Among over 3,000 patients seen in the cornea and external diseases clinic between June 2008 and November 2008 inclusive, three cases of microsporidial infection were identified, all in patients with HIV/AIDS.
Case 1
A 10-year-old female patient from Addis Ababa, discovered to be HIV seropositive a year previously, presented with 3 months history of redness, tearing, photophobia, and reduction of vision of both eyes. Her best-corrected visual acuity was 6/60 (6/24 with pin hole) and counting fingers at 4 m (no improvement with pin hole) in the right and left eyes, respectively. She had a healed zoster scar over the left side of the forehead. The conjunctivae were hyperemic with ciliary flush. Corneal sensation was diminished bilaterally, and diffuse epithelial and subepithelial whitish corneal infiltrates were present (Fig. 1), which stained with fluorescein.
Prior to her presentation, treatment with gentamicin eye drops had been followed by marked worsening of visual acuity, redness, tearing, and photophobia. After initial treatment with artificial tears, chloramphenicol eye ointment, acyclovir, and topical corticosteroids failed to improve her condition, a conjunctival swab was taken from the patient for microscopic investigation, and the CD4+ T cell count was determined. Light microscopy demonstrated myriad small, round to oval microsporidial organisms that stained positively with modified acid-fast methods (see Fig. 2, left panel). Based on these findings, and a CD4+ T cell count of 71 cells/μL, she was started on HAART.
One month after initiating the HAART, the patient continued to have symptoms of bilateral foreign body sensation, redness, tearing, and blurred vision, and examination findings were unchanged. A course of oral albendazole 200 mg daily for 14 days was initiated. Following completion of the course, symptoms of redness, foreign body sensation, and photophobia were markedly reduced. The visual acuity improved to 6/9 and 6/12 in right and left eyes respectively, the conjunctivae were white and quiet, and only scanty intraepithelial white infiltrates remained in the peripheral corneas. During monthly follow-up over the next 3 months, no recurrence was observed; the CD4 count was found to have increased to 189 cells/μL by that time.
Case 2
A married 40-year-old female from Addis Ababa presented with a 1-year history of unilateral (left eye) redness, episodic photophobia, and blurring of vision. She gave history of having had loss of vision in the right eye following severe redness, pain, photophobia, and excessive tearing 2 years prior to her presentation. She denied a previous history of contact with animals or agricultural trauma. She was known to be HIV positive, having taken HAART for the past 4 years, with a recent CD4+ T cell count of 259 cells/μL. She had not been taking topical therapies at the time of presentation.
On examination, the visual acuity of the left eye was 6/9. The bulbar conjunctiva was injected nasally, and the cornea had yellowish stromal and intraepithelial infiltrates that stained with fluorescein, although there was no epithelial defect (findings similar to those illustrated in Fig. 1). A microscopic examination of a conjunctival swab using light microscopy demonstrated myriad small, round to oval microsporidial organisms that stained positively with modified acid-fast methods, confirming microsporidial keratitis (findings similar to those illustrated in Fig. 2). After 2 weeks of treatment with albendazole 400 mg twice daily, while continuing HAART, all the ocular complaints disappeared, and the corneal opacity was less dense as compared to prior to initiating the albendazole treatment. Similar to the first case, the patient had no recurrence of signs or symptoms over 3 months follow-up.
Case 3
A 24-year-old woman from Addis Ababa presented with a 7-month history of bilateral foreign body sensation, redness, tearing, and reduction in vision, which had not improved with 1 month of topical corticosteroids. She was known to be HIV positive, but had not received HAART previously. She had no history of contact with animals or agricultural trauma. At initial presentation, her visual acuity was 6/24 and 6/9 on the right and left eyes, respectively. In each eye, the conjunctivae were hyperaemic, and there were diffuse intraepithelial whitish infiltrates over the cornea with punctate fluorescein staining. Light microscopy of a conjunctival swab revealed myriad small, round to oval microsporidial organisms that stained positively with modified acid-fast method for microsporidia.
After the CD4+ T cell count was found to be 45 cells/μL, HAART was initiated 1 day after taking the conjunctival swab. One month after HAART, there was little symptomatic or objective improvement in the ophthalmic findings, and the CD4+ T cell count had improved to 179 cells/μL. Thereafter, she was treated with albendazole 400 mg twice daily for 2 weeks. At the second month, she presented with worsening of redness and severe foreign body sensation and no visual improvement; she developed a corneal epithelial defect over the left eye, and the preexisting intraepithelial lesions had become more flocculent in appearance (Fig. 3). Although the corneal epithelial defect healed after patching, the clinical findings failed to resolve after a second course of albendazole, unlike the other two cases. However, the symptoms and signs eventually subsided. On suspicion that the continued inflammation despite albendazole was the result of an immune recovery inflammatory syndrome, additional 2-week courses of albendazole were attempted, after which symptoms improved but relapsed 3–4 months after each course.