Ophthalmic Case Study (Acanthamoeba keratitis)

  Chief Complaint:

A 39-year-old white male contact lens wearer is referred to the Ophthalmology Department at the University of Lahore with blurry vision, photophobia, and redness and pain in the right eye.

History of Present Illness: The patient is a contact lens wearer who has been using disposable soft contact lenses for the past 3 months. Three weeks prior to presenting at the University, the patient started experiencing blurry vision, photophobia, and increasing pain in the right eye (OD). The pain escalated to an 8 out of 10 on a pain scale despite topical antibiotic therapy at an external facility. When the patient presented at the University of Lahore, he was taking gatifloxacin and tobramycin drops hourly and cyclopentolate 1% twice daily (BID) in the right eye. Despite this therapy, the ulcer in the right eye persisted and worsened.

Past Ocular History: The patient switched to disposable soft contact lenses 3 months prior to presentation.

Medical History: Mild hypertension and hypercholesterolemia.

Medications: Topical gatifloxacin and tobramycin hourly in the right eye, as well as cyclopentolate BID. His systemic medications included Valsartan and Atorvastatin.

Family History: Non-contributory.

Social History: Rare social alcohol consumption. Non-smoker.

Ocular Examination:

• Visual acuity, with best correction: OD--Count fingers at 6 inches; (OS)--20/20.
• Motility: OD--Full.
• Intraocular Pressure: OD--19 mmHg; OS--18 mmHg.
• Pupils: Dark 5mm and clear 3mm, no relative afferent pupillary defect (RAPD) in either eye.
• Corneal sensation: OD--decreased; OS--normal.

External and Anterior Segment Examination:

OD: 4x4 mm stromal ring infiltrate with white blood cell (WBC) infiltration around it. Corneal precipitates line the endothelium inferiorly to the ring infiltrate, and there is a 0.5 mm hypopyon. Small epithelial defects are present over the area of the ring infiltrate. Enlarged corneal nerves (radial perineuritis) are also seen on high magnification. There is 4+ conjunctival injection, and the anterior chamber is filled with 3+ cells and 2+ flare reaction.

OS: Normal.

Dilated Fundus Examination (DFE):

Very difficult and hazy posterior view, OD. Normal disc, macula, vessels, and periphery, OS.

Additional Examinations:

Based on the history and clinical examination, Acanthamoeba keratitis should be suspected. The results for this patient are described below.

Confocal microscopy was performed in the clinic. The images were highly suggestive of Acanthamoeba keratitis. Double-walled cysts were found within the stroma. Inflamed posterior corneal nerves were evident. Bright structures with fusiform.

Epithelial scraping was performed and sent to the Ocular Pathology Laboratory at the University of Lahore for Acanthamoeba evaluation. In this case, double-walled cystic structures were observed within the epithelium

Multiple samples from swabs of the underlying stromal surface were collected and sent for pan-culture. No secondary organisms grew.

Diagnosis

The patient's history, clinical examination, and confocal microscopy all suggest Acanthamoeba keratitis in this individual who wears soft contact lenses.