Acanthamoeba keratitis is caused by the Acanthamoeba castellani parasite which exists in both trophozoite and encysted forms. It causes keratitis, granulomatous encephalitis, and fulminant meningoencephalitis in humans. Symptoms include pain, watering, photophobia, blurred vision, and pseudodendrites on the cornea. Diagnosis involves clinical examination, confocal microscopy, and laboratory tests on corneal scrapings. Treatment involves topical antiamoebic medications like propamidine isethionate, hexamidine, neomyecin, and clotrimazole, with longer multi-drug therapy needed for

1. Acanthamoeba keratitis
Gauri shankar Saini
MBBS

2. Etiology
• Acanthamoeba castellani exist in trophozoite and encysted form
• It causes in human:-
keratitis
Granulomatous encephalitis
Fulminant meningoencephalitis

3. Mode of infections
• Direct contact with material and water contaminated with organism
• Contact lens wearers
• Trauma with contaminated vegetables
• Opportunistic infections in herpetic keratitis, bacterial keratitis,
bullous keratopathy,neuroparalytic keratitis

4. Clinical features
• Symptoms:-
1. Asymptomatic
2. Foreign body sensation
3. Mild to severe pain
4. Watering
5. Photophobia
6. Blepherospasm
7. Blurred vision

5. Signs
• Epithelial lesions
1. Roughing and irregularities
2. Ridges
3. Pseudo dendrites formation
4. Epithelial and subepithelial curvilinear opacities
• Radial keratoneuritis:- Linear stromal infiltrate
• Limbal lesions :- limbitis

6. Signs
• Stromal lesions
1. Patchy and satellite stromal infiltrate
2. Ring infiltrate
3. Ring abscess
4. Persistent corneal inflammation
• Scleritis
• Anterior chamber inflammation

7. Differential diagnosis
• Viral keratitis
• Fungal keratitis
• Suppurative keratitis

8. Diagnosis
• Clinical diagnosis
• Confocal microscopy
• Laboratory diagnosis:- corneal scraping
KOH
Calcofluor white stain
Lactophenol cotton blue stained
Culture on non nutrient agar
PCR
Corneal biopsy

9. Treatment
• Nonspecific
• Specific:-
1. Topical antiamoebic agents
aromatic diamidines ( propamidine isethionate, hexamidine)
Biguanide ( polyhexamethylene, chlorhexidine)
Aminoglycosides ( neomyecin,paromycine)
Azoles ( clotrimazole,fluconazole,miconazole, ketoconazole)

10. Cont
• MDT:-epithelial lesions (3 to 4 months)
stromal lesions ( 6to 12 months)
Propamidine or hexamidine+ PHMB
Chlorhexidine+ neomyecin
Paromycine+ clotrimazole
1. Oral ketoconazole
2. Penetrating keratoplasty