Discussion
In this study, we reported a child with HLH presented to us with
bilateral painless progressive visual loss. In the ophthalmic
examination, we found bilateral optic disc swelling and hemorrhage. HLH
is an immune system dysregulation characterized by multiorgan
infiltration of macrophages, especially affecting the liver, spleen,
lungs, bone marrow, lymph nodes, and kidneys, leading to various signs
and symptoms. The mean age of occurrence is 1.8 in children and 50 years
old in adults(1).
Ocular involvement is uncommon in HLH. Wang et al., in a study in 2023,
showed that old age, autoimmune disorders, and decreasing RBC and
platelet counts are independent risk factors of ocular involvement in
HLH(2). Retinal hemorrhage, conjunctivitis, corneal infiltration,
anterior uveitis, papillitis, and choroidal involvement are the main
ophthalmic signs in these patients(2). A literature review regarding
ocular involvement in HLH is briefed in Table 2.
Optic nerve head involvement in HLH is rare. A wide range of
differential diagnoses should be considered(3). We summarized the
clinical approach to our patient in Figure 4. Regarding the patient’s
immune status, opportunistic infections such as CMV must be investigated
and ruled out. Ocular involvement in CMV infection is a serious
sight-threatening condition that could be manifested as optic nerve head
inflammation(4). The sensitivity and specificity of PCR tests for
aqueous samples are 82% and 91%, respectively. The result of the
aqueous and blood PCR tests was negative in our patient and we found no
evidence of systemic CMV infection. In the brain and orbital MRI, we
found bilateral optic nerve infiltration and the CSF analysis showed the
brain involvement with tumoral cells. However, ICP was within normal
limits. Another differential diagnosis in this patient is an adverse
drug complication. There are reports of etoposide-related optic nerve
toxicity(5). However, clinical evidence and imaging findings indicate
optic neuropathy due to tumoral infiltration, not drug toxicity.