Ophthalmoplegia

Ophthalmoplegia is a paralysis of individual groups or all the muscles of the eye. When the internal groups are affected, the pupils dilate, there is a violation of accommodation. The external form is manifested by diplopia, ptosis and the inability to carry out friendly movements with the eyeballs. To make a diagnosis, computer tomography of the brain, ultrasound of the eye, proserin test, angiography of cerebral vessels are used. Additionally, skull radiography, visometry and perimetry are used. Treatment tactics are determined by the etiology of the disease, including drug therapy, surgical interventions and physiotherapy.

General information

Ophthalmoplegia is a widespread nosology in ophthalmology, which is associated with the presence of many etiological factors leading to its development. Epidemiological information varies significantly with different forms. Severe course of infectious diseases in 85% of cases leads to paralysis of the external muscles of the eye, while the progressive supranuclear form occurs with a frequency of 1:16000. The first manifestations of ophthalmoplegia against the background of mitochondrial pathology are diagnosed in children from 9 months. Other clinical variants can develop at any age. Pathology occurs with the same frequency among men and women.

Causes

Paralysis of the external and internal muscles is a polyethological pathology. The main reasons are presented:

• Neoplasms. Tumors localized in the area of the cavernous sinus or the upper orbital fissure lead to the development of this nosology.
• Infectious diseases. The defeat of the neuromuscular apparatus of the eyes is observed in tetanus, botulism, diphtheria. Less often, paralysis of the eye muscles causes a long course of syphilis or tuberculosis of the central nervous system.
• Intoxication. The internal form often occurs with prolonged contact with lead, uncontrolled intake of barbiturates and severe alcohol poisoning.
• Brain damage. Ophthalmoplegia develops against the background of traumatic brain injury, stroke, encephalitis and a group of demyelinating diseases (multiple sclerosis, Devik’s disease).
• Endocrine ophthalmopathy. Violation of the functioning of the eye muscles is revealed against the background of hormonal imbalance associated with diabetes mellitus, thyroid pathology.
• Mitochondrial diseases. Mutations of mitochondrial DNA lead to the development of progressive ophthalmoplegia. Paralysis often occurs a second time on the background of myasthenia gravis.

Pathogenesis

The disease develops due to damage to the cranial nerves (oculomotor, block, diverting), which innervate the ocular muscles in the brain stem region, at the supranuclear, radicular, neural and muscular levels. Violation of neuromuscular transmission when external muscle fibers are damaged leads to loss of their tone and inability to perform eye movements. With the internal form, isolated damage occurs to the nuclei of the III pair of cranial nerves. The absence of pupillary reaction is caused by dysfunction of sympathetic and parasympathetic fibers, which normally innervate the sphincter and dilator of the pupil.

Paralysis of the internal rectus muscle leads to the impossibility of reflex narrowing and expansion of the iris opening of the eyeball, which is manifested by a decrease in the ability to physiological accommodation. With the mitochondrial nature of the disease, gene mutations cause a change in ATP synthesis and an excess of free radicals inside the cell. This leads to a violation of the release of energy by organic substances and its accumulation in the form of macroergic phosphate compounds. Pathology of energy metabolism caused by mutant DNA causes the development of phenotypic manifestations of ophthalmoplegia in the patient.

Classification

There are one- and two-sided ophthalmoplegia, congenital and acquired forms of the disease. The congenital variant is often combined with other malformations of the eye (splitting of the eyelid, epicanthus). Acquired paralysis has an acute or chronic course. Depending on which muscle group is involved in the pathological process, the following forms of the disease are distinguished:

• External. It is accompanied by paralysis of the external muscles, which leads to immobility of the eyeball and ptosis.
• Internal. It is manifested by paralysis of the muscles of the iris and ciliary body, which is caused by dysfunction of the internal muscle group.
• Partial. It is characterized by the defeat of individual muscle fibers, therefore only certain movements are disturbed.
• Full. This is the most severe form of ophthalmoplegia, since all muscle groups of the eye are involved in the process.
• Supranuclear. It is accompanied by a “paralysis” of the gaze due to the localization of the lesion at the level of the cerebral hemispheres.
• Internuclear. In this form, the process of passing the pulse along the nerve fibers, which are responsible for the simultaneous movements of the eyeballs in a certain direction, is disrupted.

Symptoms

Clinical symptoms are determined by the form of the disease. With external ophthalmoplegia, patients complain of the inability to move the eyeball, drooping of the upper eyelid, double vision. Patients note excessive lacrimation. Due to the uneven distribution of the tear film, dryness of the eyes increases, accompanied by pronounced discomfort, burning or itching. Paralysis of the inner group of muscle fibers is manifested by pupil dilation. Patients have impaired accommodation, there is no reaction to light, but the mobility of the eyeball is preserved. The full form is characterized by a combination of all the above symptoms.

Pain syndrome occurs only with ophthalmoplegia in patients with Toulouse-Hunt syndrome or ophthalmoplegic migraine. With a supranuclear lesion, patients are not able to direct their gaze in the right direction at will. Patients with the internuclear form note that they cannot simultaneously look in one direction with both eyes. A frequent concomitant symptom is involuntary eye movements that cannot be consciously controlled. Acute acquired ophthalmoplegia is a symptom of damage to the meninges, severe poisoning or infectious pathology. The chronic course indicates progressive paralysis or multiple sclerosis.

Complications

Paralysis of the internal muscles of the eyeball leads to a violation of accommodation and a decrease in visual acuity. The internuclear form is complicated by nystagmus. Patients with ophthalmoplegia are at risk of developing infectious and inflammatory diseases of the anterior eye (conjunctivitis, keratitis, blepharitis). This is due to the fact that some patients have impaired functioning of the eyelids, lacrimal and meibomian glands. If the disease is based on an isolated lesion of the oculomotor nerve, then there is a high probability of exophthalmos. Paralysis of the eye muscles is accompanied by facial asymmetry. A common complication of ophthalmoplegia is xerophthalmia. Patients are at risk of traumatic injuries due to disorientation in space.

Diagnostics

Diagnosis requires a physical examination and a special complex of ophthalmological studies. During an external examination, dilated pupils, ptosis, and a violation of eye movement symmetry can be visualized. Diagnostic measures include:

• CT of the brain. Computed tomography is used to visualize neoplasms of the brain and the cavity of the eye socket.
• Ultrasound of the eyes. The technique makes it possible to study the state of the orbital cavity and detect local changes in the eyeball.
• Angiography of the brain. The study reveals vascular aneurysms, signs of carotid artery arteritis, cavernous sinus thrombosis.
• A proserine sample. The results of the prozerin test are evaluated 30 minutes after it is performed. The diagnosis of ophthalmoplegia confirms the negative result of the study, in which the severity of ptosis does not change, the reaction of the pupils does not occur.
• Radiography of the skull. It is used to visualize traumatic bone injuries, to study the condition of the sinuses of the nose.
• Perimetry. The study is carried out to determine the boundaries of the field of vision. In patients with the external form of the disease, they are significantly narrowed.
• Visometry. Measurement of visual acuity is indicated, because with internal ophthalmoplegia, a number of patients have visual dysfunction. Most patients with mitochondrial etiology are diagnosed with myopia.

If the development of nosology is caused by neoplasms, an oncologist’s consultation is required. With severe neurological symptoms, a neurologist’s examination is indicated. If the mitochondrial genesis of ophthalmoplegia is suspected, molecular genetic studies are carried out. The diagnosis can be confirmed with the help of biochemical diagnostics (detection of cytochrome C-oxidase-negative fibers, decreased activity of enzymes of the respiratory chain complex).

Treatment

Therapeutic measures are aimed at eliminating the etiological factor of the disease. Regardless of the cause that caused the violation of the passage of the neuromuscular impulse, patients are shown vitamins B6, B12, C and preparations of the nootropics group. The treatment plan includes:

• Drug therapy. Conservative tactics are used for the infectious nature of the disease. In such cases, a set of therapeutic measures is needed to eliminate the underlying pathology. In inflammatory processes, nonsteroidal anti-inflammatory drugs are prescribed. Anticholinesterase drugs are indicated to restore muscle tone. With ophthalmoplegia of endocrine origin, it is necessary to correct hormonal imbalance with the help of systemic therapy. Instillation of glucocorticosteroids is applied topically.
• Surgical intervention. Surgical treatment is used to detect neoplasms of the cavernous sinus and orbital fissure or traumatic brain injuries and orbital cavity. By surgical correction, ptosis of the eyelid is eliminated in the external form of ophthalmoplegia.
• Physical therapy. This is an auxiliary method of treatment, which is used after the elimination of the etiological factor and the relief of urgent pathology. In practical ophthalmology, acupuncture, electro- and phonophoresis with drugs (antispasmodics, analgesics) are used.

With the mitochondrial genesis of the disease, only experimental treatment methods are available. To date, natural electron carriers of the respiratory chain (succinic acid preparations, Cytochrome C) are used. The effectiveness of the use of carnitine and nicotinamide is being studied.

Prognosis and prevention

In most cases, the prognosis for ophthalmoplegia is favorable. After the elimination of the underlying disease, the functions of the visual organ are fully restored. Irreversible changes occur only with the demyelinating nature of ophthalmopathology. Specific prevention has not been developed. Non-specific preventive measures are reduced to the use of personal protective equipment at work (helmets, glasses), timely treatment of infectious diseases. Patients need to minimize contact with substances whose intoxication provokes the development of ophthalmoplegia (lead, barbiturates).