Orthopedics

The articles prior to January 2012 are part of the back file collection and are not available with a current paid subscription. To access the article, you may purchase it or purchase the complete back file collection here

SALMONELLA VERTEBRAL OSTEOMYELITIS: A COMPLICATION OF SALMONELLA AORTITIS

Robert A Baird, MD; Nolan J Anderson, MD; Jack H Bloch, MD

Abstract

ABSTRACT: Salmonella vertebral osteomyelitis of the lumbar spine is encountered as a complication of Salmonella arteritis. Salmonella organisms, especially those of the choleraesuis and typhimurium species, invade the lamina intima of a diseased or atherosclerotic abdominal aorta, penetrate its wall, and cause the formation of a mycotic aneurysm. Further spread of thé infectious process through the aneurysmal aortic wall leads to infection of the retroperitoneum, psoas abscess formation, and osteomyelitis of the adjacent lumbar vertebrae. A review of the literature reveals a 77% mortality rate. Successful treatment of this association requires resection of the abdominal aneurysm and debridement of the retroperitoneum, extra-anatomic bypass grafting, and appropriate antimicrobial therapy.

Key Indexing Terms: Salmonella Vertebral Osteomyelitis; Salmonella Aortitis; Mycotic Aortic Aneurysm.

Abstract

ABSTRACT: Salmonella vertebral osteomyelitis of the lumbar spine is encountered as a complication of Salmonella arteritis. Salmonella organisms, especially those of the choleraesuis and typhimurium species, invade the lamina intima of a diseased or atherosclerotic abdominal aorta, penetrate its wall, and cause the formation of a mycotic aneurysm. Further spread of thé infectious process through the aneurysmal aortic wall leads to infection of the retroperitoneum, psoas abscess formation, and osteomyelitis of the adjacent lumbar vertebrae. A review of the literature reveals a 77% mortality rate. Successful treatment of this association requires resection of the abdominal aneurysm and debridement of the retroperitoneum, extra-anatomic bypass grafting, and appropriate antimicrobial therapy.

Key Indexing Terms: Salmonella Vertebral Osteomyelitis; Salmonella Aortitis; Mycotic Aortic Aneurysm.

Introduction

Salmonella vertébral osteomyelitis is a little known, but frequent complication of Salmonella aortitis, an infectious arteritis produced by hematogenous seeding of an intimai aortic lesion. Through invasion of the elastic lamina of the arterial wall, the infected lesion weakens the abdominal aorta, causing the formation of a mycotic aneurysm. Aneurysm formation is followed by bacterial involvement of the lamina adventitia and subsequent extension of the infectious process into the retroperitoneal space. This retroperitoneal infection becomes clinically evident by psoas abscess formation and vertebral osteomyelitis. Recently we were involved in the successful treatment of one such case of Salmonella aortitis and lumbar vertebral osteomyelitis. Our experience in this case, as well as a review of the literature, reinforces the view that Salmonella lumbar vertebral osteomyelitis, when associated with Salmonella aortitis, develops by contiguous spread of the Salmonella organism from the infected aortic lesion. Our experience also confirms that of other authors who have found that extra-anatomic bypass grafting, debridement of the retroperitoneum, and appropriate antibotic therapy are necessary for the successful treatment of these cases.

Case Report

A seventy-one year old man presented at the Kern Medical Center in August of 1977 complained of mild back pain. Roentgenograms at that time (Fig.. 1) demonstrated osteoarthritic changes in the lumbosacral spine, and the patient was treated with analgesics and anti-inflammatory medication. Approximately one month later in September, 1977 the patient presented at another institution complaining of the aCute onset of nausea, vomiting and abdominal pain. Pertinent prior history included two previous hospitalizations, one for diverticulitis of the colon, and one for abdominal pain diagnosed as pancreatitis. An exploratory laparotomy performed on his third admission revealed the bowel to be normal. However, examination of the retroperitoneum revealed a leaking abdominal aortic aneurysm with a large retroperitoneal hematoma. The patient was transferred to the Kern Medical Center for definitive care. Upon re-exploration of his abdomen, the presence of the leaking abdominal aortic aneurysm was confirmed, anda 19 mm by 9 cm Dacron bypass graft was inserted. During this procedure, a culture of the retroperitoneal hematoma was obtained which subsequently grewout Salmonella group B. Postoperatively the patient was febrile for five days with temperatures to 38.4° C. He was treated with intravenous Ampicillin for two weeks and then discharged.

We next saw the patient in January, 1978 at which time he complained of severe unremitting back pain. The pain was localized to the midlumbar region and did not radiate into the lower extremities. The severity of the pain precluded walking. Physical examination at that time revealed a temperature of 38.20C. Palpation revealed tenderness and induration about the midlumbar area in the region of the midline. Neurologic examination of the extremities was normal. No peripheral pulses were present in the legs. Laboratory results included a white blood cell count of 10,400 with a significant increase in immature polymorphonuclear leukocytes, and an erythrocyte sedimentation rate of 73 mm per hour. Roentgenographic examination revealed significant disc space destruction and osteomyelitis at the L3-L4 level (Fig. 2). Because of the proximity of the aortic graft to what appeared to be a pyogenic vertebral osteomyelitis, bilateral axillofemoral Gortex grafts were placed, and the Dacron graft was removed from the abdominal aortic position.

Figs. IA. IB: Anteroposterior and lateral roentgenograms of the patient's lower lumbar spine in August. iV77. prior to leakage of his abdominal aneurysm, reveal intact vertebral bodies surrounding a normal U- L4 disc space.

Figs. IA. IB: Anteroposterior and lateral roentgenograms of the patient's lower lumbar spine in August. iV77. prior to leakage of his abdominal aneurysm, reveal intact vertebral bodies surrounding a normal U- L4 disc space.

At the time of this operation, purulent material was found around the aortic graft and extending into the L3-L4 disc space. Cultures of this material subsequently grew out Salmonella group B, as well as £. coii. The patient was treated with intravenous Ampicillin for the Salmonella, and Gentamycin for the E. rali. Gentamycin therapy was discontinued after two weeks because of uremia, and Chloramphenicol was briefly substituted. The patient received a total course of six weeks of intravenous Ampicillin.

At the time of discharge, the pa tient was ambulatory and was gaining weight. Follow-up examination four months after the patient's second operative procedure revealed the patient to be ambulatory, and without back pain. Follow-up roentgenograms at that time revealed progression of collapse at the L3-L4 level, and non-specific changes, possibly representing inflammatory involvement at the L4-L5 level (Fig. 3). Three years post presentation, the patient was fully ambulatory, and denies having back pain. He refused further physical or roentgenographic examination.

Discussion

The genus Salmonella belongs to the family of enterobacteriaceae which includes Shigella, Proteus, and Escherichia. Salmonellae are gram negative, nonspore-forming, non-ìactose fermenting bacilli which, asa rule, are motile by means of a peritrichous flagella. Pathogenic to man, Salmonellae produce infections that can be classified into four clinical syndromes: gastroenteritis; bacteremia with or without extraintestinal localization; typhoid-like patterns (enteric fever), and carrier states. The clinical syndrome of gastroenteritis is the one most commonly seen, and comprises approximately 70% of all Salmonella cases reported. Bacteremia syndromes rarely involve gastrointestinal symptomatology. The organism most often isolated in such cases is Salmonella choleraesuis.

Excluding individuals with sickle cell hemoglobinopathies, Salmonella organisms are among the less common of those organisms causing osteomyelitis. Salmonella bone infections are rare, and occur in approximately 0.85% of cases of typhoid fever and 0.2% of cases of infections secondary to paratyphoid B.1 Salmonella osteomyelitis most commonly involves the long bones with frequent involvement of the proximal humerus, distal femur, tibia, and chondrosternal junction. Multiple bone involvement is seen in approximately 50% of cases." Unusual aspects of Salmonella osteomyelitis are its frequent diaphyseal location, and the often seen marked delay between the clinical syndrome of the initial Salmonella infection and its subsequent clinical manifestation as Osteomyelitis.2,3

Figs. 2 A , 2 B: Anteroposterior and latera) roentgenograms of the pattern's lower lumbar spine in January, 1977 (at which time the patient was readmitted for severe, unremitting hack pain), reveal bony destruction and early collapse of the U- L4 vertebral bodies.

Figs. 2 A , 2 B: Anteroposterior and latera) roentgenograms of the pattern's lower lumbar spine in January, 1977 (at which time the patient was readmitted for severe, unremitting hack pain), reveal bony destruction and early collapse of the U- L4 vertebral bodies.

Figs. JA, 3 Ii: Follou-up roentgenograms four months after axillofemoral bypass grafts and after six weeks of parenteral antibiotic therapy reveal further Li-IA collapse and non-specific changes at the U-U level. The patient has refused further roentgenograms.

Figs. JA, 3 Ii: Follou-up roentgenograms four months after axillofemoral bypass grafts and after six weeks of parenteral antibiotic therapy reveal further Li-IA collapse and non-specific changes at the U-U level. The patient has refused further roentgenograms.

Salmonella arteritis, or aortitis, begins as an infection of the arterial lamina intima- Although the intact lamina intima of elastic arteries is an extremely effective barrier against infection, pathologic lesions of the intima, such as those seen in atherosclerosis, cystic medionecrósis, or syphilitic arteritis significantly reduce this resistance to infection and permit bacterial invasion and infection of the arterial wall.4'5 This bacterial colonization results in the breakdown of the internal elastic lamina of the arterial wall, weakening it and leading to the formation of a mycotic aneurysm. ft The most frequent Salmonella species involved in producing such arterial infections are S. choleraesuis (33.3%) and S. typhimurium (29.2%).7

Salmonella choleraesuis infections are quite atypical of salmonelloses as a whole, and generally present with a bacteremia in which a large proportion of patients have positive blood cultures and negative stool cultures. In contrast to the very low incidence of osteomyelitis secondary to other Salmonella species, osteomyelitis is seen in approximately 20% of S. choleraesuis infections.8-10 The mortality rate of S. choleraesuis infections is also the highest of all Salmonella species, and ranges between 21% and 28%.8,10,11

Table

TABLE 1REVIEW OF THE LITERATURE: SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

TABLE 1

REVIEW OF THE LITERATURE: SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

TABLE 1 (continued)REVIEW OF THE LITERATURE: SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

TABLE 1 (continued)

REVIEW OF THE LITERATURE: SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

There has been some debate concerning the mechanism of the association between Salmonella aortitis and Salmonella lumbar vertebral osteomyelitis. Several authors have postulated that the primary infection is that of lumbar vertebral osteomyelitis, in which case the lumbar vertebral bodies, eroded by a pulsating aneurysm, provide a locus resistentiit minori* to infection. By contiguous spread, the aortic aneurysm then becomes infected. 12_ls However, there are several facts which diminish the credibility of this viewpoint. Statistically, Salmonella aortitis is significantly more prevalent than Salmonella lumbar vertebral osteomyelitis; and greater than 50% of Salmonella aortic lesions present without pre-existent or concurrent lumbar vertebral osteomyelitis.'6 in addition, histological examination of the Salmonella aortic lesions reveals them to be primarily infections of the laonina íntima spreading to the lamina media, rather than infections invading from without the aorta.4'17 One would also expect that, if such aortic infections were to have spread from a primary lumbar vertebralosteomyelitis, cultures from the infected aneurysm would reveal those organisms which more commonly produce vertebral infections in the general population. This is not the case. We therefore agree with Dehlinger, ls and postulate that the primary lesion is one of Salmonella arteritis with subsequent vertebral involvement by contiguous spread of infection (Fig. 4).

Since A'ngris.t arid Mollov first reported this association in 1946,19 13 cases, including ours, have been reported in the medical literature (Table I). Noteworthy in this review are significant differences between the presentation of this association and that of vertebral osteomyelitis secondary to other pyogenic organisms, the high mortality rate experienced with this association, and the therapeutic measures necessary for successful treatment of the .condition. The average age of the patients in this collected series is 67 years, with a range of 54 to 77 years. The advanced age in this group of patients appears to reflect the predisposition of Salmonella to infect atherosclerotic lesions, and is in significant contrast to the 31 year average age of patients with other pyogenic vertebral osteomyelitides.12 The lumbar spine is the site of involvement in all of the cases reviewed here. By contrast, in previously published series reviewing pyogenic vertebral osteomyelitis in the general population, approximately 50% of vertebral lesions are in the lumbar spine.17,20,22

Fig. 4: The mechanism of the association of Salmonella aortitis and vertebral osteinnyeliiis involves spread of the infection through the diseased arterial wall into the retroperitoneal». The psoas rítmeles and lumbar vertebrae then become secondarily infected.

Fig. 4: The mechanism of the association of Salmonella aortitis and vertebral osteinnyeliiis involves spread of the infection through the diseased arterial wall into the retroperitoneal». The psoas rítmeles and lumbar vertebrae then become secondarily infected.

Table

TABLE IISALMONELLA SPECIES ISOLATED IN THIRTEEN CASES OF SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

TABLE II

SALMONELLA SPECIES ISOLATED IN THIRTEEN CASES OF SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

The Salmonella species isolated from cultures either in vivo or at autopsy are summarized (Table II). Of interest is the 31% incidence of S. choleraesuis infections; an incidence greatly higher than the 5% incidence of S. choleraesuis infections as a percentage of all Salmonella infections.'* This 3l% incidence correlates more closely with the 33% incidence of choleraesuis species isolated in 48 collected cases of Salmonella arterial infections. Of those patients in this series in whom Salmonellaeholeraesuis was isolated, no patient presented with gastro-intestinal symptomatology. Seven of the 13 patients in our collected series had psoas abscesses. Eleven of the 13 patients (78%) died; a mortality rate close to the 80% mortality rate seen in Salmonella mycotic aneurysms as a group.7 In this series, and in the series of Salmonella aneurysms with and without vertebral osteomyelitis presented by others,4,7,11,23 extra-anatomic graft bypass of the infected lesion in conjunction with appropriate antibiotic therapy was the only consistantly successful therapeutic modality. Local orthotopic bypassgraf ts, such as aortoiliac and aortobifemoral bypass grafts placed in the infected retroperitoneum, almost invariably broke down in short term follow-up, leading to the demise of the patient. Two patients in this series had associated cholangitis which required cholecystectomy. One of the three survivors in the series that we have collected required surgical debridement of the lumbar lesion as a follow-up procedure before adequate control of the infection ensued.24

Comment

The association of Salmonella vertebral osteomyelitis and Salmonella aortitis should be recognized as a distinct entity. Although of a generally low incidence, the increasing frequency with which aortic aneurysms undergo surgical exploration and grafting, as well as the increasing incidence of Salmonella infection in the general population,1'25 portend an increase in occurrence of this association.

The successful treatment of this association appears to require extra-anatomic bypass grafts, such asaxillofemoral or aorto-femoral grafts distant from the infected retroperitoneal area; resection of the aneurysm and debridement of the retroperitoneum; and appropriate antibiotic therapy using either Ampicillin or Chloramphenical. Cholecystectomy is indicated acutely if the gall bladder is found to be inflamed upon exploration of theabdomen, or electivély ata later date if bile cultures at time of abdominal exploration are positive for Salmonella.7 Debridement of the lumbar lesion appears to be indicated if the patient's condition permits such a procedure. In practice, however, a significant number of these patients undergo their primary surgical procedure at the time the aneurysm has ruptured or is in the process of leaking, at which point extended operating time is unwelcome. Our experience with other osteomyelitides of the spine would suggest that medical therapy alone would beef fectiveincuring the Salmonella vertebral osteomyelitis associated with Salmonella aortitis. However, one patient in our collected series did require surgical debridement of the Iu mbar lesion as a delayed procedure. We would therefore recommend that debridement of the infected vertebral body and disc space be performed if the patient's condition so permits. Bone grafting is not indicated if this procedure is done at the time of the arterial surgery. Autofusion of the infected vertebral bodies may be expected.

The epidemiology, clinical presentation, and histology of this association support the view that the primary lesion is one of Salmonella aortitis. Bacterial invasion of the aortic wall produces a mycotic aneurysm, with ex tension of the infection into the retroperitoneal space, and subsequent psoas abscess formation and lumbar vertebral osteomyelitis. Increased awareness of this association will hopefully permit a reduction in the presently high mortality rate by increasing physicians' recognition of this disease entity, and affording a more rational basis for selection of appropriate therapy.

References

1. Black PH, Kunz LH. Swartz MN. Salmonellosis - a review of some unusual aspects. N Engl I Med I960; 262:811-817.

2. Chandra P; Mohan K, Arya SC et al. Salmonella osteomyelitis. Indian J Ortbop 196?; 1.^0-5:4.

3. Miller CAH, Ridley M. Medd WE. Typhoid osteomyelitis of the spine. Brit Med J 1963; 1:1068-1069.

4. Sower ND, Whelan TJ. Suppurative arteritis due to Salmonella. Surgery Î9.&2; 52:851-859,

5. Stengel A. Wolferrh CC Mycotic (bacterial) aneurysms of intravascular orgin. Arçh lnt Med 1923; 31:527-554.

6. Giaccai L, Idress H. Osteomyelitis due to Salmonella infection. J. Pediatr 1952; 41:73-78.

7. Wilson SE, Gordon HD; Van Wagenen PB. Salmonella arteritis. Arch Surg 1978; 113:1163-1100,

8. Harvéy AM. Salmonella suipestifer infection inhuman beings. Arch lnt Med 1937; 59:118-135

9. Mills KLC. Osteomyelitis of the spine due to Salmonella Muen.chen. ) Bone Joint Surg 1964; 46B:697-&99,

10. Ralston EL. Osteomyelitis of the spine due to Salmonella Choleraesuis. I Bone Joint Surg 1955; 37A:5.80-584.

11. Seligmann E. Saphral, Wassermann M. Salmonella infections in the U.S.A. J Immunol 1946; 54:69-87.

12. Kulowski J. Pyogenic osteomyelitis of the spine. J Bone Joint Surg 1936; 181343-364.

13. Miller AA. Salmonella Dublin osteomyelitis of the.üpine. Brit Med J 1954; 1:194-195.

14. Simon SD, Silver CM. Salmonella osteomyelitis. J Int. Coll Surg 1957; 28:197-205.

15- Wright JT, Raebufn C. Infection oí aortic aneurysm with Salmonellae. Brit Med J 1962; 1:563.

16. Reichte FA, Tyson RR, Sóloff LA, et al. Salmonellosis and aneurysm of the distal abdominal aorta. Ann Surg 1970; 171:219-228.

17. Allison MJ, Da !ton HP, Escobar MR, et al. Salmonella choleraesuis infections in man: a report of 19 cases and a critical literature review. Southern Med J 1969; 62:593-596;

18. Dehlinger K R. Salmonella osteomyelitis of the spine associated with abdoninal aortic aneurysm. N Engl J Medl948; 238:728-732.

19. Angrist A, Mollov M. Bactériologie, clinical arid pathologic experience with 86sporadic cases of salmonella infection. Am J Med Sci 1946; 212:236-346.

20. Griffiths HCD, Jones DM. Pyogenic infection of the spine. J Bone Joint Surg 1971; 538:383-391.

21. Henson AM. Salmonella suipestifer infection in human beings. Arch lnt Med 1937; 59:1 18v 135.

22. Finseth F, Abott WM. One-stage operative therapy for Samonella mycotic abdominal aortic aneurysm. Ann Surg 1974; 179:8-11,

23. Kan war YS, Malho.tra V, Andersen BR, et al. Salmonellosis associated with abdominal aortic aneurysm. N Engl J Med 1948; 238:728-73.2,

24. Hyde RD, Davis PKB. Infection of an aortic aneurysm with' Salmonella choleraesuis. Brit Med J 1962; 1:30-31.

25. Ryder RW, Merson MH, Pollard RA, .et al. Salmonellosis in the United States, 1968-1974. J Infect Dis 1976; 1334):483-486.

26. Talbot JM, Hunt JA. Infection of bone and ioint by Salmonellae. Brit Med J 1957; 2:1095-1096.

27. Zak FG, Strauss L, Saph-ra I. Rupture of diseased large arteries, in the course of enterobacterial (Salmonella) infections. N Engl J Med 1958; 258:824-828.

TABLE 1

REVIEW OF THE LITERATURE: SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

TABLE II

SALMONELLA SPECIES ISOLATED IN THIRTEEN CASES OF SALMONELLA AORTITIS AND VERTEBRAL OSTEOMYELITIS

10.3928/0147-7447-19811001-04

Sign up to receive

Journal E-contents