Ever so often, patients who have been down with a febrile systemic illness may also present with retinal manifestations that seem to be the result of an immune-mediated mechanism. While the symptoms may slightly vary on a per case basis, the diagnostic workup and treatment remain similar.

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Fever episodes could cause a variety of ocular manifestations including conjunctival congestion, uveitis, episcleritis, neuroretinitis, retinitis, and dacryoadenitis. These could be the result of direct pathogen invasion or indirectly due to activation of immune mechanisms.

Here are 3 cases that may seen unique in presentation, but are similar in diagnosis.

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Case 1

A 45-year-old female presented with complaints of diminution of vision in both eyes that was sudden in onset and painless. On examination her vision was RE 6/60 and LE 6/18. She had anterior uveitis, vitritis multifocal patches of retinitis in the posterior pole with optic nerve involvement in right eye. She had had chikungunya fever 3 weeks before the onset of ocular symptoms.

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Case 2

A 27-year-old male presented with sudden painless decrease in vision in the left eye. On evaluation, his right eye was normal. His left eye vision 2/60, anterior uveitis, vitritis, multifocal patches of retinitis at the posterior pole with optic nerve involvement. On probing the patient revealed that he had been diagnosed and treated for typhoid fever 2 weeks before the onset of ocular symptoms.

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Case 3

An 18-year-old female came with complaints of sudden painless loss of vision in the right eye. On examination, her right eye vision was 6/60. She had vitritis, multifocal patches of retinitis at the posterior pole. The patient had been treated for viral fever 10 days before the onset of ocular symptoms.

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Diagnosis

1. All 3 patients underwent fluorescein angiography which showed early hypofluorescence with late hyperfluorescence with leakage in the retinitis patches. On optical coherence tomography, these patches showed inner hyperreflectivity with thickening and shadowing of outer layers suggestive of inner layers inflammation.
2. All patients underwent basic investigations that included CBC, RBS, ELISA for HIV.
3. Patients were then started on oral prednisolone at 1mg/kg body weight tapered over 6 weeks. All patients had a fair recovery in vision.

• Patient in case 1 recovered to RE 6/12 and LE 6/6 at the end of 6 weeks
• Patient in case 2 recovered to LE 6/12
• Patient in case 3 improved to 6/9 at the end of 6 weeks

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Case discussions

Post-fever retinitis as an entity typically affects patients 2 to 4 weeks after an episode of fever due to any cause. Typically patients present with sudden painless diminution of vision. The predominant clinical picture includes focal or multifocal patches of retinitis which could be unilateral/bilateral. This may or may not be accompanied with anterior uveitis, optic neuritis.

In one case series fundus fluorescein angiography of retinitis was seen as early hypofluorescence with late hyperfluorescence with disc leakage. [1] This was similar to the findings in our series were all patients showed early hypofluorescence and late hyeprfluorescence of the retinitis patches, disc leakage, localised staining of vessels in some cases.

In the same published case series, optical coherence tomography showed hyperreflectivity of nerve fibre layer with after shadowing in the areas of retinitis associated, fluid-filled spaces in the outer retina and subfoveal serous detachment. [1] In the patients above also there were similar findings with hyper reflectivity in the inner layers with after shadowing corresponding to areas of retinitis. Some patients had associated macular edema and/or subfoveal detachment. On follow-up, the hyperreflectivity decreased in the areas of retinitis and the area showed evidence of atrophy.

Several studies have shown that the presentation of this condition several days to weeks after a systemic illness suggests an immunological basis for this condition. Immunological basis was shown in another case series of dengue maculopathy, where they demonstrated a decrease in C3 complement levels. [3] These patients typically presented about 3 weeks after the onset of fever and having a uniform good response to steroids irrespective of etiology indicates a possible immunological role in this condition.

In a few of these published case reports and case series, they have managed the patient conservatively as they believe it to be a self-limiting condition. In one case report in a patient with bilateral neuroretinitis following Chikungunya fever they treated the patient with both systemic anti-viral and steroids 1mg/kg but did not find any major benefit. [2] Another case series of patients with retinitis following chikunugunya fever were treated with systemic acyclovir and steroids at 1mg/kg body weight and were found to have significant visual benefit.[3] In the present scenario all the patients had a favourable response to oral steroids.

To conclude post fever retinitis as a condition manifested about 3 weeks after onset of fever. Irrespective of the cause of fever in these patients the clinical presentation was similar with inner retinitis at posterior pole with or without optic nerve involvement. The ocular symptoms presenting 3 weeks after the systemic symptoms suggest a possible immunological basis for this condition. All patients also had a favorable response to oral steroids irrespective of their prior systemic infection.

The highlight is the need for a high index of suspicion by the ophthalmologist to diagnose this entity and also early referral by the physician in case the patient goes to the physician first. Early institution of steroids leads to rapid improvement in symptoms and prevention of visual loss.

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This article was originally published on May 16, 2019.

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Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author, Dr. Srilatha Tirumale is a Vitreo-Retinal Consultant from Bengaluru.