What Is Entrapment Neuropathy?

As intraorbital or intracranial tumors or metastatic cancers are directly compressed or infiltrated, they are sometimes misdiagnosed clinically and should be vigilant.

Basic Information

Visiting department

Ophthalmology

Common causes

Caused by direct compression or infiltration of orbital or intracranial tumors or metastatic cancer

Common symptoms

Unilateral progressive and painless occult vision loss

Causes of oppressive optic neuropathy

Included in the eye are glioma, meningiomas, hemangiomas, lymphangiomas, teratomas, and malignancies. Occupational lesions in the saddle area are more common in the skull, such as pituitary adenoma, craniopharyngioma, etc. Other anterior wings, sphenoid winglets, saddle nodules, sphenoid ridges, and olfactory sulcus meningiomas are also not seen. The internal carotid artery is curved, hardened or aneurysms that occur in the terminal branches of the internal carotid artery or in the anterior cerebral artery or anterior communicating artery can also gradually compress the unilateral optic nerve. Metastatic cancers such as nasopharyngeal carcinoma, Hodgkin's disease, frontal glioma and astrocytoma, hamartoma, tuberculoma, sarcoidosis, and cancerous meningeal disease can all be caused. Pituitary stroke can cause sudden loss of monocular vision. Sinus cysts and polyp compression, especially sphenoid sinus and posterior ethmoid sinus are more easily concealed. Hypertrophy of the eye caused by thyroid lesions, elevated intraorbital pressure, and skeletal deformities can all compress the optic nerve.

Clinical manifestations of compression optic neuropathy

Unilateral progressive and painless occult visual loss are the main clinical features. Vision is often hazy and fuzzy, and temporary darkening can occur immediately when looking at a certain location, which is caused by direct compression of the optic nerve or blood vessels. Loss of vision is often found by accident. Aneurysms can cause eye pain. Because intracranial tumors can oppress the ipsilateral optic nerve and cause optic nerve atrophy, the contralateral eyes of the contralateral cranial hypertension can present optic disc edema, which is often called clinically Foster kennedy syndrome. Hypophysis is a common symptom of saddle-occupied lesions, especially pituitary adenomas and craniopharyngiomas. Amenorrhea, male fistula, smooth skin, and loss of pubic hair appear. Meningiomas and aneurysms do not have endocrine symptoms. .

Compression optic neuropathy

Imaging studies can assist with diagnosis and differential diagnosis. Orbital CT or enhanced MRI, saddle or pituitary enhanced MRI, and CTA or DSA of the skull vessels can be selected.

The visual field examination is of great significance. The central dark spot can be seen early, and it can quickly expand to the surrounding area. It can maintain a stage of vision, retain the peripheral edge, and finally disappear. In some cases, segmental visual field defects can be caused by different compression sites, which are early features that expand inward and eventually affect central vision. The visual field defect on the opposite side of the temporal superiority is usually mild, due to the involvement of the cross-nasal fibers. The inferior fibers sacrifice forward, close to the front of the optic bundle, and there is a dark spot connected to the ipsilateral center. If this sign appears, it can almost be considered a compression optic neuropathy, which has diagnostic significance. Occasionally, crosswise ipsilateral hemianopia is due to the involvement of the ipsilateral fascicle, and lateral arches, vertical nasal and temporal hemianopia are still visible.

Diagnosis of compression optic neuropathy

It is difficult to diagnose based on clinical symptoms and signs alone. Neuroradiological examination is of great value for orbital and cranial space occupying lesions. Orbital, plain skull or multi-layer compression optic neuropathy, optic nerve hole and other photographs are of considerable value. Recent development of CT and MRI of the skull can confirm the diagnosis of intraorbital and intracranial space occupying lesions. Arterial angiography should be performed for suspected aneurysms. Visual field and color vision tests can help identify optic nerve abnormalities, and visual electrophysiology tests can help diagnose. For unexplained unilateral or bilateral progressive vision loss, no improvement after treatment or temporary improvement in vision loss, clinical diagnosis of optic neuritis, retrobulbar optic neuritis or optic nerve atrophy, etc., intracranial space occupying lesions should be considered The possibility of oppressing the optic nerve.

Treatment of oppressive optic neuropathy

If the orbital tumor is located behind the orbit, it is generally feasible to remove the orbital surgery. If the tumor is located in the orbital and cranial joint, it can be combined with neurosurgery, especially the frontal craniotomy. It has more advantages and is now generally implemented. Intracranial space-occupying lesions require neurosurgery. Meningiomas are the most common unilateral optic nerve compression lesions and can be completely removed and cured at an early stage. Later tumors, such as the expansion of the anterior cerebral artery and internal carotid artery, are difficult to remove completely. If some cases are negative after multiple examinations, and intracranial space occupying lesions are still suspected, surgical exploration is feasible. If the optic nerve is not completely damaged after surgery, vision can be rapidly improved. Aneurysms can be treated by interventional methods in brain surgery.