The Liver

Overview• Anatomy• Function• Investigations• Symptoms and signs

– Jaundice– Encephalopathy– Hepatorenal– Cirrhosis– Portal vein thrombosis/ GIT complications– Drugs– Metastasis

• Effect of CPB• ITU management

Anatomy

• Largest organ in body

• RUQ

• Anatomical and functional differences

• Dual blood supply

• Microstructure

• Biliary system

Function

• Metabolism– Protein– Carbohydrate– Lipids– Lactate

• Bile acids• Bilirubin metabolism• Hormone and drug inactivation• Immunological

Metabolism - Protein

• Synthesis– All major proteins except IgGs– Albumin and clotting factors except VIII

• Degradation– Amino acids– ammonia to urea to kidneys

Function albumin

• Osmotic

• Carrier for H2O insoluble substances

Metabolism - carbohydrate

• Glucose

• Sources– Sugars– Glycogen (glycogenolysis)– Lactate/Protein/amino acids (gluconeogenesis)

Metabolism - Lipids

• Fat / cholesterol

• Insoluble, transport proteins – lipoproteins

• Hypercholesterolaemia– HMGCoA reductase inhibitors

• LDL receptor

Metabolism - LactateGlucose

Pyruvate

TCA cycle

ATP

Energy

Oxygen

Lactic acid

No oxygen

Bile acids

• Formed from cholesterol– Cholic and chenodeoxycholic acid– Conjugated with lycine or taurine

• GIT absorption of lipids

• Cholestyramine sequesters

Bilirubin metabolism

• Formed from RBC breakdown– Myoglobin, cytochromes, catalases

• Hb• Biliverdin• Bilirubin

– Glucuronic acid

• Bacteria form bilirubin• Urobilinogen (enterohepatic circulation)

– stool stercobilinigen– Urine urobilinogen

Hormone and drug inactivation

• Insulin

• Glucagon

• Oestrogen

• Growth hormone

• Parathormone

• Drug solubilisation

Immunological

• Reticuloendothelial– Phagocytic Kupffer’s cells

• Sieve for portal vein

• Tuftsin synthesis

Investigations

• Routine biochemistry

• Additional blood tests

• Imaging

Routine biochemistry• Normal values do not exclude severe disease• Bilirubin conjugated or unconjugated

• Aminotransferases– AST/SGOT– ALT/SGPT

• Alk Phos– Liver– Bile duct

• Gamma GT• Serum proteins

– Albumin– hyperglobulinaemia

Additional blood tests

• FBC– HB– WCC– Plt– Splenomegally / hypersplenism

• Alpha fetoprotein

• Autoantibodies

Imaging

• AXR/CXR– Stones– Size– Free air ? “Perf”

• USS

• Intrahepatic / extrahepatic

• CT

Symptoms and signs

• Acute verses chronic

• Acute– Yellow, pale stool dark urine

• Chronic– Every organ affected

Jaundice

• Gilberts syndrome– 2 – 5 % population– Raised unconjugated

• Haemolytic– Acholuric jaundice

• Cholestatic– Intrahepatic– Extrahepatic

• Raised conjugated• Choluric jaundice

The Brain / Encephalopathy / Alcohol

• Wernickes encephalopathy– Acute or chronic– Ammonia and potassium

• Korsakoff psychosis/syndrome• Alcohol withdrawal

• Ataxia, nystagmus, confusion, heart failure in an alcoholic give Vitamin B1 (thiamine)

Hepatorenal syndrome

• Renal failure in setting of deep jaundice• Kidneys normal (can be used for transplantation)

• ? Circulating factor ? NSAID

• Keep well hydrated

• ? Use mannitol

Cirrhosis

• Degeneration / regeneration / fibrosis

• Multiple causes (alcohol most common)

• Think of all the livers functions

• Think stomach ulcers

• Think oesophageal varices

Portal vein thrombosis/ GIT complications

• Always think about in a – hypotensive, – hypoglycaemic, – acidotic, – ? Not really bleeding but given clotting

factors– Especially if deteriorates over a few

hours or quicker

Metastasis

• Think about in all patients who have cancer

• Anatomical verses functional significance

Effect of CPB (peri and post op)

• Hypoperfusion particularly in cirrhosis– Reduced function

• Clotting

• Glucose

• Acid-base

Picking up liver disease

• Suspicion

• History eg alcohol

• LFTs

• Hypoglycaemia / severe acidosis

• GIT bleeds

• Clotting abnormality

• Fuscidic acid / paracetamol

ITU management - 1• THINK• Glucose• Acid-base balance Lactate• Clotting (Vitamin K)• Albumin• Sepsis• Alcohol withdrawal• Varices / stomach ulcers• Drugs

ITU management - 2

• Gastric protection• Thiamine• Type of feed• DVT prophylaxis• Renal function• Pressure sores / oedema• N acetyl cysteine• ALL TREATMENTS ARE SUPPORTIVE