A 30-year-old man presents with acute onset of unilateral optic disc edema with a macular star figure of exudate OD. The vision was 20/200 OD, there is right RAPD, and a cecocentral scotoma on visual field testing OD. There is mild vitreous cell OD. The ophthalmologist writes'“papilledema” on the chart and refers the patient to a neurologist for further testing. The neurologist orders a head MRI which is normal and performs a lumbar puncture that shows a normal opening pressure and cerebrospinal fluid analysis. The patient sees another ophthalmologist for a second opinion and the correct diagnosis of cat scratch neuroretinitis is made based upon a markedly elevated Bartonella henselae titer (IgG 1:1024).\nPapilledema for neuro-ophthalmologist represents a term that is best reserved for optic disc swelling due to elevated intracranial pressure. It is my recommendation that all other causes of optic disc swelling should be referred to by etiology (e.g., optic neuritis, or anterior ischemic optic neuropathy) or simply by describing the ophthalmoscopic finding of “optic disc edema” Clinicians should use the term “papilledema” carefully because it is potentially confusing to your colleagues in neurology, neurosurgery, and medicine if you misuse the term. This inappropriate charting could lead to inappropriate testing? (e.g., the MRI and lumbar puncture in this case). It also delays testing for the real culprit for the patient's optic disc edema and a macular star figure (i.e., infectious cat scratch neuroretinitis in this case). The misleading documentation could also lead to medicolegal implications of the missed diagnosis.\nIn general the clinician can use the clinical presentation to differentiate the three major forms of optic disc edema: papilledema, anterior ischemic optic neuropathy, and optic neuritis. Papilledema can occur at any age, is typically associated with relatively preserved central visual acuity (unless there is macular exudate, fluid, hemorrhage, or chronic or long standing papilledema), is bilateral (although markedly asymmetric or frankly unilateral cases do occur), and usually produces a big blind spot initially on visual field testing followed by nerve fiber layer loss over time. There might also be associated signs and symptoms of increased intracranial pressure (e.g., headache, nausea, vomiting, pulse synchronous tinnitus, or diplopia from a nonlocalizing sixth nerve palsy). In contrast to papilledema, optic neuritis typically affects younger patients, is often associated with decreased central acuity and dyschromatopsia, is typically unilateral (although bilateral cases can occur especially in children), and the visual field defect is usually a central scotoma (although any type of optic nerve related visual field loss may occur). Finally, in an older adult, anterior ischemic optic neuropathy is the most common unilateral cause for optic disc edema. The patient may have vasculopathic risk factors, an altitudinal visual field defect (but any optic nerve type of defect can occur), and again is usually unilateral. Thus the clinician should be wary of making the diagnosis of bilateral simultaneous optic disc edema related to either optic neuritis or non-artertic anterior ischemic optic neuropathy and probably should exclude papilledema in these clinical settings.\nThe evaluation of papilledema should include a check of the systemic blood pressure as malignant hypertension can mimic papilledema (i.e., hypertensive optic disc edema). Neuroimaging (preferably an MRI with contrast and an MR venogram to exclude venous sinus thrombosis) should be considered as the initial study in papilledema. If the neuroimaging study is normal then a lumbar puncture with an opening pressure and cerebrospinal fluid analysis should be performed. If the intracranial pressure is elevated, the neuorimaging is normal, and the CSF analysis is normal then the diagnosis of idiopathic intracranial hypertension can be confirmed but should be considered a diagnosis of exclusion. Although a CT scan might be the initial emergent neuroimaging study performed, there are many etiologies for increased ICP that may be missed on CT scan especially a noncontrast study in the emergency room. These intracranial etiologies include cerebral venous sinus occlusion, arteriovenous or dural malformation, infiltrative neoplasm or disorders that produce meningeal enhancement (e.g., inflammatory, infectious, infiltrative, or neoplastic etiologies).\nAlthough routine, typical, and medication responsive papilledema from idiopathic intracranial hypertension might be managed by a general ophthalmologist, a referral to neuro-ophthalmology might still be necessary if the patient fails maximum medical therapy or presents with acute, severe visual loss. These patients might require surgical intervention (e.g., shunting procedure or optic nerve sheath fenestration) to prevent irreversible papilledema related visual loss. In addition, the diagnosis should be made with caution in the following atypical circumstances: the patient is thin rather than obese, elderly or a child rather than a young adult, and male rather than female. Consultation is also recommended for patients with progressive visual loss despite treatment, signs or symptoms not due to increased intracranial pressure, or any inflammatory intraocular signs that might suggest an inflammatory rather than idiopathic etiology.
A 25-year-old woman presents with chronic and unresolved loss of vision OD that occurred acutely two months prior to presentation. There is a right RAPD, a central scotoma OD on visual field testing, and a normal optic disc. Computed tomography (CT) scan of the head in the emergency room was normal. A diagnosis of chronic optic neuritis” is made.\nChronic “optic neuritis” is a real diagnosis but the clinician should be careful to insure that the patient has a confirmed diagnosis of multiple sclerosis and no alternative etiology for the optic neuropathy. Typical optic neuritis resolves (20/40 or better vision) in over 90% of cases and lack of improvement should be a big “red flag” that the diagnosis is incorrect. In my experience patients with chronic”“optic neuritis” due to demyelinating disease often have a systemic MS course that mirrors the course of their optic neuropathy (i.e., primary or secondary progressive rather than relapsing-remitting course). One should also be cautious of using the term “optic neuritis” when one truly means optic neuropathy. Misusing or mixing terms (e.g., papilledema) or creating neologisms (e.g., “ischemic optic neuritis”) also is potentially misleading to your colleagues. The bottom line is that typical optic neuritis usually gets better over time and patients with an atypical course (e.g., “chronic optic neuritis”) should have evaluation for alternative etiologies for their optic neuropathy including neuroimaging. There are potentially dangerous conditions that could mimic the presentation of acute painful optic neuropathy and suggest a diagnosis of demyelinating optic neuritis (e.g., pituitary apoplexy or ophthalmic artery aneurysm). In addition there are subsets of variants of demyelinating optic neuropathy that may not have as favorable a rate of recovery and therefore might suggest alternative diagnoses (e.g., neuromyelitis optica). Finally, some patients with the mitochondrial disorder, Leber hereditary optic neuropathy (bilateral acute visual loss with cecocentral scotomas in a young male) can be associated with MS like illness. Although rare, I would accept the diagnosis of “chronic optic neuritis” as a diagnosis of exclusion if a high quality MR scan of the head and orbit with gadolinium has excluded a compressive lesion, the patient has clear diagnosis of prior multiple sclerosis, and alternative MS mimics have been considered and adequately excluded. I typically will inform the treating neurologist of the findings and my concerns and if there is any history of transverse myelitis or if the optic neuropathy is bilateral then I would consider evaluation for neuromyelitis optica (NMO) including NMO antibody testing. I would also consider ordering the mitochondrial genetic testing for Leber hereditary optic neuropathy if the patient has bilateral central or cecocentral scotomas especially in a young man.