Rhinological causes of Opthalmoplegia
Definition: Ophthalmoplegia is weakness or paralysis of one or more ocular muscles that govern ocular motility. It could be caused by paralysis of the ocular muscles or myopathies involving the ocular muscles. Total paralysis of both intrinsic and extrinsic muscles of the eye is known as total ophthalmoplegia.
Anatomically nose and paranasal sinuses are closely related to orbit. The orbit is related superiorly to the floor of the frontal sinus, medially to the lateral wall of ethmoidal labyrinth, inferiorly to the roof of the maxillary sinus, postero medially to the anterolateral wall of sphenoid sinus. Pathology affecting nose and paranasal sinuses can easily affect the orbit and its contents.
Infections from nose enter orbit by:
1. Direct extension: This is facilitated by congential dehiscences of bony barriers between the orbit and para nasal sinuses, and the thiness of lamina papyracea which seperates the medial wall of the orbit from the nasal cavity.
2. As thrombophlebitis along the valveless venous channels of orbit
Clinical photograph of a patient with ophthalmoplegia
Orbital Muscles and their nerve supply
Commonest rhinological causes of ophthalmoplegia include:
Infections involving the nose and para nasal sinuses. Infections casuing orbital complications could be either bacterial or fungal.
Commonly orbital infections can be classified into:
1. Preseptal infections: Ocurring anterior to the orbital septum and tarsal plate. It goes through three stages: oedema, cellulitis and abscess formation.
2. Post septal infections: These infections occur within the confines of bony orbital walls. Post septal infections pass through 5 stages: inflammatory edema, cellulitis, subperiosteal abscess, orbital abscess and cavernous sinus thrombosis. Among these stages, cavernous sinus thrombosis commonly causes total ophthalmoplegia. This is due to the fact that all the muscles supplying the ocular muscles are closely related to the cavernous sinus walls.
Fungal infections are common in immunocompromised patients. Mucor mycosis commonly affects the cavernous sinus causing total ophthalmoplegia.
In cases of progressive ophthalmoplegia, lateral rectus is the first muscle to be affected. This muscle is followed by involvement of other intra ocular muscles. Total ophthalmoplegia is always associated with a certain degree of ptosis due to the involvement of levator palpebrae superioris.
Painful ophthalmoplegia is due to myositis.
CT scan and MRI helps to clinch the diagnosis.
Managment: Involves management of the causative pathology.