Faculty Bibliography

Lyme disease is a multisystem disorder caused by infection with the Borrelia burgdorferi spirochete. The diagnosis of Lyme disease usually is based on several clinical criteria, with supportive data from laboratory testing. The presence of the bullseye skin lesion, erythema migrans, is the single pathognomonic criterion. In the 20 years since the initial description of Lyme disease in the United States, B. burgdorferi has been implicated as an etiologic agent in numerous ophthalmic and neuro-ophthalmic syndromes, involving most structures from the cornea to the cranial nerves. Neuro-ophthalmic and ocular manifestations of Lyme disease include meningitis with papilledema, cranial neuropathies, follicular conjunctivitis, nummular keratitis, and intraocular inflammation. Although an association with Lyme disease has been purported for numerous other syndromes, a definite causal relationship has not been proved in many cases. During a period of rapidly increasing awareness of Lyme disease, a high index of suspicion and poorly defined criteria for its presence have resulted in over-diagnosis of Lyme disease. In the authors' experience, the incorrect diagnosis of Lyme disease initially has been made in patients with allergic conjunctivitis, keratoconus, morning glory syndrome, craniopharyngioma, meningioma, CNS lymphoma, paraneoplastic syndrome, multiple sclerosis, sarcoid, syphilis, and functional illness. Nevertheless, this treatable infection must be an important consideration in the differential diagnosis of certain ocular or neurologic diseases.

We report a patient who presented with a painful pupil-involving third-nerve palsy. Cerebral angiography revealed a high-grade stenosis of the ipsilateral internal carotid artery with a 4-cm intraluminal thrombus. Following emergent carotid endarterectomy, the patient's partial third-nerve palsy resolved in 1 hour. A pupil-involving third-nerve palsy may be an unusual presentation of impending carotid occlusion.

PURPOSE: To present the magnetic resonance imaging findings for a patient with traumatic oculomotor nerve injury. METHODS: We examined a patient with a right pupil-involving oculomotor nerve palsy after severe closed head trauma. RESULTS: Magnetic resonance imaging of the brain demonstrated marked signal hypointensity on gradient-echo T2*-weighted images consistent with hemorrhage at the midbrain exit site of the right oculomotor nerve. CONCLUSIONS: Distal fascicular damage or partial rootlet avulsion is a mechanism of injury in some traumatic oculomotor nerve palsies. Gradient-echo T2*-weighted magnetic resonance imaging is the most sensitive method to detect hemorrhagic changes associated with shearing injury.

A 57-year-old awake man developed central neurogenic hyperventilation associated with a pontine mass. Serum pH reached as high as 7.72 with serum carbon dioxide of 6 torr. Examination of CSF during overbreathing showed that CSF pH was markedly alkaline. Pathologic study showed a well-differentiated pontine astrocytoma. The combination of alkaline CSF and an infiltrating pontine lesion supports a structural, rather than chemical, mechanism for central hyperventilation.

A 21-year-old woman presented with a two year history of progressive loss of vision in the left eye. Brain MRI revealed a supresellar mass felt to be most consistent with a meningioma. However, pathologic examination including special stains disclosed features characteristic of hemangioblastoma. Further evaluation established the diagnosis of von Hippel-Lindau disease by demonstrating retinal capillary hemangiomas, small renal and hepatic cysts, and cervico-medullary masses later confirmed to be hemangioblastomas. To date, no other family members have displayed features of this inherited syndrome.

Strobilation and polypoid budding occur at different locations in the scyphistoma (polyp). Initiation and completion of both forms of budding are inhibited by hydroxyurea (HU), which blocks 95% of DNA synthesis within 12 h. Gradients of thymidine incorporation into both cell layers of the body column precede and accompany strobilation, and an epidermal gradient precedes polypoid budding. In both, the highest labelling index is in the zone in which initiation will occur. Polypoid buds show high variation in labelling index, which is therefore not significantly different from body column labelling. Initiation and some elongation of polyp buds occurs in a small percentage of animals in HU, indicating that cell recruitment is important for these processes. Strobilation appears to be more highly dependent on localized nucleic acid synthesis than polypoid budding.

The pathogenesis of the autoimmune disease, myasthenia gravis (MG), involves an antibody-mediated attack against acetylcholine receptors (AChRs). Since the relevant antibody response is T cell dependent, a therapeutic strategy aimed at T lymphocytes actively participating in the immune reaction to AChR should result in relatively selective suppression of AChR antibody. During an active immune response, T cells express receptors for interleukin 2 (IL2). In this study, we have used a genetically engineered fusion protein comprised of the binding region of IL2 and the toxic portion of diphtheria toxin (DAB486-IL2), to attempt to treat an experimental animal model of MG in rodents. We examined the effects of treatment with DAB486-IL2 in vivo on primary, ongoing, and secondary antibody responses to purified Torpedo AChR. Treatment of mice with intraperitoneal injections of DAB486-IL2 beginning at the time of immunization inhibited the primary AChR antibody response by 50% during the treatment period. Ongoing and secondary antibody responses to AChR were not suppressed in vivo by treatment with DAB486-IL2. In comparison, DAB486-IL2 was far more potent in suppressing antibody responses and lymphoproliferation in cell culture. At a dose comparable to that given in vivo, cellular proliferation and antibody production were virtually eliminated in a secondary response in vitro. The suppressive effect of DAB486-IL2 was much more pronounced when it was given at the time of initial antigen stimulation, as compared with its effect when given during an already established antibody response. These findings suggest that the effect of the fusion toxin on AChR antibody production was due predominantly to inhibition of T cells rather than B cells.