Orbital apex syndrome

Orbital apex syndrome is dysfunction of cranial nerves 3, 4, 5 and 6 in varying combination due to a lesion near the apex of the orbit of the eye. This syndrome usually is caused by posterior ethmoid or sphenoid sinusitis. These sinuses are adjacent to the orbital apex, through which run the optic nerve; cranial nerves III, IV, and VI; and the first division of cranial nerve V.

Orbital apex syndrome, also known as Jacod syndrome, is a collection of cranial nerve deficits associated with a mass lesion near the apex of the orbit of the eye. This syndrome is a separate entity from Rochon–Duvigneaud syndrome, which occurs due to a lesion immediately anterior to the orbital apex.

Characteristics

Orbital apex syndrome may manifest complete ophthalmoplegia, ptosis, decreased corneal sensation, and vision loss. The most common finding is oculomotor nerve dysfunction leading to ophthalmoplegia. This is often accompanied by ophthalmic nerve dysfunction, leading to hypoesthesia of the upper face. The optic nerve may eventually be involved, with resulting visual impairment. Unlike cavernous sinus thrombosis, the vision loss is present early. Patients usually develop optic nerve signs, such as a relative afferent pupillary defect.

The most common finding is oculomotor nerve dysfunction leading to ophthalmoplegia. This is often accompanied by ophthalmic nerve dysfunction, leading to hypoesthesia of the upper face. The optic nerve may eventually be involved, with resulting visual impairment.

In orbital cellulitis, signs of marked orbital inflammation usually precede visual loss. In orbital apex syndrome (“posterior orbital cellulitis”), the opposite occurs. Patients present with severe unilateral visual loss and ophthalmoplegia, but with minimal orbital inflammation.

Causes

Rhinocerebral mucormycosis in patients with diabetes mellitus is the most frequent cause of orbital apex syndrome. Even though ketoacidosis is not always present, it is the most important risk factor. Orbital apex syndrome may be caused by a tumor of the middle cranial fossa (near the apex of the orbit) and by herpes zoster.

Aspergillus may cause an orbital apex syndrome in immunocompromised or normal hosts, and may have a subacute presentation.

Jacod Syndrome is commonly associated with a tumor of the middle cranial fossa (near the apex of the orbit); but it can have several other causes.

Neoplastic causes

• Head and neck cancer
• Neural tumors
• Hematological cancer

Inflammatory causes

• Sarcoidosis
• Systemic lupus erythematosus
• Churg–Strauss syndrome
• Wegner's granulomatosis
• Giant cell arteritis
• Thyroid disease

Traumatic causes

• Iatrogenic (following surgery)
• Orbital apex fracture
• Penetrating injury

Vascular causes

• Carotid aneurysm

Diagnosis

Diagnostic methods vary, and are based on specific possible etiologies; however, an X-ray computed tomography scan of the face (or magnetic resonance imaging, or both) may be helpful. If orbital apex syndrome is suspected, MRI or high-resolution CT with slice thickness of 3 mm or less, or both, should be obtained.

References

1) Bailey, Byron J., and Jonas T. Johnson. Head and neck surgery – Otolaryngology. 4th ed. Philadelphia: Lippincott Wilkins and Williams, 2006, p. 2792.

2) Yeh, S.; Foroozan, R. (2004). "Orbital apex syndrome". Current opinion in ophthalmology 15 (6): 490–498. PMID 15523194.  edit.

3)Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 7th edition.

4) Yanoff & Duker: Ophthalmology, 3th edition.