Case Discussion 案例病史: 林先生,69歲,過去已知 糖尿病病史十餘年.高血壓三年.最近半年進展為腎病症候群,腎臟切片顯示為FSGS(focal segmental glomerulo sclerosis),於是在89年6月起接受治療,包括Prednisolone,Cyclosporin A等.然而他的症狀(全身水腫.運動易喘.食慾不振.尿量減少)一直反反覆覆,於是在89年11月30日住院接受脈衝治療(pulse therapy Cyclophosphamide 500mg/d x 3 days, Methylprednisolone 40mg/d daily) 並因寡尿.腎衰竭而自12月15日放置雙腔導管進行血液透析.不幸於12月19日,林先生開始發燒, 同日並發現白血球數目下降,於是接受血液培養及重新置換雙腔導管,並給予第三代強效抗生素. 三日後血液及原雙腔導管尖端之細菌培養均長出MRSA.於是抗生素改給予Vancomycin 1250mg/週. 12月29日,林先生突發意識昏迷伴有心率緩脈(junctional bradycardia,40-60次/分)(圖一) 遂轉入加護病房緊急置放暫時性人工心臟節律器,並安排腦部電腦斷層掃描 （圖三） 而發現左枕葉有一個不到一公分之高密度病灶.兩天之後,林先生完全恢復意識,惟若關掉暫時性人工心臟節律器,則仍出現緩脈(圖二),另外在左下胸骨緣出現新的收縮性心雜音,經安排胸前心臟超音波 （圖七, 圖八, 圖九）, 因而發現一面積約三平方公分之贅狀物,沾黏在二尖瓣前葉之上,伴隨中等度之二尖瓣逆流,另亦發現有 中等度之三尖瓣逆流及中量之心包膜積水.持續追蹤之胸部X光片 （圖五, 圖六）則呈現肺炎惡化伴有開洞 情形.五天後追蹤腦部電腦斷層掃描 （圖四） 發現腦部有多發性低密度病灶.90年1月4日,林先生之敗血 症惡化,出現瀰漫性血管內凝血(DIC),併發消化道出血不止,經治療無效後,再度陷入休克及重度昏迷, 而於隔日病逝. 實驗室發現: 1. CBC and differential count:   WBC RBC Hb Plt Hct MCV Band Neu Baso Eos Mon Lym   /μl M/μl g/dl K/μl % fL % % % % % % 11/30 5340 2.19 6.5 159 19.2 87.8             12/19 2410 2.86 8.6 88 24.6 86.0             12/20 3420 2.40 7.1 73 20.9 87.1 0 95.3 0.3 0.9 1.5 2.0 12/29 9040 2.83 8.6 40 24.7 87.3 3.0 91.0 0 0 3.0 2.0 1/03 9120 3.31 9.6 15 27.0 85.7             1/05 17460 1.74 5.1 71 15.9 91.4             2. Biochemistry:   A/G BilT/D ALP AST ALT r-GT BUN Cre Na K Cl   g/dl   mg/dl U/L U/L U/L U/L mg/dl mg/dl mM mM mM 11/30 2.7/2.4 0.4/ 102 37 22   91.4 6.1 140 3.8 102 12/19 2.3/2.9           121.5 5.1 135 4.7 99 12/29             95 5.3 130 3.7 98 1/05             82 5.3 138 5.7 98   Ca P Mg Glu LDH TG T-CHO Lac.A CK CKMB Tn-I   mM/dl mg/dl mM/dl mg/dl U/L mg/dl mg/dl mg/dl       11/30 1.57     238               12/19 1.84 5.0 0.88                 19/29 1.64   0.89         2.3 166 13 1.75 12/30                 327 7 4.84 3. Urinalysis:   Outlook PH Pro Glu KB OB Bil Urobil RBC WBC Epi 12/21 Y,C 6.0 4+         0.1 15-18 10-12 2-4   Cast Crystal Bact                 granular                     4. EKG: to be presented 5. ABG (12/29): (O2 nasal cannula 5l/min)   PH    PaCO2 PaO2 BE HCO3 SaO2 12/29 7.548 22.6 86.2 -1.4 19.8 97.9% (O2 mask, FiO2 40%) 1/05 7.29 30.4 174.6 -11.4 14.1 95% (CMV mode, FiO2 70%) 6.Coagulation   PT PTT 12/29 14.0/12.1 43.1/37.0 1/04 23.5/11.9 69.9/37.6 7. DIC profiles (12/30): 3P (4+); FDP: 80-160ug/dl; D-D dimer: 17.9 ug/dl 8. Blood culture (12/19) II/II: MRSA Blood culture (12/29) II/II: MRSA Double lumen catheter tip culture(12/20): MRSA(3+) Double lumen catheter tip culture(12/29): MRSA(3+) Sputum culture (1/03): Enterobacter cloacae(3+) 案例分析: 一位69歲男性因Nephrotic syndrome(FSGS)惡化而接受pulse therapy ( Cyclophosphamide + steroid )及血液透析治療.治療期間免疫力因施打類固醇而下降,致感染院內菌種MRSA.之後病人突發意識昏迷伴隨心率緩脈(junctional bradycardia),腦部電腦斷層掃描僅見輕微腦水腫,在給予適量降腦壓劑後,意識完全恢復.但第三度房室傳導障礙(complete AV block)卻持續存在.這些現象皆非腦壓升高所能解釋,遂安排胸前心臟超音波,而發現一個vegetation on anterior mitral leaflet.一系列檢查包括胸部X光.腦部電腦斷層掃描.血液培養及雙腔導管尖端之細菌培養顯示為catheter-related infective endocarditis致敗血性栓塞隨血流擴散至腦(腦膿瘍)及肺(pneumonia with cavitation),並因vegetation侵蝕至mitral ring造成心律傳導障礙.最後惡化為瀰漫性血管內凝血(DIC)併發消化道出血不止,而死於敗血症及低血容積性休克. 繼續教育考題 1. (A) Which of the following is an indication for infective endocarditis prophylaxis in a patient undergoing sclerotherapy for esophageal varices? A Previous bacterial endocarditis B Isolated secundum atrial septal defect C Previous coronary artery bypass graft surgery D Prosthetic knee joint E Cardiac pacemaker 2. (A) The treatment of choice for a patient with native mitral valve endocarditis caused by methicillin-susceptible Staphylococcus aureus is: A Nafcillin or oxacillin with or without gentamicin B Vancomycin C Ceftriaxone D Cefotaxime E Gentamicin 3. (C) Cutaneous manifestations of infective endocarditis include all the following except: A Janeway lesions B Osler nodes C Erythema marginatum D Petechiae 4. (C) The most common cause of infective endocarditis in intravenous drug users is: A Viridans streptococci B Enterococcus faecium C Staphylococcus aureus D Candida parapsilosis E Kingella kingae 5. (E) Indications for surgical intervention during active infective endocarditis include all the following except: A Systemic emboli B Fungal endocarditis C Congestive heart failure and hemodynamic instability D Paravalvular invasion and abscess E Right-sided Staphylococcus aureus endocarditis 6. (A) Which of the following is true about the treatment of infective endocarditis? A When enterococci resistant to both penicillin G and vancomycin cause endocarditis, no medical therapy is reliably effective B Cefazolin may be used to treat enterococcal endocarditis C Oral agents such as fluconazole and itraconazole are the treatment of choice for fungal endocarditis D A high dose of intravenous penicillin alone is effective in curing enterococcal endocarditis caused by penicillin-susceptible enterococci 7. (C) Which of the following is true of Chaga's disease? A Most commonly, transmission occurs by the bite of a blood-sucking reduviid bug B Nifurtimox and benznidazole are useful for treatment of chronic chagesic cardiac disease C The heart is the organ most commonly involved by chronic Chagas disease D The diagnosis of Chagas disease may be made easily by the isolation of the organisms from blood cultures 8. (B) Culture-negative endocarditis commonly occurs for all the following reasons except: A Q-fever endocarditis B Escherichia coli endocarditis C Fungal endocarditis D Nutritionally variant streptococcal endocarditis E Bartonella quintana endocarditis 9. (A) A 28-year-old homeless man presents with a 2-month history of fever and night sweats. Examination is significant for heart murmur compatible with aortic insufficiency. Three sets of blood cultures are negative after 48 hours. The patient has not recently received antimicrobial therapy. The most likely diagnosis is endocarditis caused by: A Bartonella quintana B Staphylococcus aureus C Enterococcus faecium D Pseudomonas aeruginosa E Aspergillus fumigatus 10. (D) The HACEK group of organisms includes all the following except: A Eikenella corrodens B Cardiobacterium hominis C Haemophilus aphrophilus D Helicobacter pylori E Actinobacillus actinomycetemcomitans

答案解說 (A ) Certain underlying conditions such as previous bacterial endocarditis are associated with a relatively high risk of infective endocarditis. In contrast, other disorders such as isolated atrial septal defect, previous coronary artery bypass graft surgery, prosthetic joints, and cardiac pacemakers are associated with very low or negligible risk (A) In methicillin-susceptible staphylococcal endocarditis, a beta-lactam agent is more effective than vancomycin. (C) Janeway lesions, Osler nodes, and petechiae are all cutaneous manifestations of infective endocarditis. Erythema marginatum is seen in association with rheumatic fever. . (C) Staphylococcus aureus is the most common cause of infective endocarditis in injection drug users. (E) S. aureus right-sided endocarditis typically responds to antimicrobial therapy alone. (A ) When enterococci resistant to both penicillin G and vancomycin cause endocarditis, no medical therapy is reliably effective. (C ) Trypanosoma cruzi, the etiologic agent of American trypanosomiasis, or Chagas disease, is transmitted by various species of blood-sucking reduviid bugs. Nifurtimox and benznidazole may be useful in the treatment of acute Chagas disease but show minimal usefulness in the treatment of chronic Chagas disease. The diagnosis of chronic Chagas disease is usually made by detecting IgG antibodies that bind to parasite antigens in the serum of patients. (B ) Culture-negative endocarditis may occur with fungal endocarditis, and with slow-growing fastidious organisms such as nutritionally variant streptococci, Coxiella burnetii (the causative agent of Q-fever), and Bartonella Quintana; E. coli generally is not a cause of culture-negative endocarditis. (A ) Bartonella quintana has recently been associated with endocarditis in homeless persons with alcoholism and in atients in inner-city settings. Bartonella spp. are slow- growing gram-negative bacteria that may require a month or longer for culture isolation. (D) Members of the HACEK group of organisms include Haemophilus paraphrophilus, H. parainfluenzae, H. aphrophilus, Actinobacillus actinomyceterncomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae, K. dentrificans, and K. indologenes. Helicobacter pylori is not part of the HACEK group of organisms and is not associated with endocarditis.