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 H 2 O 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 - Lactate Glucose 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 B 1 (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