©1990-91 S. Kargor AG. Basel 1016-2291/90-91/0166-0321 $2.75/0
Pediatr Neurosurg 1990-91:16:321 -325
Salmonella Osteomyelitis with Epidural Abscess A Case Report with Review of Osteomyelitis in Children with Sickle Cell Anem ia1 Anthony M. M a rtinoJeffrey A. Winfieldh “Department of Neurosurgery, Childrens Hospital of Michigan. Detroit, Mich., USA: '’Departments of Neurosurgery and Pediatrics, SUNY Health Science Center at Syracuse. N.Y.. USA
Key W ords. Sickle cell anemia • Osteomyelitis • Epidural abscess • Salmonella • Bone pain • Technetium sulfur bone marrow imaging
Introduction Determining the underlying etiology of bone pain in children can be most challenging. Pathological causes in clude osteomyelitis, bone cysts, osteoblastoma, osteo genic sarcoma and Ewing's sarcoma. In children with sickle cell anemia (SCA), this problem is compounded by the presence of painful bone infarcts as a sequela of vasoocclusive phenomenon of sickle crisis 11]. In particular, the ability to differentiate between the similar clinical pre sentations of osteomyelitis, which occurs at a higher fre quency than in healthy children, and painful vaso-occlusive phenomenon in the sickle cell patient, is crucial in order to promptly begin therapy for osteomyelitis. Children afflicted with SCA have an increased inci dence of infections, including osteomyelitis. Complica tions secondary to sepsis result in death in 30% of these children [2-9], The mechanisms for this increased suscep tibility appear multifactorial and include several proposed immunologic mechanisms; opsonization due to abnorma lities in the serum complement pathway, functional auto 1 Presented in part at the American Association of Neurological Surgeons Pediatric Section Meeting, December 9. 1987, Chicago, III.. USA.
splenectomy with loss of particulate clearing and defec tive neutrophil antibacterial function [3,10], Neurologic complications of SCA occur in 26% of cases and are related to the type of hemoglobin found on serum electrophoresis 111]. In patients with the most se vere variety, hemoglobin SS. the most common neuro logic complications are, in order of frequency. (I) cerebro vascular accidents and resultant hemiplegia; (2) convul sions; (3) disorders of consciousness, and (4) visual disturbances |11|. In the less severe variety of SCA. hemoglobin SC. retinopathy far exceeds the incidence of other neurologic complications [II, 12). The pathophy siology underlying these neurologic sequelae is felt to be secondary to sickling of red blood cells in arterioles, resul ting in occlusion of the vessel. Exchange transfusion is the recommended treatment for acute, severe complications of SCA. We describe the case of a 15-year-old black male with Salmonella vertebral osteomyelitis and epidural abscess, who initially presented with progressive neurologic dete rioration in the lower extremities, to illustrate the need for accurate diagnosis of osteomyelitis in SCA patients. The literature on osteomyelitis in children with SCA is re viewed. and guidelines to the radiographic diagnosis of osteomyelitis in SCA are discussed.
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A bstract. Neurologic complications of sickle cell anemia are most commonly ischemic strokes secondary to sludg ing in cerebral arterioles. We, therefore, report a case of progressive paraparesis in a child with sickle cell anemia which was initially thought to be secondary to a spinal cord ischemic event. Further diagnostics demonstrated that the neuro logic deficits were secondary to salmonella osteomyelitis and an epidural abscess, compressing the upper thoracic spi nal cord at the T6 level. The diagnostic and radiological features which help to distinguish between bone infarct and osteomyelitis, both responsible for bone pain in sickle cell patients, are also presented. In particular, Tc-sulfur colloid bone marrow imaging is the most helpful test for distinguishing between these similarly presenting clinical entities, as early as 48 h after bone pain develops.
Martino/Winficld
322
Table 1.
Study
Silverthorn 1271 Griffiths |231 Bonfiglio 1201 Kemp [241 Ross ¡26] Frederickson [ 131 Collert [211 Digby [221 McHenry [251 Sapico 1151
Year
1986 1971 1973 1973 1976 1978 1976 1979 1975 1979
Location
Patients 20
C
T
L
S
19 5 21 2
42 23 32 13 37 17 69 22 86
5 4 2 4 2 8 8
23 13 23
25
1
-
13 8 -
II
-
II
19 6 39 9 37 2
II
33 7 14 9 36 25 42 5
2
S. epi = Staphyloccus epidermidis: S = streptococci; U = urinary; GU = genitourinary; C = cervical: T = thoracic: L = lumbar: S = sacral.
A 15-year-old black male with known sickle cell disease was ad mitted to the hospital with a 2-day history of right leg weakness. He was diagnosed with SCA at 2 years of age and had remained asymptomatic until he was 13 years old. when he complained of back and leg pain, and was treated for his first sickle crisis with analgesics. Two weeks prior to the current admission, he was diagnosed as having painful aseptic necrosis of the left femoral head, and 48 h prior to admission he noticed sudden weakness of the right leg, without any paresthesia or complaints of numbness in the effected leg. The next day. he became incontinent of urine, but not stool, and was admitted to the pediatric service. A thoracolumbar MR1 was performed from the sacrum to the T8 level, which ruled out a conus medullaris lesion. The presumed etiology of his
symptoms at that time was distal spinal cord infarct, secondary to a sickle crisis. An exchange transfusion was performed. In the ensuing 24 h. he became increasingly paraparetic, with loss of rectal tone, and a neurosurgical consult was obtained. Due to the pro gressive neurological findings and the prior MRI not studying the com plete spinal cord to the level of the foramen magnum, an emergency CT myelogram was performed. (The institution’s MRI scanner was down for maintenance at that time). This study demonstrated a large paraver tebral mass extending from T5 to T8. with epidural compression of the contrast column (fig. 1). An emergency thoracic laminectomy was per formed. At surgery, copious amounts of purulent material were drained from the epidural space, in addition to lancing several small pockets of pus located between the two leaves of the dura. Initial cultures grew out Salmonella enterilidis. which was treated with ampicillin and gentami cin.
Fig. 1. A Scout film from CT myelogram demonstrating large paravertebral mass. B Myelogram with narrowing of the dye column due to epidural compression. Note the flattended vertebra indented by intervertebral discs, illustrating the fish vertebra deformity’ seen in SCA. C CT myelogram scan demon strating posterior epidural mass com pressing thecal sac.
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Case Report
323
Salmonella Osteomyelitis with Epidural Abscess
S. aureus
S. epi
S
enteric
other
35 9 10 5 13 2 18 10 28 5
_
3 1 5 4 2 8 5 3 17 4
II
3
2 2 2
-
-
-
i 2
-
-
1 -
1
-
i 4 1
-
1 -
1 -
1 5
Complication
U
GU
dermal
death
paraplegia other
_
8 6 9 4 15 6 19 10 38 1
3 3 4 3 4 4 3 2
4 3 1
_
1 8 1 3 2 8 3 -
Rapid neurologic improvement occurred over the first 3 postopera tive days, including return of sphincter functions. Despite being on cullure-apropriate antibiotics, the patient began spiking temperatures during the 3rd week of his intravenous antibiotic course. Repeat en hanced thoracic CT revealed reaccumulation of a lateral and anterior paravertebral soft tissue mass. Because of the new CT findings and the persistent spiking temperatures, it was felt that a possible loculatcd paravertebral abscess had formed, necessitating surgical drainage. Twenty-three days after the first decompressive laminectomy, the pa tient underwent a T7-T8 left costotransversectomy with extrapleural debridement of the necrotic portions of the T7 and T8 vertebral bodies. No frank pus was discovered, and only the soft necrotic paravertebral tissue and bone were removed. Intraoperative cultures from the second procedure grew out Serralia marcescens. The patient quickly defervesccd on appropriate antibiotic regimen although, in retrospect, it is uncertain whether the fever 'broke' secondary to removal of a sterile abscess, or whether the Serratia represented a secondary infection or laboratory contaminant. Because of our concerns for spinal stability, the patient was man aged with a thoracic external orthotic device which was custom fitted. During the 6-week antibiotic course, the patient continued to improve neurologic-ally and was discharged with 4+/5 strength in the right leg and 5/5 strength in the left leg. Subsequent thoracic films showed sig nificant thoracic kyphosis at the T7 and T8 level, and the patient. I year later, was readmitted to the pediatric orthopedic spine service for posterior stabilization. Currently, at 3-year follow-up. the patient remains neurologically intact, with normal sphincter function and a stable spinal curvature.
Discussion The importance of differentiating between painful vaso-occlusive phenomenon and osteomyelitis in children with SCA is crucial, as evidenced by this case presenta
-
6 2 8 -
5 -
3 6 6 8 3 4 1 7 -
20 4 5 -
3 -
8 -
tion. Osteomyelitis in children usually affects the long bones and rarely involves the vertebrae [2. 4, 5, 9], Verte bral osteomyelitis is primarily a disease of adults, as op posed to disc space infections in children (13-17]. Coven try et al. [18] have shown that until the age of 20 there are vascular channels which penetrate the vertebral end-pla tes, providing a preferential pathway for blood-borne organisms to reach the intervertebral disc space [18]. The vertebral bodies in children are, therefore, secondarily ef fected. In adults, this capillary system does not exist, and organisms lodge themselves along the vertebral trabecu lae. Vertebral osteomyelitis in children with sickle cells may be similar to the situation in adults; infection occurs within the medullary cavity of the vertebral body. We pro pose that this is secondary to multiple vaso-occlusive phe nomenon, which occlude the vascular channels to the disc space and cortical layers in SCA, thus infection occurs preferentially within the medullary cavity, where vascular channels to bone still remain. Historically, greater than 50% of vertebral osteomyeli tis, for all age groups, was secondary to tuberculosis. The advent of adequate anti-tuberculous therapy has dramati cally reduced the incidence of tuberculous vertebral osteomyelitis, and, currently, pyogenic vertebral osteo myelitis predominates 115, 17. 19]. Exclusive of children with SCA, vertebral osteomyelitis is a disease of adults which occurs most frequently in the 6th and 7th decades (table 1) [20-271. Presenting signs and symptoms of patients with pyo genic vertebral osteomyelitis are characterized by locali zed pain and nonspecific complaints, such as fever.
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Predisposing infection
Organism
Martino/Wmfield
324
8- 10]. Roentgenologic evaluation of children with SCA pre senting with severe localized bone pain plays an important role in the diagnosis of the underlying pathology. Con ventional radiographs are the initial diagnostic steps, however, they frequently do not show changes secondary to osteomyelitis until 2-8 weeks into the course of the disease. When present, these changes include (1) soft tis sue swelling; (2) piecemeal destruction of bone, and (3) narrowing of the intervertebral disc space [5, 17]. Charac teristic plain radiographic changes also occur in SCA and are thought to be secondary to hypercellular bone marrow with reduced fat content. These changes include increased translucency and increased visibility of trabecular mark ings in bone. The bodies of vertebrae are flattened and idented by the intervertebral discs, the so-called ‘fish ver tebra deformity’ [5] (fig.lB). Nuclear medicine studies can provide earlier evidence of osteomyelitis and include two separate modalities to image bone: standard bone (WmTc methylene diphosphate, MDP) and bone marrow imaging (Tc-sulfur colloid). Standard bone scanning with 99mTC MDP shows a three
stage response with osteomyelitis: (1) absence of uptake which can be mistaken for a bone infarct; (2) normal uptake of 99mTC 1 week later, and (3) increased activity in the region of the periosteal reaction 2-4 weeks following the initial infection [28, 29|. Therefore, with MDP bone scanning, failure to image osteomyelitis early in its course can occur for up to 2 weeks following onset of symptoms. Bone marrow imaging techniques using Tc-sulfur colloid can visualize areas of osteomyelitis at an earlier stage of the disease. Whereas areas of bone infarct in SCA will be visualized by their lack of uptake of Tc-sulfur colloid, and a focus of osteomyelitis may image as a decreased area of activity within the first 48 h after onset of symptoms, thereafter a bone marrow image characteristically shows an area of intense focal uptake representing periosteal new bone formation in a focus of osteomyelitis [30]. Tc-sulfur colloid bone marrow imaging can, therefore, detect osteomyelitis as early as 48 h following the onset of bone pain. In summary, we wish to emphasize several points. Children with SCA have a 200 times increased incidence of osteomyelitis. One should always have a high index of suspicion for osteomyelitis in a patient with SCA, particu larly if presenting with an isolated area of bone pain. Because of the similarities in clinical presentation of osteomyelitis and vaso-occlusive bone infarcts of SCA, appropriate radiologic studies are necessary to facilitate the correct and early diagnosis. In particular, nuclear medicine studies using Tc-sulfur colloid bone marrow imaging can distinguish between osteomyelitis and bone infarct after the first 48 h. Newer modalities, such as MRI, may prove helpful in the future. This case also illustrates a crucial diagnostic point. In patients presenting with spinal cord dysfunction, it is imperative that the entire spinal cord is adequately imaged to the level of the foramen magnum. In our review of the available clinical literature on neurological complications of SCA, only 1 case of cord infarct was reported [31]. Therefore, it can be concluded that a vascular infarct of the spinal cord in SCA is an extremely rare complication and should not be considered as the underlying etiology in SCA patients presenting with signs of spinal cord dys function.
References 1 Keeley K, Buchannan GR: Acute infarction of long bones in chil dren with sickle cell anemia. J Pediatr 1982;101:217-127. 2 Adeyokunnu A, Hendricks RG: Salmonella osteomyelitis in child hood. Arch Dis Child 1980;55:175-184.
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malaise and weight loss. More than 90% of patients have localized pain over the affected area, and greater than 50% have temperatures of at least 100 °F. Between 50-90% of organisms isolated in reported cases were Staphylococcus aureus (table 1). The remainder were predominantly en terococci. An unequivocal primary source of hematoge nous dissemination preceded the onset of osteomyelitis in more than 40% of cases reviewed. The genitourinary tract, skin and respiratory system, respectively, were most often involved. The vertebra are affected in only 2.4% of cases of osteomyelitis [14-17], Extension of disease may pro gress in the rostrocaudal direction involving other verte bral bodies. It may also extend anteroposteriorly forming paraspinal and epidural abscesses. Cord compression secondary to epidural abscess was noted in 18% of cases reported, with a range from 4-40%. Salmonella appears to be a unique organism causing osteomyelitis almost exclusively in patients with SCA. In all cases of osteomyelitis in SCA, 74% are culture-proven salmonella [17]. One hundred and twenty-three cases of salmonella osteomyelitis have been reported in the litera ture. The clinical signs can be virtually indistinguishable from those of vaso-occlusive crisis, infarction of bone with resultant pain and tenderness over the affected bone. Salmonella osteomyelitis predominantly affects long bones at multiple sites. Only 11 cases of salmonella verte bral osteomyelitis have been described in the literature, and all of these cases were seen in patients with SCA [2,
Salmonella Osteomyelitis with Epidural Abscess
20 Bonfiglio M. Lang TA. Kim YM: Pyogenic vertebral osteomyelitis: Disc space infections. Clin Orthop 1973;96:234-247. 21 Collert S: Osteomyelitis of the spine. Clin Orthop 1976;48: 283-290. 22 Digby JM, Kersley JB: Pyogenic non-tuberculous spinal infection: An analysis of thirty cases. J Bone Joint Surg [Br] 1979:61:47—55. 23 Griffiths HED, Jones DD: Pyogenic infections of the spine: A review of twenty-eight cases. J Bone Joint Surg [Br] 1971:53: 383-391. 24 Kemp HBS, Jackson JW. Jeremia JD. et al: Pyogenic infections occuring primarily in intervertebral discs. J Bone Joint Surg [Br] 1973;55:698-714. 25 McHenry CM. Alfidi RJ. Wilde AH. et al: Hematogenous osteo myelitis: A changing disease. Cleve Clin Q 1975;42:125-153. 26 Ross PM, Fleming JL: Vertebral body osteomyelitis: Spectrum and natural history, a retrospective analysis of thirty-seven cases. Clin Orthop 1976;118:190-198. 27 Silverthom KG. Gillespie WJ: Pyogenic spinal osteomyelitis: A review of sixty-one cases. N Z Med J 1986;99:62-65. 28 Adatepe MH. Powel OM, Isaacs GH. Nichols K. Cefola R: Hema togenous pyogenic vertebra] osteomyelitis: Diagnostic value of radionucleotide bone imaging. J Nucl Med 1986;27:1680-1685. 29 Koren A, Garty I, Katzuni E: Bone infarction in children with sickle-cell disease: Early diagnosis and differentiation from osteomyelitis. EurJ Pediatr 1984; 142:93-97. 30 Lutzker LG, Alavi A: Bone and marrow imaging in sickle-cell disease: Diagnosis of infarction. Semin Nucl Med 1976;6:83-93. 31 Wolman L, Hardy AG: Spinal cord infarction associated with the sickle-cell trait. Paraplegia 1970;7:282-291.
Anthony M. Martino. MD Department of Neurosurgery 3901 Beaubien Avenue Detroit. MI 48201 (USA)
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3 Barrett-Connor E: Bacterial infection and sickle cell anemia. Medi cine 1971:50:97-112. 4 Dicli VQ, Nelson JD. Haltalin KC: Osteomyelitis in infants and children. Am J Dis Child 1975; 129:1273-1278. 5 Diggs LW: Bone and joint lesions in sickle-cell disease. Clin Orthop 1967;52:119-143. 6 Engh CA, Hughes JL, Abrams RC, et al: Osteomyelitis in the patient with sickle-cell disease. J Bone Joint Surg [Am] 1971:52:1-15. 7 Hook EW, Campbell CG, Weens HS, et al: Salmonella osteomyeli tis in patients with sickle-cell anemia. N Engl J Med 1957; 257:403^107. 8 Le CT: Salmonella vertebral osteomyelitis. Am J Dis Child 1982; 136:722-724. 9 Ortiz-Neu C, Marr JSS, Chérubin CE, et al: Bone and joint infec tions due to salmonella. J Infect Dis 1978:138:820-828. 10 Gardner RV: Salmonella vertebral osteomyelitis and epidural ab scess in a child with sickle-cell anemia. Pediatr Emerg Care 1985:1:87-89. 11 Portnoy BA. Herion JC: Neurological manifestations in sickle-cell disease. Ann Intern Med 1972;76:643-652. 12 Fabian RH. Peters BH: Neurological complication of hemoglobin SC disease. Arch Neurol 1984;41:289-292. 13 Ercdcrickson B. Yuan II, Olans R: Management and outcome of vertebral osteomyelitis. Clin Orthop 1978;131:160-167. 14 Sapico FL. Montgomerie JG: Pyogenic vertebral osteomyelitis. Rev Infect Dis 1979;1:754-775. 15 Staufer RN: Pyogenic vertebral osteomyelitis. Orthop Clin North Am 1975;6:1015-1027. 16 Henesey OJ, Coad N, Carty HM, et al: Juvenile discitis. Arc Dis Child 1983;58:983-987. 17 Waldvogel FA. Vasey H: Osteomyelitis: The past decade. N Engl J Med 1980;303:360-370. 18 Coventry MB, Ghormley RK. Kernohan JW: The intervertebral disc: Its microscopic anatomy and pathology. Its anatomy, develop ment and physiology. J Bone Joint Surg [Am] 1955:27:105. 19 Abramovitz JN, Batson RA. Yablon JS: Vertebral osteomyelitis: The surgical management of neurological complications. Spine 1986;11:418-420.
325
Pediatr Neurosurg 1990-91:16:321 -325
Salmonella Osteomyelitis with Epidural Abscess A Case Report with Review of Osteomyelitis in Children with Sickle Cell Anem ia1 Anthony M. M a rtinoJeffrey A. Winfieldh “Department of Neurosurgery, Childrens Hospital of Michigan. Detroit, Mich., USA: '’Departments of Neurosurgery and Pediatrics, SUNY Health Science Center at Syracuse. N.Y.. USA
Key W ords. Sickle cell anemia • Osteomyelitis • Epidural abscess • Salmonella • Bone pain • Technetium sulfur bone marrow imaging
Introduction Determining the underlying etiology of bone pain in children can be most challenging. Pathological causes in clude osteomyelitis, bone cysts, osteoblastoma, osteo genic sarcoma and Ewing's sarcoma. In children with sickle cell anemia (SCA), this problem is compounded by the presence of painful bone infarcts as a sequela of vasoocclusive phenomenon of sickle crisis 11]. In particular, the ability to differentiate between the similar clinical pre sentations of osteomyelitis, which occurs at a higher fre quency than in healthy children, and painful vaso-occlusive phenomenon in the sickle cell patient, is crucial in order to promptly begin therapy for osteomyelitis. Children afflicted with SCA have an increased inci dence of infections, including osteomyelitis. Complica tions secondary to sepsis result in death in 30% of these children [2-9], The mechanisms for this increased suscep tibility appear multifactorial and include several proposed immunologic mechanisms; opsonization due to abnorma lities in the serum complement pathway, functional auto 1 Presented in part at the American Association of Neurological Surgeons Pediatric Section Meeting, December 9. 1987, Chicago, III.. USA.
splenectomy with loss of particulate clearing and defec tive neutrophil antibacterial function [3,10], Neurologic complications of SCA occur in 26% of cases and are related to the type of hemoglobin found on serum electrophoresis 111]. In patients with the most se vere variety, hemoglobin SS. the most common neuro logic complications are, in order of frequency. (I) cerebro vascular accidents and resultant hemiplegia; (2) convul sions; (3) disorders of consciousness, and (4) visual disturbances |11|. In the less severe variety of SCA. hemoglobin SC. retinopathy far exceeds the incidence of other neurologic complications [II, 12). The pathophy siology underlying these neurologic sequelae is felt to be secondary to sickling of red blood cells in arterioles, resul ting in occlusion of the vessel. Exchange transfusion is the recommended treatment for acute, severe complications of SCA. We describe the case of a 15-year-old black male with Salmonella vertebral osteomyelitis and epidural abscess, who initially presented with progressive neurologic dete rioration in the lower extremities, to illustrate the need for accurate diagnosis of osteomyelitis in SCA patients. The literature on osteomyelitis in children with SCA is re viewed. and guidelines to the radiographic diagnosis of osteomyelitis in SCA are discussed.
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A bstract. Neurologic complications of sickle cell anemia are most commonly ischemic strokes secondary to sludg ing in cerebral arterioles. We, therefore, report a case of progressive paraparesis in a child with sickle cell anemia which was initially thought to be secondary to a spinal cord ischemic event. Further diagnostics demonstrated that the neuro logic deficits were secondary to salmonella osteomyelitis and an epidural abscess, compressing the upper thoracic spi nal cord at the T6 level. The diagnostic and radiological features which help to distinguish between bone infarct and osteomyelitis, both responsible for bone pain in sickle cell patients, are also presented. In particular, Tc-sulfur colloid bone marrow imaging is the most helpful test for distinguishing between these similarly presenting clinical entities, as early as 48 h after bone pain develops.
Martino/Winficld
322
Table 1.
Study
Silverthorn 1271 Griffiths |231 Bonfiglio 1201 Kemp [241 Ross ¡26] Frederickson [ 131 Collert [211 Digby [221 McHenry [251 Sapico 1151
Year
1986 1971 1973 1973 1976 1978 1976 1979 1975 1979
Location
Patients 20
C
T
L
S
19 5 21 2
42 23 32 13 37 17 69 22 86
5 4 2 4 2 8 8
23 13 23
25
1
-
13 8 -
II
-
II
19 6 39 9 37 2
II
33 7 14 9 36 25 42 5
2
S. epi = Staphyloccus epidermidis: S = streptococci; U = urinary; GU = genitourinary; C = cervical: T = thoracic: L = lumbar: S = sacral.
A 15-year-old black male with known sickle cell disease was ad mitted to the hospital with a 2-day history of right leg weakness. He was diagnosed with SCA at 2 years of age and had remained asymptomatic until he was 13 years old. when he complained of back and leg pain, and was treated for his first sickle crisis with analgesics. Two weeks prior to the current admission, he was diagnosed as having painful aseptic necrosis of the left femoral head, and 48 h prior to admission he noticed sudden weakness of the right leg, without any paresthesia or complaints of numbness in the effected leg. The next day. he became incontinent of urine, but not stool, and was admitted to the pediatric service. A thoracolumbar MR1 was performed from the sacrum to the T8 level, which ruled out a conus medullaris lesion. The presumed etiology of his
symptoms at that time was distal spinal cord infarct, secondary to a sickle crisis. An exchange transfusion was performed. In the ensuing 24 h. he became increasingly paraparetic, with loss of rectal tone, and a neurosurgical consult was obtained. Due to the pro gressive neurological findings and the prior MRI not studying the com plete spinal cord to the level of the foramen magnum, an emergency CT myelogram was performed. (The institution’s MRI scanner was down for maintenance at that time). This study demonstrated a large paraver tebral mass extending from T5 to T8. with epidural compression of the contrast column (fig. 1). An emergency thoracic laminectomy was per formed. At surgery, copious amounts of purulent material were drained from the epidural space, in addition to lancing several small pockets of pus located between the two leaves of the dura. Initial cultures grew out Salmonella enterilidis. which was treated with ampicillin and gentami cin.
Fig. 1. A Scout film from CT myelogram demonstrating large paravertebral mass. B Myelogram with narrowing of the dye column due to epidural compression. Note the flattended vertebra indented by intervertebral discs, illustrating the fish vertebra deformity’ seen in SCA. C CT myelogram scan demon strating posterior epidural mass com pressing thecal sac.
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Case Report
323
Salmonella Osteomyelitis with Epidural Abscess
S. aureus
S. epi
S
enteric
other
35 9 10 5 13 2 18 10 28 5
_
3 1 5 4 2 8 5 3 17 4
II
3
2 2 2
-
-
-
i 2
-
-
1 -
1
-
i 4 1
-
1 -
1 -
1 5
Complication
U
GU
dermal
death
paraplegia other
_
8 6 9 4 15 6 19 10 38 1
3 3 4 3 4 4 3 2
4 3 1
_
1 8 1 3 2 8 3 -
Rapid neurologic improvement occurred over the first 3 postopera tive days, including return of sphincter functions. Despite being on cullure-apropriate antibiotics, the patient began spiking temperatures during the 3rd week of his intravenous antibiotic course. Repeat en hanced thoracic CT revealed reaccumulation of a lateral and anterior paravertebral soft tissue mass. Because of the new CT findings and the persistent spiking temperatures, it was felt that a possible loculatcd paravertebral abscess had formed, necessitating surgical drainage. Twenty-three days after the first decompressive laminectomy, the pa tient underwent a T7-T8 left costotransversectomy with extrapleural debridement of the necrotic portions of the T7 and T8 vertebral bodies. No frank pus was discovered, and only the soft necrotic paravertebral tissue and bone were removed. Intraoperative cultures from the second procedure grew out Serralia marcescens. The patient quickly defervesccd on appropriate antibiotic regimen although, in retrospect, it is uncertain whether the fever 'broke' secondary to removal of a sterile abscess, or whether the Serratia represented a secondary infection or laboratory contaminant. Because of our concerns for spinal stability, the patient was man aged with a thoracic external orthotic device which was custom fitted. During the 6-week antibiotic course, the patient continued to improve neurologic-ally and was discharged with 4+/5 strength in the right leg and 5/5 strength in the left leg. Subsequent thoracic films showed sig nificant thoracic kyphosis at the T7 and T8 level, and the patient. I year later, was readmitted to the pediatric orthopedic spine service for posterior stabilization. Currently, at 3-year follow-up. the patient remains neurologically intact, with normal sphincter function and a stable spinal curvature.
Discussion The importance of differentiating between painful vaso-occlusive phenomenon and osteomyelitis in children with SCA is crucial, as evidenced by this case presenta
-
6 2 8 -
5 -
3 6 6 8 3 4 1 7 -
20 4 5 -
3 -
8 -
tion. Osteomyelitis in children usually affects the long bones and rarely involves the vertebrae [2. 4, 5, 9], Verte bral osteomyelitis is primarily a disease of adults, as op posed to disc space infections in children (13-17]. Coven try et al. [18] have shown that until the age of 20 there are vascular channels which penetrate the vertebral end-pla tes, providing a preferential pathway for blood-borne organisms to reach the intervertebral disc space [18]. The vertebral bodies in children are, therefore, secondarily ef fected. In adults, this capillary system does not exist, and organisms lodge themselves along the vertebral trabecu lae. Vertebral osteomyelitis in children with sickle cells may be similar to the situation in adults; infection occurs within the medullary cavity of the vertebral body. We pro pose that this is secondary to multiple vaso-occlusive phe nomenon, which occlude the vascular channels to the disc space and cortical layers in SCA, thus infection occurs preferentially within the medullary cavity, where vascular channels to bone still remain. Historically, greater than 50% of vertebral osteomyeli tis, for all age groups, was secondary to tuberculosis. The advent of adequate anti-tuberculous therapy has dramati cally reduced the incidence of tuberculous vertebral osteomyelitis, and, currently, pyogenic vertebral osteo myelitis predominates 115, 17. 19]. Exclusive of children with SCA, vertebral osteomyelitis is a disease of adults which occurs most frequently in the 6th and 7th decades (table 1) [20-271. Presenting signs and symptoms of patients with pyo genic vertebral osteomyelitis are characterized by locali zed pain and nonspecific complaints, such as fever.
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Predisposing infection
Organism
Martino/Wmfield
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8- 10]. Roentgenologic evaluation of children with SCA pre senting with severe localized bone pain plays an important role in the diagnosis of the underlying pathology. Con ventional radiographs are the initial diagnostic steps, however, they frequently do not show changes secondary to osteomyelitis until 2-8 weeks into the course of the disease. When present, these changes include (1) soft tis sue swelling; (2) piecemeal destruction of bone, and (3) narrowing of the intervertebral disc space [5, 17]. Charac teristic plain radiographic changes also occur in SCA and are thought to be secondary to hypercellular bone marrow with reduced fat content. These changes include increased translucency and increased visibility of trabecular mark ings in bone. The bodies of vertebrae are flattened and idented by the intervertebral discs, the so-called ‘fish ver tebra deformity’ [5] (fig.lB). Nuclear medicine studies can provide earlier evidence of osteomyelitis and include two separate modalities to image bone: standard bone (WmTc methylene diphosphate, MDP) and bone marrow imaging (Tc-sulfur colloid). Standard bone scanning with 99mTC MDP shows a three
stage response with osteomyelitis: (1) absence of uptake which can be mistaken for a bone infarct; (2) normal uptake of 99mTC 1 week later, and (3) increased activity in the region of the periosteal reaction 2-4 weeks following the initial infection [28, 29|. Therefore, with MDP bone scanning, failure to image osteomyelitis early in its course can occur for up to 2 weeks following onset of symptoms. Bone marrow imaging techniques using Tc-sulfur colloid can visualize areas of osteomyelitis at an earlier stage of the disease. Whereas areas of bone infarct in SCA will be visualized by their lack of uptake of Tc-sulfur colloid, and a focus of osteomyelitis may image as a decreased area of activity within the first 48 h after onset of symptoms, thereafter a bone marrow image characteristically shows an area of intense focal uptake representing periosteal new bone formation in a focus of osteomyelitis [30]. Tc-sulfur colloid bone marrow imaging can, therefore, detect osteomyelitis as early as 48 h following the onset of bone pain. In summary, we wish to emphasize several points. Children with SCA have a 200 times increased incidence of osteomyelitis. One should always have a high index of suspicion for osteomyelitis in a patient with SCA, particu larly if presenting with an isolated area of bone pain. Because of the similarities in clinical presentation of osteomyelitis and vaso-occlusive bone infarcts of SCA, appropriate radiologic studies are necessary to facilitate the correct and early diagnosis. In particular, nuclear medicine studies using Tc-sulfur colloid bone marrow imaging can distinguish between osteomyelitis and bone infarct after the first 48 h. Newer modalities, such as MRI, may prove helpful in the future. This case also illustrates a crucial diagnostic point. In patients presenting with spinal cord dysfunction, it is imperative that the entire spinal cord is adequately imaged to the level of the foramen magnum. In our review of the available clinical literature on neurological complications of SCA, only 1 case of cord infarct was reported [31]. Therefore, it can be concluded that a vascular infarct of the spinal cord in SCA is an extremely rare complication and should not be considered as the underlying etiology in SCA patients presenting with signs of spinal cord dys function.
References 1 Keeley K, Buchannan GR: Acute infarction of long bones in chil dren with sickle cell anemia. J Pediatr 1982;101:217-127. 2 Adeyokunnu A, Hendricks RG: Salmonella osteomyelitis in child hood. Arch Dis Child 1980;55:175-184.
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malaise and weight loss. More than 90% of patients have localized pain over the affected area, and greater than 50% have temperatures of at least 100 °F. Between 50-90% of organisms isolated in reported cases were Staphylococcus aureus (table 1). The remainder were predominantly en terococci. An unequivocal primary source of hematoge nous dissemination preceded the onset of osteomyelitis in more than 40% of cases reviewed. The genitourinary tract, skin and respiratory system, respectively, were most often involved. The vertebra are affected in only 2.4% of cases of osteomyelitis [14-17], Extension of disease may pro gress in the rostrocaudal direction involving other verte bral bodies. It may also extend anteroposteriorly forming paraspinal and epidural abscesses. Cord compression secondary to epidural abscess was noted in 18% of cases reported, with a range from 4-40%. Salmonella appears to be a unique organism causing osteomyelitis almost exclusively in patients with SCA. In all cases of osteomyelitis in SCA, 74% are culture-proven salmonella [17]. One hundred and twenty-three cases of salmonella osteomyelitis have been reported in the litera ture. The clinical signs can be virtually indistinguishable from those of vaso-occlusive crisis, infarction of bone with resultant pain and tenderness over the affected bone. Salmonella osteomyelitis predominantly affects long bones at multiple sites. Only 11 cases of salmonella verte bral osteomyelitis have been described in the literature, and all of these cases were seen in patients with SCA [2,
Salmonella Osteomyelitis with Epidural Abscess
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Anthony M. Martino. MD Department of Neurosurgery 3901 Beaubien Avenue Detroit. MI 48201 (USA)
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