Ординатура / Офтальмология / Английские материалы / Neuro-Ophthalmology_Kidd, Newman, Biousse_2008

Figure 12–6 Twin peaks papilledema.

DIAGNOSING THE UNDERLYING CAUSE OF PAPILLEDEMA

When papilledema is found, the next step is to make the correct diagnosis of the cause. Table 12–4 lists primary and secondary causes. An extensive history, neuro-ophthalmic examination, and testing are required. Usually MRI is the procedure of choice rather than CT because MRI visualizes the venous sinuses easily. Evaluation of a secondary cause of intracranial hypertension must include a search for venous sinus thrombosis, brain tumors, or other space-occupying lesions. As noted previously, MRI may also show signs of increased ICP (Fig. 12–7). Although ventricular size changes (“the slit ventricle”) were once thought to be associated with IIH, Jacobson and colleagues27 showed that ventricular size is similar to that of controls. Techniques, such as autotriggered elliptic centric-ordered (ATECO) MRV, help eliminate confusion about whether a sinus is truly or only artificially occluded by flow artifacts.28 Empty sella turcica, which can often be seen on sagittal and coronal MR views, has been reported to occur in up to 70% of patients with IIH.29 Conventional angiogram or venogram is occasionally necessary to exclude venous thrombosis as a cause of intracranial hypertension.

Once a space-occupying mass has been excluded, diagnostic LP is essential. A relaxed patient in a lateral decubitus position with legs outstretched and the neck in a nonflexed position is crucial to measure opening pressure accurately. Fluid must be sent for routine chemistries including protein and glucose, as well as for white and red cell count. When protein is elevated, spinal cord tumor should be suspected. When glucose is abnormal, one should consider meningitis, infection, sarcoid, or vasculitis. Longer term monitoring is necessary if the diagnosis is unclear or opening pressures have been disparate. The clinician should monitor pressure with lumbar catheters or subarachnoid monitoring.30 Complications of LP, including tonsillar herniation, are rare.31

Laboratory studies may also be helpful. When conditions other than IIH are suspected, one should consider antinuclear antibody, Venereal Disease Research

292Neuro-Ophthalmology: Blue Books of Neurology

TABLE 12–4 Causes of Papilledema

Primary

Idiopathic intracranial hypertension

Secondary

Nutritional

Enzyme deficiency Galactokinase Antichymotrypsin

11 B hydroxylase galactosemia Cystic fibrosis

Deprivational dwarfism Endocrine

Corticosteroid deficiency Corticosteroid excess (Cushing’s) Thyroid disease (hypothyroid; thyroid)

Replacement in hypothyroidism Pituitary disorder

Adenoma (growth hormone) Acromegaly

Parathyroid disease Idiopathic Hypoparathyroidism Pseudohypoparathyroidism

Turner’s syndrome Adipsic hypernatremia

Hematologic

Anemia: iron deficiency, blood loss, pernicious anemia Polycythemia vera

Paroxysmal nocturnal hemoglobinuria Idiopathic thrombocytopenia purpura Cryoglobulinemia Cryofibrinogenemia

Monoclonal gammopathy Hypocomplementemic urticarial vasculitis

Circulatory diseases Venous hypertension Congestive heart failure

Pulmonary emphysema; chronic pulmonary hypoventilation Sleep apnea

Superior vena cava obstruction Radical neck dissection Congenital cardiac disease

Atrial septal defect repair

Ligation of the patent ductus arteriosus Hypertensive encephalopathy

Systemic lupus erythematosus Cerebrovascular malformation Subarachnoid hemorrhage

Dural sinus thrombosis Spontaneous

Tumor (glomus jugulare, cholesteatoma, sarcoid, metastatic, eosinophilic granuloma of the temporal bone)

TABLE 12–4 Causes of Papilledema

Otogenic

Hypercoaguable state

Behc¸et’s syndrome

Leiden factor V

Protein C and S deficiency

Antithrombin III deficiency

Lupus anticoagulant

Anticardiolipin antibody

Thrombocythemia

Systemic lupus erythematosus (SLE)

Cryofibrinogenemia

Oral contraceptive use

Familial Mediterranean fever

Pregnancy

Infection

Iatrogenic trauma

Head injury

Drugs

Antibiotics

Tetracycline

Minocycline

Nalidixic acid

Nitrofurantoin

Sulfamethoxazole

Psychiatric drugs

Lithium

Chlorpromazine

Steroids

Oral contraceptives

Vitamin A

Vitamin D

Amiodarone

Etretinate

Perhexiline maleate

Indomethacin

Phenytoin

Infections

Viral meningitis (Epstein-Barr, Coxsackie B)

Upper respiratory infection

Lyme disease

Human immunodeficiency virus

Poliomyelitis

Acute lymphocytic meningitis

Coxsackie B viral encephalitis

Guillain-Barre´ syndrome

Infectious mononucleosis

Syphilis

Dengue fever

Brucella

Table continued on following page

TABLE 12–4 Causes of Papilledema (Continued)

West Nile virus

Cryptococcus

Tuberculosis

Bartonella

Malaria

Leptospirosis

Coccidioidomycosis

Parasitic disease

Sandfly fever

Trypanosomiasis

Torulosis

Neurocysticercosis

Developmental disease

Hydrocephalus

Aqueductal stenosis

Craniostenosis

Neoplastic disease

Leukemia

Spinal cord tumors

Brain tumors (gliomatosis cerebri)

Lymphoproliferative disorders (Sweet’s syndrome; Castleman’s disease)

Myeloma and POEMS syndrome

Other

Sarcoid

Paget’s disease

Renal—chronic uremia

POEMS, polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes.

Modified from Digre K, Corbett JJ: Idiopathic intracranial hypertension (pseudotumor cerebri: a reappraisal). Neurologist 2001;7:2–67. Johnston I, Hawke S, Halmagyi M, et al: The pseudotumor syndrome. Disorders of cerebrospinal fluid circulation causing intracranial hypertension without ventriculomegaly. Arch Neurol 1991;48:740–747.

Laboratory (VDRL), serum calcium, creatinine, cortisol testing (for Addison’s, or Cushing’s disease), parathyroid hormone testing, and thyroid testing.

NATURAL HISTORY AND VISUAL COMPLICATIONS

When diagnosed properly and treated promptly, many patients with papilledema do well. Visual loss, however, is the major complication of papilledema. Corbett and colleagues32 found that in patients with IIH who were followed for 5 to 41 years, 14/57 (25%) had permanent severe visual loss. Other prospective studies have found similar results.18

Prognostic factors for papilledema-associated vision loss include long-standing disc swelling, visual field/acuity loss on the first examination, older age, African American race, male gender, systemic hypertension, increased intraocular pressures, and underlying optic disc disease such as drusen.10 In addition, higher grades of papilledema increase the risk of visual loss.22

A B

C

Figure 12–7 Magnetic resonance findings of increased intracranial pressure. A, The arrowhead points to the prolapse of the papilla into the globe while the arrow points to the patulous optic nerve sheath. B, An empty sella is seen most of the time in increased intracranial pressure (arrow). Excess CSF often outlines the optic nerve within the sheath in increased pressure axially (C, arrow ) and coronally (D).

Several mechanisms, particularly ischemia, are responsible for visual loss. Orbital color flow Doppler studies have documented reduced blood flow in patients with papilledema.33 Vigorous treatment for systemic hypertension with papilledema can cause an ischemic insult.32 In addition, postrenal dialysis hypotension can lead to a precipitous decline. Other ischemic events such as central and branch retinal artery occlusions have complicated papilledema.34

furosemide has met with some success.46 Others have recommended treating the headache the same way migraine disorders are treated.14,47 Because many

of these individuals have concurrent migraine, this approach does make some sense.48 Because weight gain is problematic for IIH patients, the clinician should use amitriptyline, divalproex sodium, cyproheptadine, and similar medications cautiously because of the known side effect of increased weight gain. Topiramate has been used in a few cases with success. This medication has carbonic anhydrase activity as well as an associated weight loss, a helpful side effect in IIH. Mathew and colleagues48 found that the combination of a migraine preventative and a diuretic seemed to be the best treatment of headache associated with IIH. Treatment of acute headache symptoms with nonsteroidal anti-inflammatories, aspirin, and other simple analgesics or even anti-migraine medications such as sumatriptan or ergotamine is sometimes useful.

What Is the Cause of the Headache in Intracranial Hypertension?

Interestingly enough, no one knows for sure what is the cause of headache in intracranial hypertension. Researchers have artificially elevated the CSF pressure by infusing normal saline into the CSF. Frontal and temporal headaches occurred, but some study participants had no pain despite of the documented rise in CSF pressure.49 In 1943 Kunkle and colleagues50 also artificially elevated CSF pressure up to 850 mm for 2 minutes in four subjects and no headache resulted. Therefore, it is not clear if increased pressure alone can create head pain. Increased ICP associated with brain tumors may also be associated with compression of cranial nerves or innervated structures such as venous sinuses. Increased ICP associated with hydrocephalus often causes a positional headache, which is worse when lying down and better upright and which has many similarities to headaches associated with IIH.51 The cause of the headache in hydrocephalus is also not known but is thought to be stretching of the ventricles themselves.

Frequent causes of chronic headache associated with ICP and normal MR imaging include IIH as discussed previously; venous thrombosis, which can look very similar to IIH but is diagnosed on MRV; and chronic meningitis. Other causes of increased pressure should be considered.

Surgical Therapy Should Be Considered When Vision Is Threatened

On occasion surgical procedures are performed for increased ICP that has caused visual loss and headache. Subtemporal decompression, which was introduced in the late 19th century and early 20th century, was one of the first neurosurgical treatments for intracranial hypertension.52 Although it appeared to help headache and prevent visual loss in some patients, visual loss still occurred in up to one third.53,54 Complications from the procedure include seizure, stroke, hematoma, infection, and cosmetic changes.55

LP, although technically not a surgical therapy, has been used to treat high pressure.54,55,57 LP can be performed both to temporize the situation in visual

loss and to reduce headaches. The high ICP sometimes resolves, which in fact “cures” the disorder. Occasionally, continuous lumbar drainage to lower CSF production is also helpful. Although lumbar drainage can be considered a

temporary treatment, CSF pressures will return to previous levels within about 90 minutes.54

Lumboperitoneal and ventriculoperitoneal shunts, as well as other CSF diversion procedures, are used extensively to treat ICP resulting from hydrocephalus, IIH, posterior fossa meningoceles, and other causes. Shunts do succeed in treating papilledema, preventing visual loss and reducing headache in some patients. These procedures are performed by most neurosurgeons and therefore are read-

ily available. Many reports document reduced papilledema when shunts are used to treat high pressure resulting from both IIH and venous thrombosis.10,56

In high pressures related to venous thrombosis and severe headache, placement of a shunt may be the optimal procedure.58 Although it is tempting to use these shunts for headache reduction, they have the disadvantage of frequent failures, and reoperations can be required. Burgett et al.59 reported in a series of 36 patients with IIH that more than 95% of patients had resolution of papilledema, more than 80% had resolution of headache, and almost 75% of those with visual loss experienced some improvement. However, although the majority of the shunt revisions occurred in four patients, the average number of shunts per patient was approximately 4.2. In addition to shunt failure, other complications include obstruction, which can lead to rapid visual loss; overdrain-

age and intracranial hypotension; radiculopathies; infections; and acquired Chiari malformation.58,60–62 The possible consequence of a low-pressure head-

ache replacing the high-pressure headache also must be considered.10

Optic nerve sheath fenestration was introduced by DeWecker in 1872 but really did not gain hold as a treatment for papilledema until Hayreh reintroduced the procedure. The procedure involves making a window or slit in the optic nerve sheath to release pressure on the optic nerve head. In Hayreh’s7 original experiments in monkeys, a window made in one side relieved optic disc swelling in the other eye as well. Several large series of patients who had papilledema and underwent fenestration showed that no matter what type of surgical

approach was used (lateral, medial, or superior lid crease), papilledema was relieved and headaches reduced in about 50%.63–66 This procedure is generally

easy and safe to perform, the optic nerve is protected from pressure, the need for reoperation is rare, and the decompression may improve blood flow to the optic nerve head.33 However, complications do occur. Visual loss can ensue even if the procedure is successful, and visual loss from retinal artery occlusion is possible. Pupil abnormalities are common in the lateral approach. Motility disturbances often occur with the medial approach.10

Bariatric surgery has been purported to improve IIH by reducing weight. Although Sugerman et al.67 and others have documented successful treatment in their patients, these reports should not be construed as a recommended surgical procedure for papilledema. Successful weight reduction takes time, and treatment of progressive visual loss resulting from papilledema cannot be delayed.

A more recently developed surgical technique, venous sinus stenting, has been reported to resolve or improve papilledema and other pressure-associated signs and symptoms in refractory cases. Potential complications of stenting include headache, hearing loss, acute subdural hematoma, and venous restenosis; these possible sequelae should be considered before offering this treatment option. Further studies will be needed to determine whether or not the risks of stenting outweigh the benefits.68–70