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Postoperative Spondylodiscitis From Aspergillus Fumigatus in Immunocompetent Subjects/Comment

November 25, 2004

J. LENZI, A. AGRILLO, A. SANTORO, N. MAROTTA, G. P. CANTORE

Department of Neurosciences – Neurosurgery “La Sapienza ” University of Rome, Rome, Italy

The authors describe a case of spondylodiscitis from Aspergillus fumigatus which occurred subsequent to surgery for lumbar disc herniation in a non-immunodepressed patient. The results obtained by combined medical and surgical treatment are discussed.

KEY WORDS: Spondylodiscitis * Aspergillus fumigatus * Infectious disease * Tomography, emission computed * Biopsy * Surgery.

Aspergillus is an ubiquitous fungus in nature with more than 350 known species; only a few of these are pathogenic for men.1, 2

Aspergillosis is the most frequent of the skeletal micoses whereas Aspergillus fumigatus is the one more often responsible for osteomyelitis and micotic vertebral spondylodiscitis.1-3

Vertebral localizations of aspergillosis occur predominantly in immunologically impaired subjects, although some rare cases have been described in healthy subjects.4-6

The authors describe a case of spondylodiscitis from Aspergillus fumigatus which occurred subsequent to surgery for lumbar disc herniation in a non-immunodepressed patient. The results obtained by combined medical and surgical treatment are discussed.

Case report

This 50-year-old woman was referred to us for acute left low back pain which had begun about 1 month before admission and a deficit of dorsal flexion of the left foot which appeared 15 days later. Lumbar- sacral MRI documented a large, left, meclian-paramedian disc herniation at L4-L5. The patient was submitted to surgery which consisted of a L4-L5 microdiscectomy and clecompressive foraminotomy of the left root of L5. At the end of the procedure an antiscarring agent (Adcon) was applied around the root (Figures IA, B).

The early postoperative period was uneventful and the patient was discharged on the 3rd postoperative clay and remained in good health until about 2 weeks later. In fact, on the 151’1 day after surgery, she experienced the sudden onset of intense left paravertebral pain. After a brief period of bed-rest, the patient was advised to undergo kinesitherapy. However, after the first sitting, her painful symptoms worsened considerably, assuming the typical features of discitis. At 1-month follow-up, MRI with gadolinium detected hypointensity of the spongiosa of the L4 and L5 bodies with irregularity of the somatic borders on Tl sequences; on T2, there was market! contrast enhancement and a modest amount of esophytic tissue at L4-L5. Values of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were high. The patient was fitted with an orthopedic vest and prescribed wide-spectrum antibiotic therapy (piperacillin), (Figures 2A, B).

Despite this treatment, her symptoms continued to worsen and the low back pain and sciatica returned. Another MRI demonstrated an increase of the esophytic component, of the T2 hyperintensity at L4- L5 and of contrast enhancement, all consistent with discitis (Figures 3A, B).

We decided to submit the patient to a 2nd operation to remove the esophytic component of the discitis and to take a sample for culture.

Figure 1.-Lumbar sacral MRI showed in sagittal (A) and axial (B) view a large, left, median-paramedian disc herniation at L4-L5.

Diagnosis was spondylodiscitis from Aspergillus fumigatus and specific antibiotic therapy with Itraconzaol was begun. Twenty clays later the patient’s clinical conditions improved with normalization of VES values.

Three months after the 1st operation, the patient was free of pain and no longer taking antibiotics.

Discussion

Aspergillus is a saprophyte of the airways described for the first time by Micheli in 1729.1 Aspergillosis is a rare disease which, in healthy subjects, is often responsible for allergy-based conditions of the respiratory system, although other localizations have been observed in the skin, paranasal sinuses, orbits, skeleton/ bones or in the CNS.1,2

Aspergillosis may be primary, developing in healthy patients in the absence of pulmonary involvement, or secondary to predisposing factors such as leukemia, AIDS, chronic and/or neoplastic diseases or immunosuppressive therapy as well as in patients with general impairment of immunological status.

In 74% of Aspergillus infections 7 the localization is skeletal. The majority of vertebral infections from aspergillosis occur in immunologically impaired patients, although some very rare cases have been described in healthy subjects.4-6,8

In subjects without immunological impairment, a vertebral localization of Aspergillus infection is generally attributable to iatrogenic causes related to surgical treatment9 and the pathogenetic mechanism appears to be inoculation of the spores present in the air into the disc space during operation. When the discitis is secondaiy to a hematic dissemination,9,10 the vascularized vertebral borders are infected first and the infection subsequently spreads to the disc space. Cases of vertebral infection from Aspergillus due to contiguous dissemination of pseudoaneurysms following aortic bypass surgery have also been described.

Figure 2.-MRI with gadolinium documented hypointense of the spongiosa of the L4 and L5 bodies with irregularity of the somatic borders on T1 sequences (A) and a modest amount of esophytic tissue at L4-L5 on T2 sequences (B).

Of the 30 patients with discitis from Aspergillus reported in the literature, 80% had an immune-suppressed status.8 The clinical, biological and radiological characteristics of discitis from Aspergillus are exactly the same as those of discitis from piogens.9

The case described here demonstrates that infection of the intervertebral disc space may also occur in immunologically normal patients following surgery for lumbar disc herniation.

Features suggestive of discitis are a combination of intense pain in the area involved by the infection, a high velocity of erithrosedimentation and a radiological finding of hypointensity of the spongiosa of the vertebral bodies with irregular somatic borders on T1 and disc hyperintensity on T2 as well as marked contrast enhancement.

In our opinion, the treatment of choice should be both medical and surgical, as demonstrated by the case described here. However, in the literature there are reports of cases treated by pharmacological therapy alone, via needle-biopsy,11 as well as others in which surgical treatment was only taken into consideration following either a poor response to antimicotic therapy or neurological deterioration.10,12,13 The purpose of explorative surgery is essentially to obtain a precise diagnosis 5-9, 11-14 since needle-biopsy does not always achieve this.10 Accurate diagnosis is, in fact, the key point of treatment for discitis of micotic nature, since wide-spectrum antibiotic therapy does not resolve clinical symptoms, on the contrary to the bacterial forms of discitis. In this type of discitis, delicate curettage of the vertebral plates and removal of the esophytic component that is often present allow a more rapid recovery.

Figure 3.-Another MRI demonstrated an increase of the esophytic component, T2 hyperintensity at L4-L5 (A) and contrast enhancement on T1 sequences (B).

Moreover, it is almost impossible to make a differential diagnosis between bacterial and fungal discitis solely on the basis of neuroradiological data: this is demonstrated by our case in which wide-spectrum antibiotics were administered at the first suspicion of discitis but failed to bring about any improvement in the patient’s conditions.

The pharmacological treatment of choice for discitis is still a matter of debated Standard treatment comprises, besides itmconazol, anfotencin B and 5 flucitosin, administered at a dosage of 0.5 mg/ kg/die and 60-100 mg/kg/die, respectively.5 Itroconazol undoubtedly has the advantage of oral administration, lower toxicity and less side-effects. The advised dose is 3-5 mg/kg/die.

Conclusions

To conclude, this case illustrates how discitis may develop as a complication of spinal surgery, even in patients without immunological impairment, and how diagnosis of this condition in the early stages is not straightforward due to the almost total absence of radiological signs couple with a clinical situation difficult to interpret.

References

1. Casey AT, Wilkins P, Uttley D. Aspergillosis infection in neurosurgical practice. Br J Neurosurg 1994;8:31-9.

2. Wood M, Anderson M. Neurological infections. London: W.B. Saunders; 1988.p.300.

3. Korovessis P, Repanti M, Katsardis T, Stamatakis M. Anterior decompression and fusion for aspergillus osteomielitis of the lumbar spine associated with paraparesis. Spine 1994;23:2715-8.

4. Deshpande DH, Desai AP, Dastur HM. Aspergillosis of the central nervous system. Neurology India 1975;23:167-75.

5. McKee DF, Barr WM, Biyan CS, Lunceford EM. Primary aspergillosis of spine mimicking Pott’s paraplegia. J Bone Joint Surg 1984;66A:1481-3.

6. Seligsohn R, Rippon JW, Lerner SA. Aspergillus terreus osteomyelits. Arch Intern Med 1977;137:918-20.

7. Cortet B, Richard R, Deprez X, Lucet L, Flipo R, Le Loet X et al. Aspergillus spondylodiscitis: successful conservative treatment in 9 cases. J Rheumatol 1994;21:1287-91.

8. Govender S, Rajoo R, Goga IE, Charles RW. Aspergillus osteomyelitis of the spine. Spine 1991;16:746-9.

9. Bridwe\ll K, Campbell JW, Barenkamp SJ. Surgical treatment of hematogenous vertebral aspergillus osteomyelitis. Spine 1990;15: 281- 5.

10. Assad W, Nuchikat P, Cohen L, Esguerra JV, Whittier F. Aspergillus discitis with acute disc abscess. Spine 1994;19:2226-9.

11. Holmes PF, Osterman DW, Tullos HS. Aspergillus discitis. Report of two cases and review of the literature. Clin Orth Rel Res 1988;226:240-6.

12. Van Ooij A, Beckers JMH, Helpers MJHM, Walenkamp GHIM. Surgical treatment of aspergillus spondylodiscitis. Eur Spine J 2000;9:75-9.

13. Castelli C, Benazzo F, Minoli L, Marone P, Seghezzi R, Carlizzi CN. Aspergillus infection of the L3-L4 disc space in an immunosop-pressed hearth transplant patient. Spine 1990;15:1369-73.

14. Mawk JR, Erickson DL, Chou SN, Seljeskog EL. Aspergillus infection of the lumbar disc spaces. Report of three cases. J Neurosurg 1983;58:270-4.

Received February 4, 2004.

Accepted for publication July 15, 2004.

Address reprint requests to: J. Lena, Via dei Fienili 58A, 00186 Roma, Italy. E-mail: jacopole@yahoo.it

Comment

In this well-written report, Lenzi et al. describe the case of a patient suffering from a postoperative spondylodiscitis caused by Aspergillus fumigatus.

The authors review the literature on this topic and provide the reader with relevant information on diagnosis and treatment of this fortunately rare condition.

An important message from this paper is the indication, in selected cases, to surgical exploration, with the 2-fold purpose of reducing the exophytic component of the infected disk, and to ascertain, in cases in which the CT-guided biopsy results negative, the correct etiological diagnosis permitting to start the most appropriate therapy.

Finally the authors call to our attention that micotic postsurgical infections may develop even in non-immunodepressed otherwise healthy patients.

I think this paper is suitable for publication with minor changes. I suggest the authors to make the “Discussion” section shorter condensing in a few sentences the general information they provide about aspergillosis, and referring the interested reader to the main papers dealing with the topic they quote.

Copyright Edizioni Minerva Medica Jun 2004




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