ORAL MILTEFOSINE IN THE TREATMENT OF REFRACTORY ACANTHAMOEBA KERATITIS

Keratiits caused by the amoeba Acanthamoeba (AK) is an increasingly prevalent corneal infection, associated with contact lens users, characterized by highly symptomatic and persistent epithelial defects and corneal stromal infiltrates. The clinical course is often devastating due to the diagnostic challenges and resistance to conventional therapy with topical biguanides and aromatic diamidines.

Recently published cases report the effectiveness and safety of adjuvant therapies, in particular oral Miltefosine, which is classically used for amebiasis caused by Leishmania and Naegleria spp. Our objective is to report a case of refractory AK treated with this approach. 

We report a case of devastating AK treated with the conventional topical treatment plus oral miltefosine in the Ophthalmology department of Coimbra Hospital and University Centre, Portugal.

A 33 year-old female farmer and monthly contact lens user, with no medical comorbidities or prior history of ocular disease, presented to the emergency department due to onset of blurry vision and ocular pain in the right eye 5 days prior. Best corrected visual acuity was 8/10 and a central corneal ulcer, with no stromal abscess, was visible on observation. Topical antibiotherapy was instituted.

The lack of improvement on follow up 4 days later and the development of interstitial keratitis with anterior chamber (AC) flare and cells prompted corneal swabs for cultures (for bacteria and fungi) and PCR for Herpesvirus and Acanthamoeba. The latter yielded a positive result, confirming the diagnosis of AK. This was accompanied by an increase of pain, photophobia, visual acuity reduction to 2/10 and the development of a ring corneal infiltrate with generalized loss of corneal transparency on early follow up; thus, topical clorohexidine and propamidine 12 times daily, as well as oral metilprednisolone 1mg/kg id, were initiated.

Disease progression was poor, with frequent flares. One year after the initial infection, the patient presented with a particular increase in pain, photophobia and a visual acuity of hand motion. A new ulcer and ring infiltrate were present as well as a significant hypopion in the AC. New corneal swabs were negative for bacterial, fungal and viral infections, but positive for Acanthamoeba.

Topical clorohexidine and propamidine 12 id were reinstated in conjunction with oral corticotherapy and oral miltefosine 50 mg every 12h. After 9 months of therapy, all symptoms have dissipated and the patient presents a best-corrected visual acuity of 1.5/10. There are no signs of active infection or inflammation, with only a dense central corneal scar being present on observation

Oral miltefosine is a promising agent in the treatment of AK refractory to conventional topical therapeutic approaches.