Brucellosis sacroiliitis masquerading as inflammatory spondyloarthropathy

Alok Gupta; Ashok M Shyam; Parag K Sancheti; Siddharth N Aiyer

doi:10.4103/isj.isj_38_21

CASE REPORTS

Year : 2022 | Volume : 5 | Issue : 2 | Page : 241-245

Brucellosis sacroiliitis masquerading as inflammatory spondyloarthropathy

Alok Gupta, Ashok M Shyam, Parag K Sancheti, Siddharth N Aiyer
Department of Orthopaedic Surgery, Sancheti Institute for Orthopaedics and Rehabilitation, Pune, Maharashtra, India

Date of Submission	26-Apr-2021
Date of Decision	26-Jun-2021
Date of Acceptance	02-Sep-2021
Date of Web Publication	08-Jun-2022

Correspondence Address:
Siddharth N Aiyer
Department of Spine Surgery, Sancheti Institute for Orthopaedics and Rehabilitation, Pune, Maharashtra
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/isj.isj_38_21

Abstract

Brucellosis is the most common zoonosis globally, and it is endemic to the Indian subcontinent. It can mimic a number of febrile illnesses and inflammatory disease conditions. An 18-year-old boy presented with low back pain and a fever of three-month duration. Magnetic resonance imaging revealed a unilateral sacroiliitis, which was being treated as an inflammatory spondyloarthropathy. Because of non-resolving symptoms, a biopsy was performed, which showed a granulomatous inflammation that was consistent with tuberculosis or brucellosis infection. A history of exposure to livestock and consumption of unpasteurized milk led to a clinical suspicion of brucellosis, which was confirmed on a positive serology. He was treated with antibiotics with improvement in symptoms and complete resolution of the sacroiliitis. A high index of suspicion must be maintained for brucellosis, especially in patients with a rural residence, exposure to livestock, and febrile illness with a clinically suspected unilateral sacroiliitis.

Keywords: Brucellosis, inflammatory spondyloarthropathy, sacroiliitis, zoonosis

How to cite this article:
Gupta A, Shyam AM, Sancheti PK, Aiyer SN. Brucellosis sacroiliitis masquerading as inflammatory spondyloarthropathy. Indian Spine J 2022;5:241-5

How to cite this URL:
Gupta A, Shyam AM, Sancheti PK, Aiyer SN. Brucellosis sacroiliitis masquerading as inflammatory spondyloarthropathy. Indian Spine J [serial online] 2022 [cited 2023 Apr 1];5:241-5. Available from: https://www.isjonline.com/text.asp?2022/5/2/241/346967

Introduction

Brucellosis infections typically involve the musculoskeletal system and can present with fever, myalgia, low back pain, peripheral arthritis, spondylitis, spondylodiscitis, and even sacroiliitis.^[1] Sacroiliitis is the key radiological finding in spondyloarthropathy, and it is less frequently seen with infective conditions such as brucellosis and tuberculosis.^[1],[2]

Brucellosis is endemic in the Indian subcontinent, and because of its varied presentation, it can masquerade as a number of infective and inflammatory disorders.^[3],[4] Brucellosis is often underreported due to a lack of awareness among clinicians.^[5] Exposure to livestock and consumption of unpasteurized milk are noted to play an important role in disease transmission.^[1],[5]

We report a case of unilateral sacroiliitis that was misdiagnosed and treated as a seronegative spondyloarthropathy based on the Assessment of SpondyloArthritis international Society (ASAS) criteria.^[6] A history of exposure to livestock and unpasteurized milk suggested a possible brucellosis infection, which was confirmed on serology.

Case Report

An 18-year-old male patient presented to the spine clinic with left buttock pain for three months. The pain was insidious in onset, gradually progressive and had limited the patient’s ability to independently ambulate. There was a history of morning stiffness which improved as the day progressed. A low-grade intermittent fever in the preceding three weeks with weight loss was noted. There was no history of uveitis, dactylitis, heel enthesitis, or any other associated features of spondyloarthropathy. The left-side active straight leg raising was painful, and Faber’s test on the left side was positive with tenderness over the left sacroiliac (SI) joint.

The radiographs of the pelvis and lumbosacral spine were unremarkable; however, the magnetic resonance imaging (MRI) of the pelvis and lumbosacral spine detected features consistent with left-sided sacroiliitis as depicted in [Figure 1]. The patient was being treated by a rheumatology clinic for inflammatory spondyloarthropathy over the past two weeks with non-steroidal anti-inflammatory medication and low-potency steroids without relief.

Figure 1: A, White closed arrows show hypointense marrow signals along the left sacroiliac joint on the T1-weighted coronal section. B, White asterisk shows hyperintense marrow signals along the left sacroiliac joint on the short tau inversion recovery coronal section. C, White arrow head shows minimal periarticular soft-tissue component on axial short tau inversion recovery section deep to the iliacus muscle

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Blood investigations revealed a normal hemogram, elevated erythrocyte sedimentation rate (ESR) of 50 mm/h, elevated C-reactive protein (CRP) level of 70 mg/L; however, human leukocyte antigen (HLA) B-27 was negative. In view of the fever, unilateral sacroiliitis with minimal soft-tissue component on imaging [Figure 1], and elevated CRP, a possible infective etiology was suspected, and a percutaneous Jamshidi needle biopsy was performed from the left sacroiliac joint.

Samples were sent for histopathological analysis and microbiology assessments. No organism was isolated on cultures, and smear examinations were negative. The Gene Xpert MTB/RIF was negative. However, the histopathology was suggestive of a granulomatous inflammation without caseous necrosis as depicted in [Figure 2]. In view of granulomatous inflammation, a possible differential diagnosis of tuberculosis or brucellosis was considered. A history of exposure to livestock and consumption of unpasteurized milk was sought retrospectively, and serology testing was performed for brucellosis. Serology showed significant titer levels for IgM and IgG antibodies for brucellosis infection. A final diagnosis of skeletal brucellosis was formulated, and the patient was started on injection amikacin for a period of two weeks and oral tablet doxycycline for a period of six weeks. Serial two-week interval assessment of ESR and CRP levels showed a progressive decline to normal at six weeks. There was complete relief from gluteal pain with no fever spikes, and Faber’s test was negative at eight weeks. A follow-up MRI of the SI joints performed at 10 months showed complete resolution of the sacroiliac joint marrow edema and soft-tissue signal changes as depicted in [Figure 3]. The clinical follow-up at 12 months following treatment was satisfactory, and the patient was asymptomatic.

Figure 2: A, Low and B, high power microscope biopsy images respectively showing unremarkable bony trabeculae separated by marrow spaces replaced by foci of acute on chronic inflammatory cells and fibrosis and occasional giant cells with no evidence of caseous necrosis consistent with a granulomatous inflammation

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Figure 3: A and B indicate return of marrow signals in the T1 weighted coronal and axial. C and D, White asterisk shows resolution of short tau inversion recovery signal changes in the coronal and axial sections

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Discussion

Brucellosis is the most common zoonosis in the world, and the disease is endemic in India.^{[1],[3],[4],[5]} A considerable prevalence rate of human brucellosis has been quoted by authors in the different regions of India ranging from 8.5% in Gujarat, 11.51% in Andhra Pradesh, to 19.83% in Maharashtra.^[7],[8]

The patient presented with an MRI suggestive of unilateral sacroiliitis with a differential diagnosis of inflammatory or infective pathology.^[2],[9] Kanna et al. have reported on the utility of the MRI to differentiate inflammatory versus infective unilateral sacroiliitis with the identification of soft-tissue components and abscess findings going in favor of infection.^[2] The reported patient showed the presence of small soft-tissue collection deep to the iliacus, which was suggestive of a possible infective etiology, and hence, a tissue diagnosis was sought.

The patient was being treated as an inflammatory spondyloarthropathy based on the presence of sacroiliitis, low back pain, and elevated CRP as per the ASAS criteria^[6] [Table 1]. Based on the ASAS guidelines to diagnose spondyloarthropathy, foci of bone edema on short tau inversion recovery, or osteitis on T1 sequences must be demonstrated in the sacroiliac joint regardless of the occurrence of other inflammatory or structural lesions on the MRI.^[6],[10] Wang et al. noted that the ASAS criteria have increased the sensitivity; however, the specificity is lower and infective sacroiliitis can be misdiagnosed and treated as inflammatory spondyloarthropathy.^[10] The authors suggested that application of ASAS criteria for diagnosis in the presence of unilateral sacroiliitis should be done with care.

Table 1: ASAS criteria for diagnosis of spondyloarthritis in patients under 45 years old of age with lower back pain of 3 months duration

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The histopathology examination in the patient showed a granulomatous inflammation, which may be seen with both tuberculosis and brucellosis. In the reported case, typical caseous necrosis, epithelioid cells, and Langerhans giant cells were not seen raising the possibility of brucellosis.

The patient came from a rural residence setting, with close contact with livestock in the form of cows. There was a history of consumption of unpasteurized milk, which led to serological testing and confirmation of brucellosis infection. In a study by Mantur and Amarnath, 672 (84.8%) cases would have been missed if routine serological surveillance had not been done among the suspect population.^[5] In India, a large proportion of the population is based in a rural setting where close contact with domestic animals is noted, and this correlates with disease transmission.^[5],[7],[8]

Diagnosis of brucellosis in regions with a large prevalence of tuberculosis can be difficult. The clinical and radiological presentations of spinal brucellosis are similar to those of spinal tuberculosis.^[2],[4] A significant number of skeletal brucellosis patients present with peripheral arthritis along with axial skeletal involvement.^[4] In such a clinical scenario, epidemiological information and close proximity to livestock should be given significant cognizance.^[5] The gold standard of diagnosis is based on isolating the organism on blood cultures; however, because of low isolation rates, serological testing (IgM and IgG) has to be relied upon and is often positive.^[4],[5] Close clinical follow-up of inflammatory markers and resolution of findings on follow-up imaging can help resolve any ambiguity in the final diagnosis.

No standard and uniformly accepted drug therapy regimes have been agreed upon for the treatment of skeletal brucellosis.^[4] However, treatment with two or three antibiotics for a period of 8–12 weeks is suggested. The CDC guidelines suggest that skeletal brucellosis should be treated with aminoglycosides for the first 14 days in addition to tetracycline for six weeks or co-trimoxazole if tetracyclines are contraindicated. Therapy duration is extended for 4–6 months in cases of life-threatening complications, such as meningitis or endocarditis.^[11]

Conclusion

The case report highlights that when considering unilateral sacroiliitis, the ASAS criteria should be used with care to avoid misdiagnosis. Brucellosis should be considered as a differential diagnosis, apart from tuberculosis, especially in the background of a rural residence, close exposure to livestock, and the presence of an infective unilateral sacroiliitis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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