Subacute loss of vision, diplopia and headache in a pediatric patient

Optic disc photos showed disc edema, venous engorgement and a peripapillary splinter hemorrhage.

Catherine A. Cox

Jordana F. Goren

A 10-year-old boy was referred to the New England Eye Center because of severe bifrontal headache associated with blurry vision, vomiting and horizontal double vision for 2 weeks. The patient was currently being treated with doxycycline 100 mg by mouth twice a day, which was started 2 weeks prior to presentation for a tick bite noted on his genitalia. The patient had no other significant medical or ocular history.

Examination

On examination, the patient’s best corrected visual acuity was 20/15 in both eyes. Pupils were 5 mm and only slightly reactive to light. Extraocular motility was full. By Maddox rod, 14 ∆D of esotropia was noted in primary and left lateral gaze, with 12 ∆D of esotropia noted in right lateral gaze. Anterior segment examination of both eyes was unremarkable. Posterior segment examination was remarkable for blurred optic nerve head margins bilaterally. A peripapillary splinter hemorrhage was found superonasal to the right disc (Figures 1a and 1b).

Figures 1a-1b. Optic disc photo of the right eye showing disc edema, venous engorgement and peripapillary splinter hemorrhage superonasally (a). Optic disc photo of the left eye showing disc edema and venous engorgement (b). Images: Bhavsar K, Hedges TR

What is your diagnosis?

Bilateral disc edema

The differential diagnosis of bilateral disc edema in a pediatric patient includes processes that may increase intracranial pressure, including mass lesions such as glioma, meningitis, dural venous thrombosis and pseudotumor cerebri.

The clinical history of severe headaches associated with nausea and vomiting in our patient suggests meningeal inflammation. Potential etiologies for subacute meningitis include viral (enterovirus), which is more common in the summer months, as well as Lyme, which is a tick-borne bacterial illness.

Dural venous thrombosis may occur in conjunction with a complicated middle ear infection (acute otitis media with mastoiditis) or sinusitis with intracranial extension. The visual symptoms tend to progress more rapidly in this subset of patients as intracranial pressure can rise quickly, and cerebral edema may also occur.

Infratentorial tumors such as pilocytic astrocytoma, medulloblastoma and ependymoma are more common in the pediatric population and may be associated with optic nerve head edema. These tumors may create a rise in intracranial pressure by direct compression of the ventricles, communication of the ventricles, or compression of the veins that drain the cerebrospinal fluid (CSF). Inflammatory and tumor cells may also clog the arachnoid villi directly. Choroidal plexus papilloma may increase CSF production and thus raise intracranial pressure.

Pseudotumor cerebri is a diagnosis of exclusion, and although the prototypical patient is an obese young woman, it has also been described in pediatric patients. In children, there is no gender predilection. Several known associations have been described, including the use of medications such as doxycycline, tetracycline, minocycline, vitamin A and recombinant growth hormone. Both the use and withdrawal of steroids have also been implicated in pseudotumor cerebri.

Diagnosis and management

Visual field testing (HVF 30-2) showed mildly enlarged blind spots bilaterally (Figure 2). Optical coherence tomography revealed elevated nerve fiber layer thicknesses of 290 µm and 260 µm in the right and left eyes, respectively (Figure 3). MRI of the brain revealed normal optic nerves without enhancement, and magnetic resonance venography was negative for dural venous sinus thrombosis. A lumbar puncture was performed. The opening pressure was 35 cm H20, and CSF analysis showed 3 WBCs/mm3 with 89% lymphocytes and a negative Lyme PCR. Serum testing for Lyme was positive for both IgM and IgG titers.

Figure 2. HVF 30-2 demonstrating mild enlargement of the blind spot bilaterally.

Figure 3. OCT retinal nerve fiber layer demonstrating optic nerve head swelling bilaterally.

The patient was started on intravenous ceftriaxone 2 gm IV daily and acetazolamide 250 mg by mouth daily. At 10-week follow-up, his symptoms had fully resolved, vision was stable at 20/15 in both eyes, and his esodeviation had diminished to 4 ∆D. The papilledema had also improved, with a decrease in average nerve fiber layer thicknesses to 180 µm and 160 µm by OCT in the right and left eyes, respectively. He was discharged with a peripherally inserted central catheter to complete a 4-week course of IV ceftriaxone.

Discussion

Lyme disease is reported to occur in seven out of 100,000 children, with Lyme neuroborreliosis occurring in 30% of these cases. The most common manifestation of Lyme neuroborreliosis is facial nerve palsy, which is present in about half of Lyme cases that have nervous system involvement. Neuro-ophthalmic manifestations such as ocular motor palsies, particularly abducens nerve palsies, papilledema and optic neuritis can occur with Lyme disease involving the central nervous system.

Approximately 2% of children with Lyme disease develop chronic basilar meningitis. MRI with gadolinium may reveal enhancement of the meninges at the base of the temporal lobes. The onset of meningitic symptoms is often insidious and may be difficult to distinguish from viral or aseptic meningitis such as that from enterovirus. Formation of a post-meningitic obstructive hydrocephalus has been proposed to be a contributing mechanism to the development of papilledema in these individuals diagnosed with Lyme meningitis. Inflammatory cells and necrotic debris may impair CSF reabsorption through the arachnoid villi.

Treatment of Lyme meningitis should focus on eliminating the infectious agent and minimizing the resultant inflammatory response. Ceftriaxone and penicillin G are frequently used parenteral therapeutic agents for Lyme meningitis, with typical courses lasting 4 weeks in duration. The adjunctive use of corticosteroids and acetazolamide is controversial, with no firm treatment guidelines. Patients are followed clinically, and if progression is observed, steroids and acetazolamide may be used to alleviate the elevated intracranial pressure. Ventriculoperitoneal or lumboperitoneal neurosurgical shunting is reserved for severe vision loss or intractable progression.

References:

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• Kavita Bhavsar, MD, and Thomas R. Hedges III, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.

• Edited by Catherine A. Cox, MD, and Jordana F. Goren, MD, MS. Drs. Cox and Goren can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.