Sir,

Ocular involvement is uncommon in dengue fever, most commonly presenting as blot haemorrhages.1, 2, 3, 4 We report an unusual manifestation of dengue fever presenting bilaterally with extensive panretinal vasculitis and severe macular oedema, which resolved spontaneously without anti-inflammatory treatment.

Case report

A 37-year-old female with dengue fever diagnosed on dengue immunoglobulin (Ig)M and IgG serology and polymerase chain reaction experienced sudden, bilateral blurring of vision with metamorphopsia 6 days after the onset of fever. Her platelet count was at its nadir (26 × 109/l). Visual acuity was 20/400 OD and counting fingers OS. There was bilateral extensive retinal vasculitis at the maculae extending outwards to the peripheral retinae, complicated by macular branch vein occlusion OD. Numerous yellowish retinal infiltrates and blot haemorrhages were scattered throughout both maculae, and there was bilateral macular oedema (Figure 1). Fundus fluorescein angiogram (FFA) demonstrated leakage indicative of extensive panretinal vasculitis, more severe at, but not limited to the maculae (Figure 1). Optical coherence tomography (OCT) showed central foveal thickening of 503 μm OD and 843 μm OS.

Figure 1
figure 1

(a, b) Colour fundus photographs at the onset of visual symptoms showing perivascular sheathing around the foveal vessels, scattered blot haemorrhages and exudates. The flame haemorrhages and cotton wool spots in the right eye are caused by a branch macular vein occlusion. (c, d) Fundus fluorescein angiography demonstrates extensive panretinal vasculitis, more severe at, but not limited to the maculae. There is leakage from the perifoveal vessels in both eyes. (e, f) OCT of both eyes demonstrate severe macular oedema.

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After platelet transfusion, her platelet count improved to 67 × 109/l and gradually returned to normal levels over the next few days. Treatment with anti-inflammatory agents for her posterior retinitis and vasculitis was considered but withheld in consultation with her physician in view of her pyrexic state.

By 2 weeks, the retinal perivascular sheathing had spontaneously resolved, macular oedema had decreased, and visual acuity improved to 20/200 bilaterally. By 10 weeks, without any specific treatment, her vision had recovered to 20/20 bilaterally with no residual inflammation or macular oedema. However, there was mild-red desaturation in the right eye and visual distortion on Amsler grid monitoring. This corresponded to an area of retinal capillary nonperfusion at the infero-nasal margin of the foveal avascular zone on repeat FFA (Figure 2).

Figure 2
figure 2

(a) Fundus photograph of the right eye at 10 weeks, when visual acuity has improved to 20/20. (b) Fundal fluorescein angiography (FFA) of the right eye shows an area of ischemia infero-nasal to the right fovea with telangiectatic vessels at the margins.

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Comment

In the few reports of dengue patients with ocular involvement, common symptoms were blurred vision, central scotoma, floaters, photophobia, and haloes.1, 2, 3, 4 Ocular findings included anterior chamber and vitreous inflammatory cells, intraretinal and peripapillary haemorrhage, Roth's spots, intraretinal lesions, maculopathy with diffuse oedema, vasculitis, and blurring of the optic disc margins.1, 2, 3, 4

The precise ocular pathophysiology in dengue fever is unknown.1 Our patient's ocular manifestations occurred 1 week after dengue fever, when her platelet count was at its nadir. This time interval is consistent with those previously reported1, 2, 3 and may suggest an immune-mediated process,1 possibly coinciding with the onset of IgG production. The retinal haemorrhages may be explained by thrombocytopaenia and a transient bleeding diathesis. In contrast to another series of patients,1 our patient's ocular manifestations were not confined to the vascular arcades in the maculae region, but extended outwards to the peripheries, suggesting a more diffuse inflammatory process.

Unlike other vasculitic disorders, despite conservative management, there was complete resolution of the fundal signs and normal visual acuity by 10 weeks.

This case report demonstrates that dengue fever may manifest as severe panretinal vasculitis and macula oedema, which coincides with the nadir of the thrombocytopaenia on day 7 of the illness. Although severe, these conditions may be self-limiting and may resolve spontaneously without specific anti-inflammatory or antiviral therapy.