Description 

A 26-year-old Lithuanian man with type 1 diabetes, diagnosed at aged 14, presented to the emergency department with shortness of breath as well as left flank pain. The patient was taking a basal-bolus (Actrapid/Lantus) regimen of insulin and had no other medical conditions. The patient was found to be in diabetic ketoacidosis (blood glucose level 21 mmol/L, pH 7.10) and diagnosed with chest sepsis based on bilateral consolidation on a chest X-ray. The patient was admitted to the high dependency unit and treated empirically with intravenous flucloxacillin and ceftriaxone. Blood cultures grew a fully sensitive Staphylococcus aureus. The patient’s flank pain failed to improve and on day 3 of admission CT of the abdomen and pelvis demonstrated a left 4.9 cm intermedius muscle abscess (figure 1). There were additional small focal collections in the left psoas, right psoas and right erector spinae muscle. Radiologically guided aspiration of the left intermedius collection demonstrated the same S. aureus growth. Echocardiogram, as well as tests for HIV, blood film and tuberculosis, was normal.

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Figure 1

Axial CT image of the pelvis. Red arrow demonstrates a left intermedius muscle collection.

On day 14 of admission the patient reported poor vision in the left eye which on further enquiry had been present at the time of his original presentation. Examination of the left eye demonstrated perception of hand movements only, 2+ anterior and vitreous cells and a subretinal abscess (figure 2A). Optical coherence tomography (OCT; figure 2B) demonstrated an atrophic retina, consistent with a partially treated subretinal abscess. The right eye was normal.

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Figure 2

(A) Colour retinal photograph of the left eye demonstrating a macular abscess. (B) OCT scan demonstrating significant macular atrophy at the time of presentation.

The patient was continued on intravenous antibiotics and initiated on topical steroid eye treatment. The patient was not treated with intravitreal treatment given the resolving nature of the abscess, poor prognosis based on OCT and delayed presentation. The patient was discharged on day 20 on continued oral antibiotics for the resolving intramuscular collections. Follow-up demonstrated complete resolution of the intramuscular collections and a stable, counting fingers, vision 6 months after presentation.

Endogenous bacterial endophthalmitis (EBE) is a rare but severe intraocular infection which comprises 2%–8% of all causes of endophthalmitis.1 Jackson et al reported on a case series of 342 eyes and found that S. aureus is the most common Gram-positive causative organism and the second most common overall after Klebsiella pneumoniae.1 Patients often present with blurred vision and pain. Despite the severity of the condition the diagnosis is often delayed, with a mean delay of 3.2 days.1 Delay in diagnosis, as was the case with the above patient, is a poor prognostic indicator.2 Other poor prognostic indicators include poor initial visual acuity, centrally located lesions, presence of a hypopyon, and rapid onset of symptoms, unilateral involvement and panophthalmitis.

Risk factors for the development of EBE include hospitalisation, diabetes, immunosuppression, urinary tract infection, neutropenia, HIV, intravenous drug use and indwelling catheters.2 It has been suggested that diabetes induces increased blood-retinal barrier permeability and subsequent risk of development of EBE.3

Identification of the causative organism in EBE can be achieved through a combination of blood cultures and intravitreal sampling with respective sensitivities of these methods being 56% and 58%.1

Treatment of the condition involves a combination of intravitreal and intravenous antibiotics as well as intravitreal dexamethasone with a consideration of vitrectomy.1 Prognosis of EBE remains poor with 59% of eyes achieving hand movements vision or worse. Nineteen per cent requires enucleation or evisceration. OCT, as with this case, is a useful tool in assessing visual prognosis. Mortality from systemic involvement of the infection in EBE is 4%.1