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Ruptured Infected Popliteal Artery Aneurysm
Ruptured Infected Popliteal Artery Aneurysm Paul Wilson, FRCS, Paul Fulford, MB, ChB, John Abraham, MD, J. Vincent Smyth, FRCS, P. Dominic Dodd, FRCS, and Michael G. Walker, ChM, Manchester, United Kingdom
We describe an unusual presentation of an infected popliteal aneurysm. To our knowledge rupture of an aneurysm associated with Salmonella at this site has not previously been reported. The management of infected aneurysms is discussed. (Ann Vasc Surg 1995;497-499.)
We describe a patient w h o h a d a n u m b e r of classic features of infected a n e u r y s m but at a n u n c o m m o n a n a t o m i c site. To our knowledge, rupture of a poplitea] a n e u r y s m associated w i t h Salmonella microbial arteritis has not been reported previously.
CASE R E P O R T An 88-year-old male Jehovah's Witness was admitted to the hospital as an emergency after he collapsed at home. He complained of pain and swelling in the right leg for the past month with malaise for 1 week and abdominal pain and vomiting for 24 hours for which he had not sought treatment. He was a nonsmoker and had no significant medical history, On examination the patient was pale and had a low-grade fever. His right leg was swollen, warm, and tender with extensive thigh contusions. All pedal pulses were present. Hemoglobin level was 6.8 g/dl and peripheral white cell count was 18.7 x 109/L with predominent neutrophils. Blood cultures were negative. Duplex ultrasonography of the right leg demonstrated a popliteal aneurysm, 5.6 cm in diameter, with surrounding hematoma. There was also extensive popliteal vein thrombosis. The contralateral popliteal artery was of normal caliber. Peripheral arteriography showed a saccular, trilobular popliteal aneurysm (Fig. 1). The superficial femoral and distal popliteal arteries were not diseased.
From the Department of Vascular Surgery, Manchester Royal Infirmary and Medical School, Manchester, England. Reprint requests: Michael G. Walker, Consultant Vascular Surgeon, Department of Vascular Surgery, Manchester Royal Infirmary, Oxford Rd., Manchester M13 9WL.
Fig. 1. Digital subtraction intra-arterial arteriogram showing a large trilobular saccular aneurysm of the right popliteal artery.
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Wilson et al.
Surgical exploration through a median approach confirmed the presence of a large ruptured popliteal aneurysm (Fig2 1). There was pus within the aneurysm wall and sac. Following resection of the aneurysm, repair was performed using an autogenous reversed contralateral saphenous vein interposition graft between the proximal popliteal artery and its bifurcation. Prior to wound closure, the operation site was lavaged with 1 g of tetracycline in saline solution. Intravenous broad spectrum antimicrobial therapy (Primaxim, 500 mg 3 times a day) was instituted immediately pending results of bacteriologic culture, which subsequently showed a heavy growth of Salmonella group D organisms. The patient deteriorated in the early postoperative period and died <24 hours later from cardiac failure related to profound anemia, after having refused a transfusion.
DISCUSSION The epidemiology of infective aneurysms has changed greatly since Osler ~ first coined the term "mycotic" aneurysm in 1885. At that time such aneurysms were invariably secondary to bacterial endocarditis. With the decline in the incidence of rheumatic fever and bacterial endocarditis, together with the advent of antibiotics, such aneurysrns have become a rarity. With increasing numbers of elderly persons in the population and the concurrent increase in atherosclerotic disease, there has been a rise in the incidence of aneurysm formation associated with microbial arteritis, >4 the diseased intima being more susceptible to inoculation from bloodborne bacteria. Nevertheless, primary bacterial infection of an atherosclerotic or apparently healthy arterial wall is still an unusual event. At present most infected aneurysms are posttraumatic in origin and m a n y are the result of intraarterial injection in drug abusers. In addition, with the increasing use of invasive arterial procedures iatrogenic aetiology is a factor. ~'6 Infective aneurysms related to microbial arteritis are most commonly associated with hematogenous inoculation by Salmonella species. 2 Salmonella infections of aortic aneurysms were first reported in 1948. 7 The predilection for involvement by this organism is not understood, but Salmonella organisms tend to "seed" abnormal tissues during bacteremia (e.g., hematomas, malignant tumors, cysts, gallstones, bone infarcts, and altered endothelium [aortic aneurysms]). It has been estimated that 25% of patients over the age of 50 years who have Salmonella bacteremia have an intravascular focus of infection. 8 Salmonella organisms have been cultured from approxi-
Annals of Vascular Surgery
mately 15% of infective aneurysms and may cause damage by three mechanisms. First, a diffuse suppurative arteritis may cause arterial rupture resulting in saccular or false aneurysm. Second, a focal arteritis m ay lead to a weakening of the arterial wall and formation of a true infected aneurysm. Third, Salmonella may affect an existing aneurysm producing an infected aneurysm. 9 Seventy-five percent of Salmonella arterial infections affect the aorta and 50% the abdominal portion. 2 In contrast, staphylococcal organisms are more commonly cultured from posttraumatic aneurysms, accounting for 47% in one study, 2 with the femoral artery being the most commonly affected site. The popliteal artery is an u n c o m m o n site of aneurysm formation related to microbial arteritis. Brown et al. 2 in a review of 122 cases of infective aneurysms reported no instances of infected popliteal aneurysm, the majority affecting the aorta (42%) and the femoral (29%), superior mesenteric (11%), carotid (7%), iliac (6%), and b r a chial (4%) arteries. Vermilion et ai.1~ in reviewing a 20-year experience with 147 popliteal aneurysms reported no cases of infection. Most reported cases of infected popliteal aneurysms have been mycotic in origin and related to bacterial endocarditis, v'~l but as with other infected aneurysms there has been an increase in the incidence of popliteal aneurysms associated with microbial arteritis. 7 Complications of infected aneurysms include thrombosis and embolization in addition to the progressive enlargement and rupture seen in our patient. The incidence of rupture is > 50% as compared to 20% for noninfected aneurysms. ~2 Infected aneurysms are usually smaller t han noninfected aneurysms at the time of rupture and progression to rupture occurs rapidly. Occasionally a slow insidious course with febrile illness lasting weeks to m o n t h s has been demonstrated. ~ After rupture, survival depends on the vessel involved but the mortality rate for infected aortic aneurysms approaches 95%. ~ Aortocaval and aortoenteric fistulas have been reported as a consequence of infected aneurysms, x2"14 Prior to rupture, aortic and peripheral aneurysms m a y shed emboli causing septic arthritis and p u r p u r a ) ~ Successful m a n a g e m e n t of patients with infected aneurysms requires a high index of suspicion, accurate diagnosis, eradication of infection, and maintenance of vital circulation. If an organism is isolated preoperatively, appropriate highclose intravenous antibiotics are mandatory; otherwise broad-spectrum antibiotic coverage for
Vol. 9, No. 5 1995
gram-positive and gram-negative organisms, in particular Salmonella, should be initiated while awaiting a specific bacteriologic diagnosis and determination of sensitivities. As in our patient, it should be expected that an infected aneurysm will progress to rupture necessitating early surgery and this may occur even with extensive antibiotic therapy) 3 Surgical therapy requires excision of all septic tissue and ligation of the aneurysm with or without extra-anatomic reconstruction. The advent of minimally invasive vascular surgical techniques such as endovascular intraluminal stenting of aneurysms would be an effective mode of treatment for a number of small aneurysms including popliteal aneurysms. However, this technique should be used with caution and avoided in suspected cases of infected aneurysm because of the potentially disastrous consequences. REFERENCES 1. Osier RW. The Gulstonian lectures on m a l i g n a n t endocarditis. Br Med J 1885;h467-470. 2. Brown SL, Busutill RW, Baker JD, et al. Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms. J Vasc Surg 1984;1:541-547. 3. Bennett DE, Cherry JK. Bacterial infection of aortic aneurysms. A clinicopathologic study. A m J Surg 1967;113:321326.
Ruptured infected popliteal artery aneurysrn
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4. Jarrett E Darling C, M u n d t h ED, et al. Experience with infected a n e u r y s m s of the abdominal aorta. Arch Surg 1975; 110:1281-1286. 5. Anderson CB, Butcher HR, Ballinger WF. Mycotic aneurysms. Arch Surg 1974;109:712-717. 6. J o h n s o n JR, Lederwood AM, Lucas CE. Mycotic aneurysm. New concepts in therapy. Arch Surg 1983;118:577-582. 7. Reddy DJ, Ernst CB. Infected aneurysms. In Rutherford RB, ed. Vascular Surgery, 3rd ed. Philadelphia: WB Saunders, 1989, pp 983-996. 8. Cohen PS, O'Brien TF, S c h o e n b a u m SC, et al. The risk of endothelial infection in adults w i t h Salmonella bacteremia. A n n Intern Med 1978;89:931-932. 9. Wilson SE, Gordon HE, Van W a g e n e n PB. Salmonella arteritis: A precursor of aortic rupture a n d p s e u d o a n e u r y s m formation. Arch Surg 1978; 113:1163-1166. 10. Vermilion BD, Kkmmins SA, Pace WG, et al. A review of one h u n d r e d forty-seven popliteal a n e u r y s m s with long-term follow-up. Surgery 1981;90:1009-1013. 11. Merry M, D u n n J, W e i s m a n n R, et al. Popliteal mycotic a n e u r y s m presenting as septic arthritis and purpura. JAMA 1972;221:58-59. 12. Hardy JD, Timmis HH. Abdominal aortic aneurysms: Special problems. A n n Surg 1971;173:945-965. 13. Cooke PA, Ehrenfeld WK. Successful m a n a g e m e n t of mycotic aortic aneurysms. Report of a case. Surgery 1974;75:132-136. I4. McIntyre ICE, Malone JM, Richards E, et al. Mycotic aortic p s e u d o a n e u r y s m s with aortoenteric fistula caused by Arizona hinshawii. Surgery 1982;91:173-177.
We describe an unusual presentation of an infected popliteal aneurysm. To our knowledge rupture of an aneurysm associated with Salmonella at this site has not previously been reported. The management of infected aneurysms is discussed. (Ann Vasc Surg 1995;497-499.)
We describe a patient w h o h a d a n u m b e r of classic features of infected a n e u r y s m but at a n u n c o m m o n a n a t o m i c site. To our knowledge, rupture of a poplitea] a n e u r y s m associated w i t h Salmonella microbial arteritis has not been reported previously.
CASE R E P O R T An 88-year-old male Jehovah's Witness was admitted to the hospital as an emergency after he collapsed at home. He complained of pain and swelling in the right leg for the past month with malaise for 1 week and abdominal pain and vomiting for 24 hours for which he had not sought treatment. He was a nonsmoker and had no significant medical history, On examination the patient was pale and had a low-grade fever. His right leg was swollen, warm, and tender with extensive thigh contusions. All pedal pulses were present. Hemoglobin level was 6.8 g/dl and peripheral white cell count was 18.7 x 109/L with predominent neutrophils. Blood cultures were negative. Duplex ultrasonography of the right leg demonstrated a popliteal aneurysm, 5.6 cm in diameter, with surrounding hematoma. There was also extensive popliteal vein thrombosis. The contralateral popliteal artery was of normal caliber. Peripheral arteriography showed a saccular, trilobular popliteal aneurysm (Fig. 1). The superficial femoral and distal popliteal arteries were not diseased.
From the Department of Vascular Surgery, Manchester Royal Infirmary and Medical School, Manchester, England. Reprint requests: Michael G. Walker, Consultant Vascular Surgeon, Department of Vascular Surgery, Manchester Royal Infirmary, Oxford Rd., Manchester M13 9WL.
Fig. 1. Digital subtraction intra-arterial arteriogram showing a large trilobular saccular aneurysm of the right popliteal artery.
497
498
Wilson et al.
Surgical exploration through a median approach confirmed the presence of a large ruptured popliteal aneurysm (Fig2 1). There was pus within the aneurysm wall and sac. Following resection of the aneurysm, repair was performed using an autogenous reversed contralateral saphenous vein interposition graft between the proximal popliteal artery and its bifurcation. Prior to wound closure, the operation site was lavaged with 1 g of tetracycline in saline solution. Intravenous broad spectrum antimicrobial therapy (Primaxim, 500 mg 3 times a day) was instituted immediately pending results of bacteriologic culture, which subsequently showed a heavy growth of Salmonella group D organisms. The patient deteriorated in the early postoperative period and died <24 hours later from cardiac failure related to profound anemia, after having refused a transfusion.
DISCUSSION The epidemiology of infective aneurysms has changed greatly since Osler ~ first coined the term "mycotic" aneurysm in 1885. At that time such aneurysms were invariably secondary to bacterial endocarditis. With the decline in the incidence of rheumatic fever and bacterial endocarditis, together with the advent of antibiotics, such aneurysrns have become a rarity. With increasing numbers of elderly persons in the population and the concurrent increase in atherosclerotic disease, there has been a rise in the incidence of aneurysm formation associated with microbial arteritis, >4 the diseased intima being more susceptible to inoculation from bloodborne bacteria. Nevertheless, primary bacterial infection of an atherosclerotic or apparently healthy arterial wall is still an unusual event. At present most infected aneurysms are posttraumatic in origin and m a n y are the result of intraarterial injection in drug abusers. In addition, with the increasing use of invasive arterial procedures iatrogenic aetiology is a factor. ~'6 Infective aneurysms related to microbial arteritis are most commonly associated with hematogenous inoculation by Salmonella species. 2 Salmonella infections of aortic aneurysms were first reported in 1948. 7 The predilection for involvement by this organism is not understood, but Salmonella organisms tend to "seed" abnormal tissues during bacteremia (e.g., hematomas, malignant tumors, cysts, gallstones, bone infarcts, and altered endothelium [aortic aneurysms]). It has been estimated that 25% of patients over the age of 50 years who have Salmonella bacteremia have an intravascular focus of infection. 8 Salmonella organisms have been cultured from approxi-
Annals of Vascular Surgery
mately 15% of infective aneurysms and may cause damage by three mechanisms. First, a diffuse suppurative arteritis may cause arterial rupture resulting in saccular or false aneurysm. Second, a focal arteritis m ay lead to a weakening of the arterial wall and formation of a true infected aneurysm. Third, Salmonella may affect an existing aneurysm producing an infected aneurysm. 9 Seventy-five percent of Salmonella arterial infections affect the aorta and 50% the abdominal portion. 2 In contrast, staphylococcal organisms are more commonly cultured from posttraumatic aneurysms, accounting for 47% in one study, 2 with the femoral artery being the most commonly affected site. The popliteal artery is an u n c o m m o n site of aneurysm formation related to microbial arteritis. Brown et al. 2 in a review of 122 cases of infective aneurysms reported no instances of infected popliteal aneurysm, the majority affecting the aorta (42%) and the femoral (29%), superior mesenteric (11%), carotid (7%), iliac (6%), and b r a chial (4%) arteries. Vermilion et ai.1~ in reviewing a 20-year experience with 147 popliteal aneurysms reported no cases of infection. Most reported cases of infected popliteal aneurysms have been mycotic in origin and related to bacterial endocarditis, v'~l but as with other infected aneurysms there has been an increase in the incidence of popliteal aneurysms associated with microbial arteritis. 7 Complications of infected aneurysms include thrombosis and embolization in addition to the progressive enlargement and rupture seen in our patient. The incidence of rupture is > 50% as compared to 20% for noninfected aneurysms. ~2 Infected aneurysms are usually smaller t han noninfected aneurysms at the time of rupture and progression to rupture occurs rapidly. Occasionally a slow insidious course with febrile illness lasting weeks to m o n t h s has been demonstrated. ~ After rupture, survival depends on the vessel involved but the mortality rate for infected aortic aneurysms approaches 95%. ~ Aortocaval and aortoenteric fistulas have been reported as a consequence of infected aneurysms, x2"14 Prior to rupture, aortic and peripheral aneurysms m a y shed emboli causing septic arthritis and p u r p u r a ) ~ Successful m a n a g e m e n t of patients with infected aneurysms requires a high index of suspicion, accurate diagnosis, eradication of infection, and maintenance of vital circulation. If an organism is isolated preoperatively, appropriate highclose intravenous antibiotics are mandatory; otherwise broad-spectrum antibiotic coverage for
Vol. 9, No. 5 1995
gram-positive and gram-negative organisms, in particular Salmonella, should be initiated while awaiting a specific bacteriologic diagnosis and determination of sensitivities. As in our patient, it should be expected that an infected aneurysm will progress to rupture necessitating early surgery and this may occur even with extensive antibiotic therapy) 3 Surgical therapy requires excision of all septic tissue and ligation of the aneurysm with or without extra-anatomic reconstruction. The advent of minimally invasive vascular surgical techniques such as endovascular intraluminal stenting of aneurysms would be an effective mode of treatment for a number of small aneurysms including popliteal aneurysms. However, this technique should be used with caution and avoided in suspected cases of infected aneurysm because of the potentially disastrous consequences. REFERENCES 1. Osier RW. The Gulstonian lectures on m a l i g n a n t endocarditis. Br Med J 1885;h467-470. 2. Brown SL, Busutill RW, Baker JD, et al. Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms. J Vasc Surg 1984;1:541-547. 3. Bennett DE, Cherry JK. Bacterial infection of aortic aneurysms. A clinicopathologic study. A m J Surg 1967;113:321326.
Ruptured infected popliteal artery aneurysrn
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4. Jarrett E Darling C, M u n d t h ED, et al. Experience with infected a n e u r y s m s of the abdominal aorta. Arch Surg 1975; 110:1281-1286. 5. Anderson CB, Butcher HR, Ballinger WF. Mycotic aneurysms. Arch Surg 1974;109:712-717. 6. J o h n s o n JR, Lederwood AM, Lucas CE. Mycotic aneurysm. New concepts in therapy. Arch Surg 1983;118:577-582. 7. Reddy DJ, Ernst CB. Infected aneurysms. In Rutherford RB, ed. Vascular Surgery, 3rd ed. Philadelphia: WB Saunders, 1989, pp 983-996. 8. Cohen PS, O'Brien TF, S c h o e n b a u m SC, et al. The risk of endothelial infection in adults w i t h Salmonella bacteremia. A n n Intern Med 1978;89:931-932. 9. Wilson SE, Gordon HE, Van W a g e n e n PB. Salmonella arteritis: A precursor of aortic rupture a n d p s e u d o a n e u r y s m formation. Arch Surg 1978; 113:1163-1166. 10. Vermilion BD, Kkmmins SA, Pace WG, et al. A review of one h u n d r e d forty-seven popliteal a n e u r y s m s with long-term follow-up. Surgery 1981;90:1009-1013. 11. Merry M, D u n n J, W e i s m a n n R, et al. Popliteal mycotic a n e u r y s m presenting as septic arthritis and purpura. JAMA 1972;221:58-59. 12. Hardy JD, Timmis HH. Abdominal aortic aneurysms: Special problems. A n n Surg 1971;173:945-965. 13. Cooke PA, Ehrenfeld WK. Successful m a n a g e m e n t of mycotic aortic aneurysms. Report of a case. Surgery 1974;75:132-136. I4. McIntyre ICE, Malone JM, Richards E, et al. Mycotic aortic p s e u d o a n e u r y s m s with aortoenteric fistula caused by Arizona hinshawii. Surgery 1982;91:173-177.