Papilledema refers to swelling of the optic disc secondary to elevated intracranial pressure (ICP). This term is used exclusively for disc swelling due to elevated ICP; swelling from other causes is called optic disc edema. In Japanese, it is also called “congested optic disc” (うっ血乳頭).
Papilledema is a warning sign of serious conditions such as brain tumors, CNS inflammation, cerebral venous thrombosis, and idiopathic intracranial hypertension (IIH), and is an ophthalmologic finding that must not be overlooked. Differentiation from pseudopapilledema due to optic disc drusen, tilted disc, or small disc is also important.
Epidemiology: The annual incidence of idiopathic intracranial hypertension in the United States is 1.15 per 100,000 people 2), with a higher rate in women (1.97 vs 0.36 per 100,000 in men). The highest incidence is in the reproductive age group of 18–44 years (2.47 per 100,000), and it is increasing worldwide with the obesity epidemic 2). Normal adult ICP measured by manometer is less than 250 mmH2O, and in children less than 280 mmH2O.
Papilledema is a term limited to elevated ICP, while disc swelling from other causes (e.g., optic neuritis, ischemia, infiltrative lesions) is called optic disc edema. This distinction is important because it directly guides identification of the etiology and selection of appropriate treatment.
In the acute phase of papilledema, centripetal visual functions (best-corrected visual acuity, color vision) are usually preserved, and early subjective symptoms are often scarce.
In children, increased intracranial pressure is often discovered due to esotropia associated with bilateral abducens nerve palsy.
Fundus findings in acute papilledema:
Additional findings in chronic papilledema: Pallor of the optic disc, gliosis, optociliary shunt vessels (formed in central retinal vein occlusion, chronic congestive optic disc, optic nerve sheath meningioma), and refractive bodies.
In the chronic stage, dead nerve fibers do not swell, so edema may disappear even if ICP elevation persists.
The severity of papilledema is assessed using the Frisén scale (stages 0–5) and used as an indicator of visual prognosis.
Stages 0–1
Stage 0 (normal): Blurring of the nasal, superior, and inferior disc margins. Radial nerve fiber layer.
Stage 1 (very early): Obscuration of the nasal disc border. No elevation of the border. Subtle grayish halo. Concentric or radial choroidal folds.
Stages 2–3
Stage 2 (early): Obscuration of all borders. Elevation of the nasal border. Complete peripapillary halo.
Stage 3 (moderate): Increased disc diameter. Obscuration of some segments of major vessels. Finger-like extensions at the outer edge of the halo.
Stages 4–5
Stage 4 (marked): Elevation of the entire disc. Complete obscuration of major vessel segments on the disc.
Stage 5 (severe): Dome-shaped protrusion. The halo is narrow with smooth borders. Disappearance of the physiologic cup.
TVO is a characteristic symptom of papilledema, but it is not a direct precursor of vision loss. However, if intracranial hypertension persists for a long time, it can progress from severe peripheral visual field loss to central vision loss. If TVO occurs frequently, it is important to promptly see a specialist and investigate the cause.
The rate of papilledema formation depends on the rate of intracranial pressure increase. With mild, gradual ICP elevation, it may appear over several weeks; with severe, acute changes, it can appear within hours to a day.
When caused by idiopathic intracranial hypertension, a 5–10% weight loss has been shown to improve ICP symptoms and papilledema. However, weight management is only part of conservative treatment, and depending on the degree of papilledema and presence of visual dysfunction, combination with medication or surgical treatment may be necessary.
The diagnosis of papilledema is made through a combination of ophthalmic examination, neuroimaging, and lumbar puncture (LP). First, blood pressure is measured to rule out malignant hypertension, and emergency imaging (CT → MRI + contrast MRV) is performed to evaluate space-occupying lesions and venous sinus thrombosis. After confirming no risk of brain herniation, LP is performed.
MRI with contrast-enhanced MRV is the optimal imaging study, evaluating the following signs of elevated intracranial pressure (ICP):
A definitive diagnosis of idiopathic intracranial hypertension requires meeting all five of the following criteria:
| Criterion | Description |
|---|---|
| 1. Papilledema | Bilateral papilledema is present |
| 2. Neurologic examination | Normal except for cranial nerve abnormalities |
| 3. Neuroimaging | Normal brain parenchyma, no ventricular enlargement, no mass, no abnormal contrast enhancement |
| 4. CSF composition | Normal |
| 5. CSF opening pressure | Adults ≥250 mmH2O, children ≥280 mmH2O |
Probable diagnosis: bilateral papilledema present + criteria 1–4 met, but CSF pressure below threshold.
Pseudopapilledema can be caused by high hyperopia, high myopia, drusen, tilted disc, myelinated nerve fibers, hamartoma, etc. There is optic disc abnormality but no actual edema. The following findings suggest pseudopapilledema.
Differential diagnosis: buried drusen, tilted disc, diabetic papillopathy, hypertensive papillopathy, posterior scleritis, perioptic neuritis, uveitis (sarcoidosis, VKH), optic neuritis, thyroid eye disease, CRVO, NAION, infiltrative optic neuropathy (lymphoma, leukemia), optic nerve sheath meningioma, etc.
The three goals of treatment are: (1) treating the underlying cause, (2) preserving visual function, and (3) alleviating symptoms (such as headache).
In Japan, the following are the basics of treatment for increased intracranial pressure.
Complications of surgical treatment: Shunt failure, breakage, infection; visual loss related to surgical manipulation in ONSF require attention.
Prognosis: If intracranial pressure decreases early, papilledema resolves quickly and visual function is preserved. Delayed treatment leading to visual dysfunction is irreversible. The recurrence rate of IIH is 9–28%, and regular follow-up is important2). Visual prognosis is generally good, but severe vision loss occurs in a minority2).
Poor prognostic factors: Weight gain, severity of papilledema, baseline headache severity2).
Fulminant IIH: In severe cases with profound visual loss, severe papilledema, and visual field constriction, mean CSF opening pressure can reach 54.1 cmH2O (range 29–70 cmH2O)1); 50% progress to legal blindness, and all have residual visual field defects and optic atrophy1). If baseline HVF MD is less than -7 dB, vision did not recover1).
Acetazolamide is established as a first-line treatment for idiopathic intracranial hypertension, but it is contraindicated when cerebral venous thrombosis is the cause, as it may worsen the condition. It is essential to identify the underlying cause and select treatment accordingly. Note that it is used off-label in Japan.
Stasis of axoplasmic flow plays a central role in the formation of papilledema.
Mechanism of axoplasmic flow stasis:
Pathophysiology of idiopathic intracranial hypertension: The exact mechanism is unknown. Dysregulation of CSF dynamics, metabolic and hormonal factors are thought to be involved 2). Venous sinus stenosis leading to increased venous sinus pressure and decreased CSF absorption has also been proposed. Recently, idiopathic intracranial hypertension is increasingly recognized as a systemic metabolic disorder associated with androgen dysregulation 1).
AVM-related intracranial hypertension (rare mechanism): Unruptured arteriovenous malformations (AVMs) can cause intracranial hypertension and papilledema without hemorrhage or hydrocephalus 3). The proposed mechanism is abnormal drainage due to arterialization of cortical veins → increased pulse pressure in the subarachnoid space → impaired CSF reabsorption. A literature review reported 26 such cases 3).
Transverse sinus stenting (TSS) has been reported as a safe and effective treatment for the management of idiopathic intracranial hypertension4).
Waser et al. (2021) reported TSS in a case of papilledema with brain parenchymal herniation into the dural venous sinus (BHDVS) in a 52-year-old man4). Six months after stenting, objective resolution of papilledema and normalization of the venous sinus pressure gradient (32 mmHg → 12 mmHg, gradient >15 mmHg → 5 mmHg) were achieved.
Ghorbani et al. (2025) reported endovascular embolization in 4 cases of unruptured AVM presenting with intracranial hypertension and papilledema3). Bilateral papilledema resolved within one month after treatment, and medication adjustment was unnecessary in cases with complete embolization. In Case 1 (35-year-old man), LP opening pressure normalized from 38 cmH2O to 28 cmH2O at one week post-embolization and to 21 cmH2O at one month, with confirmed resolution of papilledema.
Idiopathic intracranial hypertension is increasingly being recognized as a systemic metabolic disease independent of obesity1). A randomized controlled trial (IIH Weight Trial, JAMA Neurol 2021) comparing bariatric surgery versus community weight management intervention demonstrated the efficacy of bariatric surgery1). Research into novel treatments targeting androgen dysregulation is ongoing1), and strengthening evidence for surgical interventions is also a priority1). Establishing the etiology, additional factors of dysfunction, and optimal treatment for idiopathic intracranial hypertension are future research challenges2).
Bonelli L, Menon V, Arnold AC, Mollan SP. Managing idiopathic intracranial hypertension in the eye clinic. Eye. 2024;38:2472-2481.
Toshniwal SS, Kinkar J, Chadha Y, et al. Idiopathic intracranial hypertension: a comprehensive review. Cureus. 2024;16(3):e56256.
Ghorbani M, Griessenauer CJ, Wipplinger C, et al. Intracranial hypertension and papilledema secondary to an unruptured arteriovenous malformation: review of the literature. Neuroradiol J. 2025;38(4):387-393.
Waser B, Wood HM, Mews P, Lalloo S. Transverse sinus stenting for treatment of papilloedema secondary to a large brain herniation into a dural venous sinus with associated tectal plate lesion: case report and literature review. Interv Neuroradiol. 2021;27(6):756-762.
