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  • 1.  Osteopetrosis

    Posted 2 hours ago

    Dear experts,

     

    I am going to see a child next week with a history of osteopetrosis. She was diagnosed at 3 months due to a bulging fontanelle, vomiting and seizure. She was found to have hypocalcemia and hypophosphatemia. At that time, her eye exam was normal with no optic disc pallor or edema. Two months later, she developed nystagmus and subtle optic disc pallor, and underwent placement of a VP shunt for hydrocephalus. She had a bone marrow transplant at age 8 months. By age 16 months, she was no longer able to maintain fixation with her right eye, and had a constant right esotropia. At 2.5 years, visual acuity was 20/640 in the right and 20/30 in the left with bilateral optic disc pallor, right worse than left. At age 7, visual acuity was 20/800 in the right and 20/20 in the left. MRI had consistently shown slit like ventricles, mild Chiari and VP shunt in situ, and she was discharged.

    In Jan of this year, at age 9, she was referred back because of vision loss to LP in the right and 20/400 in the left. The right optic disc was pale, but the left was pale and swollen. A CT orbits showed that the right optic canal was smaller than the left, but no other abnormality. The ventricles were very slightly enlarged compared to previous, so she underwent shunt revision. However, 2 weeks after the shunt revision, vision had dropped further to HM in the left eye despite improvement in the disc edema. Repeat MRI shows stable ventricular size, thin smooth dural enhancement and low lying cerebellar tonsils. She has now been referred to me for a second opinion.

    I am unfamiliar with osteopetrosis and have not seen this before. I just wonder if anyone has suggestions for what could be causing the progressive vision loss despite no evidence of compression within the canal, and even after revision of the VP shunt. Any insight would be most welcome! Thanks,

    Lulu

     

    Lulu Bursztyn

    Comprehensive and neuro-ophthalmology

    Western University, London, Ontario

    lulu.bursztyn@sjhc.london.on.ca

    519-646-6214

     


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  • 2.  RE: Osteopetrosis

    Posted 43 minutes ago
    I don't suppose you have OCT for her. It is quite possible that she had bilateral optic neuropathy in both eyes worse in the left eye and the brief period of sustained high ICP due to obstructive hydrocephalus just tipped her over. As far as progressive vision loss following shunt placement and normalization of ICP this has been described (post decompression optic neuropathy) and the mechanism is unknown but it is thought to be autoregulatory dysfunction in oculr blood flow following quick reduction of ICP. I think there is a recent report published on this https://www.tandfonline.com/doi/full/10.1080/01658107.2023.2301360

    Raed 
    Sent from my iPhone