Fungal Spinal Infection¶

Definition¶

Fungal infections of the spine are rare and occur almost exclusively in immunocompromised patients — those with HIV/AIDS, organ transplant recipients, patients on chronic immunosuppression, or those with indwelling catheters. The most common organisms are Aspergillus, Candida, and Coccidioides (endemic in the southwestern United States).

Imaging Findings¶

MRI¶

Fungal spondylodiscitis has imaging features similar to bacterial infection:

Vertebral body marrow edema (low T1, high T2/STIR)
Endplate erosion and disc involvement
Paravertebral and epidural soft tissue or abscess
Enhancement of the disc, endplates, and soft tissues

However, fungal infections may show:

More indolent appearance — Less aggressive destruction, more sclerosis
Posterior element involvement — More common than with pyogenic infection
Multiple non-contiguous levels — Similar to TB
Large paravertebral collections — Disproportionate to the bony destruction

CT¶

Lytic and sclerotic vertebral body changes
Endplate erosion
Paravertebral soft tissue mass

Coccidioidomycosis¶

Endemic in the San Joaquin Valley, southwestern US, and Mexico
May produce lytic vertebral body lesions mimicking tumor
Paravertebral and epidural abscess formation
Can involve the posterior elements

Clinical Pearl

Consider fungal spondylodiscitis when an immunocompromised patient presents with a spondylodiscitis pattern that responds poorly to empiric antibacterial therapy. The imaging may be indistinguishable from bacterial or tuberculous infection. CT-guided biopsy with fungal cultures (which require prolonged incubation) is essential for diagnosis.

Management¶

Antifungal therapy — Prolonged course (months to years), agent depends on organism
Surgery — For neurological deficit, drainage of large abscess, or tissue diagnosis
Address underlying immunosuppression when possible

Key Points¶

Occurs almost exclusively in immunocompromised patients
Imaging is similar to bacterial spondylodiscitis but may be more indolent
Posterior element involvement and multiple non-contiguous levels are clues
CT-guided biopsy with fungal cultures is essential for diagnosis
Prolonged antifungal therapy is required

References¶

Cevolani L, Facchini G, Pasini S, Bianchi G. Fungal spondylodiscitis: imaging findings and brief review of the literature. BMJ Case Rep. 2021;14(9):e242515. https://pmc.ncbi.nlm.nih.gov/articles/PMC8420698/
Simeone FJ, Husseini JS, Yeh KJ, Lozano-Calderon S, Nelson SB, Chang CY. MRI and clinical features of acute fungal discitis/osteomyelitis. Eur Radiol. 2020;30(4):2253-2260. https://pubmed.ncbi.nlm.nih.gov/31900707/
Lee SW, Lee SH, Chung HW, Kim MJ, Seo MJ, Shin MJ. Candida spondylitis: comparison of MRI findings with bacterial and tuberculous causes. AJR Am J Roentgenol. 2013;201(4):872-877. https://pubmed.ncbi.nlm.nih.gov/24059378/
Crete RN, Gallmann W, Karis JP, Ross J. Spinal coccidioidomycosis: MR imaging findings in 41 patients. AJNR Am J Neuroradiol. 2018;39(11):2148-2153. https://pmc.ncbi.nlm.nih.gov/articles/PMC7655371/
Ortiz AO, Levitt A, Shah LM, Parsons MS, et al; Expert Panel on Neurological Imaging. ACR Appropriateness Criteria® Suspected Spine Infection. J Am Coll Radiol. 2021;18(11S):S488-S501. https://pubmed.ncbi.nlm.nih.gov/34794603/
Hall WA, Graeber A, Cecava ND. Vertebral osteomyelitis. In: StatPearls. Treasure Island (FL): StatPearls Publishing; updated 2024 Nov 25. https://www.ncbi.nlm.nih.gov/books/NBK532256/
Spondylodiscitis. Radiopaedia.org. https://radiopaedia.org/articles/spondylodiscitis