Sir,

Bartonella are gram-negative rods.1 Of the 14 known species, five are associated with human disease. B. henselae causes cat scratch disease and B. quintana causes trench fever. B. henselae infections often present with fever, malaise and lymphadenopathy. A history of contact with a cat is not always present. Eye involvement can cause Parinaud oculoglandular fever, neuroretinitis2,3 and an inflammatory mass of the optic nerve head.4

Case report

A 9-year-old male presented with a history of poor vision for 2 days, with no other specific medical or ocular history of note. There was no pain, lymphadenopathy, fever or trauma. Physical examination revealed a healthy male with normal blood pressure, urinalysis, without hepatosplenomegaly, lymphadenopathy or anaemia.

Ophthalmological examination revealed a visual acuity of 6/5 in the right eye and 3/60 in the left with a dense relative afferent pupillary defect. There was no anterior segment or vitreous inflammation. The left retina had widespread hemorrhages with tortuous vessels with an area of possible focal retinitis involving the papillo-macular bundle, and a early macular star (Figure 1). The right fundus was normal.

Figure 1
figure 1

Left ocular fundus.

Full size image

Investigations, including: FBC, U & E, clotting and thromophilia screen, LFT, autoantibody screen, serum cholesterol, HDL and triglycerides, ESR, serum homocysteine, MRI scan, echocardiogram and ocular ultrasound, were normal. Fundus fluorescein angiogram was not possible. Indirect immunofluorescence titres for anti-B. henselae, taken 3 weeks after initial presentation, were one in 64. There was a cross-reactivity with B. quintana which was reported as one in 128 IgG (IgM negative).

A tentative diagnosis was made of neuroretinitis secondary to B. henselae with a subsequent central retinal vein occlusion. A 2-week course of 250 mg Clarythromycin b.d. was given. Further questioning elicited a history of contact with a stray kitten while on holiday in Italy 5 weeks prior to presentation. The titers were taken 8 weeks after this exposure. Subsequent titers were unchanged. Three months later, the vision had improved to 6/6. The retinal appearances had returned to normal with the exception of mild increased tortousity.

Comment

Central retinal vein occlusion is extremely rare in children. In a review of 17 patients with CRVO under the age of 40,5 only one was in the paediatric age group. We speculate that there was an initial optic disc swelling in association with neuroretinitis which precipitated a CRVO. Solley et al6 reviewed 24 patients with cat scratch disease, of whom 13 had unilateral disease and three were under 16 years of age. They reported one case of branch retinal vein occlusion. Epidemiological data suggest that higher cat infection rates are associated with a warm climate, fleas and kittens. Most authors advocate treatment of B. henselae with antibiotics, and Rifampicin and Doxycycline are often used. Because of the age of this patient we used Clamythromycin. There is some debate as to whether antibiotics alter long-term outcome in B. henselae associated neuroretinitis which is good in most cases.3