Aspergillus Spondylodiscitis in Immunocompetent Patients: A Report of Two Cases

Abstract

Introduction The term spondylodiscitis refers to infection of the disc space and adjacent vertebrae. It is commonly caused by Mycobacterium tuberculosis and bacterial pathogens; whereas fungal spondylodiscitis is extremely rare in immunocompetent individuals.1 The reported incidence of fungal spondylodiscitis in studies is 0.5 to 1.6%.2 Aspergillus species (normal inhabitants of the respiratory tract) are commonly responsible for fungal spondylodiscitis. They invade the spine in immunocompromised hosts, such as postorgan transplant, chronic steroid treatment, or chemotherapy.3,4 Only a few case reports are published on aspergillus spondylodiscitis in immunocompetent persons.5,6 Tubercular and pyogenic spondylodiscitis being more common, fungal causes are often ignored.1,2 The absence of specific clinical and radiological features often makes the diagnosis challenging and this delay causes more spinal destruction with devastating consequences. We are reporting two cases of aspergillus spondylodiscitis in immunocompetent patients, the diagnostic dilemma, and its management. Materials and Methods: Case 1: A 33-year-old female patient presented with severe back pain with visual analog score (VAS) as 8. She had recent history of cesarean section under spinal anesthesia. MRI was suggestive of infective spondylodiscitis L2–L3. The patient underwent surgical disco-vertebral debridement, posterior stabilization, and interbody fusion. Aspergillus fumigatus was isolated from the surgical specimen. No evidence of an immunosuppressive status was found. Postoperatively, she was treated with intravenous voriconazole 4 mg/kg body weight twice daily for 1 week followed by oral voriconazole 200 mg twice daily for 3 months. Case 2: A 40-year-old male patient presented with progressive low back pain, 4 weeks after microlumbar discectomy. Examination revealed tenderness in lower lumbar region with associated paraspinal muscle spasm without any neurological deficits. MRI was suggestive of infective spondylodiscitis L4–L5. The patient underwent surgical disco-vertebral debridement, posterior stabilization, and fusion. Aspergillus flavus was isolated from the surgical specimen. There was no evidence of immunosuppressive status. Postoperatively, he was treated with intravenous voriconazole 4 mg/kg body weight twice daily for 3 weeks followed by oral voriconazole 200 mg twice daily for 3 months. Results: The patients were evaluated after 1 week and followed-up at the 1st, 3rd, and 6th month. In case 1, ESR, C-reactive protein (CRP), and total leukocyte count (TLC) normalized in 1 week. In case 2, ESR was normal throughout and TLC normalized after 3 weeks. Pain reduced dramatically after surgery and both patients had total relief from pain by 1 month. Gradual signs of radiological union at interbody site were noticed during follow-ups and total fusion was noticed by the end of 3 months in both the patients. The course of treatment was uneventful. Conclusion: Aspergillus spondylodiscitis is a diagnostic and therapeutic challenge. Fungal spondylodiscitis affecting immunocompetent patient being rare, a differential diagnosis of the same should always be kept in mind. We recommend that tissue sample should always be sent for fungal culture and sensitivity in addition to routine bacterial and tubercular culture. Surgical debridement helps in decreasing fungal load, which in turn increases the efficacy of antifungal drugs, and thus prevents rapid progression of invasive aspergillosis and subsequent neurological damage.