TNOA Journal of Ophthalmic Science and Research

PHOTO ESSAY
Year
: 2022  |  Volume : 60  |  Issue : 1  |  Page : 110--113

Infiltrative optic neuropathy: A neuro-oncological emergency


Akruti Gunderia, Padmavathy Maharajan 
 Department of Neuro-Ophthalmology, Aravind Eye Hospital, Tirunelveli, Tamil Nadu, India

Correspondence Address:
Dr. Padmavathy Maharajan
Aravind Eye Hospital, S.N. High Road, Tirunelveli Junction, Tirunelveli - 627 001, Tamil Nadu
India

Abstract

Acute lymphoblastic leukemia (ALL) is a disorder caused by the abnormal proliferation of immature lymphocytes. Of the varied ocular manifestations seen in ALL, infiltration of the optic nerve is a rare and serious complication that heralds a relapse of the disease. It requires a high index of suspicion for diagnosis. Urgent intervention may prove to be lifesaving. We describe a case of optic neuropathy in a 12-year-old boy with ALL and wish to emphasize the need to maintain a low threshold for diagnosing optic nerve infiltration in patients with a prior history of leukemia.



How to cite this article:
Gunderia A, Maharajan P. Infiltrative optic neuropathy: A neuro-oncological emergency.TNOA J Ophthalmic Sci Res 2022;60:110-113


How to cite this URL:
Gunderia A, Maharajan P. Infiltrative optic neuropathy: A neuro-oncological emergency. TNOA J Ophthalmic Sci Res [serial online] 2022 [cited 2022 Oct 7 ];60:110-113
Available from: https://www.tnoajosr.com/text.asp?2022/60/1/110/340373


Full Text



 Introduction



Optic nerve infiltration may herald relapse of the disease in patients with acute lymphoblastic leukemia (ALL). The clinical presentation of optic neuropathy can be confused with inflammatory, ischemic, toxic-metabolic, and compressive optic neuropathy. Leukemic or lymphomatous infiltration of the optic nerve is a neuro-oncologic emergency,[1] requiring a high degree of suspicion and timely diagnosis. Management typically involves urgent initiation of therapy including corticosteroids and chemotherapy and/or radiation.

 Case Summary



A 12-year-old boy presented with sudden and painless defective vision in both eyes (BE) for 2 days. It was preceded by a mild occipital headache and photopsia in BE. He had been diagnosed with preB-cell ALL 3 years back and was prescribed tablet mercaptopurine HS (5/7), tablet methotrexate (2.5 mg) 4.5 tablets weekly, and tablet imatinib mesylate 300 mg OD. He was on remission for 3 months when he visited our clinic, with the 22nd maintenance dose given. Ocular examination revealed a vision of 5/60 (20/250) in the right eye (RE) and 1/60 (<20/1000) in the left eye (LE). Pupils were sluggishly reactive to light in BE. Fundus showed blurred disc margins with disc edema and a dull foveal reflex in the RE. Fundus was normal in the LE. Magnetic resonance imaging (MRI) brain did not reveal any abnormality. Optical coherence tomography (OCT) of optic nerve head (ONH) revealed an increased retinal nerve fiber layer thickness in the RE, suggestive of disc edema; it was normal in the LE. OCT macula revealed a serous macular detachment in the RE and normal foveal contour in the LE. Hemogram showed Hb: 3.4 g%, white blood cell (WBC): 1700 cells/mm3, and platelets: 62,000 cells/mm3. Based on the history and clinical features, we diagnosed him as a case of bilateral optic neuritis. He was started on intravenous methylprednisolone 500 mg BD for 5 days followed by oral prednisolone 20 mg OD for 10 days. On review examination, after 15 days, his vision had improved to 6/24 (20/80) in BE. Fundus examination revealed resolving disc edema in the RE and was normal in the LE. Color vision by Ishihara's isochromatic plates was found to be defective in BE, but central field examination was normal bilaterally. He was asked to taper oral steroids and review after 2 weeks. The patient was lost to follow-up and presented again after 6 months with a vision of 5/60 (20/250) in BE. Careful history revealed that he had a relapse of ALL a month back and had been restarted on tablet mercaptopurine HS (5/7), tablet methotrexate (2.5 mg) 4.5 tablets weekly, and tablet imatinib mesylate 300 mg OD by his oncologist. His anterior segment examination revealed sluggish pupils in BE. Fundus showed the presence of disc edema with disc hemorrhage in the RE [Figure 1] and mild disc pallor and attenuation of vessels in the LE [Figure 2]. Hemogram showed Hb: 6.6 g%, WBC: 5000 cells/mm3, and platelets: 87,000 cells/mm3, B-scan revealed an elevated ONH in the RE [Figure 3], and OCT ONH showed an elevation of disc and an underlying hyporeflective mass with back shadowing [Figure 4]. OCT macula showed normal foveal contour in BE. We came to a provisional diagnosis of infiltrative optic neuropathy in the RE and postneuritic optic atrophy in the LE. The patient was advised MRI brain, cerebrospinal fluid (CSF) analysis and referred to his oncologist for further management, but he succumbed to his disease before any further investigations could be done.{Figure 1}{Figure 2}{Figure 3}{Figure 4}

 Discussion



ALL is caused by abnormal growth of immature lymphocytes, typically resulting in anemia, neutropenia, and thrombocytopenia. The incidence rate of ALL worldwide is approximately 1–5/100,000[2] and it follows a bimodal distribution, peaking at 1–4 years of age and rising significantly again with age >60 years.[3] ALL can induce ocular manifestations directly through the infiltration of neoplastic cells or indirectly by causing hemorrhages due to hematological disturbances, opportunistic infections, central nervous system (CNS) complications, or complications of treatment.[4]

Although leukemic or lymphomatous infiltration of the optic nerve is rare, it is a severe neuro-ophthalmology condition. A high index of suspicion and early neuroimaging studies are important to assist in the diagnosis. Our patient had bilateral optic neuropathy at presentation. He was in remission and not on any chemotherapeutic agent at the time. He was initially misdiagnosed as bilateral optic neuritis in view of a normal MRI. He was accordingly treated with IV-MP and tapering steroids. Six months later, he suffered another attack of optic neuropathy or rather the continuation of the same with a brief recovery due to steroids. At this visit, RE showed disc edema with hemorrhage and LE showed disc pallor.

The patient had visited his oncologist a month before his second visit to us and had been restarted on systemic chemotherapy at that time. A repeat MRI scan with CSF analysis at this point would have corroborated our suspicion of recurrence of ALL.

Thus, in patients with history of ALL, bilateral optic neuropathy, even in the absence of disc edema and characteristic findings on MRI, may represent microscopic leukemic infiltrates and should always raise the suspicion of infiltrative optic neuropathy and necessitate the treatment of ALL.[5]

The optic nerve can reveal leukemic involvement of the CNS, which occurs more frequently in acute compared with chronic leukemia, in children compared with adults, and ALL compared with AML.[6],[7]

Ocular symptoms and findings in CNS leukemia include blurring of vision, diplopia, extraocular muscle palsy due to involvement of cranial nerves, and optic disc edema.[8]

The presence of disc edema, past history of ALL, response to steroids, and clinical course corroborates the diagnosis of infiltrative optic neuropathy. A prompt diagnosis and early referral to a neuro-oncological center are of utmost importance in cases.

 Conclusion



Optic neuropathy in ALL can be secondary to infiltration of the optic nerve by leukemic cells and implies the involvement of the CNS. It is important to suspect a relapse in any patient who presents with disc edema in the setting of ALL. Early diagnosis and referral to a neuro-oncological center is not only vision-saving but lifesaving.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's legal guardian has given consent for images and other clinical information to be reported in the journal. The guardian understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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