Orbital myositis is an acute or chronic inflammation of the oculomotor muscles. The main symptoms of the disease are bursting pain in the periorbital region, muscle weakness, diplopia, limited mobility of the eyeball. The eye slit is narrowed, the eyelids are swollen. Ophthalmoscopy, biomicroscopy, ultrasound, tonometry, gonioscopy, CT of the orbits and brain are used for diagnosis. Treatment tactics are reduced to the appointment of antibiotics, angioprotectors, NSAIDs, antihistamines, hormonal drugs and radiotherapy. After the acute process is stopped, electrophoresis is applied.
Orbital myositis is a disease in which one or more of the external muscles of the eye are affected. The pathology was first described in 1903 by the American scientist G. Gleason. According to statistics, the primary idiopathic variant occurs in 33% of patients suffering from myositis. The secondary form accounts for 67% of cases. Pathology is often considered in the general structure of the pseudotumor of the orbit. The development of modern diagnostic methods in ophthalmology has reduced the frequency of enucleation by 27%. Idiopathic variant of the disease is more often diagnosed in males after 40 years. Secondary damage to the muscles of the eye socket occurs in all age groups.
Causes of orbital myositis
The etiology of orbital myositis has not been fully studied. Scientists believe that the primary form is based on an autoimmune process in which skeletal muscles are damaged. At the same time, it remains unknown why the external muscles of the eyeball are involved in this process. The main causes of secondary inflammation of the oculomotor muscles are:
- Traumatic injuries. Direct injury to the muscles or bone walls of the orbit is complicated by secondary myositis, which is caused by local damage to muscle fibers. Pathology can occur against the background of contusion of the eye.
- Infectious diseases. The starting factor is the flu, sore throat, rheumatism. Toxins or decay products formed during syphilis and toxoplasmosis of the eye have a tropicity to myocytes. After the etiotropic treatment, all the symptoms of pathology disappear.
- The impact of physical factors. The onset of myositis symptoms is often preceded by hypothermia or a burn. With the formation of post-burn scars, it is not possible to eliminate the symptoms.
- Intoxication of the body. Transient myositis is one of the frequent manifestations of drug or alcohol poisoning. Intoxication with toxic chemicals in production conditions (mercury vapor, lead) also potentiates the development of the disease.
- Non-compliance with hygiene rules. Neglect of eye hygiene contributes to the penetration of pathological agents into the orbital cavity. Cosmetics that remain on the skin after untimely removal of makeup have a toxic effect on the structures of the eyeball.
- Iatrogenic effects. The clinical picture develops in the early or long-term postoperative period. Surgical intervention for the correction of strabismus is often complicated by inflammation of the oculomotor muscles.
The mechanism of development of primary idiopathic myositis has not been clarified. In the pathogenesis of the secondary form, the type of trigger factor directly depends on the etiology. In case of injuries or intraoperative muscle damage, the pathological process is triggered by pro-inflammatory agents (interleukins 1, 2, 6, 8, gamma interferon, tumor necrosis factor a). The external muscles of the eye with the infectious genesis of the disease are affected by the toxins of the pathogen and the decay products of the surrounding tissues. Acute intoxication with ethanol and narcotic substances leads to a decrease in the tone of skeletal muscles. Over time, atony is replaced by spasm, convulsive twitching, which potentiate the development of myositis. The inflammation of the muscles of the eye socket during hypothermia is based on a neurogenic mechanism.
Taking into account the cause of development, primary idiopathic and secondary myositis are distinguished. The etiology of the primary form remains unknown, the secondary variant occurs against the background of other pathological conditions and diseases of intraorbital localization. According to the clinical classification , the following types of the disease are distinguished:
- Spicy. It is characterized by a sudden onset and positive dynamics with timely appointment of treatment. Clinical symptoms are leveled independently for 6 weeks. Relapses are not observed.
- Chronic. The duration of the course is more than 2 months. Patients often claim that symptoms have been present for many years. Periods of exacerbations alternate with short-term remissions. The chronic course is most characteristic of the idiopathic form of the disease.
In the idiopathic form, the first manifestations occur against the background of complete well-being. Patients complain of acute pain in the eye socket, a feeling of pronounced muscle weakness. The puffiness of the eyelids is visually determined. The orbital gap narrows due to secondary ptosis. The mobility of the eyelids and eyeball is severely limited or impossible. With a unilateral lesion, patients note double vision. The pain syndrome increases when the eyes move towards the lesion. The phenomenon of exophthalmos is progressing very quickly. An increase in the volume of the eye muscles is accompanied by a feeling of bursting pain in the eye socket.
On the side of the lesion, a headache appears, which increases when trying to make movements with the eyeballs. The conjunctiva is hyperemic. The line of transition of the orbital conjunctiva to the palpebral one is smoothed due to edema. Deterioration of vision occurs only with compression of the DZ in patients with a high degree of exophthalmos. Clinical manifestations increase with general hypothermia of the body, emotional overstrain. In severe cases, a slight increase in body temperature, swelling of the entire periorbital zone is possible.
With secondary orbital myositis, there is a clear relationship between the development of symptoms of the disease and the action of certain factors (hypothermia, correction of strabismus, intoxication). With a traumatic or iatrogenic genesis of pathology, the reposition of the eye is practically impossible. In patients with intoxication, symptoms are temporary, and the elimination of the etiological factor makes it possible to achieve a stable clinical remission. Secondary myositis, which occurs against the background of hypothermia, is often characterized by a recurrent course.
In the absence of timely treatment, cicatricial-atrophic changes occur, which practically do not undergo reverse development. Most patients develop ophthalmohypertension resistant to hypotensive therapy. With a high degree of severity, signs of stagnation of the optic disc are observed, a subsequent transition to total atrophy is possible. Progressive decrease in visual acuity becomes the cause of amaurosis. The chronic form is complicated by restrictive myopathy. Retrobulbar fiber can be replaced by fibrous or cartilaginous tissue.
At the first stage of diagnosis, a physical examination of the patient is carried out. Exophthalmos is visually determined in combination with swelling of the ocular zone. Exophthalmometry can be used to measure the degree of retention of the eyeball. In infectious myositis, the pathogen of pathology is detected using serological techniques. Specific research methods include:
- Ultrasound of the eyes. When conducting an ultrasound examination in B-mode, an increase in the volume of the eyeball is determined. The echogenicity of the affected muscle is reduced. Splitting of echo signals from the fundus is noted.
- CT of the brain and orbits. The affected muscle is fusiformly thickened. When examining the eye socket in the axial projection, exophthalmos of moderate severity is detected. The volume of muscle tissue and eyelids is increased. The retrobulbar space has not been changed.
- Non-contact tonometry. Intraocular pressure is elevated. With additional electronic tonography, there are no changes in the circulation of intraocular fluid.
- Biomicroscopy of the eye. Examination of the anterior segment of the eyeball reveals the presence and injection of conjunctival vessels. The transparency of the cornea is not reduced. The relief of the iris is preserved.
- Gonioscopy. The front camera of the eyes is medium-sized. The transparency of the watery moisture is complete. With the traumatic nature of the disease, an admixture of blood is determined in the intraocular fluid.
- Ophthalmoscopy. When examining the fundus, a pale pink disc of the optic nerve with clear boundaries is visualized. The arteries are narrowed. Macular reflexes are preserved. A “transverse stripe” is detected on the retina.
Differential diagnosis is performed with neoplasms of the orbit and endocrine ophthalmopathy. With a progressive tumor of the orbit, the pain syndrome is less pronounced, the relationship with eye movements is practically not traced. With myositis, the muscles are affected along the entire length, while with endocrine ophthalmopathy this occurs only in limited areas.
Treatment of orbital myositis
Therapeutic tactics depend on the causes of the disease. Etiotropic therapy is used only when myositis occurs against the background of infectious pathology. In case of traumatic genesis, surgical intervention is performed aimed at restoring the integrity of the affected muscle. Conservative therapy of the disease includes:
- Antibiotics. Broad-spectrum antibacterial drugs are used in the treatment of myositis. Medications are administered retrobulbar. A short course of antibiotic therapy lasting 5-7 days is recommended.
- Nonsteroidal anti-inflammatory drugs. Medicines of this group are highly effective with a mild degree of pathology. NSAIDs are prescribed for acute course or during exacerbations.
- Hormonal drugs. They are indicated for severe or complicated course and a tendency to frequent relapses. Glucocorticosteroids are often used in the treatment of idiopathic myositis in the absence of the effect of NSAIDs.
- Angioprotectors. Vasoconstrictors prevent excessive exudation and swelling build-up. Strengthening of the vascular wall avoids the development of complications from the retina.
- Radiotherapy . It is used for the treatment of resistant forms of the disease and for the prevention of relapses in case of insufficient effectiveness of the classical therapy regimen. Irradiation with a dose of 20 Gy is carried out on the lateral wall of the orbit.
After the elimination of the acute inflammatory process, physiotherapy treatment is prescribed. Electrophoresis of antibacterial drugs in combination with antihistamines and glucocorticosteroids is alternately used. In parallel, osmotherapy is carried out. Antihypertensive agents are ineffective.
Prognosis and prevention
The prognosis for acute orbital myositis is favorable. With a chronic course, relapses of the disease are possible. Specific preventive measures have not been developed. Non-specific prevention is reduced to compliance with safety regulations (use of glasses, masks) when working in production conditions, timely removal of decorative cosmetics. The patient should be under dynamic observation by an ophthalmologist for three months after the symptoms are relieved. The development of repeated seizures requires the appointment of anti-relapse therapy by radio wave methods.