Hepatic insufficiency Wang Jing-jing Department of Pathophysiology Shandong University Introduction Concept Etiology and classification The functional and metabolic changes Hepatic encephalopathy 2 Introduction 1. Blood Supply: Portal vein: 3/4 of the blood flow (which drains the stomach, intestine, spleen, and pancreas) Hepatic artery: 1/4 of the blood flow 3 2. Internal Structure: Liver lobule A central vein (coalesce into hepatic veins, which empty into the vena cava) 4-6 portal triad (branches of hepatic artery, hepatic portal vein and bile duct) Rows of liver cells (Hepatocytes, hepatic stellate cells, sinusoidal endothelial cells, Kupffer cells and liverassociated lymphocytes which are in close contact with blood-filled sinusoids Hepatic cirrhosis: pseudolobule 肝细胞变性坏死、纤维组织 增生及肝细胞结节状再生这 三种改变反复交替进行 3. Functions Excretion: bile (help the absorption of vitamin K) Clearing: the blood of particles and infections including bacteria Synthesis: albumin, lipoproteins, coagulation factors, as well as protein C, S and antithrombin. Metabolism: protein, lipid, carbohydrate Neutralizing and destroying drugs and toxins Manufacturing, breaking down and regulating: numerous hormones including sex hormones Concept of Hepatic insufficiency Severe damage in liver cells result in degeneration, necrosis, fibrosis and cirrhosis, manifesting as jaundice, bleeding, infection, renal dysfunction or encephalopathy, termed all together the syndrome of Hepatic insufficiency 8 Etiology 1. Infections : hepatitis virus (HBV), bacteria, parasites 我国乙 肝感染 者9300 万 !丙肝 感染者 1000万! 9 HBV →入侵肝细胞→受染细胞表达 HbsAg 、 HbeAg 、 HBcAg → T 细胞识别、致敏→杀伤受染肝细胞:清除病毒 肝细胞损伤 10 Cirrhosis HBV multiplies, spreads and eventually leads to scarring, liver damage, cirrhosis and cancer. 11 Some bacteria, such as Escherichia coli ( E. coli ) or staphylococcus (staph), tubercle bacillus or amoeba caused Liver abscesses 13 市民吃生鱼虾致体内藏千条肝吸虫! 14 15 2. Medicines : Industrial toxins, drugs are modified or degraded in the liver Hepatic cytotoxicity: Degeneration and necrosis of hepatic cells or synthesis of some proteins. 如:异烟 .肼,氟烷,醋氨酚,四环素、甲氨喋呤 Cholestasis: inhibit Na+-K+ ATP, fluidity of cell membrane 如:氯丙嗪 16 17 3. Alcohol: 18 Normal liver Alcoholic Fatty Liver 19 20 4. Nutritional causes everything we eat must be refined and detoxified by the liver liver disease are always found among starving populations. good nutrition - a balanced diet can actually help the damaged liver to regenerate new liver cells. . 21 5. Inherited conditions Wilson's disease: a rare inherited condition. inability to excrete copper into bile. resulting in the toxic accumulation of copper in the liver and nervous system. 22 6. Immunosuppression: SLE, rheumatoid arthritis, Crohn's disease, Systemic infections, such as tuberculosis, may spread to the liver. 23 Classification of hepatic insufficiency Acute: short course of onset→ acute extensive necrosis chronic: long course → late-staged chronic liver disease Hepatic encephalopathy Hepatorenal syndrome Hepatic failure 24 1. Substance metabolism (1) Carbohydrate Metabolism: Glycogenolysis, Glycogenesis, Gluconeogenesis Hypoglycemia, abnormal glucose tolerance (2) Fat metabolism: synthesises lipoproteins, cholesterol, phospholipids, lipogenesis and lipolysis 脂肪泻,厌油腻,脂肪肝,高胆固醇血症 (3) Protein metabolism: CRP, urea ,albumin ↓ 腹水,出血倾向,防御功能下降 (4) Vitamine metabolism: Absorption of liposoluble vitamine ↓ Storage of Vit A, Vit D, Vit E, Vit K ↓ Synthesis of vitamine ↓ 夜盲,出血倾向,骨质疏松 (5) Energy metabolism:ATP ↓ 27 Ecchymosis of skin 28 2. Disorders of bile and hormone (1) Hyperbilirubinemia Elimination of bilirubin ↓ →serum bilirubin↑ 黄疸 (2) Intrahepatic cholestasis Production of bile salts ↓ →fat and fat –soluble vitamins ↓ → Endotoxemia (3) Elimination of hormone ↓ → estrogen ↑ aldosterone ↑, ADH ↑ 29 Jaundice : yellow discoloration of the skin and whites of the eyes 30 the liver plays important roles in hormonal modification and inactivation. Estrogen↑→ body feminization Spider angioma 31 5. Disorders of blood coagulation (1) Production of Blood coagulation factors ↓ (2) Anticoagulin↓ (3) Fibrinolytic system ↑ (4) Plt ↓ 6. Function of detoxication ↓ 7. Immunological function ↓ 32 8.metabolic disorders of water and electrolytes (1)Hepatic ascites: accumulation of fluid that fills and distends the abdomen. 33 34 Cirrhosis, scar tissue, thrombosis in the portal vein →Obstruction blocks the flow of blood through the liver→Portal hypertension ↑ →capillary pressure↑ Obstruction of lymph →capillary pressure↑ Liver insufficient →synthesis of albumin↓→ osmotic pressure↓ Hepatic failure →aldosterone ↑ADH ↑ Renal failure → Water and salt rentention 35 (2) Hyponatremia : Intake↓ Lose ↑: ADH, Diuresis, ascites (3) Hypokalemia: Intake↓ Lose ↑: aldosterone (4) Alkalosis: PaO2 ↓ anemia, Hyperammonemia 9. Disorders of organs: HE, hepatorenal syndrome 36 Hepatic encephalopathy General Concept Classification Clinical Features Pathogenesis Precipitating Factors Principles of Treatment 37 Ⅰ. General Concept, Classification Clinical Features A complex disturbance in central nervous system that occurs as a consequence of severe liver diseases. hepatic coma; portal systemic encephalopathy (PSE); HE Hepatic coma refers only to a terminal stage of HE 38 Endogenous HE “spontaneous ” No apparent pricipitating factor, the final consequence of extensive liver cell destruction. Exogenous HE Have apparent pricipitating factor, (the development of portal-systemic shunts, electrolyte ,acid-base imbalances, bleeding ,ingestion of large amounts of dietary protein, etc) 39 Portal-systemic shunts 1. Portal hypertension →collateral circulation 40 1. At the lower end of the esophagus 41 2. At rectal venous plexus 3. At periumbilical venous rete 4. Portal-retroperitoneal anastomosis 42 2. Transjugular Intrahepatic Portosystemic Shunt 43 门-奇静脉断流术 经颈静脉肝内门腔分流术 (TIPS) 44 远端脾-肾静脉分流术 45 Clinical features of HE generally divided into 4 stages slight altered mood or behavior including reversed sleep pattern Coma, no response to painful stimuli Coma but arousable slurred speech Drowsiness, personality changes intermittent flapping tremor 46 Flapping tremor 47 Precipitating factors in HE 1.Nitrogenous overload: a frequent cause of HE. 2. GI bleeding: The presence of blood in the upper gastrointestinal tract results in increased ammonia and nitrogen absorption from the gut. Bleeding may predispose to kidney hypoperfusion and impaired renal function. 48 3. Infection: Infection may predispose to impaired renal function and to increased tissue catabolism, both of which increase blood ammonia levels. 4. Constipation: Constipation increases intestinal production and absorption of ammonia. 5. Renal failure: Renal failure leads to decreased clearance of urea, ammonia, and other nitrogenous compounds 49 6. Medications: Drugs that act upon the central nervous system, such as opiates, benzodiazepines, antidepressants, and antipsychotic agents, may worsen HE. 7.Diuretic therapy: Decreased serum potassium levels and alkalosis may facilitate the conversion of NH4+ to NH3. 50 Ⅱ. Pathogenesis of HE Ammonia intoxication hypothesis False neurotransmission hypothesis Amino acid imbalance hypothesis GABA hypothesis 51 1. Ammonia intoxication hypothesis (1) History 1877 Eck, Russian physiologist who created portal-systemic shunts in healthy dogs The beginning of the surgical treatment of portal hypertension the first vascular anastomosis Ivan Pavlov “Eck-Pavlov fistula” In 1893: Observed that these dogs promptly became comatose after eating meat. “meat intoxication” in 1904: received Nobel Prize (3)Supporting evidence 60~80% of HE show increased plasma ammonia level Patients with hepatocirrhosis have elevated level of ammonia Symptom of HE and alteration in electroencephalogram (EEG) after high protein diet 54 (4) Contents NH3 production NH3 production NH3 clearance ( urea cycle ) Under normal condition, the production and the clearance of NH3 is in balance 55 NH3 clearance NH3 production Severe hepatic dysfunction Hyperammonemia HE 1) NH3 production AA deaminization: amine oxidase Intestine: unabsorbed aa or diffused urea that are broken down by bacterial amino acid oxidases or ureases. pH↑ NH3 absorbed↑ Renal tubular epithelial cells: Hydrolysis of glutamine Skeletal muscles: Deamination of other amino acids 2) NH3 clearance Liver: “Urea cycle” CO2 + 2HN3 + 3ATP + 3H2O = H2N-CO-NH2 + 2ADP + 4Pi +AMP Brain and muscle: Formation of glutamine by glutamine synthetase ammonia+glutaminic acid = glutamine 3) Why does the NH3 increase in HE? ① NH3 production ↑ Portal hypertension: Capillary blood presure ↑ → Congestion and edema of gastrointestinal tract → AA digested and absorbed ↓ Bile ↓: Intestinal bacteria ↑ → ureases ↑ → NH3↑ Foods full of high protein or hemorrhage: 59 Severe liver disease→renal failure→the urea in blood defuses into intestine → NH3↑ Tic of the muscles→ NH3↑ ② NH3 clearance↓ Liver: Urea cycle ↓ → NH3 clearance↓: ATP ↓ Function of enzyme ↓ Substrates ↓ and shunt urea NH3 protein Normal metabolism NH3 61 Brain NH3↑ Liver failure Shunting Circulation Blood NH3↑↑ urea ×NH3 protein NH3 62 The reasons of NH3↑ Production↑ clearance↓ GI tract renal muscles urea syntheses NH3 Portalsystmic shunts 63 4)How does the NH3 lead to HE? 1.Decreasing energy production In normal conditions: Because glycogen reserves are less in the brain, brain needs much of energy from oxidation of glucose. Excess ammonia ultimately may cause cerebral energy failure due to inhibition the energy production. 64 Pyruvate decarboxylase Krebs cycle 65 2. Changing neurotransmitters increasing glutamine and GABA decreasing glutamic acid and acetylcholine The neurotransmitters include excitatory transmitters (acetylcholine, glutamic acid, etc ) and inhibitory transmitters (GABA, glutamine, etc) . The correct balance of neurotransmitters is critical to the brain. HE→NH3↑→GABA, glutamine↑, glutamic acid and acetylcholine ↓→ disorder of CNS. 66 Krebs cycle 67 The reasons of NH3↑ Production↑ clearance↓ GI tract renal muscles urea syntheses NH3 Portalsystmic shunts 68 Decreasing energy production Krebs cycle Changing neurotransmitters Disturbing the ions transfer of the nervous cells membrane. 69 3. Ammonia disturbs the ions transfer of the nervous cells membrane. Na+-K+-ATPase which is located in the surface membrane of cells is responsible for the active transport of Na+ and K+ between extracellular fluid and cytoplasm. NH3 →ATP↓→ Na+-K+-ATPase ↓→ inhibits excitatory postsynaptic potentials→depressing CNS function. NH3 K+ Na+-K+-ATPase Na+ 70 However, not all data are consistent with the ammonia toxicity theory. Plasma levels of NH3 correlate poorly with HE Acute NH3 intoxication may be characterized by seizures which are unusual in either acute or chronic HE. NH3 does not induce the EEG changes of HE. 71 4. Astrocytic swelling: (1) Glutamin (2) Oxidative Stress: (3) Permeability of mitochondrion (4) AQP4↑ 72 Ⅱ.False neurotransmission hypothesis 73 False neurotransmission(FN) hypothesis What is FN? And what is true neurotransmission(TN)? History of FN hypothesis? Why FN is increased in hepatic insufficient patients? What is the mechanisms of FN in hepatic insufficient patients? 74 1. What is FN? And what is TN ? What is neurotransmitters? Information is moved around the brain, from nerve cell to nerve cell, by means of chemical substances, called neurotransmitters 75 1.A message travels along the nerve The roles of NT and when it approaches the nerve ending a neurotransmitter is released. 2.The neurotransmitter is received by the next neuron 3. some of the neurotransmitter gets reabsorbed 4.When enough neurotransmitter is received by the next nerve cell the message moves forward. 76 1. What is FN? And what is TN ? Excitatory neurotransmitter: Neuro- transmitters Ach, Aspartic acid Inhibitory neurotransmitter: GABA, Glutamine 77 The structure of FN and TN TN FNT 78 Excitation of secondary neuron Excitation of secondary neuron ↑ True NT synapse Normal FNT compete receptor Hepatic failure Mode shown replacement of TN to FN in HE 79 2. False neurotransmitter (FN) hypothesis Supporting evidence FN accumulates in liver failure. In the corpus striatum of rats with encephalopathy, concentrations of noradrenaline(NA) and dopamine(DA) decreased, octopamine increased. 80 In 1970, Parkes first reported bendopa treat HE succesfully. Fischer et al proposed FN hepothesis: In the pateint with hepatic failure, FN (phenylethanolamine and octopamine) is accumulated in the synapse of the ascending reticular activating structure (ARAS) in the brain stem. The FN can compete with true Neurotransmitter (TN): noradrenaline (NE) and dopamine (DA) because their chemical structure is similar to the TN. When FN replaces TN in RAS of brain stem, disorders of CNS occur. 81 82 3. Why FN is increased in HE patients? Congestion and edema of gastrointestinal tract→disorders of the function (motion, secretion, absorption, digestion) → inadequate digestion of protein→Phe (phenylethylamine) and Tyr (tyramine) ↑ Tyr and phe can’t be cleared by the process of enzymatic degradation in liver. Potal-systemic shunt make Tyr and phe flow in blood directly. 83 Brain Tyr and phe↑ Liver failure ↑ ↑ Blood Tyr and phe Shunting Circulation × Tyr and phe protein Tyr and phe 84 4. How does the FN compete with TN? 85 Ⅲ. Plasma amino acid imbalance hypothesis 1.What is branched chain amino acids (BCAA) and aromatic amino acids (AAA)? 2.What is the contents of Plasma amino acid imbalance hypothesis? 3.Why plasma amino acids are imbalance in HE patients? 4. What is the mechanisms? 86 1.What is BCAA and AAA? BCAA: AAA: 87 Plasma Phe Tyr Phe Tyr Try BBB Brain HPEA Hydroxylase PEA tyramine Try hydroxylase decarboxylase decarboxylase hydroxylase 5-HTA 5-HT 88 2.What is the contents of Plasma amino acid imbalance hypothesis? In HE patients, blood BCAA is decreased, AAA is increased, so, AAA enters in to the brain more and form FN. Decreased ratio of BCAA/AAA relates to HE due to FN formation in CNS. So, this hypothesis is an extension of False Neurotransmitter Hypothesis. 89 3.Why plasma amino acids are imbalance in HE patients? BCAA↓: Hepatic dysfunction→degradation of glucagon↓ Portal systemic shunts→ glucagon enter into blood directly → glucagon ↑→ BCAA is excessive used by skeletal muscle 90 AAA↑: Brain Tyr and phe↑ Liver failure ↑ ↑ Blood Tyr and phe Shunting Circulation × Tyr and phe protein Tyr and phe 91 Phe Plasma Try Tyr BBB Brain NAA Tyr hydroxylase Dopa FNT, NAA,5-HT Dopamine FNT Hydroxylase PEA tyramine Try hydroxylase FNT, Phe, Try decarboxylase decarboxylase Phe 5-HTA NA HPEA 5-HT AAA/BCAA↑→AAA enter into brain↑→TN↓→FNT↑ 92 4. The mechanisms of Plasma amino acid imbalance The decrease in BCAA is caused predominantly by their excessive use by skeletal muscle. The increase in AAA is caused predominantly by failure of hepatic failure or shunt. BCAA/AAA↓in CNS may interfere with normal neurotransmission by competitively inhibiting TN (DA, NA) and favoring formation of FN (octopamine, phenylethanolamine) 93 Ⅳ GABA hypothesis In the 1980s, Basile and Jones promoted: gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the CNS, as a cause of HE. Of all brain nerve endings, 24-45% may be GABA ergic. Increased GABA ergic tone is observed in patients with HE 94 Brain GABA↑ BBB↓ Blood GABA ↑↑ Shunting Circulation clear × GABA Liver failure Foods full of glumatic acid Liver failure bacteria in intestine ↑ GABA Edema, congestion → digestion↓,absorb↑ 95 GABA crosses the blood-brain barrier→released by Vesicle of excited presynaptic neuron cell → GABA receptors( in conjunction with receptors for benzodiazepines and barbiturates) → Cl- channel opens → Cl- influxs into the postsynaptic neuron → membrane hyperpolarization → inhibitory postsynaptic potential. Cl- BZ BR GABAR↑ Cl- GABA ↑ cell Post-synapse inhibition Liver failure 96 Treatment 1. Identification and Removal of Precipitating Factors (1)Dietary protein should be eliminated (2)Oral lactulose should be given Lactulose is degraded by colonic bacteria and converted to lactic acid and other acids, with resulting acidification of The gut lumen. This favors conversion of NH4+ to NH3 and The passage of NH3 from tissues into the lumen. 97 (3) Gastrointestinal bleeding must be stopped. The intestines must be emptied of blood. Blood breaks down into protein components that are converted to ammonia. (4)Treatment of infections, renal failure, and electrolyte abnormalities (especially potassium) is important. 98 2. reducing plasma ammonia and other toxins levodopa, a precursor of normal neurotransmitters bromocriptine, a dopamine agonist infusions of branched chain amino acids flumazenil, a benzodiazepine antagonist 3. Liver transplantation 99 Risk Factors 1. Risk Factos in People with Alcoholism Only 10% of heavy drinkers develop advanced liver disease. Not eating when drinking and consuming a variety of alcoholic beverages are factors that increase the risk for liver damage. Obesity is a major factor for all stages of liver disease. Women develop liver disease at lower quantities of alcohol intake than men. The reason for this may be due to women's inability to metabolize alcohol as quickly as men, so it stays in the bloodstream longer. Genetic factors that regulate the immune responses in the intestine also play role in increasing the risk for liver injury from alcoholism. 100 2. Risk Factors in People with Chronic Hepatitis • Hepatitis C at higher risk for liver damage, especially Coinfection with hepatitis B or HIV. • Being diabetic and overweight, particularly if fat is distributed in the abdomen (an apple-shape). This condition poses a higher risk for nonalcoholic fatty liver disease (NASH), which in turn is apt to become scarred and cirrhotic. • High exposure to toxic chemicals or environmental contaminants. 101 Weight gain in the area of and above the waist (apple type) is more dangerous than weight gained around the hips and flank area (pear type). Fat cells in the upper body have different qualities than those found in hips and thighs. 102 3. Risk Factors for Cirrhosis in Autoimmune Liver Diseases 4. Obesity and Other Risk Factors for Cirrhosis obesity increased the risk of death from cirrhosis in those who drank little or no alcohol, but not in alcoholics. Men are at higher risk than women and African Americans have a higher risk than Caucasians. 103 病案分析 男性,45岁。10年前患乙型肝炎,经治疗后痊愈。 近3年来常于劳累后乏力,进食后饱胀,纳差。半年 来上述症状逐渐加重,腹胀、大便不成形,每日2次 ,无粘液和脓血。经常出现鼻和齿龈出血。近3天腹 泻后出现精神状态差,反应迟钝、少言、随地便溺 。2小时前始处于熟睡状态,呼之可醒,但不能正确 回答问题。 辅助检查:HBsAg和HBeAg阳性。 体格检查:体温37.5℃ 脉搏78次/分 呼吸16次/分 血压15.0/8.0 kPa,嗜睡状态,压眶反射存在。面 色灰暗黝黑,巩膜黄染。颈软,颈部、前胸有多个蜘 蛛痣,可见肝掌。心肺检查正常。腹部呈蛙腹,肝脏 右肋下未及,脾左助下4Cm,移动性浊音阳性,肠 鸣音正常。 1:根据患者的病史特点,诊断什么疾病? 2:为进一步证实诊断,还需做哪些辅助检查? 3:该患者使用利尿剂时的原则和注意事项有哪些? 106