Optic Neuropathies: Ischemic, Inflammatory, Infectious, or Compressive



Optic Neuropathies: Ischemic, Inflammatory, Infectious, or Compressive


Mitchell B. Strominger

Victoria M. Hammond



THE CLINICAL CHALLENGE

Optic neuropathy is the general term that describes vision loss secondary to a disease process involving the prelateral geniculate optic nerves. Patients present with the primary complaint of acute or chronic vision loss in one or both eyes depending on the primary diagnosis. The visual defect occurs either centrally or peripherally secondary to a visual field abnormality. Occasionally, patients might also notice a decrease in color vision and have nonocular symptoms such as pain on eye movement or headaches. Clinically, it is challenging because the differential for causes of optic neuropathy is broad, taking into account age, systemic complaints, and other medical disorders.





APPROACH/THE FOCUSED EXAM


Nonarteritic Anterior Ischemic Optic Neuropathy

Unless bilateral, the examination of a patient with NAAION reveals a relative afferent pupillary defect. Funduscopic exam demonstrates an edematous optic nerve with areas of hemorrhage (Figure 50.1). On direct ophthalmoscopy, the optic nerve head may appear small and crowded with no cup. Owing to acute disc edema, this trait may be appreciated only in the uninvolved eye and is known as a “disc at risk.” The diagnosis is essentially a clinical diagnosis after other inflammatory and infectious etiologies have been ruled out. These cases can be bilateral and more severe and occur in the retrobulbar portion of the optic nerve. Therefore, these cases present a clinical challenge because exam and/or photography of the optic nerve head may appear normal. Depending on the location within the nerve, MRI with gadolinium may or may not show enhancement.


Arteritic Anterior Ischemic Optic Neuropathy

Vision loss is typically severe and central, with acuities worse than 20/200 in most patients. On funduscopic examination, the disc has “pallid” swelling (Figure 50.2), which is whiter and more ischemic, appearing in distinction to the hemorrhagic findings in NAAION. Other areas of retinal vascular ischemia can be seen as cotton wool spots.

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Nov 11, 2022 | Posted by in EMERGENCY MEDICINE | Comments Off on Optic Neuropathies: Ischemic, Inflammatory, Infectious, or Compressive

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