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Dermatological emergencies in tropical infections and infestations
Published in Biju Vasudevan, Rajesh Verma, Dermatological Emergencies, 2019
Anup Kumar Tiwary, Niharika Ranjan Lal, Piyush Kumar
The diagnosis of Acanthamoeba infection requires visualization of amebic trophozoites and/or cysts, which may be found perivascularly [51]. Definitive identification to genus and species level can be obtained by immunofluorescence, culture method, or both. The prognosis of cutaneous acanthamebiasis is dismal, with a mortality rate of at least 74% in patients without CNS involvement and 100% in patients with CNS involvement. Patients with presumed or confirmed CNS involvement developed headaches, fever, altered mental status, hemiparesis, lethargy, spasticity, and seizures. Treatment for acanthamebiasis in vivo has not been available, although ketoconazole, flucytosine, pentamidine, sulfadiazine, and polymyxin B were known to be effective in vitro [50].
Acanthamoeba castellanii
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
GAE and the disseminated infection by Acanthamoeba are rare forms and primarily involve immunocompromised patients, such as those with AIDS, malnourished individuals, those on prolonged corticosteroid therapy (3), or those suffering conditions that decrease the host defense mechanisms. Cerebral involvement commonly follows a lung or skin infection, which over a period of months to years progresses to GAE (Figure 49.2) by a hematogenous route toward the brain (24). Rarely a disseminated infection can also involve healthy children and adults. The actual number of GAE worldwide is probably higher, as diagnosis is usually made at autopsy, which is seldom done in many undeveloped countries. Infections from contaminated food sources have not been reported to occur and cause GAE, but pathogenic Acanthamoeba has been isolated from vegetable sprouts and beans (8). The latter finding raises the probability of perioral infection by Acanthamoeba in immunocompromised patients during eating, as they commonly have angular stomatitis and oral/lip ulcers. The latter breaches in the oral mucosa and skin understandably raise the chances of acquisition of Acanthamoeba infection from food resources.
Acanthamoeba
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
For disseminated Acanthamoeba infection such as GAE, which evolves rapidly, it is important to initiate treatment early. Trimethoprim–sulfamethoxazole therapy together with ketoconazole and rifampin has proven effective for treating two immunocompetent pediatric patients with CNS involvement. A 4-week course of IV pentamidine isethionate, topical chlorhexidine gluconate, and 2% ketoconazole cream has also been successfully applied for treatment of disseminated Acanthamoeba infection in a renal transplant patient. For CNS infection, 5-fluorocytosine rather than pentamidine is recommended because the latter demonstrates nephrotoxicity and fails to cross the blood–brain barrier. In addition, 40 mg of 5-fluorocytosine per kg for 2 weeks appears to be useful for treating cutaneous acanthamoebiasis (e.g., AIDS patient with cutaneous and sinus lesions). A combination of lipid formulation of amphotericin B and voriconazole may also be applied for granulomatous dermatitis secondary to Acanthamoeba infection [32].
Fulminant acanthamoebic meningoencephalitis in immunocompetent patients: an uncommon entity
Published in British Journal of Neurosurgery, 2022
Lokesh Suresh Nehete, Anil Kumar, Pooja Chavali, Prabhuraj A. R., Bhagavatula Indira Devi
Imaging studies with CT scan characteristically shows multiple enhancing lesions involving the cerebral cortex and underlying white matter with mass effect. On MRI, multifocal lesions showing T1, T2 hypo intensity and a heterogeneous or ring like pattern of enhancement with perilesional oedema are seen.19 In lesions with bleed, peripheral thin rim of T1 hyper intensity with blooming on gradient-sequences and hyper density on plain-computed tomography scans is seen. Magnetic resonance spectroscopy shows elevated lactate and choline peaks. The characteristic marginal haemorrhage on imaging studies along with chronic constitutional symptoms such as headache; vomiting and altered sensorium must prompt a differential diagnosis of Acanthamoeba infection and institution of appropriate therapy at the earliest.
Acanthamoeba Keratitis: Perspectives for Patients
Published in Current Eye Research, 2021
Stefano Bonini, Antonio Di Zazzo, Giuseppe Varacalli, Marco Coassin
Patients with AK were selected based on a culture-proven Acanthamoeba infection, or histopathological confirmation of trophozoites or cysts, as well as on polymerase chain reaction amoebic-specific genome detection.12–15 Signs and symptoms were recorded and a standard treatment regimen with a combination of 0.1% propamidine isethionate and 0.02% polyhexamethylene biguanide was started once the diagnosis was confirmed.14,16,17 On the basis of their clinical records and corneal images obtained at their first visit, a staging of the AK severity was made according to previous reports.18,19 Briefly, stage I included patients with corneal epitheliopathy; stage II included patients with corneal epithelial defects and stromal or perineural infiltrates; stage III included patients with one or more features of stage II plus a corneal ring infiltrate (Figure 1).19
A Review of Next-Generation Sequencing (NGS): Applications to the Diagnosis of Ocular Infectious Diseases
Published in Seminars in Ophthalmology, 2019
Lina Ma, Frederick A. Jakobiec, Thaddeus P. Dryja
Among the 16 cases of infectious keratitis which had organisms identified by microscopy and/or culture, NGS confirmed four cases of bacterial infection, five of fungal infection, three of Acanthamoeba, three of viral infection (including two cases of CMV co-infected with bacteria), and one case of parasitic infection. There were two unclassifiable cases by NGS. Disturbing contaminants were also observed: some cases had rat, mouse, or lemon (plant) DNA fragments. One case of microsporidia had numerous DNA fragments from Acanthamoeba DNA, yet an Acanthamoeba infection had been ruled out clinically. One case contained DNA fragments from many protozoan species, but cultural and microscopic studies revealed only Acanthamoeba. The authors concluded that sample collection procedures must be meticulous. New instruments and non-contaminated solutions and reagents are needed for each case.