obsolete Acanthamoeba keratitis

Acanthamoeba Keratitis: An Obsolete Condition?

While Acanthamoeba keratitis (AK) remains a significant concern for eye health professionals, the term "obsolete" in relation to this condition is somewhat misleading. However, it does indicate that our understanding and management of AK have evolved over time.

What does "obsolete" mean in this context?

In medical terminology, "obsolete" refers to a treatment or diagnostic method that has been superseded by more effective or safer alternatives. In the case of Acanthamoeba keratitis, the term "obsolete" likely pertains to outdated treatments or diagnostic approaches that are no longer recommended or used.

Current understanding and management of AK

Acanthamoeba keratitis is a rare but potentially sight-threatening corneal infection caused by the Acanthamoeba parasite. The condition predominantly affects contact lens wearers, although it can also occur in non-lens users exposed to contaminated water or with compromised immune systems.

The current understanding and management of AK involve:

• Early diagnosis through clinical presentation and laboratory tests (e.g., PCR, microscopy)
• Treatment with antifungal and antibacterial medications, as well as supportive care
• Avoidance of contact lens wear, especially overnight use, in high-risk individuals
• Education on proper contact lens hygiene and maintenance

Conclusion

While the term "obsolete" may be associated with Acanthamoeba keratitis, it is essential to note that this condition remains a significant concern for eye health professionals. The current understanding and management of AK have evolved over time, and continued research and education are necessary to ensure optimal care for patients affected by this rare but potentially sight-threatening disease.

References:

• [10] Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening corneal infection caused by the Acanthamoeba parasite.
• [11] Abstract. Acanthamoeba keratitis (AK) is a rare but severe corneal infection caused by the free-living amoeba, Acanthamoeba, which is ubiquitously present in the environment.
• [12] Introduction Acanthamoeba keratitis remains one of the most feared corneal infections due to its severity, potential for irreversible

Common Signs and Symptoms of Acanthamoeba Keratitis

Acanthamoeba keratitis (AK) is a rare but often misdiagnosed corneal infection that primarily affects contact lens wearers. The signs and symptoms of AK can vary, but some common ones include:

• Foreign body sensation: Many patients with AK report feeling like there's something in their eye, even when nothing is visible to the naked eye [8].
• Severe ocular pain: Pain is a hallmark symptom of AK, often described as severe and out of proportion to the slit lamp examination findings [3].
• Photophobia: Patients with AK may experience sensitivity to light, which can exacerbate their discomfort [3][8].
• Excessive tearing: Excessive tearing is another common symptom of AK, which can be accompanied by a foreign body sensation [8].
• Blurring of vision: As the infection progresses, patients with AK may experience blurring or loss of vision in the affected eye [6].

Less Common Signs and Symptoms

In some cases, AK may present with less severe symptoms, including:

• Radial keratoneuritis: This is a condition where there are radial streaks of inflammation on the cornea [1].
• Epithelial defects: In some cases, AK can cause small defects in the epithelium (the outermost layer) of the cornea [1].

Important Considerations

It's essential to note that AK can be misdiagnosed as other conditions, such as herpes simplex keratitis or bacterial keratitis. Therefore, a prompt and accurate diagnosis is crucial to prevent vision loss and other complications.

References:

[1] by MS Ward · 2022 · Cited by 1 [3] by MS Ward · 2022 · Cited by 1 [6] by MJ Lee · 2020 · Cited by 18 [8] by N Al-Yousuf · 2020

Obsolete Diagnostic Tests for Acanthamoeba Keratitis

Acanthamoeba keratitis (AK) is a sight-threatening ocular infection caused by an amoeba, and its diagnosis can be challenging. Over the years, various diagnostic tests have been used to confirm AK, but some of these methods are now considered obsolete due to their low sensitivity, specificity, or turnaround time.

Culture

• Obsolescence: Culture was once a widely used method for diagnosing AK, but it has largely been replaced by more sensitive and specific techniques.
• Limitations: The long diagnostic turnaround time (average 7-10 days) and variably low sensitivity of microbiological culture limit its use as a sole diagnostic test for

Obsolete Drug Treatments for Acanthamoeba Keratitis

Acanthamoeba keratitis, a rare but serious eye infection, has been treated with various medications over the years. While some treatments have become outdated, it's essential to understand their historical significance and how they relate to current treatment options.

• Propamidine-isethionate: This diamidine was once used for treating Acanthamoeba keratitis at a concentration of 0.1% [9]. Although generally well-tolerated, prolonged therapy can lead to ocular surface toxicity.
• Hexamidine-diisethionate and dibromopropamidine: These diamidines were also used in the treatment of acanthamoeba keratitis at a concentration of 0.1% [9].
• Amphotericin B: This antifungal medication has been considered as a potential antimicrobial agent for Acanthamoeba keratitis management, although its efficacy is still being researched [8].

Why are these treatments obsolete?

The treatment landscape for Acanthamoeba keratitis has evolved significantly since the first medical cure was reported in 1985. Current research and clinical practices have led to the development of more effective and safer treatments.

• Biguanides and diamidines: These classes of medications, particularly polyhexamethylene biguanide (PHMB) and chlorhexidine, have been reported to be highly effective against Acanthamoeba keratitis [4, 12]. They are often used as monotherapy or in combination.
• Miltefosine: This medication has received orphan drug designation for the treatment of Acanthamoeba Keratitis (AK) and has shown promising results in a hamster model of AK [14].

Conclusion

While some treatments for Acanthamoeba keratitis have become outdated, it's essential to understand their historical context. Current research and clinical practices have led to the development of more effective and safer treatments, such as biguanides, diamidines, and miltefosine. These newer treatments offer improved outcomes for patients with this serious eye infection.

Differential Diagnosis of Acanthamoeba Keratitis

Acanthamoeba keratitis (AK) is a potentially sight-threatening infection of the ocular surface that can be challenging to diagnose. The differential diagnosis for AK includes various conditions that may present with similar symptoms, making it essential to consider these possibilities when evaluating patients.

Conditions to Consider:

• Herpetic Keratitis: This condition, caused by herpes simplex virus, can present with similar symptoms to AK, including corneal inflammation and pain.
• Bacterial Keratitis: Bacterial infections of the cornea can cause similar symptoms to AK, including corneal ulcers and inflammation.
• Fungal Keratitis: Fungal infections of the cornea can also present with similar symptoms to AK, including corneal ulcers and inflammation.
• Noninfectious Keratitis: Conditions such as dry eye syndrome, contact lens-related keratopathy, and other noninfectious causes can mimic the symptoms of AK.

Key Diagnostic Features:

• Corneal Ulceration: AK is often characterized by corneal ulceration, which may be accompanied by pain, redness, and photophobia.
• Inflammatory Response: Acanthamoeba infections typically induce a strong inflammatory response in the eye, leading to corneal edema and vascularization.
• Cytological Examination: In vivo confocal microscopy (IVCM) can help identify Acanthamoeba cysts and trophozoites in the cornea.

Diagnostic Challenges:

• Delayed Diagnosis: AK is often misdiagnosed or underdiagnosed, leading to delayed treatment and potentially poor outcomes.
• Similar Symptoms: The symptoms of AK can be similar to those of other ocular conditions, making diagnosis challenging.
• Limited Diagnostic Tools: While IVCM can aid in the diagnosis of AK, it may not always be available or used in clinical practice.

References:

[2] Acanthamoeba keratitis is often misdiagnosed or underdiagnosed, leading to delayed treatment and potentially poor outcomes. [8] The symptoms of AK can be similar to those of other ocular conditions, making diagnosis challenging.