JRSM >
Volume 96, Number 6 >
Pp. 291-292
University Department of Surgery, Leicester, UK
Correspondence to: Mr Ian M Loftus, Department of Surgery, Clinical Sciences Building, Leicester Royal Infirmary, PO Box 65, Leicester LE2 7LX, UK E-mail: ianloftus{at}aol.com
Mycotic aneurysms of the aorta have a high mortality, even with surgical treatment. We report a case in which the patient's life was probably saved by an accompanying anomaly.
CASE HISTORY
A man of 43 was admitted after three months of central abdominal pain, general malaise, weight loss and anorexia. Nine months previously he had been treated for acute cholecystitis and at the age of 5 he had undergone an aortic coarctation repair. There was a history of alcoholism. On examination he was cachectic, with pyrexia to 40°C and systolic blood pressure consistently over 200 mmHg; a loud systolic heart murmur was heard and he had a periumbilical mass. After blood had been taken for culture, intravenous antibiotics and parenteral nutrition were started. Blood cultures were subsequently reported positive for a coagulase negative staphylococcus.
A CT scan demonstrated what was thought to be either a large infrarenal mycotic aneurysm with contained rupture into the left psoas muscle and direct erosion of the lumbar vertebrae, or primary spinal tuberculosis with secondary abscess formation (Figure 1). A labelled white-cell scan showed no focus of increased uptake around the aorta, and a magnetic resonance scan confirmed gross erosion of two lumbar vertebral bodies with preservation of the disc. Aspiration of the psoas collection yielded bloodstained fluid that proved negative for microbiological cultures including tuberculosis. Angiography was performed to assess whether the aorta might be suitable for endovascular stenting, to prevent massive bleeding should the vessel collapse during surgery. This revealed occlusion of the aorta just distal to the left subclavian artery at the site of the previous coarctation repair (Figure 2). Large intercostal collaterals maintained the lower body and visceral circulation. At exploratory laparotomy two weeks after admission he was found to have a ruptured infrarenal mycotic aneurysm with a thrombosed aorta distally and minimal inflow. This had formed a large retroperitoneal cavity. The aneurysm was opened and the aorta was oversewn immediately below the renal arteries and just below the aneurysm, above the bifurcation. The aorta was completely lacking in posterior wall, with the cavity extending into the left paraspinal space and directly down onto the eroded vertebrae. The cavity was debrided and irrigated. The feet remained pink and viable throughout the procedure and it was decided not to attempt extraanatomic arterial bypass.
|
|
On histological examination the aneurysm wall contained collagenous fibrous tissue with amorphous tissue and thrombus on one aspect. Small clumps of smooth-muscle cells were identified on the deeper aspect, and throughout the tissue there were groups of inflammatory cells and bacteria. Bacteriological culture was negative. The patient was slow to recover but was discharged home seven weeks after surgery. He has only slight claudication, he has gained weight and his renal function is normal.
COMMENT
In the most recent published series of aortic aneurysms 42 of 6137 were mycotic.1 53% of these had ruptured by the time of presentation, but there is often a story, as here, of insidious weight loss, anorexia and fever. Many patients are immunocompromised in some way and about half have had a recent episode of infection (ours had a history of alcoholism and cholecystitis). Staphylococci are the bacteria most commonly isolated. Operative treatment is by resection of the aneurysm, debridement and subsequent reconstruction, either in situ with the concomitant risk of graft infection or by extra-anatomic bypass. In the present case the recurrent coarctation allowed us to avoid reconstruction. The reocclusion must have been longstanding, because large collateral vessels had developed to supply the lower limbs, the kidneys and the gut. Reocclusion rates depend on the age at which the coarctation is repaired and the nature of the repair. Children who are less than eighteen months old when treated have a lower rate of recoarctation than average, as do those who have a resection and end-end anastomosis rather than patch angioplasty.2 Overall the rate of recoarctation is about 5% and the prognosis tends to be poor.3,4 This is the first published case in which recoarctation and aortic occlusion seems to have protected against the consequences of a mycotic ancurysm.
REFERENCES
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
