— Mycotic Aortic Aneurysm Infected by Clostridium septicum A Case History Liam Hurley, M.D. and Kenneth Howe, M.D.
BOSTON, MASSACHUSETTS
Abstract The authors describe a sixty-seven-year-old hypertensive, diabetic man with mycotic abdominal aortic aneurysm infected with Clostridium septicum. The patient had colonic polyps but no malignant disease. They could find only one other report of a mycotic aneurysm infected with C. septicum. In that case, as in most other cases of C. septicum bacteremia, the patient had gastrointestinal cancer. Their case suggests that treatment for a clostridial infection should be considered in patients with known gastrointestinal disease, signs and symptoms of sepsis, and abdominal pain. Conversely, patients known to have a C. septicum infection should be evaluated for gastrointestinal lesions. a
Introduction About 2.6070 of abdominal aortic aneurysms are infected.’ Various organisms have been found in mycotic aortic aneurysms, including gram-positive bacteria such as staphylococci and gram-negative organisms such as salmonella.2-5 We describe a patient with a mycotic abdominal aortic aneurysm infected with Clostridium septicum. We have found one other report of such an infection.’ Our patient, however, unlike the one described by Semel et a16 and most patients with C. septicum bacteremia,7 did not have malignant disease, although he did have colonic polyps and diabetes. Case History A sixty-seven-year-old man with hypertension (controlled by medical treatment) and diabetes came to the emergency room with fever, abdominal pain, and leukocytosis (21,000 white blood cells/mm3). A physical examination revealed a pulsatile abdominal mass and a large rectal polypoid lesion. No other abnormalities that could have represented an external source of infection and fever were observed. An abdominal computed tomographic From the Departments of Surgery Massachusetts
at
Cardinal
Cushing Hospital, Brockton, Massachusetts, and St. Elizabeth’s Hospital, Boston,
585
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
586
FIG. 1. Abdominal CT scan
showing air, indicative of an anaerobic infection, in an aneurysmal dilatation in the aortic wall.
(CT) scan showed an intrarenal abdominal aortic aneurysm (4.5 cm) with gas surrounding the aneurysmal dilatation and extending proximally to the level of the origin of the left renal artery (Figure 1). The patient was given broad-spectrum antibiotics, and blood samples were obtained for culture; these subsequently grew C. septicum. An arteriogram confirmed the presence of an aortic aneurysm about 5 cm below the origin of the renal arteries and 3 cm above the bifurcation. After five days of intravenous antibiotic therapy and repeatedly negative results on blood cultures, a right axillobifemoral bypass grafting with 8-mm polytetrafluoroethylene was performed. A day later, the infected aneurysm was resected and the aortic stump was oversewn and wrapped with omentum. Biopsy evaluation of a specimen from the aortic wall showed many polymorphonuclear cells of chronic infection; a culture of the tissue was positive for C’. septicum. The mycotic aneurysmal wall was severely atherosclerotic. The postoperative course was initially uncomplicated, with the patient continuing to receive intravenous antibiotics. However, on the ninth postoperative day, the patient began to bleed from the right axillary anastomosis, which appeared to be infected, although cultures were negative. The right axillary artery was ligated, the infected portion was resected, the axillofemoral limb of the graft was removed, and a left axillofemoral bypass graft was placed. Postoperatively, the patient was treated with intravenous antibiotics for six weeks and discharged on a regimen of oral clindamycin and penicillin. His wounds healed well and his extremities remained viable. Two months later, a complete gastrointestinal evaluation showed a 5-cm pedunculated polyp 8 cm from the anal verge; a biopsy demonstrated that it was adenomatous with mild-to-moderate atypia. Colonoscopy revealed two other adenomatous polyps-one at
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
587
splenic flexure and one in the cecum. Both were removed and characterized as exhibiting moderate atypia. No other gastrointestinal or hematologic abnormalities were observed. Nine months postoperatively, the patient was doing well, with normal results on an abdomi-
the
nal CT
scan.
Discussion
Osler first used the term &dquo;mycotic aneurysm&dquo; to describe multiple infectious aneurysms caused by septic emboli from endocarditis.1 The word &dquo;mycotic&dquo; referred to the mushroom shape, as well as to the infection. Today, the definition has been broadened to include aneurysms resulting from a variety of causes, including embolization, trauma, and localized sepsis. In the past, mycotic aneurysms were most likely to have been due to bacterial endocarditis that led to distribution of infected emboli to peripheral arterial bifurcation points. With the advent of intensive intravenous antibiotic therapy, however, there has been an overall increase in abdominal aortic aneurysms and a decrease in peripheral aortic aneurysms. The primary source of infection is unknown in 46070 of infected abdominal aortic aneurysms,9 although 74070 of infected aneurysms occur in vessels with atherosclerotic walls. Normal aortic walls are highly resistant to infection. Once infection develops, the risk of aneurysmal rupture increases greatly and survival of rupture is unlikely. Mycotic aneurysms may result from several mechanisms. In septic embolization, there is disruption of an arterial wall and spread of infection by means of arterial lodging of emboli (usually at branch points) or the arterial vasa vasorum. Arterial trauma (from iatrogenic or patient-performed procedures such as intravenous drug injection) now accounts for 4207010 of mycotic aneurysms. In these aneurysms, a hematoma becomes organized and is secondarily infected. A common mechanism involves intimal defects, as in cases in which an atherosclerotic wall becomes secondarily infected. Mycotic aneurysms can also result from a contiguous septic process such as osteomyelitis or abscess. The type of organism found in an infected mycotic abdominal aortic aneurysm may be related to its pathogenesis. Gram-positive organisms are often found in patients in whom infection has been spread by embolization, a common occurrence in the past. Organisms associated with endocarditis include pneumococci, streptococci, and enterococci. Gramnegative organisms are responsible for an increasing number of infected abdominal aortic aneurysms, with salmonella found in 33-50°70 of mycotic aneurysms. 1,5,7 Our patient had culture-proved C. septicum infection of a mycotic abdominal aortic aneurysm. Two other cases of clostridial infection of an abdominal aortic aneurysm have been reported. Semel et al6 treated a patient with spontaneous clostridial myonecrosis of her right lower extremity. Initial x-ray films showed gas in the mediastinum outlining the aortic arch. After amputation of the limb, the patient was found to have occult colon carcinoma and a mycotic aneurysm of the thoracic aorta. Rupture of the aneurysm resulted in the patient’s death. Although postmortem cultures of the aneurysm were negative, Semel et al felt that it was infected from the colon carcinoma, which they considered responsible for clostridial bacteremia that seeded the right lower extremity. Semel and coworkers
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
588 also mentioned that conditions such as diabetes, vascular disease, and cancer leading to cachexia increase susceptibility to infections with anaerobes such as clostridia. Our patient had diabetes and atherosclerosis but not cancer. Babenco et al&dquo; described an eighty-eight-year-old man with fever, tachycardia, and an area of discoloration in the left thigh. A chest roentgenogram showed a circumscribed collection of gas bubbles in the middle portion of the lower abdomen. Aspiration of the lower-extremity lesion and blood cultures revealed Clostridium paraputrificum. The patient died twelve hours after admission. An autopsy showed a ruptured mycotic aneurysm of the distal abdominal aorta, as well as adenocarcinoma of the ascending colon. Babenco and coworkers assumed that C. paraputrificum entered the blood stream from the colon carcinoma and ultimately created the aneurysm. However, in both this case and the one reported by Semel et al, the possibility that clostridial cellulitis in the lower extremity was the primary source of infection cannot be ruled out. Our patient had, however, no visible gross infection. In addition, he did not have cancer, although he had colonic polyps. It is probable that his mycotic aortic aneurysm developed from C. septicum seeding from the polyps. His diabetes, hypertension, and atherosclerosis made him especially prone to such infections. Moreover, the fact that aortic calcifications appeared on CT scanning indicated that our patient’s abdominal aneurysm was
secondarily infected. Conclusions
Several authors have noted an association between clostridial bacteremias-especially those due to C. septicum-and malignant disease.7,12,13 But our case, which involved a patient with nonmalignant gastrointestinal polyps, suggests that patients with mycotic aneurysms should be evaluated for precancerous lesions. In addition, treatment for a presumed clostridial infection, as well as for an aneurysm, should be considered in patients with known gastrointestinal lesions who present with signs and symptoms of sepsis and abdominal pain, especially if they also have diabetes and atherosclerosis. Conversely, patients found to be infected with C. septicum should be thoroughly examined for gastrointestinal lesions after treatment of their acute infection. Our case also illustrates how a clostridial infection can threaten the viability of a new anastomosis. It is unclear whether this occurs because the native vessel is already infected or because there is additional seeding of the bacteria from the anastomosis. Liam Hurley, M.D. c/o Renee Robillard
Departmen t of Surgery St. Elizabeth’s Hospital 736 Cambridge St. Boston, MA 02135
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
589
References 1. Mendelowitz DS, Ramstedt R, Yao JS, et al: Abdominal aortic salmonellosis. Surgery 85:514-519, 1979. 2. Kaufman SL, White RI Jr, Harrington DP, et al: Protean manifestations of mycotic aneurysms. AJR 131: 1019-1025, 1978. 3. Anderson CB, Butcher HR, Ballinger WF: Mycotic aneurysms. Arch Surg 109:712-716, 1974. 4. Castaneda-Zuniga WR, Nath PH, Zollikofer C, et al: Mycotic aneurysm of the aorta. Cardiovasc Intervent Radiol 3:144-149, 1980. 5. Davies OG Jr, Thorburn JD, Powell P: Cryptic mycotic abdominal aortic aneurysms: Diagnosis and management. Am J Surg 136:96-101, 1978. 6. Semel L, Aikman WO, Parker FB, et al: Nontraumatic clostridial myonecrosis and mycotic aneurysm formation. N Y State J Med 84:195-196, 1984. 7. Kornbluth AA, Danzig JB, Berstein LH: Clostridium septicum infection and associated malignancy : Report of two cases and review of the literature. Medicine (Baltimore) 68:30-37, 1989.
W: Gulstonian lectures on malignant endocarditis. Br Med J 1:467-470, 1885. 9. Bennett DE, Cherry JK: Bacterial infection of aor-
8. Osler
10.
11.
12.
13.
tic aneurysms: A clinicopathologic study. Am J Surg 113:321-326, 1967. Brown SL, Busuttil RW, Baker JD, et al: Bacteriologic and surgical determinants of survival in patients with mycotic aneurysm. J Vasc Surg 1:541-547, 1984. Babenco GO, Joffe N, Tischler AS, et al: Gasforming clostridial mycotic aneurysm of the abdominal aorta. Angiology 27:602-609, 1976. Pelfrey TM, Turk RP, Peoples JB, et al: Surgical aspects of Clostridium septicum septicemia. Arch Surg 119:546-550, 1984. Tanabe KK, Jones WG, Barie PS: Clostridial sepsis and malignant disease. Surg Gynecol Obstet 169:423-428, 1989.
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
BOSTON, MASSACHUSETTS
Abstract The authors describe a sixty-seven-year-old hypertensive, diabetic man with mycotic abdominal aortic aneurysm infected with Clostridium septicum. The patient had colonic polyps but no malignant disease. They could find only one other report of a mycotic aneurysm infected with C. septicum. In that case, as in most other cases of C. septicum bacteremia, the patient had gastrointestinal cancer. Their case suggests that treatment for a clostridial infection should be considered in patients with known gastrointestinal disease, signs and symptoms of sepsis, and abdominal pain. Conversely, patients known to have a C. septicum infection should be evaluated for gastrointestinal lesions. a
Introduction About 2.6070 of abdominal aortic aneurysms are infected.’ Various organisms have been found in mycotic aortic aneurysms, including gram-positive bacteria such as staphylococci and gram-negative organisms such as salmonella.2-5 We describe a patient with a mycotic abdominal aortic aneurysm infected with Clostridium septicum. We have found one other report of such an infection.’ Our patient, however, unlike the one described by Semel et a16 and most patients with C. septicum bacteremia,7 did not have malignant disease, although he did have colonic polyps and diabetes. Case History A sixty-seven-year-old man with hypertension (controlled by medical treatment) and diabetes came to the emergency room with fever, abdominal pain, and leukocytosis (21,000 white blood cells/mm3). A physical examination revealed a pulsatile abdominal mass and a large rectal polypoid lesion. No other abnormalities that could have represented an external source of infection and fever were observed. An abdominal computed tomographic From the Departments of Surgery Massachusetts
at
Cardinal
Cushing Hospital, Brockton, Massachusetts, and St. Elizabeth’s Hospital, Boston,
585
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
586
FIG. 1. Abdominal CT scan
showing air, indicative of an anaerobic infection, in an aneurysmal dilatation in the aortic wall.
(CT) scan showed an intrarenal abdominal aortic aneurysm (4.5 cm) with gas surrounding the aneurysmal dilatation and extending proximally to the level of the origin of the left renal artery (Figure 1). The patient was given broad-spectrum antibiotics, and blood samples were obtained for culture; these subsequently grew C. septicum. An arteriogram confirmed the presence of an aortic aneurysm about 5 cm below the origin of the renal arteries and 3 cm above the bifurcation. After five days of intravenous antibiotic therapy and repeatedly negative results on blood cultures, a right axillobifemoral bypass grafting with 8-mm polytetrafluoroethylene was performed. A day later, the infected aneurysm was resected and the aortic stump was oversewn and wrapped with omentum. Biopsy evaluation of a specimen from the aortic wall showed many polymorphonuclear cells of chronic infection; a culture of the tissue was positive for C’. septicum. The mycotic aneurysmal wall was severely atherosclerotic. The postoperative course was initially uncomplicated, with the patient continuing to receive intravenous antibiotics. However, on the ninth postoperative day, the patient began to bleed from the right axillary anastomosis, which appeared to be infected, although cultures were negative. The right axillary artery was ligated, the infected portion was resected, the axillofemoral limb of the graft was removed, and a left axillofemoral bypass graft was placed. Postoperatively, the patient was treated with intravenous antibiotics for six weeks and discharged on a regimen of oral clindamycin and penicillin. His wounds healed well and his extremities remained viable. Two months later, a complete gastrointestinal evaluation showed a 5-cm pedunculated polyp 8 cm from the anal verge; a biopsy demonstrated that it was adenomatous with mild-to-moderate atypia. Colonoscopy revealed two other adenomatous polyps-one at
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
587
splenic flexure and one in the cecum. Both were removed and characterized as exhibiting moderate atypia. No other gastrointestinal or hematologic abnormalities were observed. Nine months postoperatively, the patient was doing well, with normal results on an abdomi-
the
nal CT
scan.
Discussion
Osler first used the term &dquo;mycotic aneurysm&dquo; to describe multiple infectious aneurysms caused by septic emboli from endocarditis.1 The word &dquo;mycotic&dquo; referred to the mushroom shape, as well as to the infection. Today, the definition has been broadened to include aneurysms resulting from a variety of causes, including embolization, trauma, and localized sepsis. In the past, mycotic aneurysms were most likely to have been due to bacterial endocarditis that led to distribution of infected emboli to peripheral arterial bifurcation points. With the advent of intensive intravenous antibiotic therapy, however, there has been an overall increase in abdominal aortic aneurysms and a decrease in peripheral aortic aneurysms. The primary source of infection is unknown in 46070 of infected abdominal aortic aneurysms,9 although 74070 of infected aneurysms occur in vessels with atherosclerotic walls. Normal aortic walls are highly resistant to infection. Once infection develops, the risk of aneurysmal rupture increases greatly and survival of rupture is unlikely. Mycotic aneurysms may result from several mechanisms. In septic embolization, there is disruption of an arterial wall and spread of infection by means of arterial lodging of emboli (usually at branch points) or the arterial vasa vasorum. Arterial trauma (from iatrogenic or patient-performed procedures such as intravenous drug injection) now accounts for 4207010 of mycotic aneurysms. In these aneurysms, a hematoma becomes organized and is secondarily infected. A common mechanism involves intimal defects, as in cases in which an atherosclerotic wall becomes secondarily infected. Mycotic aneurysms can also result from a contiguous septic process such as osteomyelitis or abscess. The type of organism found in an infected mycotic abdominal aortic aneurysm may be related to its pathogenesis. Gram-positive organisms are often found in patients in whom infection has been spread by embolization, a common occurrence in the past. Organisms associated with endocarditis include pneumococci, streptococci, and enterococci. Gramnegative organisms are responsible for an increasing number of infected abdominal aortic aneurysms, with salmonella found in 33-50°70 of mycotic aneurysms. 1,5,7 Our patient had culture-proved C. septicum infection of a mycotic abdominal aortic aneurysm. Two other cases of clostridial infection of an abdominal aortic aneurysm have been reported. Semel et al6 treated a patient with spontaneous clostridial myonecrosis of her right lower extremity. Initial x-ray films showed gas in the mediastinum outlining the aortic arch. After amputation of the limb, the patient was found to have occult colon carcinoma and a mycotic aneurysm of the thoracic aorta. Rupture of the aneurysm resulted in the patient’s death. Although postmortem cultures of the aneurysm were negative, Semel et al felt that it was infected from the colon carcinoma, which they considered responsible for clostridial bacteremia that seeded the right lower extremity. Semel and coworkers
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
588 also mentioned that conditions such as diabetes, vascular disease, and cancer leading to cachexia increase susceptibility to infections with anaerobes such as clostridia. Our patient had diabetes and atherosclerosis but not cancer. Babenco et al&dquo; described an eighty-eight-year-old man with fever, tachycardia, and an area of discoloration in the left thigh. A chest roentgenogram showed a circumscribed collection of gas bubbles in the middle portion of the lower abdomen. Aspiration of the lower-extremity lesion and blood cultures revealed Clostridium paraputrificum. The patient died twelve hours after admission. An autopsy showed a ruptured mycotic aneurysm of the distal abdominal aorta, as well as adenocarcinoma of the ascending colon. Babenco and coworkers assumed that C. paraputrificum entered the blood stream from the colon carcinoma and ultimately created the aneurysm. However, in both this case and the one reported by Semel et al, the possibility that clostridial cellulitis in the lower extremity was the primary source of infection cannot be ruled out. Our patient had, however, no visible gross infection. In addition, he did not have cancer, although he had colonic polyps. It is probable that his mycotic aortic aneurysm developed from C. septicum seeding from the polyps. His diabetes, hypertension, and atherosclerosis made him especially prone to such infections. Moreover, the fact that aortic calcifications appeared on CT scanning indicated that our patient’s abdominal aneurysm was
secondarily infected. Conclusions
Several authors have noted an association between clostridial bacteremias-especially those due to C. septicum-and malignant disease.7,12,13 But our case, which involved a patient with nonmalignant gastrointestinal polyps, suggests that patients with mycotic aneurysms should be evaluated for precancerous lesions. In addition, treatment for a presumed clostridial infection, as well as for an aneurysm, should be considered in patients with known gastrointestinal lesions who present with signs and symptoms of sepsis and abdominal pain, especially if they also have diabetes and atherosclerosis. Conversely, patients found to be infected with C. septicum should be thoroughly examined for gastrointestinal lesions after treatment of their acute infection. Our case also illustrates how a clostridial infection can threaten the viability of a new anastomosis. It is unclear whether this occurs because the native vessel is already infected or because there is additional seeding of the bacteria from the anastomosis. Liam Hurley, M.D. c/o Renee Robillard
Departmen t of Surgery St. Elizabeth’s Hospital 736 Cambridge St. Boston, MA 02135
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
589
References 1. Mendelowitz DS, Ramstedt R, Yao JS, et al: Abdominal aortic salmonellosis. Surgery 85:514-519, 1979. 2. Kaufman SL, White RI Jr, Harrington DP, et al: Protean manifestations of mycotic aneurysms. AJR 131: 1019-1025, 1978. 3. Anderson CB, Butcher HR, Ballinger WF: Mycotic aneurysms. Arch Surg 109:712-716, 1974. 4. Castaneda-Zuniga WR, Nath PH, Zollikofer C, et al: Mycotic aneurysm of the aorta. Cardiovasc Intervent Radiol 3:144-149, 1980. 5. Davies OG Jr, Thorburn JD, Powell P: Cryptic mycotic abdominal aortic aneurysms: Diagnosis and management. Am J Surg 136:96-101, 1978. 6. Semel L, Aikman WO, Parker FB, et al: Nontraumatic clostridial myonecrosis and mycotic aneurysm formation. N Y State J Med 84:195-196, 1984. 7. Kornbluth AA, Danzig JB, Berstein LH: Clostridium septicum infection and associated malignancy : Report of two cases and review of the literature. Medicine (Baltimore) 68:30-37, 1989.
W: Gulstonian lectures on malignant endocarditis. Br Med J 1:467-470, 1885. 9. Bennett DE, Cherry JK: Bacterial infection of aor-
8. Osler
10.
11.
12.
13.
tic aneurysms: A clinicopathologic study. Am J Surg 113:321-326, 1967. Brown SL, Busuttil RW, Baker JD, et al: Bacteriologic and surgical determinants of survival in patients with mycotic aneurysm. J Vasc Surg 1:541-547, 1984. Babenco GO, Joffe N, Tischler AS, et al: Gasforming clostridial mycotic aneurysm of the abdominal aorta. Angiology 27:602-609, 1976. Pelfrey TM, Turk RP, Peoples JB, et al: Surgical aspects of Clostridium septicum septicemia. Arch Surg 119:546-550, 1984. Tanabe KK, Jones WG, Barie PS: Clostridial sepsis and malignant disease. Surg Gynecol Obstet 169:423-428, 1989.
Downloaded from ang.sagepub.com at CARLETON UNIV on March 16, 2015
