대한내과학회지 : 제 75 권제 1 호 2008 Special Review in Portal Hypertension - 문맥압항진증과합병증 간성뇌증 가톨릭대학교의과대학내과학교실의정부성모병원소화기내과 김창욱 Hepatic encephalopathy Chang Wook Kim, M.D. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Uijeonbu St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea Hepatic encephalopathy, one of the major complications of cirrhosis, is a neuropsychiatric syndrome caused by accumulation of toxins in the central nervous system following dysfunction in liver detoxification. Various manifestations makes it difficulty to diagnose and categorize hepatic encephalopathy. For the consistency in diagnosis and staging of hepatic encephalopathy, standardized nomenclature regarding forms of hepatic encephalopathy was proposed recently. Due to the poor understanding of pathophysiology, effective prevention or treatment options are limited. Based on the theory that intestinal-derived ammonia plays major role in the development of hepatic encephalopathy, therapeutic approaches are directed at reducing intestinal bacterial production of ammonia and facilitating its elimination. Non-absorbable disaccharides, antibiotics such as rifaximin and L-ornithine-L-aspartate are main therapies for hepatic encephalopathy. Alternative therapies such as benzodiazepine receptor antagonists, branched-chain amino acids, sodium benzoate and acarbose have limited data supporting their use. Precipitating factors must be looked into carefully and corrected immediately because most patients are usually present with precipitating factors. Hepatic encephalopathy without precipitating factors shows poor prognosis and could be candidate of liver transplantation. (Korean J Med 75:27-36, 2008) Key Words : Hepatic encephalopathy; Terminology; Physiopathology; Therapy 서론간성뇌증은심한간기능저하상태에서발생하는의식, 인격, 지력, 행동및신경학적이상등을특징으로하는신경정신과학적증후군 (neuropsychiatric syndrome) 이다. 증상이분명한간성뇌증은간경변환자의약 30~45% 에서발생하며 1, 2), 경미한운동및인지장애를특징으로하는최소증상간성뇌증 (minimal hepatic encephalopathy) 은간경변환자의약 20~60% 에서나타난다고알려져있으나 2-6), 간성뇌증은증상이다양하고심한정도의차이도크며, 최소증상간성뇌증의진단은더욱어려워실제간성뇌증의발병률및유병률은확실치않다. 간성뇌증의예후는그원인및기저간 기능상태에따라영향을받으며 1년생존율은약 20~42%, 3년생존율은약 15~23% 로보고하고있으나 7-9), 최근항바이러스제제의발전으로간경변의생존율향상에따라호전되는양상이다. 간성뇌증의병인기전은장에서발생한각종질소화합물들이신경독성물질로작용하여뇌기능을저하시키는것이가장중요한기전으로생각되나, 정확한기전은아직확실치않으며, 따라서임상적으로사용되는예방법이나치료방법도완전하지못하고제한적이다. 이에간성뇌증의병인기전을밝히고예방과치료법개발을위한연구가절실하다. 이글에서는간성뇌증의진단및치료를위해알아야할간성뇌증의병인기전을간략히정리하고, 진단과치료에필요한연구결과를정리하여간성뇌증환자에대한 - 27 -
- The Korean Journal of Medicine : Vol. 75, No. 1, 2008 - Table 1. Proposed nomenclature for hepatic encephalopathy 10) Category Subcategory Type Description (by duration and (by duration and characteristics) characteristics) A (Acute liver failure) Hepatic encephalopathy associated with acute NA NA liver failure B (Bypass) Hepatic encephalopathy associated with C (Cirrhosis) portosystemic bypass and no intrinsic hepatocellular disease Hepatic encephalopathy associated with cirrhosis and portal hypertension or Episodic Precipitated Spontaneous Recurrent portosystemic shunts Persistent Mild Severe Treatment-dependent Minimal NA NA, not applicable 효과적인대처방안을알아보고자한다. 간성뇌증의분류 1998년비엔나에서개최된간성뇌증에대한회의에서제시된간성뇌증의특성에따른분류 ( 표 1) 가현재임상및연구에적용되고있다 10). A형간성뇌증은급성간부전시발생하는간성뇌증으로대게수시간에서수일안에혼수, 발작, 대뇌제거경축 (decerebrate rigidity) 및사망으로빠르게진행한다. 이경우별아교성상세포 (astrocyte) 의부종으로대뇌부종이발생하고이에의한두개내압상승으로대뇌의저산소증및이탈 (herniation) 이발생하여사망하게된다. B형간성뇌증은간세포의손상없이문맥- 전신순환우회로 (portosystemic bypass) 에의한간성뇌증으로인위적이거나선천적인우회로에의하며매우드물다. C형간성뇌증이간경변에서발생하는간성뇌증이며, B형및 C형간성뇌증은다시간헐적 (episodic), 지속적 (persistant) 및최소증상 (minimal) 으로분류하고급성이나만성간성뇌증이란용어는사용을지양하기로하였다. 간헐적간성뇌증은증상이수시간에서수일간계속되나더이상지속되지않는경우로간성뇌증의가장흔한경우이다. 간헐적간성뇌증은대게증상을유발하는유발인자가존재하는데이러한경우를유발성 (precipitated) 이라하고유발인자가없는경우자발성 (spontaneous) 이라분류한다. 이러한유발성또는자발성간헐적간성뇌증이 1년에 2회이상발생하는경우재발성 (recurrent) 이라분류한다. 과거문헌에서언급된만성간성뇌증은재발성간헐적간성뇌증을의미하는경우가대부분이다. 지속적간성뇌증은엄격한의미로는간성뇌증의증상이호전되기는하나없어지지않고지속되는것을의미하며기술적으로대게 4주이상간성뇌증이지속되는경우를의미한다. 지속적간성뇌증은환자가주로나타내는임상양상에따라경증, 중증및치료의존성으로분류하는데, 간성뇌증의정도인임상등급 ( 표 2) 이 1 등급인경우경증으로그이상등급인경우중증으로분류하며, 경증및중증지속적간성뇌증에서치료중단시다시악화되는경우를치료의존성으로분류한다. 최소증상간성뇌증은경미한운동및인지장애를보이는간성뇌증으로운전과같은일상활동에서집중력결여, 반응시간의증가, 수면장애, 생산성감소등의변화를나타내며, 숫자연결검사 (Number connection test) 나 digit symbol test와같은신경심리학적검사에서는이상을보이나신경학적진찰은정상인경우로과거아임상형 (subclinical) 간성뇌증으로불렸다 11-15). 진단 1. 임상특징간성뇌증은간기능이상환자에서수면형태의변화가오거나, 의식및지남력장애, 인격의변화및여러신경학적증상들이출현할때의심할수있다. 의식의장애는건망증 - 28 -
- Chang Wook Kim : Hepatic encephalopathy - 등미미한정신적변화에서부터착란, 혼미, 혼수에이르기까지다양하다. 인격의변화로는평소보다민감해지고, 가족에대한관심이감소하며유치한행동들을보일수있다. 지적인장애로는시각공간인식에장애가오거나구성행위상실증 (constructional apraxia) 으로인해단순블록설계나필기능력등단순작업에장애를보이며, 언어의구사능력또한감소한다. 신경학적증상으로는퍼덕이기진전 (asterexis), 경직 (rigidity), 과다반사 (hyperreflexia), 발바닥전근반사 (extensor plantar sign), 발작 (seizure) 등이나타날수있다. 퍼덕이기진전은가장특징적인신경학적이상소견으로관절과다른구심성정보들의뇌간으로의정보전달에장애가발생하여고정적자세가유지되지못해발생된다. 양팔을펴고손목관절을신전시킬때고정자세를취하지못하고손이퍼덕거리게되며, 혀를내밀거나눈을꼭감게하거나주먹을쥐게하는등의고정적자세에서관찰된다. 이런퍼덕이기진전은요독증, 저칼륨혈증등전해질장애, 심부전, 다른대사성뇌질환및전두엽종양등에서도발생할수있는비특이적인증상이다. 간성구취 (fetor hepaticus) 는간성뇌증환자에서호흡시에맡을수있는시큼한분변냄새로정상적으로박테리아에의해대변에서형성되는 Methanethiol 의유도체인 dimethylsulphide와같은휘발성물질로인한것이다 16). 2. 임상등급간성뇌증의정도를임상증상에따라단계적으로구분하는것이환자의경과관찰이나치료반응평가에도움이되므로의식상태를반정량적으로구분한 West Haven 판정기준을흔히이용하고있다 ( 표 2) 17). 또한, 이러한의식상태의등급과함께인격및인지능력, 신경학적이상및뇌파검사소견을종합하여신경심리학적시기를나누고이를간성뇌증의심한정도를평가하는데이용하고있다 ( 표 3) 18). 이기준은정신신경학적평가를기반으로마련되었는데 0 등급은인격이나행동에서인지되는임상적변화가없으나, 신경심리학적검사에서는이상이있으며, 1 등급은수면형태의변화, 과면증, 불면증, 인지의사소한결여, 주의력감소, 덧셈과뺄셈의곤란, 쾌감혹은우울증이나타나며퍼덕이기진전이나타날수있다. 2 등급은무기력상태, 느린반응, 지남력상실, 부적절한행동, 느린발음을보이며뚜렷한퍼덕이기진전이나타난다. 3 등급은기면및착란상태로구두자극에반응하는혼미를보이며심한지남력상실과괴상한행동을나타내고퍼덕이기진전은소실된다. 4 등급은혼수상태로구두자극이나독한냄새등에반응을보이지않는다. 3. 검사실및영상검사간성뇌증에서혈중암모니아농도가증가해있는경우가많아서진단에도움이될수있으나모든환자에서혈중암모니아농도가증가해있는것은아니고혈청암모니아가상승된경우라도간성뇌증의정도와비례하지않기때문에검사가필수적인것은아니다. 그러나간질환의존재여부나의식저하의원인이불확실할경우에는혈청암모니아가간성뇌증의진단에보조적인도움을줄수있다. 뇌파검사에서는높은전압과느린삼상파 (high voltage slow triphasic wave) 가처음전두엽에나타나고간성뇌증이진행되면후두엽으로전파된다 19). 영상검사로자기공명촬영에서기저핵부위에망간침착에의해 T1강조영상에서고신호강도소견을보인다 20). 그밖에뇌자기공명분광검사 (magnetic resonance spectroscopy), 양전자방출단층법 (positron emission tomography) 등신경영상기술의발달로간성뇌증에서적극적으로연구되고있으나현재까지간성뇌증의특이적소견을규정할수없고구조적뇌질환을감별하는데더유용하며아직임상에적용하기에는고가라는단점이있다 21). 4. 감별진단간성뇌증의진단에특이적인임상증상이나검사방법은없으므로가능성있는다른질환을배제함으로써간성뇌증을진단한다. 감별해야할질환으로는급성알코올중독, 안정제과다복용, Wernicke 뇌병증, Korsakoff 정신증, 두개내출혈, 뇌막염, 저혈당을비롯한대사성뇌병증등이있으며, 젊은연령에서는윌슨병도감별해야한다 22). 병태생리간성뇌증의병리기전은아직확실치않다. 신경병리학적으로신경세포에는특이한변화가나타나지않으나별아교성상세포의형태학적및기능적변화를보인다 23). 급성간부전증에서는뇌부종이초래될정도로별아교성상세포가팽창되는데이는별아교성상세포내에암모니아의대사산물인글루타민 (glutamine) 이축적되고글루타민의삼투압효과로나타나는현상이다. 반면만성간부전증에서는별아교성상세포의미토콘드리아가증식하고세포질이커지며핵소체가뚜렷해지는 Alzheimer type II 별아교성상세포라는변화가나타난다 24). 간성뇌증의원인물질로는가장중요한암 - 29 -
- 대한내과학회지 : 제 75 권제 1 호통권제 575 호 2008 - Table 2. West Haven criteria for semiquantitative grading of mental state 17) Grade Grade 1 Grade 2 Grade 3 Grade 4 Criteria Trivial lack of awareness Euphoria or anxiety Shortened attention span Impaired performance of addition Lethargy or apathy Minimal disorientation of time or place Subtle personality changes Inappropriate behaviour Impaired performance of subtraction Somnolence to semi-stupor but responsive to verbal stimuli Confusion Gross disorientation Coma (unresponsive to verbal or noxious stimuli) 모니아를비롯하여 γ-aminobutyric acid (GABA), 가성신경전달물질 (false neurotransmitter), 내인성벤조디아제핀 (intrinsic benzodiazepine) 그리고망간등을들수있다. 체내암모니아는주로대장내의단백성분이장내세균에의해분 해되면서생산되며신장에서도근육에서유리된글루타민으로부터만들어진다. 문맥을통해간으로유입된암모니아는요소회로 (urea cycle) 를통해요소와글루타민으로전환되는데, 간기능저하환자에서는요소합성이감소하여암모니아가제거되지못한다. 대뇌에서는암모니아에대한혈액뇌장벽 (blood brain barrier) 의투과성이증가되어많은양의암모니아가뇌로유입된다 25). GABA는장에서생성되는억제성신호전달물질로간에서제거되지못한 GABA가혈액뇌장벽의결함으로뇌에유입되고시냅스후막에존재하는 GABA 수용체에결합하여염소통로 (chloride channel) 가열리면과다분극현상이일어나신경전도를억제한다 26, 27). 간경변에서분지쇄아미노산이감소하고방향족아미노산이증가하여가성신경전달물질의전구물질인방향족아미노산이뇌로더쉽게전달되어가성신경전달물질이만들어지고이에의하여신경억제증상이나타날수있다 28, 29). 망간은정상적으론간담도를통해제거되는데간부전증환자에서는혈중망간농도가증가하여뇌의담창구 (globus pallidus) 에침착되고도파민수용체의밀도를감소시켜서신경억제증상이나타날수있다 30, 31). 간성뇌증의주요한병리기전을표 4에서나타내었다 32). Table 3. Neuropsychiatric staging of hepatic encephalopathy 18) Stage Consciousness Personality and intellect Neurologic EEG findings 0 (minimal) Normal Normal Impaired psychomotor testing Normal 1 Insomnia, disturbed Confusion, Tremor, Slightly abnormal sleep pattern forgetfulness, constructional apraxia, agitation uncoordination 2 Lethargy, slow responses Disorientation, bizarre behaviour Asterixis, ataxia Slowing of triphasic waves 3 Somnolence, but Disorientation, Asterixis, Slowing of triphasic patient may be aggression hyperactive reflexes, waves arousable positive Babinski 's reflex 4 Coma, unresponsive Coma Decerebrate posture Slow waves (2 3 cycles per second) EEG, electroencephalogram - 30 -
- 김창욱 : 간성뇌증 - Table 4. Pathogenesis of hepatic encephalopathy 32) Mechanism Accumulation of toxins (ammonia, mercaptans) Enhanced GABAergic neurotransmission Accumulation of false neurotransmitters Hypothesis Levels of ammonia and mercaptans produced by the action of intestinal bacteria on urea and protein are elevated in blood and brain as a result of defective hepatic clearance, leading to impaired neural function through cytotoxicity, cell swelling, and depletion of glutamate Defective hepatic clearance of GABA produced by intestinal bacteria, increased neuronal GABA synthesis, and increased production of benzodiazepine receptor agonists lead to neuronal inhibition through stimulation of the GABA receptor complex in postsynaptic membranes Increase in the ratio of plasma aromatic amino acids to branched-chain amino acids results in an increase in brain levels of aromatic amino acid precursors of false neurotransmitters GABA, γ-aminobutyric acid Table 5. Precipitating factors for hepatic encephalopathy 33) Precipitating factor Excessive protein intake Constipation Hyponatremia Gastrointestinal bleeding Infection (e.g. SBP) Sedative drugs Azotemia Hypokalemia Surgery Alkalosis Dehydration Fluid restriction Diuretics Excessive paracentesis Diarrhoea Vomiting Arterial hypotension/hypovolaemia Gastrointestinal bleeding Peripheral vasodilatation Shock, operation Hypoxia Anaemia Fever Psychotropic medications Benzodiazepines, morphine Portosystemic shunts Alcohol Possible mechanism Increased ammonia production Increased ammonia absorption Astrocyte swelling Increased ammonia production Synergistic effects of cytokines Increased brain sensitivity Increased ammonia generation Increased renal production of ammonia Protein catabolism Increased diffusion of ammonia through BBB Mechanism uncertain Protein catabolism Protein catabolism Central nervous system depression Reduced metabolism of toxins Hepatic dysfunction SBP, spontaenous bacterial peritonitis; BBB, blood brain barrier - 31 -
- The Korean Journal of Medicine : Vol. 75, No. 1, 2008 - 치료 33) 치료는장내독소의생성및흡수억제, 간에서독소대사의증가, 혈액뇌장벽의통과억제, 뇌에서신경억제성신경전달물질의길항작용을목표로한다. 1. 유발인자확인및제거간경변으로인한간성뇌증환자들의대부분은유발요인을가지고있다 ( 표 5) 34). 이런유발요인을교정하는것만으로도간성뇌증이호전될수있으므로적극적으로유발인자를찾아서제가하는노력을기울여야한다. 확인해야할유발요인으로는단백질과다섭취, 위장관출혈, 감염, 변비, 향정신성약제의사용, 신기능장애및전해질불균형, 급성간기능악화등이있다. 토혈, 흑색변, 혈변, 혈색소치감소등위장관출혈을시사하는소견이있는경우비위관삽입을통해출혈을확인하여적절한지혈술을시행하고위장관으로유출된혈액을신속히배출시킨다. 감염에대해서는자발성세균성복막염, 폐렴, 요로감염등의유무를확인하기위해모든체액에대한검사및세균배양을실시한다. 또한, 신부전, 대사성알칼리증, 저칼륨혈증, 탈수, 이뇨제사용에의한신기능장애나전해질불균형이확인되면적절히교정해준다. 유발요인들은동시에여러가지가함께있을수있으며입증하기어려울수있는데따라서가능성이높은유발인자에대해먼저조치를취하고검사결과에따라치료를조정할수있다. 뇌증으로인해의식저하가심할경우감염이확실치않더라도일단감염이있는것으로간주하고혈액배양이나복수등체액검사및배양을실시하고항생제를투여할수있다. 2. 암모니아등독소물질생성및흡수억제 1) 단백질섭취제한과도한단백질섭취는장내세균에의한암모니아형성을증가시키므로간성뇌증이심할경우단백질섭취를엄격히제한하나장기간의단백질섭취제한은영양불량을초래하여예후를악화시킬수있으므로간성뇌증의초기단계에는단백질섭취를하루 0.5 g/kg으로제한하다가임상상태에따라하루 1~1.5 g/kg로늘려나간다 35, 36). 식이단백질섭취를견디지못하는지속적간성뇌증에서는경구용분지쇄아미노산을단백질공급원으로복용할수있으며, 동물성단백질보다식물성단백질이나유제품이대장산성화를유도할수있어간성뇌증에는더유리하다 37). 2) 비흡수성이당류암모니아를형성할수있는장내물질을신속히배출하기위해삼투성하제의역할을하는비흡수성이당류인락툴로스 (lactulose, β-galactosidofructose) 는간성뇌증치료의중요한근간이다 38). 락툴로스는하제로서의효과뿐만아니라대장내 ph를낮추는효과가있는데, 장내세균에의해초산과젖산으로분해되어장을산성화시킨다. 이러한장의산성화는요소분해효소를생산하는장내세균을억제하여암모니아생산을줄이고암모니아의혈액내흡수를억제하는효과가있다 39). 간성뇌증초기에는경구혹은비위관으로락툴로스를 30~50 ml 가량투여하여설사가나타날때까지 1~2 시간마다동량을투여한다. 이후하루 2~4 회의묽은변을볼수있도록용량을조절하는데, 대게 8~12시간마다 15~45 ml을투여한다. 락티톨 (lactitol, β-galactosidosorbitol) 은락툴로스와유사한효과를나타내는것으로알려져있고 40), 유당분해효소결핍증이있는환자에서는 lactose를하루 100 g 정도투여할수있다 41). 장폐쇄나장마비가있거나의식저하가심한환자에서는락툴로스관장요법을사용할수있는데, 물 1 L에락툴로스 300 ml을희석하여사용하며이경우관장액이전대장에골고루퍼지도록해야하며 30분이상관장액이장내에머물러있도록노력한다 42). 3) 항생제암모니아를생산하는장내세균을억제하는항생제는암모니아형성을줄이므로비흡수성이당류의대체요법으로사용될수있다. 이러한항생제로서대표적인네오마이신 (neomycin) 은장내흡수율이낮아대장내세균을효과적으로억제한다 43, 44). 메트로니다졸 (metronidazole) 도장내세균을억제하여간성뇌증을호전시킬수있다 45). 이들항생제는부작용으로장기사용이어려운데네오마이신은장내흡수율이낮으나장기사용시청력저하나신부전을유발할수 있으며 46) 메트로니다졸은신경독성을일으킬수있으므로 주의를요한다 47). 따라서항생제는비흡수성이당류에잘반응하지않는경우단기간사용할수있는데, 네오마이신은 0.5~1 g을매 6시간마다경구투여하거나, 메트로니다졸 250 mg을매 8시간마다경구투여하며약 1~2 주정도사용한다. 최근에비흡수성항생제인리팍시민 (rifaximin) 이간성뇌증에서좋은효과를보이면서도부작용이없었음을보고하고있는데, 리팍시민 (1,200 mg/day) 과네오마이신및비흡수성이당류와의비교연구들에서리팍시민이간성뇌증의증상완 - 32 -
- Chang Wook Kim : Hepatic encephalopathy - 화에네오마이신이나비흡수성이당류와비슷하거나더좋은결과를보이면서도약물사용에의한부작용이없음을보고하여리팍시민이간성뇌증에서부작용없이효과적으로사용될수있음을보였다 48-53). 4) 기타치료법간에서요소회로를활성화시켜서신경독성물질의처리를증가시켜주는치료로서 L-ornithine-L-aspartate가있다. 이는암모니아를요소와글루타민으로대사하는데중요한기질로작용하여체내암모니아를감소시켜서간성뇌증을호전시킨다 54, 55). 경구로 9 g을하루 3회 2주투여하거나정주로하루 20 g을글루코오스용액에섞어서 1주일간투여한다. 아연은요소회로효소들의보조인자로작용하는데간경변에서결핍되기쉬우므로혈청아연이결핍된경우경구아연제를투여할수있다 56). 아연은 zinc sulfate로하루 600 mg, 혹은 zinc acetate로 220 mg 하루에두번씩 3개월간투여한다. 안식향산나트륨 (Sodium benzoate) 은소변으로암모니아배출을증가시켜체내암모니아를감소시키는효과로간성뇌증의증상호전에기여할것으로생각되나아직자료가부족하다 57). 당뇨약으로사용되는아카보즈 (acarbose, 150 ~300 mg/day) 를간성뇌증에투여시혈중암모니아를감소시키고신경심리학적검사에서호전을보였다는보고가있으나, 그기전은아직잘모르며이에대한연구가좀더필요하다 58). 3. 신경전달물질관련약제 1) Benzodiazepine 수용체길항제간성뇌증의기전중내인성벤조디아제핀이간성뇌증에서발생하여뇌내 GABA-벤조디아제핀수용체복합체에결합하여신경억제효과를나타낼수있는데따라서간성뇌증에서벤조디아제핀수용체길항제인 flumazenil의효과에대한연구가시행되었으나그효과가일시적이고미미하며표준치료로권장되지않는다 59). 다만, 벤조디아제핀계약을복용한간성뇌증에서는투여할수있다. 2) 도파민작용제간성뇌증에서뇌기저핵에망간의침착으로도파민수용체의감소가나타나고간성뇌증에서추체외로증상이나타나는것은도파민성자극이간성뇌증을호전시킬가능성을시사하나, 도파민작용제인 levodopa나 bromocryptine은그효과가입증되지않았다 60, 61). 3) 분지쇄아미노산가성신경전달물질은방향족아미노산과분지쇄아미노산의불균형으로가성신경전달물질의전구물질인방향족아미노산이뇌내로쉽게이동하여뇌증을유발할수있다. 이러한불균형을교정하기위해분지쇄아미노산을투여해볼수있으나실제분지쇄아미노산의투여가간성뇌증을호전시키는지는확실치않다 62, 63). 따라서간성뇌증의예방및치료목적으로분지쇄아미노산의투여가추천되지는않으나간성뇌증을악화시키지않으면서단백질섭취를유지할목적으로사용할수있다. 결론간성뇌증은간경변의주요한합병증중하나로서심한간기능저하상태에서발생하는의식, 인격, 지력, 행동및신경학적이상등을특징으로하는신경정신과학적증후군이다. 체내에서발생하는각종독소를제거하는간의능력에장애가생기면서중추신경계에영향을미치는독소가축적되어발생하는데아직정확한발생기전은확실치않으나장내세균에의해발생하는암모니아가간성뇌증발생에주요한역할을하는것으로알려져있다. 간성뇌증의임상양상은다양하고그정도차이도심하여진단및분류에어려움이있으며, 좀더정확하고통일성있는진단및분류를위한새로운명명법이 1998년이후제시되어사용되고있다. 간성뇌증의발생기전이확실치않아현재임상에서사용되는예방법이나치료법은완전하지못하고한계가있다. 간성뇌증의주치료법은장내세균에의한발생하는암모니아의발생을줄이고이미발생한암모니아를신속히배출시키기위한것이며이는장에서발생하는암모니아가간성뇌증의발생에주요한역할을한다는이론하에정립된치료법으로서비흡수성이당류, 리팍시민과같은항생제, L- ornitine-l-aspartate 등이있으며, 이외에도벤조디아제핀수용체이론및가성신경전달물질이론등에기초하여벤조디아제핀수용체길항제나분지쇄아미노산, 안식향산나트륨, 아카보즈등이치료에이용될수있으나아직임상정보가부족한실정이다. 대부분의간성뇌증환자는간성뇌증을유발하는유발인자를가지고있으므로어떤유발인자가있는지찾아서교정하는것이매우중요하다. 유발인자가없는간성뇌증은예후가나쁘며간이식대상이된다. 중심단어 : 간성뇌증 ; 용어 ; 병태생리 ; 치료 - 33 -
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