Cat-Scratch neuroretinitis (Ocular bartonellosis):

44-year-old female with non-specific "blurriness" of vision, left eye (OS)

Cat-Scratch neuroretinitis (Ocular bartonellosis):

44-year-old female with non-specific "blurriness" of vision, left eye (OS)

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Chief Complaint: Non-specific "blurriness" of vision, left eye (OS).

History of presenting illness: 44-yo female with no previous ocular history presents after a 9 day history of non-specific blurred vision in the left eye. This "graying out" quality is painless and not associated with any known infection nor precipitating factor nor other ocular symptoms. There were no associated systemic symptoms (including no parasthesias, numbness, weakness, nor ataxia). Over several days the vision steadily dropped. The patient first went to her family doctor four days after symptoms began and was referred to her local ophthalmologist. After examination, a single 80 mg dose of prednisone was administered. There were no special studies locally, and the patient was referred to the University of Iowa for consulation thereafter.

Ocular History: No previous ocular history. No eye surgery, trauma, nor contact lens use.

Medical History: Gallbladder surgery, ileus, and borderline high blood pressure. Review of systems negative.

Family History: Cataract, glaucoma, diabetes, heart disease, hypertension, and renal disease.

Social History: Patient works as a nurse. She has no tobacco nor alcohol use.

EXAM OCULAR

• General: well-appearing adult in no acute distress
• Visual Acuity: OD—20/15; OS—Count fingers at 4 ft.
• Extraocular motility full
• Pupils: 6mm in dark, 4mm in light, OU. 0.6 log unit afferent pupillary defect (APD), OS.
• Intra-ocular pressure: 22 mmHg, OU
• External and anterior segment examination normal.
• Goldmann visual fields (GVF): OD—essentially normal; OS—large cecocentral scotoma (see Figure 1).
• Dilated fundus exam (DFE): OD—small optic disc and some peripapillary atrophy; OS—sectoral disc edema temporally. No vitreous cell. Suspicion for fluid tracking toward the macula, but no evidence of exudate (see Figure 2).

Figure 1

1A: GVF, OS reveals a large cecocentral scotoma.	1B: GVF, OD is essentially normal.

Figure 2

2A: Stereo photos, OD.
2B: Stereo photos, OS. No vitreous cell, sectoral disc edema temporally.

There was suspicion for subretinal fluid tracking into the macula, but this was not clearly evident on fundus exam alone. Optical coherence tomography (OCT) was performed and did confirm subretinal fluid extending throughout the macula (see Figure 3).

Figure 3: OCT, OS, reveals extensive fluid as a dark space beneath the neurosensory retina throughout the macula.

Clinical Course: At this point, several possible diagnoses were considered. The patient had no pain, the optic disc edema was sectoral, and magnetic resonance imaging (MRI) was negative making demyelinating disease less likely. Ischemic optic neuropathy was a consideration, but the patient is of the wrong age, in overall good health, and without any symptoms of giant cell arteritis. Neuroretinitis was also considered as a possible diagnosis.

The patient was asked about pets, and she volunteered that she has cats at home. When asked about scratches from the cats, she rolls up her sleeves and shows multiple examples of scratches from 3-4 weeks old.

Laboratory work-up was initiated and results included:

• White blood cell count: 18,200 with left shift (12,194 segmented neutrophils and 3276 bands)
• Bartonella Henselae IgG 1:1024 (strongly positive)

The infectious disease team was consulted for what appeared to be cat-scratch disease (ocular bartonellosis). They agreed with that assesment and recommended treatment based on reasonable indicators of poor vision, high titer, elevated white blood cell count, and known scratch from a cat. A review of the literature suggested that a one month course of doxycycline or erythromycin (with or without rifampin) is adequate to treat the organism and hasten recovery. Consistent with their recommendation, we treated the patient with a one month course of doxycycline 100 mg PO twice daily.

The patient returned for follow-up appointments one and two months after this initial diagnosis. At these follow-up appointments, the patient was found to have vision improving to 20/60 in the affected eye, improving visual fields (Figure 4), decreased optic disc edema (Figure 5), and resolving sub-retinal fluid (Figure 6).

Figure 4

4A: Repeat GVF, OS at 1 month follow-up demonstrates significant improvement with a much reduced cecocentral scotoma.	4B: GVF, OS at 2 month follow-up confirms stabilization of the visual field.

Figure 5. Stereo images of optic disc, OS, at 2 month follow-up reveals decreased optic disc edema. Exudates that had been briefly present in earlier follow-up exam were gone by the time of this photo. A classic macular star of exudates is shown in Figure 7.

Figure 6: OCT, OS, at follow-up confirms resolution of sub-retinal fluid.

Discussion

Cat-scratch disease is caused by the organism Bartonella Henselae. There are approximately 22,000 cases of in the United States every year. Diagnosis of the disease officially requires 3 out of 4 criteria:

• Lymphadenopathy in the absence of other reason (can be missed because it is not present yet or subclinical)
• Positive Bartonella H. titer or skin test
• Known cat contact, preferably with pustule or papule at the site
• Lymph node biopsy with bacilli present, necrosis

As a matter of fact, we only have 2 of the 4 criteria in this case since the patient was not found to have identifiable lymph nodes at the time of examination.

Bartonella is transmitted from the flea, to the cat, to (potentially) the human host. Ophthalmic manifestations of Bartonellosis may occur in up to 13% of patients with systemic cat-scratch disease and includes:

• Parinaud's oculoglandular syndrome: granulomatous conjunctivitis with associated preauricular lymphadenopathy
• Neuroretinitis
• Focal chorioretinitis

Treatment is controversial. In fact, it has been well documented that patients will almost always get better on their own. However, literally hundreds of reports exist suggesting different regimens used to treat the condition and shorten recovery times. Treatments include doxycycline, erythromycin, rifampin, azithromycin, ciprofloxacin, later addition of steroid drop, and many others. A review article published in the American Journal of Ophthalmology (Cunningham & Koehler 2000) suggests a one-month course of doxycycline or erythromycin, with or without rifampin.

After resolution of the disease, final outcome can include residual visual field defect, decreased contrast sensitivity and visual acuity, and sectoral disc pallor on exam. Classically, a macular star of lipid exudates is seen as subretinal fluid is resorbed (see Figure 7 for a classic macular star). Indeed, most cases of unilateral macular star with optic disc swelling is related to ocular bartonellosis, as is the case with this patient's (however, a differential diagnosis is offered below). Eventually, the macular exudates also resolve.

Figure 7. A macular star of lipid exudates is classically described in neuroretinitis. Though the patient described in this case had only a few such exudates, this more classic photo from another similar patient is here provided for educational reference.

Diagnosis: Cat-Scratch neuroretinitis (Ocular bartonellosis)

EPIDEMIOLOGY 22,000 cases yearly in the U.S. (about 6.6 cases per 100,000) no racial nor gender predilection majority of cases are in pediatric patients with cat contacts known contact with cats can usually be elicited from the history fleas (ie. ctenocephalides felis) carry B. henselae in their intestinal tract and excrete it in their feces	OCULAR SIGNS granulomatous conjunctivitis with preauricular lymphadenopathy (in cases of Parinaud's oculoglandular syndrome—POGS) systemic lymphadenopathy optic nerve edema subretinal fluid, exudates, or a macular star focal chorioretinitis enlarged blind spot on visual field testing positive skin test or serum titer for Bartonella H.
SYMPTOMS systemic symptoms of disease may resemble a flu-like illness (malaise/weakness, low-grade fever, headache, and joint or muscle pains) patients may also notice enlarged regional lymph nodes in the axillae, groin, neck, or head decreased/blurry vision, usually in one eye red eye (in patients with POGS) patients may notice decreased visual field	TREATMENT patients will almost always get better on their own several treatments to shorten the duration of symptoms have been described (doxycycline, erythromycin, rifampin, azithromycin, ciprofloxacin, and steroids later in the course) doxycycline (i.e. 100 mg PO 2x/day) or erythromycin with or without rifampin (300 mg PO 2x/day) is likely sufficient

Differential Diagnoses for Neuroretinitis

• Cat Scratch — Bartonella Henselae
• Lyme disease
• Syphilis
• Toxoplasmosis
• Hypertensive retinopathy
• Tuberculosis
• Polyarteritis nodosa
• Tularemia
• Other causes of edema (idiopathic intracranial hypertension, intracranial arteriovenous malformation)