History

Acanthamoeba keratitis usually is associated with a history of excessively long lens wear and/or contamination of the lens with unsterile water. Typical sources include swimming, showering, using nonsterile lens cleaners, contaminating lenses and cases by "topping off" or other unhygienic practices, and handling lenses with wet hands.^{[18, 19]}The incubation period for Acanthamoeba keratitis is unknown but thought to range from several days to several weeks.^[5]Keratitis typically begins with a unilateral foreign-body sensation followed by pain, tearing, photophobia, blepharospasm, and blurred vision.^{[18, 17]}. Although pain out of proportion to inflammation in early keratitis has been observed, it can present as a painless keratitis, so lack of pain should not be used to rule out this disease process.^[16] Bilateral involvement has been described in up to 11% of cases.^[20]

Granulomatous amebic encephalitis (GAE) is a subacute to chronic meningoencephalitis. The incubation period is unknown but is probably weeks to months. The duration of illness until death ranges from 7-120 days (average, 39 days). Patients with GAE may have concurrent sinus, lung, or skin disease. Most patients present with focal neurologic deficits coupled with signs of increased intracranial pressure; other symptoms may include confusion, seizures, headache, focal weakness or ataxia, visual disturbances, and fever.

Skin disease may precede the onset of CNS manifestations by weeks to months and may include ulcers, nodules, or subcutaneous abscesses. Disseminated disease without CNS involvement may manifest as skin lesions, sinusitis, and/or pneumonitis. Other unusual manifestations of Acanthamoeba infection include osteomyelitis, adrenalitis, and vasculitis.

Physical

Early physical findings in amebic keratitis include punctate keratopathy, pseudodendrites, epithelial or subepithelial infiltrates, and perineural infiltrates.^[17]Confocal microscopy assists in identifying 5 stages of keratopathy, as described by Tu^[21]: epitheliitis, epitheliitis with radial neuritis, anterior stromal disease, deep stromal keratitis, and ring infiltrates. Ring infiltrates are characteristic, but are found in only 50% of cases. Early infection can mimic herpes keratitis, and late infection can mimic fungal keratitis. Perineural infiltrates are also highly suggestive of amebic keratitis.

The physical findings of GAE are highly dependent on location of lesions and result from increased intracranial pressure and focal neurological damage. These include abnormal mental status examination results, focal weakness or ataxia, and papilledema.

Disseminated disease without GAE may manifest as skin lesions that are typically hard, erythematous nodules or skin ulcers.

Differential Diagnoses

Visvesvara GS. Infections with free-living amebae. Handb Clin Neurol. 2013. 114:153-68. [QxMD MEDLINE Link].
Siddiqui R, Khan NA. Biology and pathogenesis of Acanthamoeba. Parasit Vectors. 2012 Jan 10. 5:6. [QxMD MEDLINE Link].
Willcox MD, Holden BA. Contact lens related corneal infections. Biosci Rep. 2001 Aug. 21 (4):445-61. [QxMD MEDLINE Link].
Collier SA, Gronostaj MP, MacGurn AK, Cope JR, Awsumb KL, Yoder JS, et al. Estimated burden of keratitis--United States, 2010. MMWR Morb Mortal Wkly Rep. 2014 Nov 14. 63 (45):1027-30. [QxMD MEDLINE Link].
Amebic Meningoencephalitis and Keratitis. Kimberlin DW, Brady MT, Jackson MA, Long SS. Red Book: 2018 Report of the Committee on Infectious Diseases. American Academy of Pediatrics; 2018. 211-214.
Nazar M, Haghighi A, Niyyati M, Eftekhar M, Tahvildar-Biderouni F, Taghipour N, et al. Genotyping of Acanthamoeba isolated from water in recreational areas of Tehran, Iran. J Water Health. 2011 Sep. 9(3):603-8. [QxMD MEDLINE Link].
Kao PM, Hsu BM, Chen CT, Huang SW, Kao ES, Chen JL, et al. Identification and quantification of the Acanthamoeba species and genotypes from reservoirs in Taiwan by molecular techniques. Acta Trop. 2014 Apr. 132:45-50. [QxMD MEDLINE Link].
Abdul Majid MA, Mahboob T, Mong BG, Jaturas N, Richard RL, Tian-Chye T, et al. Pathogenic waterborne free-living amoebae: An update from selected Southeast Asian countries. PLoS One. 2017. 12 (2):e0169448. [QxMD MEDLINE Link].
Acanthamoeba keratitis multiple states, 2005-2007. MMWR Morb Mortal Wkly Rep. 2007 Jun 1. 56(21):532-4. [QxMD MEDLINE Link].
Sison JP, Kemper CA, Loveless M, et al. Disseminated acanthamoeba infection in patients with AIDS: case reports and review. Clin Infect Dis. 1995 May. 20(5):1207-16. [QxMD MEDLINE Link].
Reddy R, Vijayasaradhi M, Uppin MS, Challa S, Jabeen A, Borghain R. Acanthamoeba meningoencephalitis in an immunocompetent patient: an autopsy case report. Neuropathology. 2011 Apr. 31 (2):183-7. [QxMD MEDLINE Link].
Migueles S, Kumar P. Primary cutaneous acanthamoeba infection in a patient with AIDS. Clin Infect Dis. 1998 Dec. 27(6):1547-8. [QxMD MEDLINE Link].
Nachega JB, Rombaux P, Weynand B, et al. Successful treatment of Acanthamoeba rhinosinusitis in a patient with AIDS. AIDS Patient Care STDS. 2005 Oct. 19(10):621-5. [QxMD MEDLINE Link].
Lorenzo-Morales J, Martín-Navarro CM, López-Arencibia A, Arnalich-Montiel F, Piñero JE, Valladares B. Acanthamoeba keratitis: an emerging disease gathering importance worldwide?. Trends Parasitol. 2013 Apr. 29(4):181-7. [QxMD MEDLINE Link].
Schaumberg DA, Snow KK, Dana MR. The epidemic of Acanthamoeba keratitis: where do we stand?. Cornea. 1998 Jan. 17(1):3-10. [QxMD MEDLINE Link].
Dart JK, Saw VP, Kilvington S. Acanthamoeba keratitis: diagnosis and treatment update 2009. Am J Ophthalmol. 2009 Oct. 148 (4):487-499.e2. [QxMD MEDLINE Link].
Maycock NJ, Jayaswal R. Update on Acanthamoeba Keratitis: Diagnosis, Treatment, and Outcomes. Cornea. 2016 May. 35 (5):713-20. [QxMD MEDLINE Link].
Carnt N, Stapleton F. Strategies for the prevention of contact lens-related Acanthamoeba keratitis: a review. Ophthalmic Physiol Opt. 2016 Mar. 36 (2):77-92. [QxMD MEDLINE Link].
Brown AC, Ross J, Jones DB, Collier SA, Ayers TL, Hoekstra RM, et al. Risk Factors for Acanthamoeba Keratitis-A Multistate Case-Control Study, 2008-2011. Eye Contact Lens. 2017 Jan 17. [QxMD MEDLINE Link].
Wilhelmus KR, Jones DB, Matoba AY, et al. Bilateral acanthamoeba keratitis. Am J Ophthalmol. 2008 Feb. 145(2):193-197. [QxMD MEDLINE Link].
Tu EY, Joslin CE, Sugar J, Booton GC, Shoff ME, Fuerst PA. The relative value of confocal microscopy and superficial corneal scrapings in the diagnosis of Acanthamoeba keratitis. Cornea. 2008 Aug. 27 (7):764-72. [QxMD MEDLINE Link].
Costa AO, Furst C, Rocha LO, Cirelli C, Cardoso CN, Neiva FS, et al. Molecular diagnosis of Acanthamoeba keratitis: evaluation in rat model and application in suspected human cases. Parasitol Res. 2017 Apr. 116 (4):1339-1344. [QxMD MEDLINE Link].
Carrijo-Carvalho LC, Sant'ana VP, Foronda AS, de Freitas D, de Souza Carvalho FR. Therapeutic agents and biocides for ocular infections by free-living amoebae of Acanthamoeba genus. Surv Ophthalmol. 2017 Mar - Apr. 62 (2):203-218. [QxMD MEDLINE Link].
Clarke B, Sinha A, Parmar DN, Sykakis E. Advances in the diagnosis and treatment of acanthamoeba keratitis. J Ophthalmol. 2012. 2012:484892. [QxMD MEDLINE Link]. [Full Text].
Gupta D, Panda GS, Bakhshi S. Successful treatment of acanthamoeba meningoencephalitis during induction therapy of childhood acute lymphoblastic leukemia. Pediatr Blood Cancer. 2008 Jun. 50(6):1292-3. [QxMD MEDLINE Link].
Brondfield MN, Reid MJ, Rutishauser RL, Cope JR, Tang J, Ritter JM, et al. Disseminated Acanthamoeba infection in a heart transplant recipient treated successfully with a miltefosine-containing regimen: Case report and review of the literature. Transpl Infect Dis. 2017 Apr. 19 (2):[QxMD MEDLINE Link].
Siddiqui R, Aqeel Y, Khan NA. The Development of Drugs against Acanthamoeba Infections. Antimicrob Agents Chemother. 2016 Nov. 60 (11):6441-6450. [QxMD MEDLINE Link].
Faber K, Zorzi GK, Brazil NT, Rott MB, Teixeira HF. siRNA-loaded liposomes: Inhibition of encystment of Acanthamoeba and toxicity on the eye surface. Chem Biol Drug Des. 2017 Jan 30. [QxMD MEDLINE Link].
Martín-Navarro CM, López-Arencibia A, Sifaoui I, Reyes-Battle M, Fouque E, Osuna A, et al. Amoebicidal activity of caffeine and maslinic acid by the induction of Programmed Cell Death in Acanthamoeba. Antimicrob Agents Chemother. 2017 Mar 20. [QxMD MEDLINE Link].
Sarnicola E, Sarnicola C, Sabatino F, Tosi GM, Perri P, Sarnicola V. Early Deep Anterior Lamellar Keratoplasty (DALK) for Acanthamoeba Keratitis Poorly Responsive to Medical Treatment. Cornea. 2015 Nov 9. [QxMD MEDLINE Link].
Singhal T, Bajpai A, Kalra V, Kabra SK, Samantaray JC, Satpathy G, et al. Successful treatment of Acanthamoeba meningitis with combination oral antimicrobials. Pediatr Infect Dis J. 2001 Jun. 20(6):623-7. [QxMD MEDLINE Link].
Saxena A, Mittal S, Burman P, Garg P. Acanthameba meningitis with successful outcome. Indian J Pediatr. 2009 Oct. 76 (10):1063-4. [QxMD MEDLINE Link].
Siddiqui R, Khan NA. Biology and pathogenesis of Acanthamoeba. Parasit Vectors. 2012 Jan 10. 5:6. [QxMD MEDLINE Link].
Willcox MD, Holden BA. Contact lens related corneal infections. Biosci Rep. 2001 Aug. 21 (4):445-61. [QxMD MEDLINE Link].
Collier SA, Gronostaj MP, MacGurn AK, Cope JR, Awsumb KL, Yoder JS, et al. Estimated burden of keratitis--United States, 2010. MMWR Morb Mortal Wkly Rep. 2014 Nov 14. 63 (45):1027-30. [QxMD MEDLINE Link].
Kimberlin DW, Brady MT, Jackson MA, Long SS. Amebic Meningoencephalitis and Keratitis. Red Book: 2018 Report of the Committee on Infectious Diseases. American Academy of Pediatrics; 2018. 211-214.
Petry F, Torzewski M, Bohl J, Wilhelm-Schwenkmezger T, Scheid P, Walochnik J, et al. Early diagnosis of Acanthamoeba infection during routine cytological examination of cerebrospinal fluid. J Clin Microbiol. 2006 May. 44 (5):1903-4. [QxMD MEDLINE Link].
Webster D, Umar I, Kolyvas G, Bilbao J, Guiot MC, Duplisea K, et al. Treatment of granulomatous amoebic encephalitis with voriconazole and miltefosine in an immunocompetent soldier. Am J Trop Med Hyg. 2012 Oct. 87 (4):715-8. [QxMD MEDLINE Link].

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Author

Theresa M Fiorito, MD, MS, FAAP, CTH® Assistant Professor of Pediatrics and Pediatric Infectious Diseases, NYU Long Island School of Medicine; Attending Physician, Pediatric Infectious Diseases, Director, Family Travel Clinic, NYU Winthrop Hospital; Attending Physician, Pediatric Infectious Diseases, Hassenfeld Children's Hospital at NYU Langone

Theresa M Fiorito, MD, MS, FAAP, CTH® is a member of the following medical societies: American Academy of Pediatrics, Infectious Diseases Society of America, International Society of Travel Medicine, Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Richard B Brown, MD, FACP Chief, Division of Infectious Diseases, Baystate Medical Center; Professor, Department of Internal Medicine, Tufts University School of Medicine

Richard B Brown, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Chest Physicians, American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, Massachusetts Medical Society

Disclosure: Nothing to disclose.

Chief Editor

Pranatharthi Haran Chandrasekar, MBBS, MD Professor, Chief of Infectious Disease, Department of Internal Medicine, Wayne State University School of Medicine

Pranatharthi Haran Chandrasekar, MBBS, MD is a member of the following medical societies: American College of Physicians, American Society for Microbiology, International Immunocompromised Host Society, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

David R Haburchak, MD, FACP Key Faculty, Wellstar Kennestone Internal Medicine Residency Program, Wellstar Health System

David R Haburchak, MD, FACP is a member of the following medical societies: American College of Physicians, American Osler Society, American Society for Microbiology, Christian Medical and Dental Associations, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

David Hall Shepp, MD Program Director, Fellowship in Infectious Diseases, Department of Medicine, North Shore University Hospital; Associate Professor, New York University School of Medicine

David Hall Shepp, MD is a member of the following medical societies: Infectious Diseases Society of America

Disclosure: Received salary from Gilead Sciences for management position.

Nancy F Crum-Cianflone, MD, MPH Consulting Staff, Department of Internal Medicine, Division of Infectious Diseases, Naval Medical Center at San Diego

Nancy F Crum-Cianflone, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous coauthor William B. Harley, MD, to the development and writing of this article.

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