Site Editor
Jeremy S. Abramson, MD, MMSc
Jeremy S. Abramson, MD, MMSc
Posted: Thursday, February 24, 2022
A case report published in the Journal of Antimicrobial Chemotherapy detailed the successful treatment of cutaneous acanthamoebiasis with a novel antiprotozoal agent miltefosine in a patient with chronic lymphocytic leukemia (CLL) treated with ibrutinib. Although rare, infections involving the ubiquitous environmental protozoa can occur among immunosuppressed transplant recipients and in patients on immune-modulating therapies, according to Joanne S.K. Teh, MBBS, BMedSc, Infectious Diseases Registrar at the Flinders Medical Centre, Adelaide, South Australia, and colleagues.
A 70-year-old immunocompromised man with CLL was receiving treatment with the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib; he presented with tender, erythematous, subcutaneous nodules that developed over 2 months. A skin biopsy revealed amoebic trophozoites associated with histiocytic and lymphocytic inflammation, ulceration, and necrosis. The causative organism Acanthamoeba castellanii was subsequently confirmed via culture and molecular methods.
Following this diagnosis, ibrutinib was withheld and induction therapy with intravenous pentamidine and oral miltefosine was initiated. Supportive therapies such as prophylaxis for Pneumocystis jirovecii with co-trimoxazole, antifungal prophylaxis with posaconazole, intravenous immunoglobulin, human granulocyte–colony stimulating factor, and blood transfusions were continued. Two weeks later, the miltefosine dose was decreased, and pentamidine was replaced with azithromycin due to therapy-related nephrotoxicity. All skin lesions resolved within 2 months, and antiprotozoal therapy was discontinued after 3 months.
Factors predisposing atypical infection in patients with CLL treated with BTK inhibitors include impaired clonal expansion of B cells and diminished innate and antibody-mediated immunity. To diagnose acanthamoebiasis, biopsies of the affected regions followed by histologic analysis, culture, and molecular testing are essential. Combination therapy with antibiotics and antifungals in addition to miltefosine is often required to successfully treat acanthamoebiasis.
“Acanthamoeba infections pose a diagnostic and therapeutic challenge for clinicians. Early recognition, prompt diagnosis, and rapid initiation of treatment are essential to improve patient survival,” concluded the authors.
Disclosure: The study authors reported no conflicts of interest.
Journal of Antimicrobial Chemotherapy
JNCCN Spotlights
