Marcus Gunn syndrome is a polyethological disease of the visual organ, manifested by blepharoptosis of the upper eyelid, which spontaneously rises during movements in the temporomandibular joint. Diagnostics includes anamnesis collection, external examination, radiography, magnetic resonance imaging (MRI), ophthalmoscopy, visometry, biomicroscopy. Treatment tactics depend on the severity of ptosis. With minimal manifestations, surgical intervention is not indicated. In severe cases, tarzomyectomy is performed, partial resection of the upper eyelid levator with its subsequent strengthening with the help of an autograft.
Marcus Gunn syndrome or palpebromandibular synkinesia is a rare, often congenital pathology in ophthalmology, manifested by ptosis of the upper eyelid in combination with synkinesia. This disease was first described in 1883 by the English ophthalmologist M. Gunn, who observed the clinical symptoms of the syndrome in a fifteen-year-old child. According to statistics, pathology occurs in 5% of patients with congenital blepharoptosis. Marcus Gunn syndrome is widespread everywhere. Among the representatives of the female and male sex, it occurs with the same frequency. As a rule, the first signs of the disease in children are detected during breastfeeding. Parents pay attention to the movements of the upper eyelid synchronized with the opening of the mouth.
The congenital form of Marcus Gunn syndrome often develops sporadically. In rare cases, an autosomal dominant type of inheritance is noted. The acquired form may occur in patients with progressive cerebral ischemia, traumatic brain injury, encephalitis. Less often, the provoking factor is the defeat of the facial nerve during surgical interventions, tooth extraction or invasive cosmetic procedures. In the mechanism of development of Marcus Gunn’s palpebromandibular synkinesia, the formation of pathological connections between the oculomotor, trigeminal and facial nerves plays a major role. In this case, the focus of abnormal pulsation is located supranuclearly.
According to the phylogenetic theory, the cause of the disease is rudimentary gill-oral synkinesia, because in fish, during the opening of the oral cavity, the gill arches are raised. The basis for their formation in humans can be congenital or acquired lesions of the pyramidal system. At the same time, compensatory activation of subcortical structures of the brain provokes the development of clinical manifestations of Marcus Gunn syndrome.
Marcus Gunn synkinetic syndrome is characterized by ptosis of the upper eyelid in combination with uncontrolled lifting of the eyelid during movements in the temporomandibular joint. The first manifestations of the congenital form are found during the feeding of the child. When opening the mouth, the eyelid affected by blepharoptosis rises. This process is not controlled by volitional efforts and occurs with all provoking movements of the lower jaw. At a more mature age, patients note that the opening of the eye also provokes movements of the lower jaw in the direction opposite to the affected area, forward extension, teeth clenching and even lip movements. However, the intensity of clinical symptoms can vary significantly in specific individuals.
As a rule, Markus Gunn syndrome develops monocularly, in rare cases there is a lesion of both eyes. In early childhood, nonspecific symptoms are swelling of the eyelid, lacrimation, general weakness. Patients note a decrease in the severity of clinical manifestations of the disease with age. In turn, diagnostic tests indicate that patients acquire certain skills of masking symptoms. Markus Gunn syndrome in most cases occurs together with strabismus and amblyopia. Palpebromandibular synkinesia can develop in isolation or be combined with Waardenburg and Hirschsprung syndromes.
The diagnosis of Markus Gunn syndrome is based on anamnestic data, the results of external examination, radiography, magnetic resonance imaging (MRI), ophthalmoscopy. Additional research methods are visometry, biomicroscopy. In rare cases, patients have a history of familial forms of the disease, but more often congenital pathology develops sporadically. Patients with the acquired form of Markus Gunn syndrome often note traumatic eye injuries preceding the appearance of clinical symptoms. During external examination, ptosis of one, less often both eyelids is visualized, which is independently eliminated during movements in the temporomandibular joint.
Radiography is performed in the case of an acquired form to detect organic damage. The MRI method allows you to detect a pathological relationship between the oculomotor, trigeminal and facial nerves. As a rule, abnormal foci are located supranuclearly. The consequence of these changes may be hypotrophy of the masticatory muscle and the circular muscle of the eye. During ophthalmoscopy, pathological changes on the part of the optic nerve are not detected. By the method of biomicroscopy, hyperemia and swelling of the conjunctiva can be detected. Visual acuity, as a rule, corresponds to the norm. Differential diagnosis of Markus Gunn syndrome should be carried out with congenital ptosis. With this pathology, the movements of the lower jaw do not contribute to raising the eyelid. Palpebromandibular synkinesia belongs to the number of neurogenic ptoses, therefore, in addition to an examination by an ophthalmologist, a neurologist’s consultation is necessary to make a diagnosis.
Surgical treatment for Markus Gunn syndrome is indicated for patients with severe ptosis and synkinesias that disrupt normal functioning. Palpebromandibular synkinesia in combination with strabismus and amblyopia is also an indication. With a mild course, the disease does not require specific treatment. The choice of surgery technique depends on the severity of ptosis. In case of minimal clinical manifestations, tarzomyectomy is recommended. While maintaining the functional ability of the upper eyelid levator, its partial resection is performed, followed by strengthening with the help of an autograft (Whitnall ligament).
To prevent the development of strabismus and amblyopia, ptosis in children with severe Marcus Gunn syndrome is eliminated after 3-4 years. In order to eliminate the cosmetic defect in patients with uncomplicated course, the operation is recommended to be performed after 15 years. Timely surgical interventions ensure the restoration of eyelid function, the normal development of the visual analyzer, but cannot completely eliminate the manifestations of synkinesis. In the postoperative period, local application of antiseptic solutions for washing, antibacterial agents in the form of drops or ointments is indicated.
Prognosis and prevention
Specific methods for the prevention of Marcus Gunn syndrome have not been developed. Non-specific preventive measures of the acquired form consist in compliance with safety rules at work (wearing a protective mask, glasses). With a congenital variant of pathology in childhood, it is recommended to wear bandages during wakefulness. This contributes to the normal development of the visual analyzer. All patients with an established diagnosis need to be examined by an ophthalmologist 2 times a year. The prognosis for Marcus Gunn syndrome is favorable for life and work capacity. The disease does not lead to a decrease in visual acuity. In rare cases, secondary conjunctivitis may develop.