Main

Sir,

After an episode of endophthalmitis, an eye with pre-existing diabetic retinopathy may experience rapid, asymmetrical progression in the severity of the retinopathy compared to the other (noninfected) eye.1, 2 Most of the previously reported cases had a history of diabetes mellitus of 12 years or more.1, 2 We report a similar occurrence in a patient with a much shorter (4-year) duration of diabetes.

Case report

A 53-year-old Chinese female diabetic with concurrent hypertension and ischaemic heart disease developed severe nonproliferative diabetic retinopathy (NPDR) and maculopathy in both eyes within 3 years of diagnosis of diabetes mellitus (Figure 1) and required repeated laser photocoagulation to both eyes.

Figure 1
figure 1

Colour fundus photograph of the right eye prior to the endophthalmitis showing nonproliferative diabetic retinopathy and maculopathy.

Full size image

While hospitalized for Staphylococcus aureus and Bacillus sepsis secondary to pneumonia and urinary tract infection, she complained of a sudden onset of pain and blurring of vision in the right eye. Visual acuity in the right eye was counting fingers at 1 ft. Clinical examination revealed vitritis and vitreous clumps as well as a choroidal abscess at the temporal periphery. The view of the posterior pole was very hazy. After a vitreous tap was performed, intravitreal vancomycin was given. The endophthalmitis subsequently resolved and visual acuity improved to 6/7.5 in the right eye. The maculopathy persisted in both eyes and the patient required additional focal laser photocoagulation.

At 5 months after the infection, she developed proliferative diabetic retinopathy (PDR) with neovascularization and vitreous haemorrhage in the right eye (Figure 2), while the retinopathy in the left eye remained unchanged. Visual acuity in the right eye was reduced to counting fingers at 2 ft. After 3 months, the vitreous haemorrhage had not resolved and a vitrectomy was performed. At a follow-up 1 year later, the affected eye was stable but the left eye had not progressed to PDR (Figure 3).

Figure 2
figure 2

Colour fundus photograph of the right eye showing proliferative diabetic retinopathy with neovascularisation and vitreous haemorrhage.

Full size image
Figure 3
figure 3

Colour fundus photograph of the left eye after the episode of endophthalmitis in the right eye, showing no progression of the diabetic retinopathy.

Full size image

Comment

Diabetic retinopathy involves chronic inflammatory processes associated with a breakdown of the blood–retina barrier. 3, 4 Worsening of diabetic retinopathy in the operated eye has been reported after cataract surgery.5, 6 It has been postulated that intraocular inflammation, whether from endophthalmitis or following cataract surgery, may act through similar biochemical mediators and pathways to worsen the breakdown of the blood–retina barrier and hence accelerate the progression of diabetic retinopathy.1

In our patient, diabetic retinopathy progressed within 5 months of endophthalmitis, a time frame that is consistent with the 2–6 months previously reported.1, 2 The short duration between endophthalmitis and progression of retinopathy highlights the need for frequent monitoring of these patients to detect and treat complications.

One interesting difference in our patient's presentation compared to most of the other reported cases is the 4-year duration of diabetes at the time of progression, compared to 12–30 years in all but one other case.1, 2 Dev and associates pointed out that patients with a shorter duration of diabetes mellitus and no pre-existing diabetic retinopathy did not manifest with rapid progression of retinopathy and suggested that these patients may not have reached a ‘critical level’ of breakdown of the blood–retinal barrier.1 However, other factors such as glycaemic control, hypertension, nephropathy, and the general health of the patient influence the severity and rate of progression of diabetic retinopathy.3, 7, 8 It is possible that our patient may have had diabetes mellitus for a number of years prior to its diagnosis. In addition, her concurrent medical conditions and acute illness may have hastened the development and progression of diabetic retinopathy.

This case highlights the potential for rapid, unilateral progression of diabetic retinopathy following an episode of endophthalmitis, even in patients with a short duration of diabetes. These patients require frequent and careful follow-up in order to detect and treat progression of diabetic retinopathy.