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Right iliac fossa pain: A case report of abdominal aorta mycotic aneurysm in a patient with methicillin-resistant Staphylococcus aureus
European Journal of Radiology Extra 65 (2008) 105–107
Right iliac fossa pain: A case report of abdominal aorta mycotic aneurysm in a patient with methicillin-resistant Staphylococcus aureus Morag E. Hogg a , Struan W.A. Wilkie a,∗ , Lawrence L.M. Li a , Kevin B. Cassar b a b
Division of Surgery, Dr Gray’s Hospital, Main Road, Elgin, Moray IV30 1PX, United Kingdom Vascular Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB25 2ZN, United Kingdom Received 27 November 2007; accepted 18 December 2007
Abstract Mycotic aneurysms are uncommon and the pattern of causative organism appears to have changed with time. This condition is associated with a high mortality rate. Here we present a case of an infrarenal mycotic abdominal aortic aneurysm, where the causative organism was methicillin-resistant Staphylococcus aureus (MRSA). © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Mycotic aneurysm; Aorta; Methicillin-resistant Staphylococcus aureus; Computed tomography
1. Case study A 76-year-old man was admitted with a 2-day history of worsening right iliac fossa and back pain. It was colicky in nature and worsened on movement. It was severe enough to wake him from sleep and associated with loose stool. He denied passing blood or mucus per rectum. Background history included diverticulosis diagnosed on barium enema and a transurethral resection of the prostate for benign prostatic hypertrophy. He had undergone outpatient investigation 4 months previously for rectal bleeding and patchy inflammatory changes were noted in the distal colon on colonoscopy. Biopsies from the rectum demonstrated mild active chronic inflammatory bowel disease. He had also been admitted to a nearby hospital 1 month previously with a flare-up of distal colitis and commenced on colofoam enemas, Asacol MR with a reducing course of oral steroids. A blood culture during that admission had also yielded methicillin-resistant Staphylococcus aureus (MRSA), but due to his clinical state specific treatment was not given for this. On this admission he was pyrexial and haemodynamically stable, with no heart murmur. He was tender in the right lumbar region with blood on urinalysis. Inflammatory markers were elevated with a white cell count of 11.9 × 109 /l and CRP of
∗
Corresponding author. Tel.: +44 7765243070. E-mail address: [email protected] (S.W.A. Wilkie).
1571-4675/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2007.12.004
143 mg/l. A CT scan was performed which demonstrated a calcified plaque within a normal calibre aorta, and a soft tissue mass just proximal to the bifurcation, suggestive of a periaortitis (Fig. 1). Blood cultures taken on admission grew MRSA and he was therefore commenced on intravenous vancomycin. He continued to have severe episodes of abdominal pain, worse during the night and requiring opiate analgesia, associated with a swinging pyrexia. A thorough secondary survey revealed only a tiny blister on the right heel which also grew MRSA. A transthoracic echocardiogram did not reveal any obvious valvular vegetations. A repeat CT scan was performed 3 days later (Fig. 1), demonstrating progression of the inflammatory process, now indistinct from the antero-lateral wall of the abdominal aorta. Advice was sought from the vascular surgeons and the patient was transferred to their unit. There was a significant increase in size of the infrarenal abdominal aortic aneurysm and in view of this it was felt that urgent surgery was required to prevent rupture. The following day he underwent right axillo-bifemoral grafting using a gelatin sealed Dacron graft. This was followed by a laparotomy. There was a large inflammatory mass anterior to the abdominal aorta which contained significant volumes of pus. The aorta itself was aneurysmal just above the bifurcation and the aortic wall itself was extremely friable. Indeed after proximal and distal control was obtained at a level where the arterial wall was relatively normal, the aortic wall in the aneurysmal segment simply fragmented. This was
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M.E. Hogg et al. / European Journal of Radiology Extra 65 (2008) 105–107
Fig. 1. (a) Previous transverse slice showing non-aneurysmal, atherosclerotic aorta. (b) Non-contrast transverse slice, an inflammatory mass surrounding aorta. (c) Contrast-enhanced arterial phase transverse slice showing an ill-defined inflammatory change involving anterior and right lateral wall of aorta but no contrast leak.
excised with oversewing of the aortic stump. He made a gradual recovery, continuing on oral rifampicin and intravenous daptomycin for 2 weeks post-operatively. At the time of discharge, 5 weeks after admission, he completed a 14-day course of linezolid. 2. Discussion An MRSA positive mycotic aneurysm of the infrarenal abdominal aorta has not been previously described in the literature. Previously mentioned cases refer to an MRSA infected aneurysm of the innominate artery [1], a mycotic aneurysm of the infrarenal aorta infected with Clostridium septicum [2] and a suprarenal mycotic aneurysm due to Streptococcus pneumoniae [3,5] and S. aureus [4,6]. The overall trend appears to have been that prior to 1990, the most common infecting organism was Salmonella, though subsequently gram positive infections are more frequently found [6,7]. There is a considerable mortality
related to mycotic aneurysms related to both gram positive and negative infections (25% and 72%, respectively) [3]. 3. Summary In conclusion, we present a rare cause of abdominal pain with an unusual form of mycotic aneurysm. Serial CT scans demonstrated progression of the inflammatory process and enabled timely surgery to be carried out. The source of infection has not been definitely elucidated in this case and we are unable to comment on whether treatment of the bacteraemia during the earlier admission may have prevented the aneurysm formation. With the rising incidence of MRSA bacteraemia, this complication may become a more common occurrence. References [1] Oh S, Won YY, Jin GJ, et al. Spontaneous disruption of mycotic aneurysm involving innominate artery. J Korean Med Sci 2003;18(4):589–91.
M.E. Hogg et al. / European Journal of Radiology Extra 65 (2008) 105–107 [2] Takano H, Taniguchi K, Kuki S, et al. Mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum: a case report of surgical management and review of the literature. J Vasc Surg 2003;38(4):847–51. [3] Lussier N, Girouard Y, Chapleau D. Mycotic aneurysm of the suprarenal aorta due to Streptococcus pneumoniae: case report and literature review. Can J Surg 1999;42(4):302–4. [4] Schrander-vd Meer AM, Guit GL, van Bockel JH, van Dorp WT. Mycotic aneurysm of the suprarenal abdominal aorta. Neth J Med 1994;44(1):23– 5.
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[5] Gelabert HA, Quinones-Baldrich WJ. Mycotic aneurysm of the suprarenal aorta secondary to Streptococcus pneumoniae: an unusual pathogen. Ann Vasc Surg 1991;5(6):529–32. [6] Lee CC, Ng YY, Chou YH, et al. Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia. Clin Infect Dis 2000;30(5):823–4. [7] Cina CS, Arena GO, Fiture AO, Clase CM, Doobay B. Ruptured mycotic thoracoabdominal aortic aneurysms: a report of three cases and a systematic review. J Vasc Surg 2001;33(4):861–7.
Right iliac fossa pain: A case report of abdominal aorta mycotic aneurysm in a patient with methicillin-resistant Staphylococcus aureus Morag E. Hogg a , Struan W.A. Wilkie a,∗ , Lawrence L.M. Li a , Kevin B. Cassar b a b
Division of Surgery, Dr Gray’s Hospital, Main Road, Elgin, Moray IV30 1PX, United Kingdom Vascular Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB25 2ZN, United Kingdom Received 27 November 2007; accepted 18 December 2007
Abstract Mycotic aneurysms are uncommon and the pattern of causative organism appears to have changed with time. This condition is associated with a high mortality rate. Here we present a case of an infrarenal mycotic abdominal aortic aneurysm, where the causative organism was methicillin-resistant Staphylococcus aureus (MRSA). © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Mycotic aneurysm; Aorta; Methicillin-resistant Staphylococcus aureus; Computed tomography
1. Case study A 76-year-old man was admitted with a 2-day history of worsening right iliac fossa and back pain. It was colicky in nature and worsened on movement. It was severe enough to wake him from sleep and associated with loose stool. He denied passing blood or mucus per rectum. Background history included diverticulosis diagnosed on barium enema and a transurethral resection of the prostate for benign prostatic hypertrophy. He had undergone outpatient investigation 4 months previously for rectal bleeding and patchy inflammatory changes were noted in the distal colon on colonoscopy. Biopsies from the rectum demonstrated mild active chronic inflammatory bowel disease. He had also been admitted to a nearby hospital 1 month previously with a flare-up of distal colitis and commenced on colofoam enemas, Asacol MR with a reducing course of oral steroids. A blood culture during that admission had also yielded methicillin-resistant Staphylococcus aureus (MRSA), but due to his clinical state specific treatment was not given for this. On this admission he was pyrexial and haemodynamically stable, with no heart murmur. He was tender in the right lumbar region with blood on urinalysis. Inflammatory markers were elevated with a white cell count of 11.9 × 109 /l and CRP of
∗
Corresponding author. Tel.: +44 7765243070. E-mail address: [email protected] (S.W.A. Wilkie).
1571-4675/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2007.12.004
143 mg/l. A CT scan was performed which demonstrated a calcified plaque within a normal calibre aorta, and a soft tissue mass just proximal to the bifurcation, suggestive of a periaortitis (Fig. 1). Blood cultures taken on admission grew MRSA and he was therefore commenced on intravenous vancomycin. He continued to have severe episodes of abdominal pain, worse during the night and requiring opiate analgesia, associated with a swinging pyrexia. A thorough secondary survey revealed only a tiny blister on the right heel which also grew MRSA. A transthoracic echocardiogram did not reveal any obvious valvular vegetations. A repeat CT scan was performed 3 days later (Fig. 1), demonstrating progression of the inflammatory process, now indistinct from the antero-lateral wall of the abdominal aorta. Advice was sought from the vascular surgeons and the patient was transferred to their unit. There was a significant increase in size of the infrarenal abdominal aortic aneurysm and in view of this it was felt that urgent surgery was required to prevent rupture. The following day he underwent right axillo-bifemoral grafting using a gelatin sealed Dacron graft. This was followed by a laparotomy. There was a large inflammatory mass anterior to the abdominal aorta which contained significant volumes of pus. The aorta itself was aneurysmal just above the bifurcation and the aortic wall itself was extremely friable. Indeed after proximal and distal control was obtained at a level where the arterial wall was relatively normal, the aortic wall in the aneurysmal segment simply fragmented. This was
106
M.E. Hogg et al. / European Journal of Radiology Extra 65 (2008) 105–107
Fig. 1. (a) Previous transverse slice showing non-aneurysmal, atherosclerotic aorta. (b) Non-contrast transverse slice, an inflammatory mass surrounding aorta. (c) Contrast-enhanced arterial phase transverse slice showing an ill-defined inflammatory change involving anterior and right lateral wall of aorta but no contrast leak.
excised with oversewing of the aortic stump. He made a gradual recovery, continuing on oral rifampicin and intravenous daptomycin for 2 weeks post-operatively. At the time of discharge, 5 weeks after admission, he completed a 14-day course of linezolid. 2. Discussion An MRSA positive mycotic aneurysm of the infrarenal abdominal aorta has not been previously described in the literature. Previously mentioned cases refer to an MRSA infected aneurysm of the innominate artery [1], a mycotic aneurysm of the infrarenal aorta infected with Clostridium septicum [2] and a suprarenal mycotic aneurysm due to Streptococcus pneumoniae [3,5] and S. aureus [4,6]. The overall trend appears to have been that prior to 1990, the most common infecting organism was Salmonella, though subsequently gram positive infections are more frequently found [6,7]. There is a considerable mortality
related to mycotic aneurysms related to both gram positive and negative infections (25% and 72%, respectively) [3]. 3. Summary In conclusion, we present a rare cause of abdominal pain with an unusual form of mycotic aneurysm. Serial CT scans demonstrated progression of the inflammatory process and enabled timely surgery to be carried out. The source of infection has not been definitely elucidated in this case and we are unable to comment on whether treatment of the bacteraemia during the earlier admission may have prevented the aneurysm formation. With the rising incidence of MRSA bacteraemia, this complication may become a more common occurrence. References [1] Oh S, Won YY, Jin GJ, et al. Spontaneous disruption of mycotic aneurysm involving innominate artery. J Korean Med Sci 2003;18(4):589–91.
M.E. Hogg et al. / European Journal of Radiology Extra 65 (2008) 105–107 [2] Takano H, Taniguchi K, Kuki S, et al. Mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum: a case report of surgical management and review of the literature. J Vasc Surg 2003;38(4):847–51. [3] Lussier N, Girouard Y, Chapleau D. Mycotic aneurysm of the suprarenal aorta due to Streptococcus pneumoniae: case report and literature review. Can J Surg 1999;42(4):302–4. [4] Schrander-vd Meer AM, Guit GL, van Bockel JH, van Dorp WT. Mycotic aneurysm of the suprarenal abdominal aorta. Neth J Med 1994;44(1):23– 5.
107
[5] Gelabert HA, Quinones-Baldrich WJ. Mycotic aneurysm of the suprarenal aorta secondary to Streptococcus pneumoniae: an unusual pathogen. Ann Vasc Surg 1991;5(6):529–32. [6] Lee CC, Ng YY, Chou YH, et al. Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia. Clin Infect Dis 2000;30(5):823–4. [7] Cina CS, Arena GO, Fiture AO, Clase CM, Doobay B. Ruptured mycotic thoracoabdominal aortic aneurysms: a report of three cases and a systematic review. J Vasc Surg 2001;33(4):861–7.