The Liver. Overview Anatomy Function Investigations Symptoms and signs –Jaundice –Encephalopathy...
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Transcript of The Liver. Overview Anatomy Function Investigations Symptoms and signs –Jaundice –Encephalopathy...
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