Volume VII, Number 1 | April 2023

Bilateral Foot Drop in the Setting of a Rare Disseminated Aspergillus Spinal Epidural Abscess

1. Anthony Kamson DO – University of Pittsburgh Medical Center – Pinnacle
2. David Phillips DO – University of Pittsburgh Medical Center – Pinnacle
3. Curtis Goltz DO – Orthopedic Institute of Pennsylvania

KEYWORDS: Disseminated, Aspergillus, Epidural Abscess, Foot Drop, Back Pain, Decompression, Osteodiscitis, Fungus

INTRODUCTION: The diagnosis of a spinal epidural abscess (SEA) as the cause of low back pain and lower extremity weakness is rare. However, in recent years, the occurrence of SEAs has increased secondary to higher IV drug use, increased spinal instrumentation, an aging population, and advances in chemotherapeutics (1,2,4). The majority of SEAs are due to bacteria such as Staphylococcus Aureus, although fungal organisms such as Candida and Aspergillus may be responsible in the immunocompromised host (7).

We present a case of an immunocompetent patient who developed a lumbar epidural abscess secondary to Aspergillus. In the current literature there appears to be less than 50 cases reported, with the majority of these occurring outside of the United States (8).

CASE REPORT: 64-year-old male presented to the general medical floor with bilateral foot drop for 1 month duration. He was recently discharged from an outside facility after being diagnosed with L3-4 osteodiscitis and undergoing treatment with IV antibiotics and PO voriconazole. Bone biopsies were negative. Over the following month, he rapidly lost his ability to ambulate independently. He denied any bowel or bladder changes, fever, and chills. Past medical history was significant for immune thrombocytopenic purpura treated with IVIG and long-term prednisone which was discontinued 3 months prior and a lung aspergilloma treated with VATS and IV antibiotics/antifungal 1 year prior. Labs on presentation were WBC 17.4, CRP 11.8 (0-1 mg/dL), ESR 105 (0-20 mm/hr). An MRI Brain demonstrated a focal 1 cm density in the left frontal lobe. CT Chest/Abdomen/Pelvis was significant for an aspergilloma in the right upper lobe. MRI of the lumbar spine demonstrated L3-4 discitis with an epidural abscess measuring 7 cm x 2.4 cm x 0.9 cm with severe thecal sac effacement with the abscess extending into bilateral neural foramen, diffuse nerve root enhancement, possible intrathecal spread of infection. He subsequently underwent an urgent L3-S1 decompression, intraoperatively a hypertrophic ligamentum flavum was engorged with pus, and hour-glassing of the spinal canal was noted. Postoperatively, he progressed with physical therapy and there was noted improvement of neurologic status. He was successfully discharge to a rehab facility. He later underwent a posterior L3-S1 decompression with instrumented fusion performed at an outside hospital 5 months later. No operative notes are available. He as well completed courses of IV Voriconazole, PO Voriconazole, IV Micafungin and started on chronic Isavuconazole

DISCUSSION: Given the high morbidity and mortality associated with fungal spinal infections, it remains paramount to effectively treat these patients. Surgical intervention may ultimately be necessary in the setting of new or progressive neurologic deficits. Early identification of a spinal abscess pathogen is essential to provide appropriate treatment. There needs to be a high index of suspicion of Aspergillus in order to start the necessary empiric medications while awaiting culture results (4,6-8). Studies have shown that even in rare cases, an Aspergillus spinal epidural abscess can appear in immunocompetent patients

Aspergillus remains a rare cause of infection, most commonly presenting itself in the immunocompromised patient. These patients can include those with malignancy, diabetes, organ transplants, or acquired immunodeficiencies. Invasive aspergillosis classically affects the pulmonary system, possibly appearing as an aspergilloma. It has been estimated that invasive aspergillosis affects bone in only 3% of cases (6).

CONCLUSION: Fungal discitis associated with a spinal epidural abscess is a rare condition, complicated by high morbidity and mortality if not treated promptly. Early definitive diagnosis remains challenging given the non-specific radiologic features of a fungal abscess. Therefore, early anti-fungal coverage should be considered in all patients, whether immunocompromised or immunocompetent. Surgical biopsy can help establish the diagnosis and ensure proper treatment.

Figure 1 | Figure 2 | Figure 3 | Figure 4 | Figure 5

REFERENCES:

  1. Batra S, Arora S, Meshram H, Khanna G, Grover SB, Sharma VK. A rare etiology of cauda equina syndrome. The Journal of Infection in Developing Countries. 2010;5(01):079-082.
  2. Darouiche RO. Spinal Epidural Abscess. New England Journal of Jiang Z, Wang Y, Jiang Y, Xu Y, Meng B. Vertebral osteomyelitis and epidural abscess due to Aspergillus nidulans resulting in spinal cord compression: Case report and literature review. Journal of International Medical Research. 2013;41(2):502-510.
  3. Mackenzie AR, Laing RBS, Smith CC, Kaar GF, Smith FW. Spinal epidural abscess: the importance of early diagnosis and treatment. Journal of Neurology, Neurosurgery & Psychiatry. 1998;65(2):209-212.
  4. Nandeesh B, Kini U, Alexander B. Vertebral osteomyelitis with a rare etiology diagnosed by fine-needle aspiration cytology. Diagnostic Cytopathology. 2009.
  5. Raj K, Srinivasamurthy B, Sinduja MI, Nagarajan K. A rare case of spontaneous Aspergillus spondylodiscitis with epidural abscess in a 45-year-old immunocompetent female. Journal of Craniovertebral Junction and Spine. 2013;4(2):82.
  6. Shweikeh F, Zyck S, Sweiss F, et al. Aspergillus spinal epidural abscess: case presentation and review of the literature. Spinal Cord Series and Cases. 2018;4(1).
  7. Yang H, Shah AA, Nelson SB, Schwab JH. Fungal spinal epidural abscess: a case series of nine patients. The Spine Journal. 2018;19(3):516-522.
The Journal of the American Osteopathic Academy of Orthopedics

Steven J. Heithoff, DO, FAOAO
Editor-in-Chief

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