Ординатура / Офтальмология / Английские материалы / Handbook of Pediatric Neuro-Ophthalmology_Wright, Spiegel, Thompson_2006

Once sufficient history is obtained to classify the symptoms into one of the four headache types, proceed with directed questioning appropriate to the causes within each group. For example, ask the parents of a child with subacute headaches if the headaches awaken the child at night, if projectile vomiting has been noted, and if any changes in balance or coordination have been observed.

A complete ophthalmologic and ocular motility examination should be performed. Particular attention should be paid to cycloplegic retinoscopy, ocular motility testing, measurement of fusional convergence amplitudes and near point of accommodation, and assessment of the optic nerve. If the child has normal strength, symmetrical deep tendon reflexes, and normal gait and balance, neurological consultation is probably not necessary. If there is any question regarding focal neurological designs, the patient should see a pediatric neurologist as soon as possible. Patients with subacute headaches, as well as the patient presenting with a first episode of an acute severe headache, should have cranial neuroimaging. If the scan does not show an intracranial mass lesion, lumbar puncture with cerebrospinal fluid analysis and measurement of intracranial pressure should be performed. Patients with a good history for migraine who have normal ocular and neurological examinations can be given the clinical diagnosis of migraine. Any atypical features warrant neuroimaging followed by a lumbar puncture. Patients with chronic, nonprogressive headaches do not require evaluation beyond that discussed.

Headache Treatment

The following discussion assumes that treatable causes of headaches such as pseudotumor cerebri have been ruled out. Patients with significant hyperopia or convergence insufficiency need appropriate eye care. Functional patients need reassurance and possibly psychiatric consultation.

Once the foregoing specific causes have been excluded, treatment has four phases: (1) reassurance, (2) exclusion of precipitating factors, (3) abortive treatment, and (4) preventive treatment. Many patients will have a significant improvement once they have been reassured that their headaches are not the sign of a brain tumor or other life-threatening problem. A common precipitating factor of headaches is stress. Unfortunately, stress is almost impossible to avoid in modern society.

Rather than avoiding the stress, the patient needs to learn to modify his response to it. Some patients may have their headaches triggered by a variety of foods including chocolate, red wine, caffeine, nitrates, and certain cheeses. Patients should initially exclude these foods from their diet. Once the headaches are controlled, they can restart these items one at a time to see if they exacerbate the headaches. Oral contraceptives may exacerbate headaches, and a trial off these medications is warranted.

If the patient’s headaches are not frequent or incapacitating, treatment can be initiated when the first symptoms of headache appear. Patients should be instructed to lie down in a dark, quiet room and to take an appropriate dose of aspirin, acetaminophen, a nonsteroidal antiinflammatory agent, or Fiorinal. An antiemetic such as Tigan or Compazine is often helpful to keep the preceding medications in the stomach. Ergot preparations are poorly tolerated in children because these produce nausea.34

If the patient has frequent or incapacitating headaches or if abortive treatment is not satisfactory, then prophylactic treatment should be initiated in children 7 years of age and older. The three most commonly used medications are (1) Inderal, a beta-blocker, (2) Verapamil, a calcium channel blocker, and

(3) Elavil, a tricyclic antidepressant. Inderal is started at 10 to 20 mg orally once daily, and is gradually increased to 40 to 80 mg/day. If a satisfactory response is not obtained in 6 weeks at the higher dose, discontinue the medication gradually over several weeks. Verapamil is used at 40 to 80 mg orally twice daily. Elavil is started at 10 to 20 mg orally at bedtime; the dose can be increased to 40 mg/day.

“SWOLLEN” OPTIC DISC

Pediatricians, pediatric neurologists, pediatric neurosurgeons, and ophthalmologists examine optic discs of children for various reasons including complaints of headache or history of ventriculoperitoneal shunt placement. Occasionally, the optic disc appears abnormal, and the patient is then referred to rule out optic disc edema or papilledema.

To start, some definitions are necessary. Optic disc edema and papilledema have essentially identical ophthalmoscopic features. The increased intracranial pressure transmitted to the optic nerves by the cerebrospinal fluid causes papilledema.

FIGURE 12-2. Papilledema demonstrating obscuration of the retinal vessels, disc hyperemia, hemorrhages, and exudates.

Optic disc edema can be caused by a variety of optic and systemic conditions including pseudotumor cerebri, hypertension, juvenile diabetes, uveitis, anemia, lymphoma, and papillitis.11 Unilaterality is not particularly helpful, as localized processes can cause unilateral optic disc edema, and optic atrophy on the contralateral side can be associated with unilateral papilledema. The characteristic ophthalmoscopic features of papilledema and disc edema include opacification of the peripapillary nerve fiber layer and consequent haziness or obscuration of the retinal vessels at the disc margin, disc hyperemia, as well as exudates, splinter hemorrhages, and cotton wool spots (Fig. 12-2). One should carefully observe the retinal veins for spontaneous venous pulsations. If venous pulsations can be visualized, the cerebrospinal fluid pressure is typically less than 200 mm of water.41

Pseudopapilledema can be defined as any disc appearance that can be confused with papilledema. The distinction is obviously important because of the profound implications associated with papilledema. The most frequently encountered causes of pseudopapilledema include (1) hyperopia, (2) hyaloid remnants,

(3) optic disc drusen, (4) congenital disc elevations without visible drusen, and (5) myelinated nerve fibers.31

BLURRED DISC MARGINS

The optic disc can have blurred margins from a variety of causes. Myelinated nerve fibers obscure the disc margins but should not pose a diagnostic dilemma. Myelinated nerve fiber layers can be a component of neurofibromatosis. Drusen may also give blurring of the disc margin. Drusen are more commonly found in the nasal disc tissue. A peripapillary halo of pigment epithelial loss and hyperplasia may be noted in association with buried drusen. In pseudopapilledema, the outline of subsurface retinal vessels is not obscured; additionally, one does not see wrinkling of the peripapillary internal limiting membrane around the disc (Paton’s lines).

OPTIC CUP

The optic disc with pseudopapilledema has no central optic cup. The optic disc with papilledema still has a cup unless the papilledema is advanced and obvious. Because optic disc characteristics are often similar among family members, examining the patient’s parents for anomalous discs provides useful evidence in favor of pseudopapilledema.

VENOUS PULSATIONS

Venous pulsations occur spontaneously in most normal eyes. Increased intracranial pressure causes congestion of the veins and loss of venous pulsation. The presence of venous pulsations indicates that the intracranial pressure is below 200 mm of water.41 The absence of venous pulsations yields little information unless they have been previously documented to be present.

VASCULAR ABNORMALITIES

Anomalies of disc vasculature are characteristic of pseudopapilledema. The vessels exit the disc centrally and show a pattern of anomalous branching or trifurcations of the arterioles or venules.

HEMORRHAGE

Although splinter hemorrhages in the nerve fiber layer are characteristic of papilledema, patients with pseudopapilledema may also rarely have nerve fiber layer hemorrhages as well as preretinal hemorrhages and subretinal hemorrhages. These hemor-

rhages may be caused by contact between blood vessels and the drusen. An infarct of the nerve fiber layer along with hemorrhages strongly suggests papilledema.

Patient Management

As discussed, differentiating papilledema from pseudopapilledema requires careful biomicroscopic evaluation of the optic disc. Patients whose optic discs show pseudopapilledema can be reassured although patients with optic nerve drusen are at risk of retinal hemorrhage, as well as development of an arcuate scotoma in the inferior nasal quadrant of the visual field.31 Patients with disc edema need a CT scan followed by a lumbar puncture to distinguish between papilledema and pseudotumor cerebri. Despite careful examination, some patients elude definitive diagnosis. In this situation, remember to look at the optic disc of other family members, as well as to perform serial evaluations including photography of the patient’s optic discs. One should also keep in mind the general health status of the patient. The existence of neurological signs or symptoms demands further evaluation. Given the relative safety of today’s CT and MRI scanners, as well as the lack of radiation exposure with the MRI scan, we are encouraged to err on the side of conservatism and order a head scan in patients where the diagnosis cannot be obtained by ophthalmoscopy.

ANISOCORIA

Neuroanatomy

Evaluation of patients with anisocoria requires a good understanding of the relevant neuroanatomy. The pupillomotor system can be divided into the sympathetic and parasympathetic systems. The sympathetic nervous system fibers, which cause pupillary dilation, form a three-neuron system (Fig. 12-4). The first-order neurons originate in the hypothalamus and travel downward in the brainstem to the C8–T2 level of the spinal cord called the ciliospinal center of Budge. They synapse with the second-order neurons in the ciliospinal center of Budge. The second-order neurons exit the spinal cord, enter the paravertebral sympathetic chain, and run upward to the superior cervical ganglion. These preganglionic second-order neurons then

FIGURE 12-4. The oculosympathetic pathway. (Reproduced from Slamovits TL, Glaser JS. The pupils and accommodation. In: Glaser JS (ed) Neuro-ophthalmology, 2nd edn. Philadelphia: Lippincott, 1990:464, with permission.)

synapse with the postganglionic third-order neurons in the superior cervical ganglion. The third-order neurons travel upward along the internal carotid artery. The pupillomotor fibers of the third-order neuron travel with the nasociliary nerve and then the long ciliary nerves and eventually reach the dilator muscle of the iris. The sympathetic fibers of the third-order neuron to Muller’s muscle and the inferior tarsal muscle travel with branches of the ophthalmic artery. Sudomotor and vasoconstrictor fibers to the facial skin travel along branches of the external carotid artery.

The parasympathetic fibers cause pupillary constriction. Preganglionic fibers leave the Edinger–Westphal nucleus and travel along the third cranial nerve. The preganglionic fibers then enter the ciliary ganglion in the orbit, where they synapse with postganglionic fibers. The postganglionic fibers are then

distributed to the iris sphincter and the ciliary body via the short ciliary nerves.

Causes

SIMPLE ANISOCORIA

Up to 20% of normal children have measurable anisocoria. Most of these patients have simple anisocoria in which the degree of anisocoria is equal in dim and bright conditions or the anisocoria is greater in dim light. Intermittancy or variability is also a hallmark of simple anisocoria. There are no associated findings suggestive of a sympathetic or parasympathetic lesion.

SYMPATHETIC LESIONS

A lesion somewhere in the three-neuron sympathetic chain characterizes Horner’s syndrome. The classical findings include a small pupil on the involved side with more anisocoria being measured in the dark. There is an associated ptosis of the upper lid on the involved side due to the lack of Mueller’s muscle function. An “upside-down” or “inverse” ptosis of the lower lid also occurs secondary to lack of inferior tarsal muscle function. Additionally, there is anhydrosis due to involvement of the sudomotor fibers to the skin of the face. Patients with a long-standing Horner’s syndrome may show cool, blanched skin as a result of denervation supersensitivity to circulating catecholamines. Patients with a congenital Horner’s syndrome show these findings as well as iris heterochromia, with the involved iris being lighter (Fig. 12-5). Depending on the location of the lesion, fewer signs may be present, or additional signs may be present, reflecting other cranial nerve involvement. For example, a lesion at the base of the skull will affect only the fibers to the pupil and the lids. There would be no anhydrosis. On the other hand, a lesion at the apex of the thorax (Pancoast’s tumor) would present with anhydrosis. Alternatively, a lesion in the cavernous sinus might present with a Horner’s syndrome as well as evidence of a third nerve palsy.

Because the sympathetic fibers are not functioning properly in Horner’s syndrome, the anisocoria is largest under conditions requiring the sympathetic pupillomotor fibers to be working, that is, in the dark. This dilation lag is extremely characteristic of Horner’s syndrome, but cannot always be reliably treated in

FIGURE 12-5A,B. (A) Iris hypochromia, left eye, due to congenital Horner’s syndrome. (B) Left congenital Horner’s syndrome showing ptosis, miosis, and iris heterochromia. (Courtesy of Dr. R. Kardon.)

children. Cocaine testing and Paredrine (hydroxyamphetamine) testing are more reliable and useful. Cocaine has a sympathomimetic effect by blocking the reuptake of norepinephrine from the synaptic junction. Topical cocaine solution will dilate a normal pupil, but fails to dilate a Horner’s pupil. It fails to dilate the pupil because norepinephrine is not released from the