Young girl has swollen optic nerves, no visual, systemic manifestations
A 10-year-old Caucasian female presented to our clinic for her initial eye examination with no reports of visual or ocular complaints. Her mother reported a history of preterm labor at 32 weeks gestation with complications including a cleft palate and hole in the girl’s eardrum.
Medical history was also remarkable for a nonverbal auditory processing disorder, speech delay and attention deficit and hyperactivity disorder. She reported no headaches, dizziness or nausea and was oriented as to person, place and time. She was taking no medications and had no known drug allergies.
Uncorrected visual acuity was 20/20 OU, and cycloplegic refraction revealed mild compound hyperopic astigmatism. With the exception of scattered, flesh-colored bumps inferior to the lower lid margins of each eye, the anterior segment was unremarkable. Her pupils were equal, round and reactive to light, with no afferent pupillary defect. Motilities were full and smooth, and confrontation visual fields were full in both eyes. Color vision was normal in each eye, and IOP was 15 mm Hg OD and 16 mm Hg OS at 1:26 p.m.
Anterior segment evaluation revealed normal cornea, anterior chamber and iris in both eyes with mild flakes on the superior and inferior lashes of both eyes. Posterior segment evaluation revealed clear lenses. Examination of the fundus showed the optic nerve head to be elevated with irregular disc margins, no spontaneous venous pulse and a dark ring-like shadow surrounding the nerve margin in each eye.
The cup-to-disc ratio was estimated to be 0.2 in each eye with crowded, raised disc margins in the left eye more than the right eye. A flame hemorrhage was present superior to the left optic nerve head. The macula was flat with a positive foveal reflex in each eye. Retinal vasculature was mildly tortuous, and the periphery showed no signs of predisposing conditions to retinal detachment in either eye.
Children presenting with the appearance of swollen optic nerves are cause for concern. The major rule-out is papilledema associated with elevated intracranial pressure. A nonexhaustive list of differential diagnoses for swollen nerves includes: papilledema, pseudopapilledema or optic nerve head drusen (ONHD), an intracranial mass, venous sinus thrombosis, malignant hypertension, meningitis, side effects of certain medications (oral contraceptives, tetracyclines, growth hormone and vitamin A), idiopathic intracranial hypertension, hydrocephalus, arteriovenous malformation, juvenile diabetic papillopathy, subdural and epidural hematomas and subarachnoid hemorrhage.
This young patient underwent a workup including optical coherence tomography (OCT), B-scan ultrasonography and fundus photography. OCT revealed considerable elevation at the optic nerve head in the left eye more than the right eye, as noted during clinical observation. B-scan ultrasonography confirmed optic nerve head drusen of both eyes. Fundus photography showed swelling of the optic nerve heads in the left eye more than the right eye and a flame-shaped hemorrhage with a white center superior to the left optic nerve.
Images: Dinkel J
An MRI scan was ordered without contrast and showed no intracranial pathology. To rule out blood disorders associated with swelling of the optic nerve, a CBC with differential was ordered. The blood test revealed mild anemia. Ocular findings, imaging results and lack of systemic and neurological symptoms are consistent with ONHD in combination with mild anemia.
ONHD are estimated to be present in 0.3% to 2.4% of the population, with 75% of the cases occurring bilaterally (Johnson et al.). ONHD is observed, on average, at a mean age of 12.1 years in one or both eyes and becomes more prominent with age. It has no sex predilection and can be an isolated finding or associated with neurological disorders including: epilepsy, migraine, pseudotumor cerebri, mental retardation, tuberous sclerosis or ataxia-telangiectasia.
Upon ophthalmoscopic examination, ONHD may present at the surface as lumpy-bumpy, refractile deposits. However, drusen may also be buried below the surface, mimicking elevation observed in papilledema. As in this case, overlapping clinical findings often cause confusion when drawing conclusions about the underlying condition.
Papilledema is defined as swelling of the optic disc caused by elevated intracranial pressure (ICP), according to Friedman et al. Clinical signs and symptoms of increased ICP may include, but are not limited to: optic nerve head edema with or without spontaneous venous pulsation, cranial nerve VI palsy, vomiting, headache, blurred vision, photophobia, diplopia, altered color perception, visual field defects, peripapillary nerve fiber layer hemorrhages and retinal folds.
After complete ophthalmic evaluation and testing, patients with the appearance of swollen optic nerves should be referred for an MRI, lumbar puncture and, pending normal lumbar puncture results, blood tests (FBS, CBC, ESR, CRP, ANA, ANCA, ACE), recommend Friedman, et al.
Differentiating condition from papilledema
It is important to remember that ONHD are generally benign, while papilledema requires an urgent neurological evaluation to rule out life-threating conditions. Although it is not common, individuals may present with swelling of the optic nerve, resulting from papilledema or other optic neuropathies, with simultaneous ONHD. In the U.S. population, the coexisting presentation is estimated to be at least 19.4 persons per 1 million each year, according to Johnson et al.
Several tests can aid in making an exclusive diagnosis of ONHD. Research suggests that B-scan ultrasonography has been considered the most reliable method to confirm ONHD. However, drusen are often not calcified in young patients and, therefore, may not always present as the highly reflective deposits that typically remain on B-scan ultrasonography after the gain has been reduced.
Spectral domain OCT (SD-OCT) has recently been utilized in the diagnosis of ONHD vs. papilledema with variable results. On SD-OCT, ONHD has been reported ranging from focal, hyperreflective masses with clear posterior margins outside the outer plexiform and nuclear layers to optically empty spaces surrounded by lines of reflectance anteriorly and posteriorly (Kulkarni et al.). Severity of retinal nerve fiber layer thinning on OCT has been shown to correlate with increasing ONHD surface exposure.
On a cross-sectional view, a hyporeflective space was observed between sensory retina and retinal pigment epithelium and choriocapillaris complex in both ONHD and optic disc edema (Johnson et al.). However, optic disc edema generally revealed a smooth internal contour, with the thickest area of hyporeflectivity near the optic nerve head that gradually tapered into a “lazy V” pattern. In contrast, ONHD appeared “lumpy-bumpy” internally with an abrupt drop in the area of hyporeflectivity.
In this young patient’s case, an MRI without contrast was done to rule out intracranial pathology. With the exception of mucous buildup in the patient’s sinuses, the MRI scan was normal with no evidence of a mass, hemorrhage, infarction, intracranial hypertension or abnormal ventricular size. The pediatrician addressed the mild anemia revealed through blood testing with iron supplements.
A follow-up at 2 months revealed resolution of the hemorrhage and a possible superior arcuate visual field defect of the right eye. The visual field will be retested in 1 month to confirm.
If papilledema is present, the underlying etiology should be addressed by the child’s pediatrician, neurologist or other specialist. While there is no current treatment for ONHD, regular eye examinations should be performed to monitor the condition and rule out subretinal neovascularization and elevated ICP.