A 20-year-old man complained of his left eye vision loss and pain for 1 week. Slit lamp examination of left eyes showed defected corneal epithelium, interstitial edema of the left cornea, with a white irregular infiltrative lesion and ulcer 2mm * 2.5mm in size in the inferior temporal region (Fig. 1). Anterior chamber reactions include several pigment keratic precipitates, ++ flare and formed pigmented exudation was noted. Moreover, the patient’s conjunctiva was mixed with congestion, and the fundus was unclear. The best corrected visual acuity(BCVA) of the left eye was finger counting, while the BCVA of the right eye was 20/20(snellen chart), and the intraocular pressure of both eyes was 18mmHg(right eye), T + 2(left eye).The diagnosis of PUK, secondary glaucoma and uveitis was made. The patient was administered with intravenous mannitol and topical treatment with eye drops(2%Cartenolol、0.2%Bromonidine、Tobramycin and Dexamethasone ).
The patient was from Linzhi County, Tibet Province, and lives in Tibet all the year round, where tuberculosis(TB) has a high incidence area in China. Clinical symptoms like weight loss, malaise, or fever were not mentioned by patient. Simultaneously, no other medical history or lifestyle history such as keeping pets.Systemic examination were checked, including purified protein derivative (PPD) skin test revealed an induration of 10 mm,T-spot was strongly positive results, erythrocyte sedimentation rates sped but other blood tests (antinuclear antibody, rheumatoid factor, antineutrophil cytoplasmic antibody, and HIV serology etc.) were unremarkable. Chest computed tomography (CT) scans showed multiple spots and nodules.We highly suspected ocular tuberculosis-related lesions, thus corneal ulcer scraping was performed and sent for microbiological examination. Surprisingly,acid fast staining was negative, while mycobacterium TB DNA polymerase chain reaction(PCR) was positive. Furthermore ,ulmonary fibrobronchoscopy, sputum acid fast staining and culture of Mycobacterium Tuberculosis DNA PCR were both negative. Collectively, a diagnosis of ocular and pulmonary tuberculosis was made. On the basis of previous treatment, the patient started anti-tuberculosis quadritherapy.
After one week of medication, the patient's corneal edema improved, with anterior chamber flash (-), BCVA improved to 2/20, and intraocular pressure was 20mmHg. Fundus examination revealed 1 + vitreous haze, scattered round circular white-yellowish lesion, and occlusive vasculitis. After a month of oral anti tuberculosis treatment, the corneal ulcer was completely controlled(Fig. 2).
TB is a common public health problem [1], especially in Tibetan living areas in China. TB often invaded the lungs, but ocular tuberculosis was relatively rare. The prevalence of ocular TB among TB has been reported to be 6.8% [2]. TB had been reported in all eye tissues [3], but corneal tuberculosis was extremely rare [4].TB may cause PUK, which is characterized by progressive peripheral corneal stromal thinning with an associated epithelial defect or present in an idiopathic form (Mooren ulcer) [5]. Ocular lesions can be caused by a direct invasion of microorganisms or result from immunologic reactions (delayed hypersensitivity type IV) in the absence of the infectious agent [4].
In this case, PUK was caused by direct invasion of Mycobacterium TB rather than by immune response.According to our hypothesis, pulmonary infection may precede corneal lesions, and Mycobacterium Tuberculosis may be transferred form lungs to the cornea through blood. This patient was diagnosed through corneal scraping and microbiological examination, but the multiple sputum examinations of the lungs did not show positive results.