Acanthamebiasis - Clinicals, Diagnosis, and Management

Infectious diseases

Clinicals - History

Fact Explanation
Keratitis Common in swimmers and contact lenses users. Clinical symptoms are pain, tearing, photophobia, blepharospasm, and blurred vision . The above symptoms are preceded by the sensation of foreign body in eyes. Keratitis usually occurs in immune-competent individuals. Keratitis
Common in swimmers and contact lenses users. Clinical symptoms are pain, tearing, photophobia, blepharospasm, and blurred vision . The above symptoms are preceded by the sensation of foreign body in eyes. Keratitis usually occurs in immune-competent individuals.
Granulomatous amebic encephalitis (GAE) This is common in immunocompromised patients. Usually this is an insidious onset sub acute diffuse meningoencephalitis. Most of the patients will have focal neurologic signs. Seizures, change in mental status, hemiparesis, Headache, visual disturbances (diplopia and photophobia), ataxia, hallucinations, personality changes and sleep disturbances are other symptoms. Granulomatous amebic encephalitis (GAE)
This is common in immunocompromised patients. Usually this is an insidious onset sub acute diffuse meningoencephalitis. Most of the patients will have focal neurologic signs. Seizures, change in mental status, hemiparesis, Headache, visual disturbances (diplopia and photophobia), ataxia, hallucinations, personality changes and sleep disturbances are other symptoms.
Skin manifestations These include papules, pustules, non-healing ulcers, nodules with overlying erythema, or subcutaneous abscesses. The skin papules may be painful. In immune-competent individuals the first manifestation of disseminated disease is the skin lesions. Skin manifestations
These include papules, pustules, non-healing ulcers, nodules with overlying erythema, or subcutaneous abscesses. The skin papules may be painful. In immune-competent individuals the first manifestation of disseminated disease is the skin lesions.
Disseminated acanthamebiasis This is an extremely rare entity of the disease and the disease involves organs other than the central nervous system. Disseminated acanthamebiasis
This is an extremely rare entity of the disease and the disease involves organs other than the central nervous system.
Osteomyelitis This is an extremely rare presentation. Osteomyelitis
This is an extremely rare presentation.

Clinicals - Examination

Fact Explanation
Signs of keratitis The conjunctiva is hyperemic. Corneal ulceration and lid edema are evident. The intraocular pressure may be elevated. Accumulated pus will produce a hypopyon in latter stages of the disease. Cataract formation will produce absent red reflex on examination with an ophthalmoscope. A corneal ring stromal infiltrate (dendritiform epitheliopathy) is pathognomonic. Signs of keratitis
The conjunctiva is hyperemic. Corneal ulceration and lid edema are evident. The intraocular pressure may be elevated. Accumulated pus will produce a hypopyon in latter stages of the disease. Cataract formation will produce absent red reflex on examination with an ophthalmoscope. A corneal ring stromal infiltrate (dendritiform epitheliopathy) is pathognomonic.
Central nervous system examination This will reveal focal neurological signs, hemiparesis, meningismus (positive Babinski sign, and Kernig sign), ataxia, and cranial nerve lesions. Central nervous system examination
This will reveal focal neurological signs, hemiparesis, meningismus (positive Babinski sign, and Kernig sign), ataxia, and cranial nerve lesions.
Examination of the mental status Often altered mental status is found. Examination of the mental status
Often altered mental status is found.
Fever Fever may or may not present. Fever
Fever may or may not present.
Skin lesions Common in the extremities but can appear over the face and trunk as well. Usually these are papules, pustules, non-healing ulcers, nodules with overlying erythema, or subcutaneous abscesses. Skin lesions
Common in the extremities but can appear over the face and trunk as well. Usually these are papules, pustules, non-healing ulcers, nodules with overlying erythema, or subcutaneous abscesses.

Investigations - Diagnosis

Fact Explanation
Corneal scrapings or biopsy If keratitis is suspected this will show Acanthamoeba trophozoites or cysts. The sample can be processed in a wet-mount to look for motile trophozoites or can be cultured. The biopsy sample can be used for polymerase chain reaction. Corneal scrapings or biopsy
If keratitis is suspected this will show Acanthamoeba trophozoites or cysts. The sample can be processed in a wet-mount to look for motile trophozoites or can be cultured. The biopsy sample can be used for polymerase chain reaction.
Immunohistological staining of the scrapings or biopsy This will stain Acanthamoeba specific monoclonal antibodies. Immunohistological staining of the scrapings or biopsy
This will stain Acanthamoeba specific monoclonal antibodies.
Confocal microscopy This is a non-invasive and quick way to diagnose Acanthamoeba keratitis. Confocal microscopy
This is a non-invasive and quick way to diagnose Acanthamoeba keratitis.
Cerebrospinal fluid examination The lymphocytes and protein levels are elevated and glucose level is low. Cerebrospinal fluid examination
The lymphocytes and protein levels are elevated and glucose level is low.
Biopsy and or culture This will enable diagnosis from any other site. Biopsy and or culture
This will enable diagnosis from any other site.
CT brain Multiple nonenhancing lesions are seen in the cerebral cortex. CT is mandatory before the lumbar puncture to prevent the risk of cerebral herniation after the procedure. CT brain
Multiple nonenhancing lesions are seen in the cerebral cortex. CT is mandatory before the lumbar puncture to prevent the risk of cerebral herniation after the procedure.

Management - Supportive

Fact Explanation
Patient education Contact lens users should adhere to proper cleaning techniques and should regularly clean there lenses. Patients are advised not to wear the lenses while showering and swimming. Patient education
Contact lens users should adhere to proper cleaning techniques and should regularly clean there lenses. Patients are advised not to wear the lenses while showering and swimming.
Treatment of glaucoma Acanthameba keratitis may result in glaucoma and permanent visual loss. Intraocular pressure measurements should be done for early detection of glaucoma and treated as necessary. Treatment of glaucoma
Acanthameba keratitis may result in glaucoma and permanent visual loss. Intraocular pressure measurements should be done for early detection of glaucoma and treated as necessary.
Treatment of cataracts Cataract is a known complication of keratitis and also may arise secondary to use of topical steroids. Treatment of cataracts
Cataract is a known complication of keratitis and also may arise secondary to use of topical steroids.

Management - Specific

Fact Explanation
Topical antimicrobial agents Chlorohexidine and polyhexamethylen biguanide are effective topical antimicrobials against trophozoites and cysts. Topical antimicrobial agents
Chlorohexidine and polyhexamethylen biguanide are effective topical antimicrobials against trophozoites and cysts.
Topical steroid The use of topical steroids is controversial but topical steroids are added after the completion of antimicrobial treatment. Topical steroid
The use of topical steroids is controversial but topical steroids are added after the completion of antimicrobial treatment.
Corneal debridement Often patients need aggressive treatment with both medical and surgical approaches. Corneal debridement
Often patients need aggressive treatment with both medical and surgical approaches.
Laser photokeratectomy Newer treatment option for keratitis. Laser photokeratectomy
Newer treatment option for keratitis.
Medical treatment for Granulomatous amebic encephalitis Combined therapy of pentamidine, an azole (fluconazole or itraconazole), a sulfadiazine is effective. Flucytosine can also be combined. Medical treatment for Granulomatous amebic encephalitis
Combined therapy of pentamidine, an azole (fluconazole or itraconazole), a sulfadiazine is effective. Flucytosine can also be combined.
Combined therapy for disseminated disease Intravenous pentamidine is used mainly. In addition topical chlorhexidine gluconate , and 2% ketoconazole cream andoral itraconazole is prescribed to the patient. Flucytosine can also be used. Combined therapy for disseminated disease
Intravenous pentamidine is used mainly. In addition topical chlorhexidine gluconate , and 2% ketoconazole cream andoral itraconazole is prescribed to the patient. Flucytosine can also be used.

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