Papilledema is defined as bilateral optic disc swelling secondary to increased intracranial pressure, which is typically the result of a space-occupying lesion in the brain. Optic disc swelling is due to increased cerebral spinal fluid (CSF). It is always a bilateral presentation, although it can be asymmetric to the point of appearing unilateral. No racial or sexual predilection exists, and it can occur at any age.

• Pathophysiology
• Symptoms
• Signs
• Causes
• Diagnosis/Management

	URL: http://www.opt.indiana.edu/ce/ondx/pap.htm Revised: July 9, 2007
	IU Optometry home page: http://www.opt.indiana.edu/ Comments (content): Dr. Tiffenie Harris at tlarkins@indiana.edu Comments: Web Administrator Page design and coding: Terri Greene Copyright © 2007, The Trustees of Indiana University

Pathophysiology

Swelling or edema of the optic nerve head is seen. Next, swelling and leakage of prelaminar nerve fibers and vessels occurs. Compromised vessels of ONH lead to hemorrhages, hyperemia, CWS, and tortuosity.

There is an increase in cerebral spinal fluid--thus an increase in intracranial pressure which takes place in the subarachnoid space, a space between the brain and spinal cord and its coverings, the meninges. The eye is an outgrowth of the brain, and with this outgrowth the subarachnoid space continues right up to the optic nerve head (optic disc, papilla). Increased pressure is transmitted from the subarachnoid space to the nerve head via the optic sheath. When the pressure increases in this space, fibers in the optic nerve are compressed. This makes it harder for the neurons to transport their proteins and organelles, so there is a decrease or slow down in axmoplasmic flow. The buildup is seen as swelling or edema of the optic nerve head (aka papilla), hence the term papilledema.

Symptoms

Headache and transient visual obscurations (TVO) are the most common symptoms with papilledema.

• Headaches

  With or without nausea, with or without dizziness. When the intracranial pressure advances, patients will experience headaches and nausea (with or without vomiting). The headaches are often worse in the morning. Valsalva maneuvers such as coughing will exacerbate the headaches. Patient complaints include: Worse ever, AM, wake from sleep, no relief.

• Transient visual obscurations (TVO)

  68% complain of TVO (graying-out of vision) lasting 5 to 30 seconds. Associated with postural changes.

• Tinnitus

  58% experience tinnitus or "whooshing," describing it as a pulsing synchronous rhythmic sound, heard in one or both ears, with pulsing often exacerbated by the supine or bending positions. The sound is often unilateral.

• Diplopia

  Diplopia with lateral gaze associated with a sixth nerve palsy (SNP) occurs in 38% of the patients. Caution: Make sure it is isolated! If patient presents with SNP and a recent history of head trauma, rule out basilar skull fracture. Unilateral or bilateral? Metastatic lesions?

Signs

• Visual acuities and color vision are normal in early stages, but when advanced swelling occurs, optic atrophy and lipid accumulation of the macula result. Patients are at risk of complete vision loss from optic atrophy. Decreased VA occurs if exudates in macula.
• Pupillary findings are normal.
• Extraocular muscles (EOM) normal in most cases or can be associated with a sixth nerve palsy (SNP). ICP can cause a shift in the brain's pressure such that it will press down on CN-VI
• Diplopia with lateral gaze associated with a sixth nerve palsy (SNP) occurs in 38% of the patients. Caution: Make sure it is isolated! If patient presents with SNP and a recent history of head trauma, rule out basilar skull fracture. Unilateral or bilateral? Metastatic lesions?
• Visual fields (VF) are normal in early stage, but most often an enlarged blind spot is detected on Humphrey's VF. As the nerve continues to swell and create axoplasmic statis, further nerve destruction results in optic atrophy. The visual field then includes arcuate, nerve bundle, constrictive and generalized depressions. Depending on location and severity of a brain lesion, neurological visual field defects such as quadranopsia or hemianopsia can occur. The patient is at risk of complete vision loss from optic atrophy. Rule out neurological-visual pathway defects.
  
  
  Increased blind spot (papilledema)
• Optic nerve head is hyperemic and elevated. There is no spontaneous venous pulsation.
  
  
  • Neural rim tissue: hyperemic.
  • Disc margins: blurred, raised, flame-shaped (splinter) hemorrhages, cotton wool spots (CWS), exudates. Rim and peripapillary NFL edema (hazy/opacified) which obscures the vessels as they leave the disc!
  • Peripapillary retina: Buckling or retinal folds or "rippling" typically seen off the temporal aspect of the disc (Paton's lines) may be present.
  • Cup: No spontaneous venous pulsation (SVP), elicited venous pulsation (EVP)? Indistinct with cup frequently obliterated in advanced cases.
  • ON function: No afferent pupillary defect (APD). No conduction defects.

Causes

Papilledema: Guilty until proven innocent!

• Space-occupying brain lesions (aka brain tumors!) compress the ventricular system and inhibit cerebral spinal fluid (CSF) drainage. Slow and insidious rise in intracranial pressure occurs. Papilledema tends to have a "compensated" appearance characterized by swollen discs with minimal vascular changes and loss of spontaneous venous pulsation. It is always a bilateral presentation, although it can be asymmetric to the point of appearing unilateral.
• No racial or sexual predilection exists and can occur at any age.
• Pseudotumor cerebri (aka Idiopathic Intracranial hypertension) typically occurs in obese women of child-bearing age (20-45 years); however, pseudotumor cerebri (PTC) can occur in patients as young as 10 and as old as 50. The patient's signs and symptoms are the same for true papilledema--tumors along with increased incidence of tinnitus and sixth nerve palsy (SNP).
  
  [Read more about pseudotumor cerebri]
• No mass, normal CSF composition, increased opening pressure on lumbar puncture (LP), normal range is 50-200 mmH₂0 Should not be thought of as benign--25% of patients are at risk of permanent vision or VF loss.
• Malignant hypertension is a medical emergency occurring in up to 1% of the hypertensive population of all ages. (Not so rare when they're in your chair!).
  
  One-year survival was only 10%; now 5-year survival is up to 75%. Death is caused by congestive heart failure (CHF), myocardial infarct (MI) aka heart attack, renal failure, and stroke.
• Accelerated hypertension with the presence of target organ damage.

Established papilledema		Moderate papilledema
Note hemorrhages.	Obscured peripapillary.	Hemorrhages, elevation, obscured vessels.

Diagnosis/Managment of Papilledema

What to do . . .

• Run a 30-2 Humphrey's visual field.
• Take stereo photos.
• Identify the source of swelling. Immediate neuroimaging and then lumbar puncture (LP). Send patient for MRI within 24 hours; otherwise, you are negligent! Immediate neuroimaging MUST be done before the lumbar puncture!

  1st:	Write order for MRI (can be written on your Rx pad): MRI of orbits and brain with and without gadolinium contrast; fat suppression Dx: Papilledema Don't write, "Rule out pseudotumor." Must have a diagnosis.
  2nd:	Call neurologist to set up LP and medical management.

  Neuroimaging: MRI vs CT scan MRI is superior to CT scan for soft tissue structures such as the orbits and visual pathways. MRI is the study of choice because it provides sensitve screening of the brain. It provides gadolinium enhancement (similar to FA technique) and fat suppression required for orbital scans. The MRI can also detect inflammatory disease as well as cerebral venous thrombosis (CVT). (MRV: venography can be reserved for patients who are at greater risk for CVT, such as those with suggestion of thrombosis on MRI, nonobese or male individuals, or those with a documented procoagulant state.) Sagittal T1-weighted images often provide excellent views of the superior sagittal sinus, and these typically are included in routine MRI. CT scan is superior for bone studies, but often used to rule out large brain masses. It is best at detecting calcified lesions. A CT scan is less expensive than an MRI and a faster study with quicker results than MRI when an immediate diagnosis is needed. CT scan is used most in the diagnosis of ACUTE hemorrhagic/ischemic strokes as well as in patients with MRI contraindications (metal implants, pacemakers, claustrophobia, aneurysm clips, cochlear implants, and obesity).

  Why MRI before lumbar puncture? Imaging the brain structures is mandatory before performing a diagnostic lumbar puncture. The absence of a posterior fossa mass lesion makes the complication of herniation due to lumbar puncture unlikely.

If a space-occupying lesion or anatomical abnormality is identified, surgical and/or medical treatment for underlying condition is required.

Pseudotumor diagnosis is made if:

• MRI is normal
• ICP >200 mmHg in non-obese patients or >250 mmHg in obese patients
• Cerebral spinal fluid (CSF) is normal

Pseudotumor cerebri (PTC) treatment objective is to lower increased intracranial pressure (ICP), prevent optic atropy, and control symptoms. Treatment consists primarily of weight loss in combination with carbonic anhydrase inhibitor (CAI). The drug of choice for this condition is Diamox (500-2000mg per day). Topamax is a recent alternative with some success (CAI?). If recalcitrant, then repeated LP or lumbar peritoneal shunt is indicated. With PTC, 80% improve within 8 months. There is a tendency for recurrence (12%).

Management of Papilledema (PE)

• Closely monitor patient's acuities, visual fields, and optic nerve function
• Communicate findings to patient's neurologist
• Monitor every 4-6 weeks, then every 3 months as signs and symptoms resolve
• Optic nerve sheath fenestration: Last resort to treat persistent PE in patients who are nonresponsive to medical management with severe VA and VF loss. Always done on ONE eye with 50% improvement in contralateral eye. Neuro-ophthalmologist makes "fenestrations" (small cuts in the optic nerve sheath to release the pressure). Invasive and risky!!

Let's look at a case example.