430 K. Yamamoto et al.: Mycotic Aneurysm and MDSSurg TodayJpn J Surg (1998) 28:430–432

Case Report

A 59-year-old man was admitted complaining of lowerback pain and a high fever. He had a past history ofdiabetes mellitus and had thus been treated with oralhypoglycemic agents. He had been diagnosed withmoderate anemia the previous year. On admission,petechiae and ecchymoses were observed on his trunkand extremities. His body temperature was 38.4°C. Ablood examination revealed moderate anemia (redblood cell count, 2.38 3 106/µl; hemoglobin, 8.5 g/dl;hematocrit, 25.4%), leukocytopenia (white blood cellcount, 3.4 3 103/µl), thrombocytopenia (platelet count,4.2 3 104/µl) and an elevated C-reactive protein level of12.6mg/dl. An elevated fibrin degradation product levelof more than 40µg/ml, a D-dimer lever of 31.3 µg/ml,a decreased antithrombin III level of 15.1mg/dl, a pro-thrombin time of 49.3%, as well as hemorrhagicdiathesis led to a diagnosis of disseminated intravascu-lar coagulation (DIC), Staphylococcus aureus was con-firmed as an etiologic microorganism by a blood culture.The computed tomography (CT) scan findings showed aslight thickening of the abdominal aortic wall (Fig. 1).Bone marrow aspiration showed myelodysplasia, 0.4%myeloblasts, and no sideroblasts. These findings werecompatible with a diagnosis of MDS. A chromosomalanalysis revealed an abnormal karyotype: 47, XY, der(7)t (1;7) (q11;q11), 18 / 46, XY, which indicated amosaic karyotype.

Antithrombin III agent, antibiotics (Clindamycin,Doxycycline) and human recombinant granulocyte sti-mulating factor (GCSF) were all effective for treatingthe DIC and sepsis. However, the patient had abdomi-nal pain in the month following admission, and anabdominal pulsating mass was noticed. A CT scan re-vealed a 4-cm AAA, with a localized rupture and amarked thickening of the aortic wall, outside the rim ofaortic calcification (Fig. 2). An emergency surgical ex-ploration was thus performed. The retroperitoneum

Abstract: A 59-year-old man, who manifested lower backpain, was admitted with sepsis and disseminated intravascularcoagulation (DIC). A computed tomographic scan showed aslight thickening of the abdominal aortic wall. A blood exami-nation revealed pancytopenia. Myelodysplastic syndrome wasdiagnosed after bone marrow aspiration and a chromosomeanalysis. Sepsis due to a Staphylococcus aureus infectionand DIC subsided after medical treatment; however, anaortobifemoral bypass was performed upon the detection of alocalized rupture of a mycotic abdominal aortic aneurysm 1month later. The patient is still alive 2 years after operationdespite the presence of a hematological disorder.

Key Words: mycotic aneurysm, myelodysplastic syndrome,abdominal aortic aneurysm, granulocyte colony stimulatingfactor. DIC

Introduction

Surgery for an abdominal aortic aneurysm (AAA) iscommon; however, the incidence of mycotic AAA islow.1,2 The mortality rate for mycotic aneurysms re-mains high because of the high rate of postoperativesepsis.3,4 Myelodysplastic syndrome (MDS) can be cat-egorized as the triad of chronic cytopenia, bone marrowhyperplasia, and dysmyelopoietic abnormalities in oneor more cell lines of bone marrow precursors, and it isan immunocompromised state that may be a stage ofpreleukemia. We herein report a successful surgicalcase of rapidly expanding mycotic AAA resulting fromsepsis and disseminated intravascular coagulation asso-ciated with MDS.

Reprint requests to: K. Yamamoto(Received for publication on Aug. 6, 1996; accepted on May12, 1997)

Mycotic Abdominal Aortic Aneurysm Associated withMyelodysplastic Syndrome (MDS): Report of a Case

Kazuo Yamamoto1, Yukio Maruyama1, Osamu Namura1, Jun-ichi Hayashi2, and Satoru Koyama3

1Department of Cardiovascular Surgery, Niigata Kobari Hospital, 3-27-11 Kobari, Niigata 951, Japan2 Department of Thoracic and Cardiovascular Surgery, Niigata University School of Medicine, 1-754 Asahimachidori, Niigata 951, Japan3 Division of Hematology, Saiseikai Niigata Second Hospital, 280-7 Teraji, Kurosaki Town, Niigata 950-11, Japan

431K. Yamamoto et al.: Mycotic Aneurysm and MDS

a suspected local recurrence of infection. The patient’swhite blood cell count increased to 8–9 3 103/µl and heeventually recovered. Air bubbles surrounding the graftwere found to have disappeared on a subsequentCT scan. He was discharged from the hospital on the36th postoperative day, and is still alive 2 years afteroperation. Serial abdominal CT scans revealed both thegraft and periprosthetic graft tissue to be clear and freefrom infection despite the presence of a hematologicaldisorder.

Discussion

Although mycotic aortic aneurysms constitute only asmall percentage of all aortic aneurysm diseases,1,2 sur-gical treatment is difficult and the mortality rate re-mains high. Brown et al. reported a mortality of 40% in51 patients who underwent surgery for mycotic AAA.3

Fichelle et al. reported 5 deaths in 25 of their ownpatients and 27 deaths in a review of 106 reportedcases.4 Hypovolemic shock in the case of rupture, pain-ful aneurysm, and fever are the chief clinical features ofmycotic AAA. Salmonella species and Staphylococciare the most popular organisms of infectious AAA.3,5

The diagnosis can be confirmed by CT scanning or anultrasound examination besides sepsis or inflammatorysigns. The surgical treatment remains controversial.Extraanatomic bypass such as an axillobifemoral bypassis required for the cases with an extensive infection,6

and is standard in a sense. However, in localized infec-tions, in-situ bypass grafting could be justified becauseof its good long-term patency.4 Pasic et al. reported atotal of five thromboses of the axillofemoral bypasses inthe three patients among six patients with infected

had severely thickened and adhered to the AAA, thussuggesting a mycotic AAA. The amount of infectioustissue was small and was fully removed. Aortobifemoralbypass grafting using Hemashield 18 3 9 mm (MeadoxMedicals, Oakland, NJ, USA) was performed becausethe resection of infected tissue seemed to be complete.Neither of the iliac arteries could be used for distalanastomoses due to arterial occlusive disease. Thepathogen was confirmed to be S. aureus by cultures ofboth the resected AAA wall and periaortic tissue. Thepatient had a high fever with elevated CRP on postop-erative day 18 without leukocytosis (white blood cellcount, 4.6 3 103/µl). A CT scan showed air bubblessurrounding the prosthetic graft (Fig. 3). Although ablood culture revealed no growth, he was treated with adaily dose of 100 µg of GCSF and antibiotic coverage for

Fig. 1. Abdominal computed tomographic (CT) scan on ad-mission shows a slight thickening (T) of the abdominal aorticwall

Fig. 2. A CT scan 1 month after admission shows a 4 cmAAA, with a localized rupture (arrow) and a marked thicken-ing (T) of the aortic wall, outside the rim of aortic calcificationand thick retroperitoneum (R)

Fig. 3. A CT scan shows small air bubbles (B) surrounding theprosthetic aortic graft (G) on postoperative day 18

432 K. Yamamoto et al.: Mycotic Aneurysm and MDS

AAA.7 Another disadvantage of extraanatomic bypassis the fact that the suture line of the aortic stump has arisk of rupturing due to the exposure of high pressure.Coverage of prosthetic graft by a pedicled omental flap4

might be safer for the prevention of recurrence of infec-tion. However, we did not use this technique in ourpatient because a sterilization of the operative fieldseemed to be adequate after the removal of localizedinfected tissue.

In an immunocompromised host, infection or sepsismay occur more frequently than in other persons. Oz etal. reported three surgically treated patients who devel-oped mycotic AAA while receiving steroids.5 One wastreated by an extraanatomic bypass and two by an in-situ bypass. There was one survivor who received in-situgrafting. This case seems to be the first report of asurgically treated mycotic AAA complicated by MDS.Myelodysplastic syndromes are clonal disorders, mostoften occurring in patients exceeding 50 years of age.The disorders are characterized by one or morecytopenias, with anemia typically present. The MDSarises as a consequence of acquired defects in the DNAof one or more chromosomes of a hematopoietic pro-genitor. As seen in this case, chromosomal abnormali-ties are recognized in approximately 50% of all patientswith MDS.8 Some investigators believe the disorders areleukemic from the outset. Refractory anemia (RA) isone of the five MDS subclassifications developed bya cooperative French, American, and British (FAB)group, and it comprises about 25% of all MDS cases.Sanz et al. has reported the prognosis of RA to berelatively good for MDS and the median survival was 37months.9 Pancytopenia, as seen in our patient, is presentat the time of diagnosis in 50% of MDS patients. Theprognosis of MDS depends on the development of leu-kemia or infection. Sanz et al. reported that the evolu-tion to leukemia occurred in 19% of 1783 patients withMDS.9 Among MDS patients who do not develop acuteleukemia, the principal causes of morbidity are bleed-ing, infection, and heart failure.10

Recombinant human GCSF may be effective for in-creasing neutrophil concentrations in MDS patients.11,12

The apparently normal function of neutrophils releasedduring GCSF treatment has not yet been studied thor-

oughly. Fears that GCSF might provoke evolution toacute leukemia have not been realized. Because of thehigh cost and the temporary effect of recombinantGCSF, it is therefore considered to play a small role inthe management of patients with MDS. However, itdoes seem to be very useful for patients with MDSundergoing surgery.

References

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12. Yamagishi T, Fuse K, Saito T, Kato M, Misawa Y, Kamisawa O,Hasegawa N, Kawashima T (1996) Successful coronary arterybypass grafting for a patient with myelodysplastic syndrome:Report of a case. Surg Today 26:740–743