Year : 2006 | Volume
: 54 | Issue : 3 | Page : 177--183
Visual outcome after intravenous dexamethasone therapy for idiopathic optic neuritis in an Indian population: A clinical case series
Harinder Singh Sethi, Vimla Menon, Pradeep Sharma, Sudarshan Khokhar, Radhika Tandon
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi - 110 029
Purpose: To evaluate the clinical profile, response to dexamethasone treatment and visual function outcome in Indian patients with acute optic neuritis.
Materials and Methods: We conducted an observational study of patients with acute optic neuritis who were treated with intravenous dexamethasone (100 mg in 250 ml of 5% dextrose over 1-2 hours daily, for three consecutive days) and had completed at least two years of follow-up. Parameters assessed included visual acuity, contrast sensitivity, color vision, visual fields, relative afferent pupillary defect (RAPD) and visually evoked potentials. Out of 40 patients studied, 26 patients (33 eyes) had all visual function parameters assessed. Twenty three patients (28 eyes) had completed two years of follow-up and were included for statistical analysis.
Results: Improvement in visual acuity was statistically significant for distance after 24 hours of the first dose ( P = < 0.001) and for near vision after 24 hours of the second dose ( P = 0.006); improvement in color and contrast sensitivity was statistically significant 24 hours after the third dose ( P = < 0.001 for color vision and P = 0.013 for contrast sensitivity). Significant improvement in RAPD and visual fields were seen by 1 month ( P = 0.005). Recurrence was seen in 4 eyes of 4 patients. No serious side effects were observed. At two years, 82.14% (23 out of 28) eyes had visual acuity > 20/40.
Conclusion: Treatment with intravenous pulsed dexamethasone led to rapid recovery of vision in acute optic neuritis, without any serious side effects.
|How to cite this article:|
Sethi HS, Menon V, Sharma P, Khokhar S, Tandon R. Visual outcome after intravenous dexamethasone therapy for idiopathic optic neuritis in an Indian population: A clinical case series.Indian J Ophthalmol 2006;54:177-183
|How to cite this URL:|
Sethi HS, Menon V, Sharma P, Khokhar S, Tandon R. Visual outcome after intravenous dexamethasone therapy for idiopathic optic neuritis in an Indian population: A clinical case series. Indian J Ophthalmol [serial online] 2006 [cited 2020 May 29 ];54:177-183
Available from: http://www.ijo.in/text.asp?2006/54/3/177/27069
Optic neuritis is clinically characterized by a sudden diminution of vision to varying extent, with associated pain on ocular movements. Although more than three-quarters of patients make an excellent spontaneous recovery to a visual acuity of 20/30 or better, some have a lasting visual deficit. The treatment had been controversial until the optic neuritis treatment trial (ONTT) provided convincing evidence, that intravenous methylprednisolone leads to quicker recovery of vision. However the long term visual outcome was comparable with placebo and oral steroids.,,, Oral steroids are not only ineffective, but lead to more frequent recurrences and hence should be avoided.,
As methylprednisolone is expensive and the 6 hourly regimen of methylprednisolone as recommended by ONTT is cumbersome, dexamethasone as a daily single injection is used as an alternative in Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS). Intravenous dexamethasone has been reported to be equally effective as an alternative to methylprednisolone in multiple sclerosis, kidney transplant rejection, progressive systemic sclerosis and systemic lupus erythematosis and has been successfully used in several departments in AIIMS, a multispeciality referral hospital.,,,, A prospective randomized controlled clinical trial comparing the effectiveness of dexamethasone with methylprednisolone in acute optic neuritis was designed, but was abandoned, as several patients who were randomized to the methylprednisolone group could not afford the drug and some preferred a single daily injection. These patients have been treated as per our neuro-ophthalmology service protocol [Table 1] and their clinical course has been recorded. We hereby present the results of this analysis and share our experience of using dexamethasone, which has not so far been extensively reported in the literature.
Materials and Methods
It was an observational case series study. We analyzed the clinical course of patients with acute optic neuritis in the age group of 15-50 years, who were treated in Rajendra Prasad Centre from 1996-1998. In all, 40 patients were seen and treated. All patients were treated with intravenous dexamethasone, as per the treatment criteria followed by the neuro-ophthalmology service at our Centre [Table 1].
All the patients presented with complaints of sudden onset of decrease in vision, which rapidly deteriorated over the next few days. The average time lag at presentation after onset of symptoms was 8.03+3.9 days (range of 2-15 days). History of previous episodes of optic neuritis was present in 4 patients. Out of these, two patients had a history of involvement of the same eye, one of the other eye and one had bilateral involvement in the past. Eight patients had a history of taking oral steroids, with no visual improvement before presenting to the neuro-ophthalmology clinic.
Best corrected distance visual acuity (BCVA) [Snellen's and early treatment diabetic retinopathy (ETDRS) charts], near vision (near vision test plates), color vision (Ishihara pseudoisochromatic color vision plates), contrast sensitivity (Cambridge low contrast gratings), visual fields examined by Goldmann and Humphrey full threshold technique, relative afferent pupillary defect (RAPD) [quantified using neutral density filters in unilateral or bilateral asymmetric cases], pattern and flash- induced visual evoked potentials (VEPs, which were recorded using Lace Elettronica Erev 99 Recording equipment), were evaluated up to three months. Thereafter, these patients were followed up at six months and two years intervals, when only visual acuity was recorded and note was made of any recurrence during this period. The pulse rate and blood pressure (BP) were recorded during intravenous infusion therapy, serum electrolytes, blood sugar (fasting and post-prandial) taken before and after treatment and weight recorded before treatment and at subsequent follow-up visits, were also analyzed. Magnetic resonance imaging (MRI) of the brain and orbit was performed in all cases, either before or after intravenous treatment.
As is our routine practice, visual acuity including near vision, color vision, pupillary reactions and fundus findings, were recorded daily during the period of intravenous treatment and thereafter at each follow-up visits, which were scheduled after 1 week, 1 month, 3 months, 6 months and 24 months thereafter. The result of the treatment was assessed by comparing post-treatment vision with pre-treatment visual function status, in all cases. Complete evaluation of all the above mentioned parameters was possible for 26 patients (33 eyes). Twenty three patients (28 eyes) completed 2 years of follow-up.
Statistical analysis was done using methods such as Friedman two-way non-parametric analysis of variance (ANOVA), Wilcoxon signed rank test, paired T test and Chi-square test for the different clinical parameters, as appropriate.
The mean age (SD) of this group of patients was 30.5±10.6 years. Mean age ± S.D in men was 32±10 years and 25.4±9.6 years in women. Thirty cases were unilateral and 10 were bilateral. There were 30 males and ten females. A clinical diagnosis of papillitis was made in twenty patients and retrobulbar neuritis in seventeen patients. Neuroretinitis was found only in three patients.
Visual function parameters showed rapid recovery following treatment with intravenous dexamethasone, as compared with pretreatment levels in all patients. Out of 40 patients, 26 patients (nineteen unilateral and seven bilateral) were able to complete all tests for assessment of visual functions. Twenty three patients (twenty eight eyes) completed two years of follow-up. Statistical analysis of visual outcome has been done for these twenty eight eyes (of twenty three patients), in whom all the tests of visual function assessment were done and who completed two years of follow-up. Statistically significant improvement began within 24 hours for distance ( P = P = 0.006) [Table 2],[Table 3] and [Figure 1]. Color vision and contrast sensitivity showed statistically significant improvement after 3 days ( P = P = 0.013 for contrast sensitivity) [Table 4]. RAPD and visual fields were slower to recover [Table 4][Table 5]. Statistically significant improvement was seen by 1 month ( P = 0.005). No significant variation in pulse, blood pressure, serum electrolytes, blood sugar or systemic condition of the patients, was observed during the period of dexamethasone therapy. The therapy was well tolerated in general, with one patient complaining of insomnia during the treatment and one developing acne after it. Both side effects resolved spontaneously without any active intervention. No significant variation in weight was observed during the follow-up. MRI of the brain revealed evidence of silent coexistent sinusitis in 3 patients, craniopharyngioma, and multiple sclerosis in one patient each.
Four patients (4 eyes) developed recurrence. Three patients had recurrence in the same eye and one patient in the other eye. Three patients developed recurrence within one month and one after one month. Of these patients, Craniopharyngioma was detected after MRI scan of brain in one patient (who was thus excluded from the study), one patient was found to have evidence of multiple sclerosis on brain MRI and two patients had a history of prior treatment with oral steroids. The patients with recurrence were treated with a repeat intravenous dexamethasone therapy. These patients responded again to treatment. Their visual parameters have been included in final statistical analysis. The recurrence rate was 11.54% at six months (three out of 26 patients, as the patient with craniopharyngioma was excluded for calculation of recurrence rate). No further recurrence occurred in the patients who completed two years of follow-up.
Three months after treatment, VA ³ 20/20 was achieved in 16 (57.14%) eyes, 20/30 in 5 (17.85%) and 20/40 in 2 (7.14%). Two eyes (7.14%) had a VA of 20/120-20/60 and 3 eyes (10.72%) had VA 20/40 and 7.14% eyes VA of 20/120-20/60. Only 10.72% eyes failed to improve beyond 10/200 at 6 months. In our study, 57.14% of eyes regained the normal VA of 20/20 at 6 months. This is as compared with 57.33% (61.59% in the methylprednisolone group, 56.66% in the placebo group and 53.85% in the oral prednisolone) in the ONTT. The rate of recurrence in our study group at 6 months was 11.54%, which is comparable to the 13% recurrence rate reported in the intravenous methylprednisolone group. Out of 26 patients (33 eyes) who were able to complete all tests for assessment of visual functions initially, three patients (5 eyes) were lost to follow-up. Twenty three patients (twenty eight eyes) completed two years follow-up. Statistical analysis of visual outcome has been done for these twenty eight eyes (of twenty three patients). This is an inherent problem in situations where the patients come from far off places. Since we do not know the exact clinical status, they have not been included in analysis and the intention to treat analysis was not applied. Overall, 5 eyes (of three patients) were not included in the final analysis.
In detecting fellow eye abnormality, pattern VEP was found to be the most sensitive test, followed closely by contrast and Humphrey visual fields [Table 7]. It is noteworthy that among asymptomatic fellow eyes, 31.57% of eyes by VEP, contrast sensitivity and Humphrey visual fields, improved on follow- up, suggesting simultaneous involvement of asymptomatic fellow eyes during the acute phase of optic neuritis, which improved after treatment.
All patients tolerated the intravenous dexamethasone therapy well, with no pulse or blood pressure variation and serum electrolyte disturbance during the period. No serious complications or side effects were observed in any of the treated patients and no oral steroids were given after intravenous dexamethasone therapy. Good results with intravenous dexamethasone therapy alone, suggests that tapered treatment with oral steroids may not be required. Although our study group is small and did not include controls, as the standard patterns have already been laid down by randomized controlled trials such as the ONTT, our experience of the clinical profile, response to intravenous dexamethasone and outcome of visual function, does show resemblance and trends similar to that seen in the ONTT.,,,,,, Although intravenous methylprednisolone is considered the standard treatment to enhance the recovery of visual function in optic neuritis, our results suggest that dexamethasone can also be used for this purpose, in case there are financial constraints.
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