Tuberculosis – July 2019
History
A 71 year old man presented to the Illinois Retina for baseline eye exam upon starting Ethambutol. He has no vision complaints and has no history of eye problems or eye surgery.
Exam:
On exam, he is 20/25 in both eyes. His pressure is 9 and 13. His anterior segment exam displayed 1.5+ nuclear sclerotic cataracts in both eyes. He had no anterior chamber cell or flare.
He had an OCT nerve and HVF performed as a baseline for Ethambutol. The OCT nerve was full, as was the 24-2 HVF.
Posterior segment exam showed no vitreous inflammation. A fundus photograph of each eye is displayed below:
A widefield fundus photo of the right eye demonstrating clear media, peripapillary atrophy, normal vasculature, and multiple yellow choroidal lesions.
A widefield fundus photo of the left eye demonstrating clear media, peripapillary atrophy, normal vasculature, and a single yellow choroidal lesion.
Differential Diagnosis:
- Tuberculosis
- Metastatic Lymphoma
- Candida endophthamitis
- Sarcoidosis
- Multifocal Choroiditis
OCT Imaging:
Swept source OCT through one of the lesions in the right eye demonstrating that the lesion is in fact choroidal.
Late fluorescein angiogram of the right eye demonstrating staining of the lesions without leakage.
Late fluorescein angiogram of the left eye demonstrating staining of the lesion without leakage.
Discussion:
This patient has tuberculosis, so consequently, a baseline evaluation is necessary prior to starting Ethambutol. Ethambutol has been known to cause optic neuropathy, therefore baseline testing is important to monitor any signs of progression so that the drug may be stopped early. Most importantly, Ethambutol toxicity is generally regarded as reversible if the drug is stopped.
The lesions in the choroid are classic for tuberculous granulomas, one of the many manifestations of tuberculosis in the eye. These granulomas are secondary to hematogenous spread of the organism, which is why it affects the choroid primarily. With time, a granulomatous uveitis can occur, with vasculitis, vitritis, and anterior uveitis with large granulomatous KP. In conclusion, there are many diseases that present with similar findings, and therefore TB should always be considered with any of the above findings. Typically, a tissue diagnosis is required to definitively confirm tuberculosis, however, the diagnosis of presumed ocular tuberculosis is made with typical ocular findings and a positive quantiferon or PPD test, as well as a positive chest x-ray or evidence of extrapulmonary TB. Our patient has biopsy confirmed extrapulmonary TB, and is already on appropriate treatment.
References:
- Chamberlain, P. et al. Ethambutol Optic Neuropathy. Current Opinion in Ophthalmology. 28(6):541-441, November 2017.
- Rathinam, et al (2018). Retinal Artery Occlusions. In Ryan’s Retina (6th ed.,). Philadelphia, PA.