Scedosporium apiospermumis is a rare cause of meningitis and cerebral aneurysm. A large sample of cerebrospinal fluid may need to be cultured to make the diagnosis.
A 36-year-old female stable groom was trampled by a horse in January, 2000. She sustained open skull, left orbital, mandibular, and left tibial fractures. She underwent a left frontal craniotomy for debridement of contused tissue, elevation of depressed fracture and orbital reconstruction, and was treated postoperatively with cefazolin, metronidazole, and dexamethasone. On her 19th day in the hospital she had a low-grade fever. A cerebrospinal fluid (CSF) sampling showed 630 white blood cells (WBC) /mm3 (81% segmented forms and 18% lymphocytes), 930 red blood cells (RBC) /mm3, glucose 67 mg/dL, and total protein 49 mg/dl. CSF cultures grew Staphylococcus epidermidis very late. She was treated with antibiotics for 10 days and then discharged to a rehabilitation unit 4 months after the injury.
From the rehabilitation unit she was readmitted to the hospital twice for headache, meningismus, and confusion. Each time CSF studies were consistent with meningitis, and she was treated with antibiotics. No bacteria, mycobacteria, or fungi were isolated. On her third readmission (in late June) for similar symptoms, her CSF findings again were consistent with meningitis, with 3975 WBC/mm3 (38% segmented forms and 52% lymphocytes), 1 RBC/mm3, glucose 36 mg/dL, and total protein 856 mg/dL. She was started on antibiotics. Computerized tomography showed new hydrocephalus, and a ventriculostomy was placed. After 8 days all antibiotics were stopped because CSF cultures were sterile. She continued to have bouts of confusion, headache, and meningismus. Studies for C. immitis, B. abortus, T. pallidum, and C. neoformans all were negative. In mid-July, because no organisms had been isolated, we obtained and centrifuged a large volume (15ml) of CSF. The pellet was planted for bacterial, mycobacterial, and fungal cultures. Two days later she had the first of two successive subarachnoid hemorrhages and eventually died. A few days before her death, the large volume culture grew a mycelial fungus in liquid mycobacterial media. This was identified as Scedosporium apiospermum. At autopsy she was found to have a ruptured true mycotic aneurysm of the left vertebral artery at the origin of the posterior inferior cerebellar artery. Histologic sections showed septate hyphal fungal elements compatible with Scedoporium infiltrating the artery (see figure).
Scedosporium apiospermum (formerly called Allescheria boydii, Petriellidium boydii, Monosporium apiospermum, or Pseudallescheria boydii) is found in soil and stagnant or polluted water. It has been implicated in serious central nervous system (CNS) infections . These infections are very rare, and have been associated with near-drowning, head trauma, and fungal sinusitis [1,2]. There is one report of true mycotic aneurysm of the basilar artery from S. apiospermum. This case was related to direct extension from a known Scedosporium sinusitis. Like our case, that patient died . We speculate that our patient’s CNS was directly inoculated with fungus during the trauma. Treatment of S. apiospermum infections is difficult, because most isolates are resistant to amphotericin B and many are resistant to the azoles. Most cures, inside and outside the CNS, result from combined surgical and medical (azole) treatment [1,3], but there is one report of cure with fluconazole alone . Many CNS infections are diagnosed post-mortem . It is unlikely that treatment after 6 months would have altered our patient’s clinical course. This case demonstrates the diagnostic dilemma of chronic meningitis in a young immunocompetent patient after trauma. The centrifugation of a large volume of CSF may have helped in isolating the fungus. Fungal infection should be considered as a possible cause of protracted culture-negative meningitis. Diagnosis may be aided by culture of large volumes of CSF.
1. Hospenthal DR, Bennett JE. Miscellaneous Fungi and Prototheca. In: Mandell GL, Bennett JE, Dolin R eds. Principles and Practice of Infectious Disease 5th
ed. Philadelphia: Churchill Livingstone; 2000:2773–4.
2. Watson JC, Myseros JS, Bullock MR. True fungal mycotic aneurysm of the basilar artery: a clinical and sugical dilemna. Cerebrovascular Diseases 1999; 9:50–3.
3. Berenguer J, Diaz-Mediavilla J, Urra D, et al. Central nervous system infection caused by Pseudallescheria boydii: case report and review. Reviews of Infectious Diseases 1989; 11:890–6.
4. Pickles RW, Pacey DE, Muir DB, et al. Experience with infection by Scedosporium prolificans including apparent cure with fluconazole therapy. J Infection 1996; 33:193–7.