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- Presentation
Disseminated Acanthamoeba Infection Causing Midline Destructive Facial Lesions
Description
This case describes an elderly man with an immunocompromising history, chronic sinus disease, and a painful ulcerative, destructive midline facial lesion involving the nose and upper lip. The differential for a midline destructive lesion included malignancy, inflammatory disease, infection, toxic injury, and trauma, but biopsy showed a dense granulomatous inflammatory infiltrate with round organisms highlighted on PAS staining, consistent with amoebic infection. PCR from skin and sinus tissue, sent to multiple reference centers, was positive for Acanthamoeba. The speaker reviewed Acanthamoeba as a ubiquitous free-living amoeba acquired through the eyes, nasal passages, or broken skin, and noted that non-keratitic infections can present as localized cutaneous/nasopharyngeal disease, granulomatous amoebic encephalitis, or disseminated disease with high mortality. In this patient, the key risk factors were immunosuppression and use of tap water for nasal rinses, which can harbor free-living amoebae. The CDC recommends combination therapy for disseminated disease, but despite multidrug treatment and specialist input, the patient worsened, developed renal failure from therapy, and died within a month. The speaker also noted another similar case in a renal transplant recipient and emphasized the need to consider free-living amoebae in destructive midline lesions and to counsel patients to use only sterile, distilled, or boiled water for nasal irrigation.
View moreConclusions
- Acanthamoeba can cause progressive destructive cutaneous and nasopharyngeal disease that may mimic malignancy, vasculitis, or other midline destructive lesions.
- Diagnosis is often difficult because the organisms can be sparse and hidden within mixed inflammatory infiltrates, so biopsy, special stains, and PCR may all be needed.
- Immunocompromised patients are at especially high risk for severe non-keratitis Acanthamoeba infection, but localized skin disease still carries substantial mortality.
- Chronic nasal irrigation with tap water is a plausible and preventable source of infection, particularly when mucosa is damaged or when devices are contaminated.
- Public awareness of the risks of tap water for nasal rinsing is poor, despite measurable contamination of household tap water with Acanthamoeba.
- Free-living amoebae should be included in the differential diagnosis of non-healing destructive facial or wound lesions, especially in patients with sinus disease or immunosuppression.
- Combination antimicrobial therapy is generally favored over monotherapy, but optimal treatment remains uncertain and outcomes can still be poor.
- Patient counseling on using only sterile, distilled, or boiled water for nasal rinses is a key preventive step in clinical practice.
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