ABSTRACT
Background & objectives: Optic neuritis (ON) is characterized by sudden and rapid impairment of vision. Bartonella henselae is a known aetiological agent of cat scratch disease (CSD), which is a common cause of neuroretinitis, the least common type of optic neuritis. The present study was carried out to determine the microbiological aetiology of optic neuritis in patients attending a tertiary care eye hospital in north India, which was later confirmed with molecular characterization. Methods: Of the 50 patients suffering from optic neuritis reported to the Ophthalmology OPD of a tertiary care eye hospital in New Delhi, India, 29 were included in the study. Blood culture from these patients were processed for aerobic and anerobic cultures to rule out infective aetiology. Subsequently, PCR was done on archive, glycerol-stocked cultures. Results: Gram-negative pleomorphic coccobacilli grew in four of 29 patients tested. Characterization of these revealed Bartonella like organism as tested by the API 20E, API Staph, API Strept and RapID ANA systems. Electron microscopy revealed presence of polar flagella and bleb like projection all over the bacterial surface. PCR performed on preserved culture confirmed these as Bartonella sp. Interpretation & conclusions: Infections with Bartonella like organisms have not been demonstrated from India in cases of optic neuritis or in any of the other clinical syndromes in the past. The present study shows the isolation and characterization of Bartonella like organisms from optic neuritis patients. From clinical point of view it will be important to look for these organisms as aetiological agents in ON cases in order to treat with appropriate antibiotics.
ABSTRACT
AIM: To compare the efficacy of intravenous methylprednisolone and intravenous dexamethasone on visual recovery and evaluate their side-effects for the treatment of optic neuritis. MATERIALS AND METHODS: Prospective, randomized case-controlled study including 21 patients of acute optic neuritis presenting within eight days of onset and with visual acuity less then 20/60 in the affected eye who were randomly divided into two groups. Group I received intravenous dexamethasone 200 mg once daily for three days and Group II received intravenous methylprednisolone 250 mg/six-hourly for three days followed by oral prednisolone for 11 days. Parameters tested were pupillary reactions, visual acuity, fundus findings, color vision, contrast sensitivity, Goldmann visual fields and biochemical investigations for all patients at presentation and follow-up. RESULTS: Both groups were age and sex-matched. LOGMAR visual acuity at presentation was 1.10 +/- 0.52 in Group I and 1.52 +/- 0.43 in Group II. On day 90 of steroid therapy, visual acuity improved to 0.28 +/- 0.33 in Group I and 0.36 +/- 0.41 in Group II ( P =0.59). At three months there was no statistically significant difference in the color vision, contrast sensitivity, stereoacuity, Goldman fields and the amplitude and latency of visually evoked response between the two groups. The concentration of vitamin C, glucose, sodium, potassium, urea and creatinine were within the reported normal limits. CONCLUSION: Intravenous dexamethasone is an effective treatment for optic neuritis. However, larger studies are required to establish it as a safe, inexpensive and effective modality for the treatment of optic neuritis.