Bartonella henselae (formerly Rochalimaea henselae), a small, fastidious, gram-negative rod, initially isolated from the tissue of patients with bacillary angiomatosis of AIDS, is now known to be the principal etiologic agent of cat-scratch disease (CSD) and is associated with an expanding spectrum of ocular manifestations. Cat-scratch disease is a felineassociated zoonotic disease found worldwide, with an estimated annual incidence rate in the United States of 9.3 cases per 100,000 persons. The highest age-specific incidence is among children younger than 10 years of age. Cats are the primary mammalian reservoir of B henselae and B quintana, and the cat flea is an important vector for the transmission of the organism among cats. The disease follows a seasonal pattern, occurring predominantly in the fall and winter, and is most prevalent in the southern states, California, and Hawaii. The disease is transmitted to humans by the scratches, licks, and bites of domestic cats, particularly kittens.
Systemic manifestations of CSD include a mild to moderate flulike illness associated with regional adenopathy that usually precedes the ocular manifestations of the disease. An erythematous papule, vesicle, or pustule usually forms at the primary site of cutaneous injury 3–10 days after primary inoculation and 1–2 weeks before the onset of lymphadenopathy and constitutional symptoms. Less commonly, more severe and disseminated disease may develop that is associated with encephalopathy, aseptic meningitis, osteomyelitis, hepatosplenic disease, pneumonia, and pleural and pericardial effusions.
Biancardi AL, Curi AL. Cat-scratch disease. Ocul Immunol Inflamm. 2014;22(2):148–154.
Roe RH, Jumper JM, Fu AD, Johnson RN, McDonald HR, Cunningham ET. Ocular bartonella infections. Int Ophthalmol Clin. 2008;48(3):93–105.
Ocular involvement, which occurs in 5%–10% of patients with CSD, includes Parinaud oculoglandular syndrome (unilateral granulomatous conjunctivitis and regional lymphadenopathy) in approximately 5% of patients and a wide array of posterior segment and neuro-ophthalmic findings. Entities to be considered in the differential diagnosis of Parinaud oculoglandular syndrome include tularemia, tuberculosis, syphilis, sporotrichosis, and acute Chlamydia trachomatis infection (see also BCSC Section 8, External Disease and Cornea, for discussion on Parinaud oculoglandular syndrome).
The best-known posterior segment manifestation of B henselae infection is neuroretinitis, a constellation of findings that includes abrupt vision loss, unilateral optic disc swelling, and macular star formation. This syndrome, formerly known as idiopathic stellate maculopathy and later renamed Leber idiopathic stellate neuroretinitis, is now known to be caused by B henselae infection in approximately two-thirds of cases. It occurs in 1%–2% of patients with CSD. Focal or multifocal retinitis may also be identified. Table 10-3 lists other entities that may cause neuroretinitis. Visual acuity loss varies between 20/25 and 20/200 or worse and follows the onset of constitutional symptoms by approximately 2–3 weeks. Although the presentation is most often unilateral, bilateral cases of neuroretinitis have been reported and are frequently asymmetric. Optic disc edema, associated with peripapillary serous retinal detachment, has been observed 2–4 weeks before the appearance of the macular star and may be a sign of systemic B henselae infection. The development of the macular star is variable (Fig 10-15) and may be partial or incomplete, usually resolving in approximately 8–12 weeks.
Patients with Bartonella-associated neuroretinitis may exhibit some degree of anterior chamber inflammation and vitritis. Discrete, focal, or multifocal retinal and/or choroidal lesions measuring 50–300 μm are common posterior segment findings. Both arterial and venous occlusive disease, as well as localized neurosensory macular detachments, have been described in association with focal retinitis. Other posterior segment ocular complications include epiretinal membranes, inflammatory mass of the optic nerve head, peripapillary angiomatosis, intermediate uveitis, retinal white dot syndromes, orbital abscess, isolated optic disc swelling, and panuveitis. Immunosuppressed individuals may display a retinal vasoproliferative response, leading to single/multiple angiomatoid lesions involving retina/choroid.
Table 10-3 Differential Diagnosis of Neuroretinitis
Left, color fundus photograph of the left eye of a patient with cat-scratch disease shows neuroretinitis with optic disc involvement associated with a macular star. Punctate retinal infiltrates are also visible superiorly (arrows). Upper right, spectral-domain optical coherence tomography scan delineates the inner retinal infiltrate (arrow). Lower right, scan reveals subretinal fluid (peripapillary serous retinal detachments, arrows), intraretinal exudates, vitreous inflammatory infiltration, and optic disc and macular edema.
(Courtesy of Daniel V. Vasconcelos-Santos, MD, PhD.)
Chi SL, Stinnett S, Eggenberger E, et al. Clinical characteristics in 53 patients with cat scratch optic neuropathy. Ophthalmology. 2012;119(1):183–187.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.