Slowly progressive or subacute visual impairment

Slowly progressive or subacute visual impairment

I. On one eye

1. 1. Optic neuropathy or retrobulbar neuritis
2. 2. Ischemic neuropathy
3. 3. "Alcohol-tobacco" (B12-deficiency) optic neuropathy.
4. 4. Tumor of the anterior cranial fossa and orbit, pseudotumor of the orbit.
5. 5. Eye diseases (uveitis, central serous retinopathy, glaucoma, etc.)

II. On both eyes

1. Ophthalmological causes (cataract, some retinopathies).
2. Leber's hereditary optic neuropathy and Wolfram syndrome.
3. Uremic optic neuropathy.
4. Mitochondrial diseases, in particular, Kearns-Sayre syndrome (more often - pigmentary retinopathy, rarely - optic neuropathy).
5. Dysthyroid orbitopathy (optic neuropathy due to compression of the optic nerve by enlarged rectus muscles at the apex of the orbit).
6. Nutritional neuropathy.
7. Neurofibromatosis Recklinghausen type I.
8. Degenerative diseases of the nervous system involving the optic nerves and retina.
9. Chronic increase in intracranial pressure.
10. Iatrogenic (chloramphenicol, amiodarone, stepomycin, isoniazid, penicillamine, digoxin).

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]

I. Slowly progressive or subacute deterioration of vision in one eye

Optic neuropathy or retrobulbar neuritis. Subacute monocular visual loss in young adults without headache and normal ultrasound imaging suggests the possibility of developing optic neuropathy.

A tumor may be suspected if the optic disc protrudes. With optic disc edema, vision also deteriorates gradually. In the case of retrobulbar neuritis, the inflammatory process occurs in the retroorbital part of the nerve. Therefore, in the acute stage, ophthalmoscopy does not reveal anything. Conducting visual evoked potentials reveals functional disorders in the optic nerve. In more than 30% of cases, retrobulbar neuritis is the first manifestation of multiple sclerosis, but it can also occur at later stages of the disease. If the patient is known to have multiple sclerosis, then there are no diagnostic problems. If not, then it is necessary to carefully question the patient about typical symptoms and signs of the disease and fully examine him/her using clinical and paraclinical methods. If optic neuritis appears at the initial stage of multiple sclerosis, then clinical searches for other focal symptoms may be unsuccessful. In this case, a full electrophysiological study program should be performed, including bilateral visual evoked potentials (cranial nerves II), blink reflex (cranial nerves V and VII), somatosensory evoked potentials with stimulation of the median and tibial nerves, as well as neuroimaging examination.

Ischemic retinopathy. In the elderly, ischemic damage to the optic nerve may cause slow development of similar symptoms. Fluorescein angiography is required to demonstrate impaired arterial perfusion. Atherosclerotic narrowing of the internal carotid artery is often seen.

"Alcohol-tobacco" optic neuropathy (vitamin B12-deficiency) may begin with deterioration of vision in one eye, although damage to both eyes is possible. The time of development is rather uncertain. The cause of the disease is not the toxic effect of tobacco or alcohol, but a lack of vitamin B12. The presence of vitamin B12 deficiency is often observed with alcohol abuse. B12 deficiency, causing subacute combined degeneration of the spinal cord, also leads to scotomas and optic atrophy.

Blood alcohol levels are measured, and general and neurological examinations are performed. Often, a "glove and sock" type of sensory loss, absent reflexes in the legs, and electrophysiological evidence of a demyelinating process, mainly in the spinal cord, are found. This is demonstrated by some impairment of SSEPs (somatosensory evoked potentials) with normal or nearly normal peripheral nerve conduction. Vitamin B12 absorption deficiency is detected by blood and urine tests.

Tumor. Tumors of the anterior cranial fossa and orbit may manifest as a steadily increasing deterioration of vision in one eye. In young patients, this is usually a case of optic nerve glioma (compression neuropathy of the optic nerve). Apart from loss of vision, it is difficult to identify any other symptoms at first. Then, compression of the optic nerve or chiasm manifests itself as pallor of the optic disc, often various defects in the visual fields of both eyes, headache. The disease progresses over several months or years. Causes of compression include a tumor (meningioma, optic glioma in children, dermoid tumors), carotid artery aneurysm (leading to impaired eye movements), carotid calcification, etc.

Often, children do not even complain of headaches. Routine X-ray examination can reveal the expansion of the optic canal. Neuroimaging (CT, MRI) makes it possible to detect a tumor.

In adult patients, tumors may appear anywhere in the anterior cranial fossa that can ultimately cause compression optic neuropathy (meningioma, metastatic tumor, etc.).

Often, visual impairment is accompanied by personality changes. Patients become inattentive to their work and family, do not take care of their appearance, and their sphere of interests changes. People around them notice a decrease in initiative. The degree of these changes is tolerable. Patients rarely seek medical help for this reason.

Neurological examination reveals pallor of the optic disc and decreased direct and consensual pupillary light reactions. Other "anterior cranial fossa findings" may include unilateral anosmia, which does not alter the patient's sense of smell or taste but is detectable by special examination methods, and sometimes a congested optic nerve papilla on the other side (Foster-Kennedy syndrome).

Slow development of compression neuropathy is observed in aneurysm, arteriovenous malformation, craniopharyngioma, pituitary adenoma, pseudotumor cerebri.

Ocular (orbital) pseudotumor, caused by enlargement of one or more muscles in the orbit, is accompanied by impaired eye movements, mild exophthalmos, and conjunctival injection, but rarely causes decreased visual acuity. This syndrome is unilateral, but sometimes the other eye is involved. Ultrasound reveals enlargement (increase in volume) of the orbital muscles, as in dysthyroid orbitopathy syndrome.

Some ophthalmological diseases (uveitis, central serous retinopathy, glaucoma, etc.) can lead to a slow deterioration of vision in one eye.

II. Slowly progressive or subacute deterioration of vision in both eyes

Ophthalmologic causes (cataract; some retinopathies, including paraneoplastic, toxic, nutritional) lead to a very slow decrease in visual acuity in both eyes; they are easily recognized by an ophthalmologist. Diabetic retinopathy is one of the common causes of such a decrease in vision. Retinopathy can develop with systemic (systemic lupus erythematosus), hematological (polycythemia, macroglobulinemia) diseases, sarcoidosis, Behcet's disease, syphilis. Elderly people sometimes develop the so-called senile macular degeneration. Pigmentary degeneration of the retina accompanies many storage diseases in children. Glaucoma, if inadequately treated, can lead to a progressive decrease in vision. Volumetric and inflammatory diseases of the orbit can be accompanied not only by a decrease in vision, but also by pain.

Leber's hereditary optic neuropathy and Wolfram syndrome. Leber's hereditary optic neuropathy is a multisystem mitochondrial disorder caused by one or more mitochondrial DNA mutations. Less than half of affected patients have a family history of the disease. Onset is usually between 18 and 23 years of age with decreased vision in one eye. The other eye is inevitably affected within a few days or weeks, i.e. subacutely (rarely after a few years). Visual field examination reveals a central scotoma. Fundus examination shows characteristic microangiopathy with capillary telangiectasias. Dystonia, spastic paraplegia, and ataxia are sometimes associated with this disorder. Some families may have these neurological syndromes without optic atrophy; other families may have optic atrophy without associated neurological syndromes.

Wolfram syndrome is also a mitochondrial disease and is characterized by a combination of diabetes mellitus and diabetes insipidus, optic atrophy, and bilateral sensorineural hearing loss (abbreviated to DID-MOAM syndrome). Diabetes mellitus develops in the first decade of life. Vision loss progresses in the second decade, but does not lead to complete blindness. Diabetes is not considered a cause of optic atrophy. Sensorineural hearing loss also progresses slowly and rarely leads to severe deafness. The disease is based on a progressive neurodegenerative process. Some patients have concomitant neurological syndromes, including anosmia, autonomic dysfunction, ptosis, external ophthalmoplegia, tremor, ataxia, nystagmus, epileptic seizures, central diabetes insipidus, and endocrinopathy. Various mental disorders are common. The diagnosis is established clinically and by DNA diagnostic methods.

Uremic optic neuropathy - bilateral disc edema and decreased visual acuity, sometimes reversible with dialysis and corticosteroids.

Kearns-Sayre syndrome (a variant of mitochondrial cytopathy) is caused by a deletion of mitochondrial DNA. The disease begins before age 20 and presents with progressive external ophthalmoplegia and pigmentary degeneration of the retina. In addition, at least one of the following three manifestations must be present for the diagnosis to be made:

1. intraventricular conduction disturbance or complete atrioventricular block,
2. increased protein in cerebrospinal fluid,
3. cerebellar dysfunction.

Dysthyroid orbitopathy rarely leads to optic neuropathy due to compression of the optic nerve by the dilated rectus muscles at the orbital apex. However, such cases do occur in neurological practice. Orbital ultrasound is used for diagnosis.

Nutritional neuropathy of the optic nerve is known in alcoholism, B12 deficiency. The literature describes a similar so-called Jamaican neuropathy and Cuban epidemic neuropathy.

Neurofibromatosis Recklinghausen type I - multiple brown spots on the skin of a "café au lait" color, hamartoma of the iris, multiple neurofibromas of the skin. This picture may be accompanied by optic glioma, neurofibromas of the spinal cord and peripheral nerves, macrocephaly, neurological or cognitive deficits, scoliosis and other bone abnormalities).

Degenerative diseases of the nervous system, involving the optic nerves and retina (mucopolysaccharidoses, abetalipoproteinemia, ceroid lipofuscinoses, Niemann-Pick disease, Refsum disease, Bardet-Biedl syndrome, etc.) In these diseases, slowly progressive vision loss is observed in the context of massive polysystemic neurological symptoms, which determine the clinical diagnosis.

Chronic increase in intracranial pressure, regardless of its cause, can lead to slowly progressive decrease in vision even in the absence of local impact on the visual pathways. These diseases are accompanied by headache, swelling of the optic disc, and an increase in the size of the blind spot. Focal neurological symptoms associated with decreased vision depend on the localization and cause of the pathological process (tumors of the occipital or temporal lobe, other volumetric processes of this localization, pseudotumor cerebri).

Iatrogenic optic neuropathy can develop with long-term use of certain medications (chloramphenicol, cordarone, streptomycin, isoniazid, penicillamine, digoxin).

Rare causes of acute and/or chronically progressive visual impairment such as Behcet's disease, radiation damage to the optic nerve, sinus thrombosis, fungal infections, and sarcoidosis are not described here.

Diagnostics

Clarification of the cause of slowly progressing visual impairment requires measurement of visual acuity, examination by an ophthalmologist to exclude eye disease, clarification of the nature of the visual field limitation, neuroimaging examination, examination of cerebrospinal fluid, evoked potentials of different modalities, and somatic examination.

[ 8 ], [ 9 ], [ 10 ], [ 11 ]