Lanning B. Kline

Radiation Optic Neuropathy after Stereotactic Radiosurgery

PURPOSEnThe purpose of the study is to report the occurrence of optic neuropathy after stereotactic radiosurgery for perichiasmal tumors.nnnMETHODSnRecords of four patients with visual deterioration after stereotactic radiosurgery were reviewed, including clinical findings, neuroimaging results, and treatment methods.nnnRESULTSnOptic neuropathy developed 7 to 30 months after gamma knife radiosurgery. All patients experienced an abrupt change in visual function. Clinical findings indicated anterior visual pathway involvement. Patterns of field loss included nerve fiber bundle and homonymous hemianopic defects. Gadolinium-enhanced magnetic resonance imaging (MRI) showed swelling and enhancement of the affected portion of the visual apparatus in three patients. Systemic corticosteroids were administered in all patients and one partially recovered. One patient also received hyperbaric oxygen without improvement.nnnCONCLUSIONSnAlthough rare, optic neuropathy may follow radiosurgery to lesions near the visual pathways. Careful dose planning guided by MRI with restriction of the maximal dose to the visual pathways to less than 8 Gy will likely reduce the incidence of this complication.

Radiation optic neuropathy.

Following surgery for pituitary adenoma, radiation therapy is an accepted treatment in reducing tumor recurrence. However, a potential therapeutic complication is delayed radionecrosis of perisellar neural structures, including the optic nerves and chiasm. This particular cause of visual loss, radiation optic neuropathy (RON), has not been emphasized in the ophthalmologic literature. Four cases of RON seen in the past five years are reported. Diagnostic criteria include: (1) acute visual loss (monocular or binocular), (2) visual field defects indicating optic nerve or chiasmal dysfunction, (3) absence of optic disc edema, (4) onset usually within three years of therapy (peak: 1-1 1/2 years), and (5) no computed tomographic evidence of visual pathway compression. Pathologic findings, differential diagnosis and therapy will be discussed in outlining the clinical profile of RON.

The Tolosa-Hunt syndrome

Painful ophthalmoplegia due to idiopathic granulomatous inflammation of the cavernous sinus/superior orbital fissure has been termed Tolosa-Hunt syndrome (THS). This report is based upon 146 patients with this syndrome published in the English literature. The clinical profile, natural history, diagnostic evaluation, pathologic findings, differential diagnosis, and therapy of THS are presented. Careful initial patient examination and scrupulous follow-up evaluation are essential, as THS is categorically a diagnosis of exclusion. While the etiology of THS is unknown, current pathogenetic theories are reviewed.

Congenital Horner's syndrome resulting from agenesis of the internal carotid artery

OBJECTIVEnTo report a patient with agenesis of the right internal carotid artery associated with ipsilateral, congenital Homers syndrome.nnnDESIGNnCase report.nnnMETHODSnA 30-year-old woman, with a past history of migraine headaches, underwent neuro-ophthalmologic and neuroradiologic evaluation for transient visual obscurations and congenital Horners syndrome.nnnRESULTSnA right, third-order neuron Horners syndrome was confirmed with 1% hydroxyamphetamine topical drops. Cranial magnetic resonance imaging revealed an absent right internal carotid artery flow void, computed tomography demonstrated absence of the right carotid canal, and cerebral angiography confirmed absence of the right internal carotid artery. No atheromatous lesions were found and the results of coagulation studies were normal.nnnCONCLUSIONSnAgenesis of the internal carotid artery is a rare cause of congenital Horners syndrome. The cause of transient visual blurring in the current patient remains unproven.

Progression of Visual Defects in Ischemic Optic Neuropathy

Six patients with nonarteritic ischemic optic neuropathy experienced worsening of visual acuity and field loss during the six-week period after onset (range, three to six weeks), without apparent ophthalmoscopic changes. Thereafter, visual function remained unchanged. Various medications were used, but none prevented deterioration of visual function. Although not a widely recognized phenomenon, progression of visual deficit occurred in these patients in the early weeks after onset of ischemic optic neuropathy.

Computed Tomographic Evaluation of the Cavernous Sinus

In evaluating over 300 patients with sellar and parasellar lesions, the computed tomographic (CT) appearance of the cavernous sinus was studied. Optimal visualization of the cavernous sinus was obtained with continuous contrast enhancement of both axial and coronal tomograms. The coronal projection and reformatted views provided imaging of the cranial nerves within the cavernous sinus. In addition to the physiologic CT appearance of the cavernous sinus, a variety of pathologic conditions are illustrated. CT criteria suggesting an abnormal cavernous sinus are: (1) asymmetry of size; (2) asymmetry of shape, particularly the lateral wall; and (3) focal areas of abnormal density within the sinus.

Ophthalmologic involvement in the syndrome of headache, neurologic deficits, and cerebrospinal fluid lymphocytosis ☆

PURPOSEnTo emphasize that papilledema and other ophthalmic manifestations may occur in the syndrome of headache, neurologic deficits, and cerebrospinal fluid lymphocytosis (HaNDL).nnnDESIGNnTwo interventional case reports.nnnMETHODSnTwo patients were seen with ophthalmologic findings, including decreased vision, papilledema, sixth nerve palsy, and a variety of neurologic deficits. Each underwent cerebrospinal fluid analysis and intracranial pressure measurement by spinal tap and neuroimaging studies to confirm the diagnosis of HaNDL.nnnRESULTSnBoth patients received acetazolamide to lower intracranial pressure. The first patient had complete resolution of signs and symptoms. The second, who was also given systemic corticosteroids, was left with diminished visual acuity in the right eye with nasal visual field loss and optic atrophy.nnnCONCLUSIONSnThe diagnosis of HaNDL is one of exclusion, which must be made in conjunction with a neurologist. HaNDL may be accompanied by elevated intracranial pressure and papilledema. As in other disorders causing papilledema, these patients may have permanent visual sequelae. Recognition by the ophthalmologist of this rarely reported syndrome will facilitate prompt patient diagnosis and treatment.

Magnetic resonance imaging of the optic chiasm

Magnetic resonance imaging (MRI) has become an important diagnostic modality for the evaluation of patients with chiasmal or perichiasmal disease. In this review, normal chiasmal anatomy and various pathologic conditions will be illustrated to demonstrate the advantages of MRI over computed tomography (CT). MRI is the neuroimaging method of choice in chiasmal evaluation, but sometimes it may be complemented by CT scanning.

Big muscles and big nerves

For 11 years, a 50-year-old woman with euthyroid Graves disease experienced intermittent exacerbations of her orbitopathy associated with a decline in visual acuity. On each occasion, treatment with systemic corticosteroids led to prompt recovery of vision. Upon referral for consideration for orbital decompressive surgery, computed tomography and magnetic resonance imaging scanning detected bilateral optic-nerve sheath meningiomas, as well as typical findings of Graves disease. Orbital radiation therapy led to stabilization of visual function and orbital findings, eliminating the need for systemic steroids. To our knowledge, this is the first reported case of Graves disease associated with bilateral optic nerve sheath meningiomas.

Recovery of Vision after Presumed Direct Optic Nerve Injury

Immediate loss of light perception after direct optic nerve injury is usually irreversible. Our patient sustained presumed direct optic nerve injury because of a shotgun injury with loss of light perception, absent pupillary response, and absent visual-evoked potential. A small pupillary response was noted 12 days after injury, light perception returned by 15 days, and visual acuity was 20/100 at 4 months. A variety of pathophysiologic mechanisms may lead to visual loss after direct optic nerve injury. It is important to recognize that blindness is not always permanent in these cases despite the results of initial clinical and electrophysiologic testing.