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From the Mitochondrial Research Group (G.S.G.), The Medical School, Newcastle University, Newcastle upon Tyne; and Department of Neurology (N.T., M.H.), St. Vincents University Hospital, Dublin, UK.
Address correspondence and reprint requests to Dr. Grainne Gorman, Mitochondrial Research Group, 4th Floor, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK grainne.gorman{at}ncl.ac.uk
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On examination she was alert and oriented. Visual acuity was 6/60 on the right and 6/36 on the left. Color vision was impaired bilaterally as tested with the Ishihara pseudoisochromatic plates. There was enlargement of both blind spots and severe constriction of fields with relative preservation of inferior nasal fields only. Ophthalmoscopic examination and fluorescein angiography showed bilateral pale swollen optic discs with peripapillary hemorrhages and venous engorgement (figure). The remaining neurologic examination was normal.
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Questions for consideration:
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Twenty-four–hour ambulatory blood pressure monitoring was normal. Free thyroxin and thyroid stimulating hormone levels were normal. Thyroid antibodies were negative. Inflammatory markers were normal. Gadolinium-enhanced MRI of brain, orbits, pituitary, and optic nerves revealed increased signal uptake in the left optic nerve only, excluding intracranial and optic nerve tumors, demyelination, hematomas, vascular malformations, and hydrocephalus. MR venography and angiography were normal, reducing the likelihood of cerebral sinus thrombosis and subarachnoid hemorrhage.
Questions for consideration:
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The differential diagnosis for a lymphocytic pleocytosis includes parameningeal infections (partially treated bacterial meningitis), non-viral infectious meningitides (fungi, mycobacteria, parasites, syphilis, listeria, brucella, Coxiella, mycoplasma), neoplastic meningitis, non-infectious inflammatory disease (Behcet disease, sarcoid), HIV, herpes simplex virus (HSV), cytomegalovirus (CMV), human herpes virus 6 (HHV6), varicella zoster virus (VZV) (Artus), polyomavirus, Epstein-Barr virus (EBV), and demyelinating and neoplastic conditions.
CSF culture, Gram stain, acid-fast staining, Indian ink preparation, and cryptococcal antigen were negative. CSF cytology suggested reactive lymphocytes only. CSF PCR testing and serum titers for HIV were negative. Serum toxoplasma antibodies were negative. CSF Venereal Disease Research Laboratory was negative. CT of the thorax, abdomen, and pelvis was normal. The absence of enhancement of the pia mater or white matter lesions on gadolinium-enhanced MRI made the diagnosis of sarcoid less probable but did not definitively exclude it as a possible diagnosis at this stage. Normal brain imaging and no history of mucocutaneous disease or pathergy made Behcet disease unlikely.
CSF lymphocyte immunophenotyping showed proliferation of both helper and cytotoxic T cells demonstrating activation markers, a minor population of natural killer cells (6%), and non-clonal proliferation of B cells (4%), consistent with a reactive response to an established viral infection.
PCR for HSV, CMV, HHV6, VZV (Artus), and polyomavirus DNA were negative. A total of 108 copies/mL of EBV DNA were detected in CSF. Whole blood EBV IgM viral load was 41,090 copies/mL, consistent with active EBV infection.
Questions for consideration:
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Her immunosuppressive therapy was reduced and she was commenced empirically on dexamethasone to preserve residual vision. Her vision improved to 6/24 on the left and 6/36 on the right with persistence of initial disc changes. She was treated with valacyclovir and discharged well with close follow-up surveillance of vision and CSF EBV DNA levels.
At follow-up 2 years after presentation, she remained well; her visual acuity had improved to 6/36 on the right and 6/18 + 1 on the left. Repeat CSF examination showed normal pressure, protein of 0.73 g/L, and white cell count of <1 cell/mm3, and EBV DNA was not detected. She continued on mycophenolate mofetil 500 mg twice daily, cyclosporine 50 mg twice daily, and valacyclovir 450 mg twice daily.
| DISCUSSION |
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Most PTLD is driven by EBV infection. Acquired CD3 immunodeficiency secondary to immunosuppressant agents reduces the clearance of EBV, promoting primary infection or reactivation of the virus. EBV in turn promotes oncogenic activation and increases the incidence of lymphoma posttransplantation by up to 40 times that of the general population.4
The clinical presentation is often subtle, leading to a delay in diagnosis, with the mean time to diagnosis posttransplant of 20 to 35 months.5
Nonspecific symptoms may include fever, weight loss, and anorexia, as present 3 months prior in this patient. Ocular PTLD is recognized in the differential diagnosis of uveitis after organ transplantation, with anterior chamber cells and iris nodules being the most common ocular signs. But the posterior segment can be involved without evidence of systemic disease, again, as in this case.
The incidence of PTLD has risen with the introduction of more potent immunosuppressant agents. Different sites may be involved, with the incidence of CNS involvement up to 27%.5 CNS involvement in transplant recipients with PTLD carries a poor prognosis; however, isolated CNS involvement without extracranial involvement has a better prognosis.6
Risk factors for the development of PTLD include intensity and type of immunosuppressant, EBV status prior to transplantation, and titers of whole blood EBV DNA.7 Circulating levels of EBV DNA between 20,000 and 200,000 copies/µg are associated with the development of PTLD.8
Management of PTLD involves reduction of immunosuppression. The presence or absence of bcl-6 has been associated with favorable response to this therapeutic intervention.9 The role of antiviral agents remains controversial. Acyclovir and ganciclovir inhibit viral replication but have little effect on latent virus. However, antiviral therapy is incorporated into treatment schemes to eliminate replicating virus. Other novel treatments have been used with varying success, including IV immunoglobulin, interferon-alfa, and rituximab. Chemotherapy including the CHOP regimen alone or combined with low-dose cyclophosphamide has been reserved for patients with overt malignancy, with monitoring EBV DNA levels suggested as a measure of response to treatment.10
The patient we describe has an unusual cause of visual blurring and papilledema that exemplifies the need for vigilance and early detection of PTLD in the setting of unexplained infectious syndrome after solid organ transplantation.
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Disclosure: Author disclosures are provided at the end of the article.
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