Faculty Bibliography

PURPOSE: To report the case of a 58-year-old man with sequential bilateral retrolaminar leukemic infiltration of the optic nerves who presented with normal-appearing optic nerves and no optic nerve enhancement. DESIGN: Interventional case report. METHODS: A 58-year-old man with chronic myelogenous leukemia (CML) developed progressive vision loss to no light perception in both eyes over four days. The patient received 14 doses of external beam irradiation and 10 cycles of intrathecal cytarabine. Despite treatment, he developed optic nerve pallor, and visual acuity remained no light perception in both eyes. CONCLUSIONS: In a patient with leukemia, leukemic optic nerve infiltration may occur even with normal-appearing optic nerves and a normal magnetic resonance image. It is important to maintain a high clinical suspicion for optic nerve infiltration so that prompt local irradiation may be initiated.

Orbital pseudotumor, also known as idiopathic orbital inflammatory syndrome (IOIS), may have protean clinical manifestations. Some presentations of IOIS may mimic common conditions such as orbital cellulitis and optic neuritis. IOIS should be considered a diagnosis of exclusion, with evaluation directed toward eliminating other causes of orbital disease. Orbital magnetic resonance imaging is the single most important diagnostic test, but serologic studies are necessary to exclude a systemic cause. Biopsy is usually not performed at presentation, as the risk of producing damage to vital structures within the orbit outweighs the benefits. Patients with multiple recurrences, or those unresponsive to therapy, should have biopsy samples taken. Corticosteroids are the mainstay of therapy and are administered for several months to ensure remission. Radiotherapy may be used in patients who fail to respond to steroids or who have a rapidly progressive course. For those patients who are refractory to both corticosteroids and radiotherapy, anecdotal reports have suggested the use of chemotherapeutic agents such as cyclophosphamide, methotrexate, and cyclosporine.

BACKGROUND: Within the past 10 years, several immunomodulatory agents (IMAs) have become available for the treatment of relapsing multiple sclerosis (MS), making therapeutic decisions more complex. We performed a systematic review of the literature to assess the efficacy and safety of these agents on physical, inflammatory, and cognitive measures of disease activity. METHODS: We identified relevant studies by searching electronic databases (MEDLINE and Current Contents) from January 1, 1993, through August 31, 2001. We included English-language reports of data from phase 3 trials of interferon beta-1b (Betaseron), 2 preparations of interferon beta-1a (Avonex and Rebif), or glatiramer acetate (Copaxone) for the treatment of relapsing MS. RESULTS: Twenty-one studies met explicit inclusion criteria. Comparison of study results indicated no differences among IMAs regarding their efficacy on relapse-related measures. Interferon beta-1a significantly reduced disability progression, whereas no significant effect of glatiramer acetate or interferon beta-1b on disability progression was seen. On inflammatory measures, all of the IMAs showed reductions in the burden of disease (T2-weighted lesions) to varying degrees. Interferon beta and glatiramer acetate reduced new lesion activity; however, interferon beta had a more profound effect. One interferon beta-1a preparation (Avonex) appeared to reduce brain atrophy, whereas glatiramer acetate showed an effect in 1 of 2 studies. Only Avonex demonstrated efficacy in slowing progression of cognitive dysfunction. CONCLUSIONS: Data show that the IMAs have similar effects on several physical and inflammatory measures. In addition, Avonex has demonstrated efficacy in slowing cognitive progression in relapsing MS. One disadvantage of interferon beta is the possibility of immunogenicity, which may occur more often with subcutaneous administration. The IMAs have similar safety and tolerability profiles.

BACKGROUND: It remains controversial whether transcervical thymectomy offers results equivalent to thymectomy by way of a median sternotomy in the treatment of myasthenia gravis. Furthermore, preoperative prognostic factors have not been clearly defined. METHODS: This study is a retrospective chart review and interview of 78 patients completing transcervical thymectomy for myasthenia gravis between 1992 and 1999. RESULTS: There were 24 men and 54 women. Mean age was 40 years (range, 13 to 78 years). Twelve patients were in Osserman class 1, 25 in class 2, 30 in class 3, and 11 in class 4 (mean, 2.5). There was no perioperative mortality and 6 (7.7%) morbidities. Mean length of stay was 1.5 days and mean follow-up, 54.6 months. The crude cumulative complete remission (asymptomatic off medications for 6 months) rate was 39.7% (n = 31). Only 8 patients (10.3%) failed to improve after transcervical thymectomy. Kaplan-Meier estimates of complete remission were 31% and 43% at 2 and 5 years, respectively. Eight patients with thymoma had a 5-year estimated complete remission rate of 75% in contrast to 43% in 38 patients with thymic hyperplasia and 36% in 32 patients with neither thymoma nor hyperplasia (p = 0.01). Twelve patients with ocular myasthenia had a 5-year estimated complete remission rate of 57%, whereas patients with mild-to-moderate (n = 55) or severe (n = 11) generalized symptoms had 5-year complete remission rates of 43% and 30%, respectively (p = 0.21). CONCLUSIONS: Overall, extended transcervical thymectomy offers results that are comparable to those published for the transsternal procedure. Patients with milder disease (including isolated ocular disease) and taking no preoperative immunosuppressive agents appear to experience higher remission rates. In contrast to previous studies, we also find that small thymomas predict better responses to thymectomy.

Idiopathic orbital inflammatory syndrome (IOIS) is a diagnosis of exclusion, requiring an evaluation to rule out other causes of orbital disease. Orbital MRI is the test of choice, but serologic studies are necessary to exclude a systemic etiology. Biopsy is usually not indicated at presentation, as the risk of causing damage to vital structures within the orbit outweighs the benefits. Patients unresponsive to therapy or those with multiple recurrences should be biopsied. The first-line treatment is corticosteroids, which may be tapered over several months. Although data is limited, radiotherapy is indicated for patients who fail to respond to steroids, or who have a rapidly progressive course. For those patients who are refractory to both corticosteroids and radiotherapy, anecdotal reports have supported the use of chemotherapeutic agents such as cyclophosphamide, methotrexate, and cyclosporine.

BACKGROUND: Despite the plenitude of reports concerning partial or complete third nerve palsies, especially as presenting symptoms with posterior communicating artery (PCoA) aneurysms, we present a patient with an unusual variation. CASE DESCRIPTION: A 66-year-old woman presented with progressive right-sided headaches and diplopia and was found to have a partial, pupil-sparing third nerve palsy. A small right-sided PCoA aneurysm, nearly indistinguishable from an infundibulum, was identified on magnetic resonance angiography and subsequent digital subtraction angiography. The third nerve palsy improved before surgical repair of the aneurysm. RESULTS: Microsurgical exploration revealed a small PCoA aneurysm, which was tethered to the third nerve by arachnoid adhesions. Adhesions were lysed and the aneurysm was repaired sparing the PCoA and its branches. The patient's third nerve function recovered completely postoperatively. CONCLUSIONS: Even a very small PCoA aneurysm may present with an improving, pupil-sparing partial third nerve palsy. Selection of patients for imaging studies should take this unusual variant into consideration. We describe the anatomy and potential mechanisms of this pupil-sparing third nerve palsy

A 21-year-old man developed an ipsilateral fourth nerve palsy, contralateral hemianopia, and contralateral hemisensory deficit as manifestations of a proximal right posterior cerebral artery aneurysm. This unusual constellation of signs reflects the involvement of the structures that run in the ambient cistern. The fourth nerve palsy and homonymous hemianopia are attributed to compression by the aneurysm. The hemisensory loss is ascribed to compromise of thalamoperforate arteries emanating from a thrombosed portion of the aneurysm.

We report a case of a patient who developed a left posterior cerebral artery aneurysm 5 years after balloon occlusion of the right internal carotid artery for a giant cavernous aneurysm. The location of the new aneurysm was outside of the primary collateral pathways to the contralateral, proximally occluded, anterior circulation, illustrating the complexity of hemodynamic factors contributing to the development of intracranial saccular aneurysms. The appearance of an aneurysm in this setting supports the hypothesis that degenerative factors and hemodynamic stresses are important in the etiology of intracranial aneurysms