Unilateral septic sacroiliitis caused by Brucella Melitensis in the postpartum period: A rare case report

Abstract

Brucellosis is one of the most common zoonotic diseases, presenting with a wide range of clinical manifestations. The most common symptoms include undulating fever and musculoskeletal issues. Frequent complications tend to involve osteoarticular surfaces, leading to spondylitis, osteomyelitis, and peripheral arthritis. Septic arthritis is another serious complication, the early diagnosis of which can be challenging, especially in the postpartum period, as the symptoms are often non-specific and easily misinterpreted. A 21-year-old female presented to our clinic in the fourth week of her postpartum period with severe unilateral buttock pain. She was sub febrile and had no apparent abnormalities on a pelvic X-ray. The pain was intense to the point that she could not walk properly. Sacroiliac MRI during the acute pain episode revealed mild bilateral sacroiliac (SI) joint effusion, predominantly on the right side, with bone marrow edema in the sacral and iliac aspects of the right SI joint, accompanied by some articular erosions and adjacent myofascial edema. The patient tested seropositive for brucellosis and completely recovered with antibiotic therapy. The patient was under follow-up for 3 months and she underwent a significant remission in symptoms with her pain substantially reduced. Brucella sacroiliitis should be considered in postpartum patients presenting with unilateral buttock pain that is unresponsive to analgesics and associated with difficulty walking.

Introduction

Brucellosis is associated with occupational and domestic exposure to infected animals or their products. Farmers, shepherds, veterinarians, and slaughterhouses are at high risk [1]. The incubation period is 1–2 months, and up to one-third of patients present with musculoskeletal system involvement and symptoms such as pain and fever. Osteomyelitis is more common in lumbar and lower thoracic vertebrae. Osteomyelitis commonly affects the lumbar and lower thoracic vertebrae, while septic arthritis frequently involves large joints, including the knee, hip, sacroiliac, and shoulder [3].

Brucellosis is a bacterial zoonotic infection transmitted to humans either directly or indirectly from infected animals, predominantly from domesticated ruminants such as sheep, goats, camels, and swine, through contact or consumption of contaminated products, especially unpasteurized milk and dairy [1]. It is commonly referred to as "undulant fever" due to its remittent nature. Brucella melitensis is the most frequent cause of human brucellosis, with sheep, goats, and camels as primary reservoirs [2]. While the global prevalence is challenging to determine due to diagnostic limitations and inadequate surveillance, the incidence of brucellosis has been significantly reduced in developed countries through effective vaccination programs. However, outbreaks still occur, particularly in regions like Central and Southern Asia and parts of Africa [3].

Brucellosis is occupationally and domestically linked to contact with infected animals or their products, putting individuals such as farmers, shepherds, veterinarians, and slaughterhouse workers at high risk [1]. The incubation period of the disease ranges from 1 to 2 months, and up to one-third of patients present with musculoskeletal complications, with common symptoms including fever and pain. Osteoarticular involvement is frequent, with osteomyelitis occurring predominantly in the lumbar and lower thoracic vertebrae. Septic arthritis often affects large joints, particularly the knee, hip, sacroiliac, and shoulder joints [3]. Seroprevalence of brucellosis during pregnancy varies between 1.5 % and 3.5 % in Southeastern Asia, with a cumulative incidence rate of 0.42–3.3 per 1000 obstetrical discharges [3]. These statistics emphasize the significance of early diagnosis and tailored management in pregnant and postpartum women, where the disease can present atypically, making prompt detection critical.

CASE report

A 21-year-old female from a rural village, one month postpartum (P2L2) following a lower segment cesarean section (LSCS), presented with severe throbbing pain in the right buttock for 20 days, significantly impairing her functional level (Class 4 A) and a productive cough for 25 days. Obstetric history is insignificant and LSCS was performed as per previous LSCS indication. She was asymptomatic one month ago, but 5–10 days before delivery, she developed a cough with whitish sputum, which worsened in the mornings. Her cough persisted intermittently for 25 days. Five days post-delivery, she experienced high-grade fever with chills, which subsided after receiving intravenous antibiotics for three days. Shortly afterward, she developed right buttock pain, initially mild but progressively worsening until she was unable to walk or move her limb. The pain was exacerbated by movement and was unresponsive to analgesics. There was no associated skin rash, psoriasis, or oral ulcers. Her past and family history was insignificant. The patient did not reside in a pastoral area, had no known contact with cattle or sheep, and denied consumption of raw or unpasteurized dairy products.

On admission, she had severe tenderness in the hip and a body temperature of 38.5°C (remained intermittently febrile). Laboratory tests showed a normal complete blood count (CBC) [Table 1], elevated erythrocyte sedimentation rate (ESR) at 86 mm/hr, C-reactive protein (CRP) at 30 mg/dL, elevated serum glutamic-oxaloacetic transaminase (SGOT) at 140 U/L, and normal serum glutamate pyruvate transaminase (SGPT) at 33 U/L. Total protein was 5.5 g/dL, and albumin was 2.43 g/dL. Autoimmune markers, including antinuclear antibody (ANA) and HLA-B27, were negative, and viral markers were negative. Urine and blood cultures were sterile. Sputum gram staining revealed pus cells with both gram-positive cocci and gram-negative bacilli. Brucella abortus antibody was negative, but Brucella melitensis antibody tested positive at 1:640.

Table 1.

Laboratory findings of patient during course of admission.

Lab test name	On admission	After 4 days	After 6 weeks	Reference values
CBC
WBC Hb RBC Platelets	12.8 k/ul 9.3 g/dl 3.40 mil/ul 4.2 lakhs/ml	8.8 k/ul 9.4 g/dl 3.46 mil/ul 4.2 lakhs/ml	9.2k /ul 9.5 g/dl 4.12 mil/ul 4.12 lakhs/ml	4.5–11.0 k/ul 11.6–15 k/ul 3.5–5.50 mil/ul 1.5–4.5 lakhs/ml
ESR	86 mm/hr	78 mm/hr	25 mm/hr	0–20 mm/hr
CRP	30 mg/dl	18 mg/dl	1.2 mg/dl	0.3–1.0 mg/dl
SGOT	140 u/l	106 u/l	52 u/l	8–45 u/l
SGPT	33 u/l	36 u/l	43 u/l	7–56 u/l
ALP	62 IU/L	69 IU/L	64 IU/L	44–147 IU/L
TP	5.5 g/dl	5.8 g/dl	6.2 g/dl	6–8.3 g/dl
ALBUMIN	2.43 g/dl	2.56 g/dl	3.9 g/dl	3.4–5.4 g/dl

Magnetic resonance imaging (MRI) of the lumbosacral spine revealed bilateral SI joint effusion, more pronounced on the right side, with bone marrow edema in the sacral and iliac regions of the right SI joint, along with articular erosions and adjacent myofascial edema (Fig. 1). MRI of the pelvis and hip was normal.

Fig. 1.

Coronal T1-weighted image (left) and axial T2-weighted image (right) demonstrate asymmetrical sacroiliitis, with predominantly right-sided sacroiliac joint involvement. Findings include mild bilateral sacroiliac joint effusion (right > left), bone marrow edema in the right iliac and sacral aspects, articular erosions, and adjacent soft tissue/myofascial edema features which are consistent with active infectious sacroiliitis.

The patient was initially treated with ceftriaxone 2 g intravenously, followed by oral rifampicin 600 mg daily and trimethoprim/sulfamethoxazole (TMP-SMX) twice daily. After four days, her fever subsided, and she was discharged with a prescription for ceftriaxone 2 g for one month, rifampicin 600 mg for three months, TMP-SMX twice daily, ibuprofen 400 mg for two weeks, and Buvalor 10 mg transdermal patch (buprenorphine) for one week. The patient was closely monitored following discharge to prevent relapse and ensure complete recovery. Monthly follow-ups for the first six months included clinical evaluations, inflammatory marker assessments (ESR, CRP), and Brucella serology at three, six, and twelve months showed no evidence of persistent infection. The patient was counseled on early relapse symptoms, dietary precautions, and adherence to antimicrobial therapy. Over a one-year follow-up period, the patient remained symptom-free, with no recurrence or complications. The case report was conducted and reported in accordance with CARE statement [4].

Discussion

Most postpartum patients present with generalized myalgia, arthralgia, and lower back pain, but these symptoms are often non-specific and may be misinterpreted as post-operative discomfort due to increased pelvic movements and ligament relaxation. However, when pain does not respond to analgesics and is associated with fever, further investigation is warranted. Although brucella infections have been reported, their occurrence in the early postpartum period remains rare 5), 6).

Lower back pain in the postpartum period, also known as pregnancy-related pelvic girdle pain (PPGP), is common and has a higher prevalence in cesarean deliveries compared to vaginal deliveries 6), 7). This condition is frequently misdiagnosed as hormonal postpartum pelvic pain. In our case, the presence of fever and cough with sputum, in addition to sacroiliac pain, raised the possibility of several differential diagnoses, including pregnancy-associated arthropathy, brucella-induced pyogenic sacroiliitis, tuberculosis, staphylococcal abscess, and ankylosing spondylitis. Pregnancy-associated arthropathy typically resolves with analgesic treatment, which was not the case here, prompting further investigation. Although synovial fluid aspiration is a diagnostic gold standard, it was not attempted in this case due to technical challenges of accessing the sacroiliac joint and lack of image-guided intervention facilities at our center. Initially tuberculosis & Spondyloarthritis were considered as differential diagnosis. however, there was no history of TB exposure, chronic cough, night sweats, or constitutional symptoms. Chest X-ray was unremarkable, and Mantoux test was negative. Advanced TB-specific investigations like IGRA could not be performed due to financial constraints.

Spondyloarthritis was excluded based on the absence of inflammatory back pain features, enthesitis, dactylitis, uveitis, or family history. HLA-B27 was negative, and there were no radiographic signs suggestive of chronic spondyloarthropathy

Infective sacroiliitis, especially postpartum, should be considered due to potential post-delivery complications like chorioamnionitis or pelvic infections. While brucellosis is rare, it should be considered when pain persists and does not resolve with conventional treatment. Unilateral sacroiliitis can affect either side, although bilateral involvement is also frequently observed in Brucella infections 7), 8). Given the patient's rural background and proximity to livestock, brucellosis became a strong suspect once other possibilities were excluded. For adults with acute, non-focal brucellosis (duration <1 month), a six-week course of two antimicrobial agents is generally effective 9), 10). In this case, due to potential side effects from doxycycline, a safer alternative of triple-drug therapy (ceftriaxone, TMP-SMX, and rifampicin) was chosen, particularly because of its compatibility with breastfeeding.

A limited number of postpartum sacroiliitis cases have been documented in the literature. Ozturk et al. reported a case of bilateral Brucella sacroiliitis in a 31-year-old woman two weeks postpartum following vaginal delivery, who presented with progressive bilateral buttock pain and gait disturbance unresponsive to analgesics. Diagnosis was established through positive Rose Bengal and Wright agglutination tests, and MRI demonstrated bilateral sacroiliac bone marrow edema and effusion. The patient responded favorably to doxycycline and rifampin therapy, though pain persisted intermittently for several months [9]. In contrast, Imagama et al. described unilateral right-sided sacroiliitis caused by methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy 37-year-old woman one week postpartum following cesarean section. MRI revealed an abscess adjacent to the right sacroiliac joint, and culture-confirmed MRSA from sacroiliac aspiration fluid prompted targeted anti-MRSA antibiotic therapy, with full recovery [10]. Compared to these cases, our report is distinctive in its right-sided, unilateral sacroiliitis caused by Brucella melitensis in the postpartum period, confirmed serologically without abscess formation or aspiration.

Conclusion

In regions where brucellosis is endemic, postpartum women presenting with persistent sacroiliac joint pain, particularly when unresponsive to analgesics and accompanied by low-grade fever or difficulty walking, should be carefully evaluated for brucellar sacroiliitis. A detailed history – especially of rural residence, contact with livestock, or consumption of unpasteurized dairy products can be crucial in guiding early diagnosis. This case highlights the clinical importance of maintaining a high index of suspicion for Brucella infection as a rare but significant cause of postpartum sacroiliitis. Prompt recognition and targeted antimicrobial therapy are essential to prevent long-term complications and ensure favorable outcomes.

CRediT authorship contribution statement

Navya Sree Keshetty: Writing – review & editing, Writing – original draft, Project administration, Formal analysis. Tarun Kumar Suvvari: Writing – review & editing, Writing – original draft, Validation, Supervision, Project administration, Formal analysis, Conceptualization. Laxmi Supriya Yarrabathina: Writing – review & editing, Writing – original draft, Visualization, Resources, Formal analysis. Greeshma Rangari: Writing – review & editing, Writing – original draft, Resources, Formal analysis. Sai Pavan lagishetty: Writing – review & editing, Writing – original draft, Resources, Methodology, Formal analysis, Data curation, Conceptualization. Ridhinayani Nalam: Writing – review & editing, Writing – original draft, Resources, Methodology, Formal analysis, Data curation.

Informed consent

Written informed consent was obtained from the patient for the research and the publication.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethics statement

In our university, Ethics approval was not required for case reports and case series.

funding

No Funding Received

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The Authors Declare No Conflicts of Interests

Data availability

Not Applicable.