(a) Fundus photograph shows disc edema and macular scar in the left eye of a 22-year-old healthy man with 1 week history of blurry vision OS (20/200). (b) Fluorescein angiography shows leakage confined to the optic nerve
(a) Fundus photograph shows unilateral disc edema. (b) Fluorescein angiography shows disc leakage without macular leakage
Twelve-year-old healthy girl referred for a neuro-ophthalmologic consultation of disc edema OS > OD of unclear etiology. Sinus X-rays, head CT scan, MRI with contrast and lumbar puncture with opening pressure were ordered by the outside ophthalmologist, and these were all normal. Visual acuities were 16/13 OD and 16/200 OS (down from 20/60 2 weeks earlier). A positive left afferent pupillary defect was present. (a) Trace disc hyperemia with mild blurring of the inferonasal margin was noted in the right eye. (b) In the left eye, moderate disc edema with peripapillary subretinal fluid extending into the fovea was noted
Fluorescein angiography shows dilated disc capillary OS in the early phase (a) followed by increasing disc leakage with time (b). Late images show mild disc leakage and no macular leakage OD (c)
In the same patient, fundus photography of the left eye at 8 days after initial consultation shows marked disc edema and a newly formed macular star (a). Fundus photography at 11 months later shows normal appearing macula and mild disc pallor (b). Visual acuity improved from 16/200 to 16/30 OS. (Courtesy of Joseph F. Rizzo, MD)
A small chorioretinitis lesion in the contralateral eye of a patient with classic neuroretinitis
The more common ocular complication caused by Bartonella infection is Parinaud’s oculoglandular syndrome, which affects approximately 2–5% of symptomatic patients (Carithers 1985). Parinaud’s oculoglandular syndrome is a rare condition consisting of chronic low-grade fever, granulomatous follicular conjunctivitis, and ipsilateral regional lymphadenopathy involving either the preauricular or the submandibular of cervical lymph nodes. Transmission is generally from hand–eye contact from infected cat feces. Most patients experience localized disease that resolve within several months.
Differential Diagnosis
The differential diagnosis for neuroretinitis includes malignant hypertension, central retinal vein occlusion, diabetes mellitus, pseudotumor cerebri, sarcoidosis, syphilis, tuberculosis, toxoplasmosis, toxocariasis, Lyme disease, mumps, varicella, herpes simplex, and leptospirosis (Dreyer et al. 1984). It is important to remember that unilateral disc edema precedes the formation of a macular star by 1–4 weeks. As in the case in Fig. 18.2, this 12-year-old patient presented with asymmetrically bilateral disc edema and underwent extensive workup including a lumbar puncture prior to the development of a macular star and subsequent diagnosis of Bartonella. Invasive diagnostic procedures can be avoided by obtaining a thorough history and considering Bartonella in the differential for disc edema even in the absence of a macular star. Causes of a macular star include hypertensive retinopathy, papilledema, anterior ischemic optic neuropathy, diabetic papillopathy, posterior vitreous traction, disc, and juxtapapillary tumors. Either by inflammatory or ischemic mechanisms, these entities can compromise the microvasculature of the optic disc and result in leakage of serum and lipids with macular star formation.
Bartonella henselae has been isolated as the etiologic agent, and serologic testing for B. henselae is available. There are two different serologic tests for the diagnosis of cat scratch. The first is an indirect fluorescent antibody test (IFA) for the detection of serum anti-B. henselae antibodies. This test was found to be 88% sensitive and 94% specific in the immunocompetent host and may fall to 70% or below in HIV-infected individuals (Dalton et al. 1995). The second is an enzyme immunoassay (EIA) with a sensitivity of 86–95% and specificity of 96% compared with IFA (Litwin et al. 1997; Barka et al. 1993). All tests have the potential for cross-reactivity with B. quintana as well as other species.
Management
There are no treatment guidelines for CSD as it is known to have a self-limited course in immunocompetent patients. The visual prognosis is good with or without treatment. Antibiotics are generally reserved for those with the most severe infections. Immunocompromised patients affected with CSD tend to require antibiotics such as erythromycin or doxycycline to control their infection (Schlossberg et al. 1989).
Given its superior intraocular penetration, doxycycline is preferred to erythromycin in patients older than 9 years of age. Doxycycline is contraindicated in younger children given its propensity for teeth discoloration. Both doxycycline and erythromycin can be given intravenously or combined with rifampin in more severe infections. Other antibiotics that can be used include azithromycin, ciprofloxacin, gentamycin, and trimethoprim-sulfamethoxazole (Relman et al. 1990). After resolution of the disease, final outcome can include residual visual field defect, decreased visual acuity, and contrast sensitivity and disc pallor on examination.
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