A 21-year-old Asian male with no significant medical history presented to us with complaints of pain in the right gluteal region radiating down to right thigh since 6 days and fever since 2 days. There was no history of recent trauma to lower extremity or back. He denied any history of rash, joint pains, weight loss, or high-risk behavior. History of travel was absent. Family history was noncontributory. There was no history of tuberculosis contact or intravenous drug abuse. There was no history of raw milk consumption or undercooked meat exposure. There was no history of contact with pet animals. On presentation, he was tachycardic and febrile with respiratory rate 24/min and blood pressure 120/80 mmHg. Regional lymphadenopathy was absent. Local tenderness over the right gluteal region was present with no overlying skin changes of inflammation seen. Straight leg raising test was negative. Lower limb reflexes were normal.
Laboratory investigations showed leukocytosis with neutrophilic predominance and eosinopenia (Hb 12.7 g%, total leukocyte count 14,580/cmm, neutrophils 81.7%, and eosinophils 0.1%). Blood chemistry showed normal renal function and electrolyte levels. Malaria antigen test was negative. He was empirically started on intravenous ceftriaxone 2 g 24 h after sending blood culture. Liver function test showed borderline elevated enzymes (serum glutamic oxaloacetic transaminase 62 IU/L, serum glutamic pyruvic transaminase 69 IU/L, and alkaline phosphatase 415 IU/L) with normal bilirubin levels. HbA1C level was 5.5%. C-reactive protein (CRP) was positive (32.37 mg/L) and erythrocyte sedimentation rate (ESR) was raised 34 mm/h.
Chest, pelvis radiographs, and abdominal ultrasonography were unremarkable. Pelvis magnetic resonance imaging (MRI) showed peripherally enhancing fluid collection within the right piriformis muscle measuring 3.2 cm x 3.0 cm size, representing an abscess with subtle bony involvement of the right sacroiliac joint [Figure 1a and b]. Surgical incision and drainage of abscess were deferred taking the small size and deep seatedness of abscess into consideration. Brucella antibodies tested was negative. HIV and hepatitis B surface antigen serology were negative. However, blood culture sent earlier yielded Gram-negative bacilli, later identified to be Salmonella serotype typhi. Ceftriaxone was continued as per antibiotic sensitivity pattern for 2 weeks more following which fever intensity reduced to a significant extent. Meanwhile, Widal test done 1 week after symptom onset yielded significant titers of Salmonella agglutinogens (1:240 Salmonella typhi O, >1:1920 S. typhi H).
Repeat pelvis MRI after 2 weeks showed no interval change in size of abscess but marrow edema involving iliac and sacral portions of the right sacroiliac joint was more pronounced, with postcontrast enhancement [Figure 1c and d]. Intravenous ceftriaxone dose was stepped up to 2 g 12 h and was continued for 4 weeks more on outpatient basis taking into consideration the deep seatedness of abscess and the bony involvement. After 4 weeks, ESR normalized to 07 mm/h and CRP was negative (0.00 mg/L). Pelvis MRI after 4 weeks showed the signs of resolution with a significant reduction in abscess size and reduced marrow edema of the involved sacroiliac joint [Figure 2a-c]. A gradual improvement was seen clinically, laboratory-wise, and radiologically over 6 weeks course of intravenous ceftriaxone and complete recovery was noted without any complication.