Evolving infectious aortitis caused by Streptococcus pneumoniae.

Abstract: Infections of major vessels leading to mycotic aneurysms can be a diagnostic dilemma for clinicians, and can be accompanied by a high mortality rate. Successful treatment of this condition often requires a high index of suspicion and prompt medical and surgical attention. The authors report two cases of infectious aortitis caused by pneumococcus that evolved during hospitalization, and discuss diagnostic difficulties that accompany this entity.

Key Words: aortitis, pneumococci, Streptococcus pneumoniae

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Infections of major vessels leading to mycotic aneurysm and rupture pose a challenge to clinicians. Once universally fatal, (1) mortality still approaches 90% without early surgical intervention, despite aggressive use of antibiotics. (2) The condition's rarity and nonspecific symptoms hamper early diagnosis and surgical attention.

We report two cases of pneumococcal aortitis that evolved during hospitalization, and discuss the difficulties in diagnosis. Testicular pain, seen in one case, may be an important clue to the diagnosis.

Case Reports

Patient 1

A 69-year-old female with a history of diabetes mellitus presented to the emergency department (ED) with a 1-week history of fever and shoulder and hip pain. She denied trauma, cough, and chest or abdominal pain. A nonsmoker, she worked in a day care center for children.

Temperature was 101.7[degrees]F. The shoulder and hip were tender to motion but there was no swelling or erythema. Otherwise examination was normal. White blood cell (WBC) count was 19,400 cells/[mm.sup.3]. Radiographs of the painful joints were normal. Two grams of cefotaxime delivered intravenously (IV) every 8 hours-was begun. Blood cultures were later reported to be growing Streptococcus pneumoniae. Fever and leukocytosis resolved but on the fifth hospital day she complained of abdominal pain. Examination was unremarkable but leukocytosis recurred. Abdominal ultrasound was normal and the lumen of the aorta was traced to the bifurcation. Her symptoms resolved over the next several days and she was discharged home on ceftriaxone 2 g IV daily to complete a 6-week course.

Three days later she returned to the ED with recurrent abdominal pain following an episode of diarrhea. She was afebrile. The abdomen was soft and mildly distended with hypoactive bowel sounds. WBC was 18,200 cells/[mm.sup.3]. Computed tomography (CT) revealed a 3.7 cm eccentric aortic aneurysm just below the origin of the left renal artery. The aneurysm was resected and a prosthetic graft was placed. Postoperatively she was discharged to continue ceftriaxone for another 28 days. One year later she continued to do well.

Patient 2

A 62-year-old male smoker with a history of multiple myeloma presented to the ED with a 2-day history of fever and nonproductive cough. Temperature was 104[degrees]F. Examination and chest radiograph were normal. WBC was 16,200 cells/[mm.sup.3]. Two grams of cefotaxime IV every 8 hours was begun. Blood cultures later grew S pneumoniae. Testicular pain developed on the fourth hospital day, and abdominal pain developed a day later. Testicular and abdominal examinations were normal. Because of pain and persistent fever despite antibiotics, abdominal CT was performed and revealed calcification of the abdominal aorta. On the 10th day of hospitalization, abdominal examination revealed mild diffuse tenderness.

After a bowel movement the following day, the patient described his pain as being sharper and extending to his back. Abdominal distention was noted and the patient resisted examination. Lumbar spine tenderness was noted. Magnetic resonance imaging of the lumbar spine showed a 4 cm aortic aneurysm. CT performed two days later showed that the aneurysm had increased to 6 cm in diameter (Fig. 1). During this 48-hour interval the patient's pain improved, but fever persisted.

Fourteen days after admission the patient underwent resection of the aortic aneurysm with placement of a prosthetic graft. Fever and leukocytosis resolved postoperatively. He was discharged on ceftriaxone 2 g IV daily for an additional 28 days. Two years after surgery he continued to do well.

Discussion

Infection of the abdominal aorta leading to mycotic aneurysm has been variously classified. Wilson et al (3) described the difference between "infected aneurysm" where an existing aneurysm becomes infected, and "infectious arteritis" where a normal or arteriosclerotic aneurysm becomes infected, leading to formation of a pseudoaneurysm. These aneurysms tend to be saccular and more prone to rupture. (4) Risk factors for infection of the aortic wall include arteriosclerosis, immunosuppression, diabetes, and other chronic illnesses. (5-7)

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Infectious aortitis and mycotic aneurysms are uncommon occurrences. Of 42,993 autopsies from 1902 to 1954, 16 were found to have infections of the aorta. (8,9)

The spectrum of organisms infecting aortae has changed since the advent of antibiotics. In the preantibiotic era, when infectious aortitis usually resulted from bacterial endocarditis, streptococci, staphylococci, and gonococci were most commonly reported. (10) While salmonellae have been frequently implicated causative agents, (11-13) S pneumoniae has been an infrequent cause of infective aortitis in the antibiotic era. (14) Bronze et al (2) described 37 cases reported since 1908. More recently, Brouwer et al (15) reported that 5 of the 14 cases of infective aortitis seen in their institution since 1986 were due to pneumococci. These cases had a mortality rate of 40%, including those treated with surgery as well as antibiotics.

Diagnosis of infectious aortitis before rupture is difficult. Only half of the 18 cases described by Sessa et al (16) had an intact aneurysm at the time of surgery. In many cases the diagnosis was made at autopsy. Only half of the patients had a pulsatile abdominal mass with fever. Frequently the presentation was subacute, with progressive back and abdominal pain and fever occurring over several weeks. In Sessa's series, the average delay until surgery was 15 days (range 4 to 30 d). (16) In our cases, the diagnosis was made 14 and 12 days after admission.

The cases described here offer a glimpse of the dynamic period between infection and aneurysm formation. Both patients had abdominal pain, and efforts were made to diagnose the etiology of the pain. In the first case, no abnormality was shown on ultrasound 7 days after admission, but a 3.7 cm aneurysm was demonstrated by CT 7 days later. CT done 8 days after admission of the second patient was normal, but 4 days later an aneurysm was shown by magnetic resonance imaging.

Testicular pain as a symptom of aortic aneurysm has not been commonly reported. An online search of the medical literature revealed six case reports (17-20) describing testicular pain associated with impending rupture of atherosclerotic abdominal aneurysm, but no case reports of such pain associated with mycotic aneurysm. In our second case, testicular pain was one of the earliest symptoms, and persisted with normal findings until surgery. Testicular pain may be the only symptom, (19) and could represent referred pain from an expanding aneurysm.

Once universally fatal, mortality associated with infectious aortitis still ranges from 14 to 100%. (1,2) Since progression of "infectious arteritis" is faster with development of a false aneurysm and rupture as compared with "infected aneurysm," mortality in the former is likely to be higher. (4)

Conclusion

Early diagnosis is the key to successful management of this uncommon problem. In the cases described above, we have tried to highlight the importance of having a high index of suspicion for this condition, especially in the presence of uncharacteristic pain (eg, testicular pain) and of repeating imaging studies. The course of development, expansion, and rupture of an infectious aneurysm may span a few days, and thus abnormal findings may be absent initially.

Maybe this world is another planet's Hell.
--Aldous Huxley

Accepted April 7, 2004.

References

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2. Bronze MS, Shirwany A, Corbett C, et al. Infectious aortitis: an uncommon manifestation of infection with Streptococcus pneumoniae. Am J Med 1999 Dec;107:627-630.

3. Wilson SE, Van Wagenen P, Passaro Jr E. Arterial Infection. Curr Probl Surg 1978;15:1-89.

4. Zak FG, Strauss L, Saphra I. Rupture of diseased large arteries in the course of enterobacterial (Salmonella) infection. New Engl J Med 1958;258:824-828.

5. Farah I, Giudicelli H, Voirin L, et al. Salmonella aortitis complicated by rupture. Diagnostic and therapeutic problems [in French]. Chirugie. 1993-1994;119:196-199.

6. Ewart JM, Burke ML, Bunt TJ. Spontaneous abdominal aortic infections. Essentials of diagnosis and management. Am Surg 1983;49:37-50.

7. Woods IV JM, Schellack J, Stewart MT, et al. Mycotic abdominal aortic aneurysm induced by immunotherapy with bacilli Calmette-Guerin vaccine for malignancy. J Vasc Surg 1988;7:808-810.

8. Parkhurst GF, Decker JP. Bacterial aortitis and mycotic aneurysm of the aorta: a report of twelve cases. Am J Pathol 1955;31:821-835.

9. Sommerville RL, Allen EV, Edwards JE. Bland and infected arteriosclerotic abdominal aortic aneurysms: a clinicopathologic study. Medicine (Baltimore) 1959;38:207-221.

10. Revell STR. Primary mycotic aneurysms. Ann Intern Med 1945;22:431-440.

11. Bennett DE, Cherry JK. Bacterial infection of aortic aneurysms. A clinicopathologic study. Am J Surg 1967;113:321-326.

12. Mendelowitz DS, Ramstedt R, Yao JS, et al. Abdominal aortic salmonellosis. Surgery 1979;85:514-519.

13. Bardin JA, Collins GM, Devin JB, et al. Nonaneurysmal suppurative aortitis. Arc Surg 1981;116:954-956.

14. Ioannidis JP, Merino F, Drapkin MS, et al. Pneumococcal aortitis in the antibiotic era. Arch Intern Med 1995;155:1678-1680.

15. Brouwer RE, van Bockel JH, van Dissel JT. Streptococcus pneumoniae, an emerging pathogen in mycotic aneurysms? Neth J Med 1998;52:16-21.

16. Sessa C, Farah I, Voirin L, et al. Infected aneurysms of the infrarenal abdominal aorta: diagnostic criteria and therapeutic strategy. Ann Vasc Surg 1997;11:453-463.

17. DeMarco R, Evans JM. An unusual case of testicular pain. Hosp Prac (Off Ed). 1997;32:197, 201.

18. Cawthorn SJ, Giddings AE, Taylor RS, et al. Isolated testicular pain: an unrecognized symptom of the leaking aortic aneurysm. Br J Surg 1991;78:886-887.

19. O'Keefe KP, Skiendzielewski JJ. Abdominal aortic aneurysm rupture presenting as testicular pain. Ann Emerg Med 1989;18:1096-1098.

20. Artman MR, Burkle FM Jr. Acute abdominal aortic aneurysm presenting as isolated testicular pain. Am J Emerg Med 1987;5:45-47.

RELATED ARTICLE: Key Points

* Infectious aortitis is difficult to diagnose clinically, and even when the diagnosis is made has a high mortality rate.

* A variety of microorganisms may cause infectious aortitis.

* Symptoms attributable to evolving infectious aortitis may be seen prior to development of frank aortitis, and testicular pain may be an important clue when making a diagnosis.

Rekha Goswami, MD, Kerry O. Cleveland, MD, and Michael S. Gelfand, MD

From the Division of Infectious Diseases, Department of Medicine, University of Tennessee Health Science Center, Memphis, TN.

Reprint requests to Kerry O. Cleveland, MD, 956 Court Avenue, Room H308, Memphis, TN 38163. Email: [e-mail]