Faculty Bibliography

We examined four patients with dorsolateral pontomedullary lesions and skew deviation, with ocular torsion of varying symmetry. In three patients, the hypotropic eye was excyclodeviated relative to the fellow eye. Observations of these patients, combined with recent evidence, suggest that cyclodeviation is a frequent component of skew deviation and may result from variable involvement of utricular, semicircular canal, and cerebelloocular pathways. Although cyclodeviation is a feature of trochlear-nerve palsies, its presence does not exclude skew deviation and underlying brainstem lesions.

Spontaneous regression of hematologic malignancies is not uncommon and occurs in a wide variety of lymphomas and leukemias. In contrast, spontaneous remission of neurologic symptoms produced by these tumors is exceedingly rare. We report a patient with central nervous system acute lymphoblastic leukemia who experienced at least one spontaneous remission of papilledema and sixth nerve palsy. This represents, to our knowledge, the first case of spontaneous remission of neuro-ophthalmologic signs in a patient with acute leukemia. We conclude that meningeal leukemia may have a protracted course, and that spontaneous remission of neuro-ophthalmologic findings should not be so readily ascribed to a benign process in a patient with preexisting leukemia.

We present four patients with sarcoidosis of the anterior visual pathways. The first patient presented with unilateral visual loss, a mass lesion at the optic nerve head, and an enlarged orbital optic nerve. The second patient presented with bilateral progressive painless visual loss, associated with optic nerve pallor and visual field loss. In these two patients, optic nerve biopsy was diagnostic of sarcoidosis. The third patient developed optic nerve and chiasmal involvement after sarcoidosis was established by lacrimal gland biopsy. The fourth patient had optic nerve, pulmonary, and lymph node involvement with sarcoidosis. A conjunctival and lung biopsy were diagnostic. Computed tomography and magnetic resonance imaging have greatly facilitated diagnosis of sarcoidosis of the anterior visual pathways. Sarcoidosis of the anterior visual pathways may occur alone or in association with other ocular or systemic manifestations. A conjunctival or lacrimal gland biopsy may be preferable as the initial diagnostic approach. Treatment of patients with this condition may require systemic immunosuppression, in addition to corticosteroids, to prevent permanent visual loss.

A patient with Lyme disease developed an isolated sixth nerve palsy at the end of a 1 month course of oral antibiotics. Magnetic resonance imaging disclosed high-signal abnormality at the left pontomedullary junction, implicating involvement of the distal sixth nerve fascicle. Although facial numbness ensued during a subsequent course of intravenous antibiotics, corticosteroid therapy was associated with prompt improvement of neurologic signs, suggesting an immunologic mechanism for the central nervous system dysfunction.

Pregnancy may exacerbate underlying neurologic illness or may precipitate an acute neurologic emergency such as pituitary apoplexy. Care is directed to both mother and fetus in a manner designed to optimize the physiologic stability of both. A 'team approach' is often needed

Single-photon emission computed tomography (SPECT) with 99mTc-hexamethylpropyleneamine oxime (HMPAO) was used to investigate changes in cerebral blood flow in seven patients with cortical visual impairment. Traumatic brain injury (TBI) was the cause of cortical damage in two patients, cerebral ischemia in two patients and carbon monoxide (CO) poisoning, status epilepticus and Alzheimer's Disease (AD) each in three separate patients. The SPECT scans of the seven patients were compared to T2-weighted magnetic resonance image (MRI) scans of the brain to determine the correlation between functional and anatomical findings. In six of the seven patients, the qualitative interpretation of the SPECT studies supported the clinical findings (i.e., the visual field defect) by revealing altered regional cerebral blood flow (rCBF) in the appropriate regions of the visual pathway. MR scans in all of the patients, on the other hand, were either normal or disclosed smaller lesions than those detected by SPECT. We conclude that SPECT may reveal altered rCBF in patients with cortical visual impairment of various etiologies, even when MRI studies are normal or nondiagnostic.

Two patients with thalamic infarctions presented with vertical gaze palsies. Magnetic resonance imaging (MRI) demonstrated extension of the lesions into the upper midbrain. A common vascular supply to both areas, and the inability of computed tomography (CT) scans to adequately assess posterior fossa structures, necessitate MRI of the mesencephalon in the assessment of all patients with vertical gaze dysfunction. These cases shed further doubt regarding a specific role of the thalamus in control of vertical eye movements.

We report 2 patients who had eyelid retraction and eyelid lag with minimal impairment of vertical gaze. In both patients, magnetic resonance imaging demonstrated a circumscribed unilateral lesion immediately rostral and dorsal to the red nucleus involving the lateral periaqueductal gray area. Our clinical and radiological findings support the existence of a premotor eyelid control center in the region of the nucleus of the posterior commissure.

OBJECTIVE: A retrospective study was performed to delineate the clinical characteristics of symptomatic unruptured aneurysms. DESIGN: Patient histories, operative reports, and angiograms in 111 patients with 132 unruptured aneurysms were reviewed. SETTING: Tertiary care university hospital. PATIENTS: One hundred eleven patients with 132 unruptured intracranial aneurysms were studied. There were 85 women and 26 men, with a mean age of 51.2 years (age range, 11 to 77 years). Many patients were referred by community neurologists and neurosurgeons for further evaluation and neurosurgical management. RESULTS: Fifty-four symptomatic patients were identified. Group 1 (n = 19; mean aneurysm diameter, 2.1 cm) had acute symptoms: ischemia (n = 7), headache (n = 7), seizure (n = 3), and cranial neuropathy (n = 2). Group 2 (n = 35; mean aneurysm diameter, 2.2 cm) had chronic symptoms attributed to mass effect: headache (n = 18), visual loss (n = 10), pyramidal tract dysfunction (n = 4), and facial pain (n = 3). Group 3 (n = 57; mean aneurysm diameter, 1.1 cm) had asymptomatic aneurysms. CONCLUSIONS: Acute severe headache, comparable to subarachnoid hemorrhage headache, but without nuchal rigidity, was associated with the following mechanisms: aneurysm thrombosis, localized meningeal inflammation, and unexplained. Unruptured aneurysms may be misdiagnosed as optic neuritis or migraine, or serve as a nidus for cerebral thromboembolic events. Internal carotid artery and posterior circulation aneurysms were more likely to cause focal symptoms from mass effect than were anterior cerebral artery and middle cerebral artery aneurysms. Weeks to years may elapse before their diagnosis. The absence of subarachnoid blood does not exclude an aneurysm as a cause for acute or chronic neurologic symptoms.