J Korean Ophthalmol Soc.  2015 Dec;56(12):1997-2003. 10.3341/jkos.2015.56.12.1997.

Bitemporal Hemianopsia in Ethambutol-Induced Optic Neuropathy

• Lee HJ
• Rhiu S
• Lee SH
• Jeong JH

• KMID: 2148768
• DOI: http://doi.org/10.3341/jkos.2015.56.12.1997

Abstract

PURPOSE
To report three cases with bitemporal hemianopsia after using ethambutol to treat tuberculosis.
CASE SUMMARY
A 50-year-old male with chronic renal failure and tuberculous pleurisy, a 57-year-old male with diabetic retinopathy and pulmonary tuberculosis, and a 59-year-old male with diabetes and pulmonary tuberculosis were referred for evaluation due to decreased visual acuity for several months after taking ethambutol to treat tuberculosis. All 3 patients had abnormal color vision and visual evoked potential in both eyes. Visual field showed bitemporal hemianopsia with or without central scotoma. Brain imaging tests were normal. Although ethambutol was discontinued in all three patients, one patient with renal disease showed further decrease in visual acuity and visual field worsened to total field defect.
CONCLUSIONS
Ethambutol-induced optic neuropathy is a wide spectrum disorder and based on our cases, can present as bitemporal hemianopsia mimicking compressive chiasmal lesions. A thorough history should be taken and immediate discontinuation of ethambutol is recommended in cases when bitemporal hemianopia occurs.

Keyword

Bitemporal hemianopsia; Ethambutol; Optic chiasm; Optic neuropathy; Tuberculosis

MeSH Terms

Color Vision
Diabetic Retinopathy
Ethambutol
Evoked Potentials, Visual
Hemianopsia*
Humans
Kidney Failure, Chronic
Male
Middle Aged
Neuroimaging
Optic Chiasm
Optic Nerve Diseases*
Scotoma
Tuberculosis
Tuberculosis, Pleural
Tuberculosis, Pulmonary
Visual Acuity
Visual Fields
Ethambutol

Figure

• 

  Figure 1. Case 1. VF (A), fundus photography (B) and VEP (C) shows asymmetric ceco-central scotoma, normal fundus, and de-layed latency at the initial presentation. Although discontinuation of ethambutol, VF demonstrates temporal hemifield defects worse after one month (D) and 2 months (E). VF after 6 months (F) shows bitemporal VF defects with alignment on vertical midline. Follow-up 6 months later fundus photography (G) and VEP (H) demonstrates bilateral optic disc pallor and no response of VEP. VF and optical coherence tomography shows near complete VF loss worse in the temporal hemifields (I) and thinning of superior and inferior peripapillary retinal nerve fiber layer (J) in both eyes after 1 year. RNFL = retinal nerve fiber layer; S = superior; N = nasal; I = inferior; T = temporal; NA = not applicable; VF = visual field; VEP = visual evoked potential.

• 

  Figure 2. Case 2. (A) VF shows bitemporal hemianopsia with alignment on vertical midline. (B) Epiretinal membrane in the right eye and mild nonproliferative diabetic retinopathy are observed on fundus photography. No response of VEP (C) and relatively nor-mal optical coherence tomography (D) are observed. Follow-up 1 (E), 2 (F), 6 (G) months and 1 year (H) later, VFs show improve-ment of bitemporal hemianopsia persisting central scotoma. RNFL = retinal nerve fiber layer; S = superior; N = nasal; I = in-ferior; T = temporal; NA = not applicable; VF = visual field; VEP = visual evoked potential.

• 

  Figure 3. Case 3. (A) Initial VF demonstrates bitemporal visual field defects respecting vertical midline without central scotoma. (B) Normal fundus photography. (C) Visual evoked potential shows delayed latency. Follow-up 2 weeks (D), 1 month (E), and 3 months (F) later, VFs show near complete resolution of defects except paracentral scotoma in the left eye. VF = visual field.

Reference

References

1. Choi SY, Hwang JM. Optic neuropathy associated with ethambutol in Koreans. Korean J Ophthalmol. 1997; 11:106–10.

2. Lee EJ, Kim SJ, Choung HK. . Incidence and clinical features of ethambutol-induced optic neuropathy in Korea. J Neuroophthalmol. 2008; 28:269–77.

3. Choi JY, Lee SH, Seo SU. . A case of optic neuropathy asso-ciated with ethambutol. Chonnam Med J. 2006; 42:53–6.

4. Karmon G, Savir H, Zevin D, Levi J. Bilateral optic neuropathy due to combined ethambutol and isoniazid treatment. Ann Ophthalmol. 1979; 11:1013–7.

5. Kho RC, Al-Obailan M, Arnold AC. Bitemporal visual field de-fects in ethambutol-induced optic neuropathy. J Neuroophthalmol. 2011; 31:121–6.

6. Boulanger Scemama E, Touitou V, Le Hoang P. Bitemporal hemi-anopia as presenting sign of severe ethambutol toxicity. J Fr Ophtalmol. 2013; 36:e163–7.

7. Kim JD, Hashemi N, Gelman R, Lee AG. Neuroimaging in ophthalmology. Saudi J Ophthalmol. 2012; 26:401–7.

8. Lessell S. The histology and histochemistry of the rat’s optic nerve and chiasm. Am J Ophthalmol. 1977; 84:681–8.

9. Schmidt IG. Central nervous system effects of ethambutol in monkeys. Ann N Y Acad Sci. 1966; 135:759–74.

10. Osaguona VB, Sharpe JA, Awaji SA. . Optic chiasm involve-ment on MRI with ethambutol-induced bitemporal hemianopia. J Neuroophthalmol. 2014; 34:155–8.