver failure?
- fluid retention – ascites
- Portal Hypertension - Oesophageal Varices
- inability to remove ‘waste’ - urea
- Encephalopathy
- build up of haem breakdown products - JAUNDICE
What is the INR for liver failure?
- raised INR and prolonged bleeding
- 1.3 is HIGH for non warfarin patient
due inadequate liver synthesis of clotting factors
What is the treatment of liver failure?
transplantation
possibly artificial liver systems similar to dialysis (MARS)
How much of the liver can be used?
each liver has 3 lobes that can be transplanted for a different patient
What are the metabolic considerations for liver failure in dentistry?
Prolonged effect of sedatives
- Avoid intravenous sedation!!
Care with antifungals
* avoid miconazole, erythromycin and tetracycline (toxic injury
Suitable analgesics
- Paracetamol probably the safest
- NSAIDS increase bleeding risk
What are the synthetic considerations for liver failure in dentistry?
Reduced clotting factor synthesis
- Bleeding tendency
- Work with Haematologist - fresh frozen plasma?
- Reduced plasma transport protein synthesis
- Drug binding reduced - dose may need reduced
- Reduced ‘gamma globulin’ synthesis
- More prone to infections?
NO problem with Local Anaesthetics
-Metabolised in the plasma, not the liver!
