Updated: 12/23/2021

Leishmaniasis

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  • Snapshot
    • A 38-year-old recent immigrant from Brazil comes into the clinic with a 4-month history of painless, ulcerated plaques on his left arm. He denies fever, fatigue, or weight loss. Physical exam revealed ulcers of varying sizes on the left arm, covered with a yellow-white fibrinous material. There are no mucosal lesions, pallor, lymphadenopathy, or hepatosplenomegaly. A complete blood count and liver function test were within normal limits. HIV serology, AFB for lepra bacilli, and serum VDRL were all negative. Histopathological exam of a skin biopsy showed amastigotes inside histiocytes and inflammatory cells. (Cutaneous leishmaniasis)
  • Introduction
    • Definition
      • a vector-borne disease transmitted by the sandfly and caused by Leishmania donovani, an intracellular protozoan parasite
    • Diseases
      • 2 clinical manifestations of leishmaniasis are
        • cutaneous leishmaniasis
        • visceral leishmaniasis ("kala-azar")
  • Epidemiology
    • Incidence
      • rare in the United States and more common in Africa
  • ETIOLOGY
    • Pathogenesis
      • the obligate intracellular parasite is transmitted to mammals via the sandfly
        • the parasite binds to macrophages of the reticuloendothelial system
          • within the macrophage (as amastigotes), the parasite undergoes binary fission and multiply until it lyses, releasing more parasite, which infect other cells, spreading the infection
        • coinfection with HIV
          • leishmaniasis accelerates the development of AIDS via
            • cummulative immunosuppression
            • stimulating the replication of the HIV virus
  • Presentation
    • Symptoms
      • cutaneous leishmaniasis
        • cutaneous lesions
          • nontender ulceration
          • nonpruritic
        • diffuse cutaneous lesions can be seen in immunocompromised hosts
          • lesions may be plaques, ulcers, and nodules
          • diffuse lesions can appear similar to lepromatous leprosy
      • visceral leishmaniasis
        • darkening of the skin
        • fever
        • weight loss
        • hepatosplenomegaly
        • pancytopenia
        • hypergammaglobulinemia
        • leukopenia
        • thrombocytopenia
  • Studies
    • Cutaneous leishmaniasis
      • confirming the diagnosis
        • Giemsa smear of a biopsy, dermal scraping, and/or needle aspirate
          • allows for direct visualization of the amastigote
        • culture
        • polymerase chain reaction (PCR)
    • Visceral leishmaniasis
      • confirming the diagnosis
        • Giemsa smear of a bone marrow aspiration (most commonly) or splenic puncture (high risk of hemorrhage)
          • allows for direct visualization of the amastigote
        • culture
        • PCR
  • Differential
    • Lepromatous leprosy
      • differentiating factors
        • skin biopsy and PCR will demonstrate Mycobacterium leprae organisms
        • results in sensory loss
  • Treatment
    • Conservative
      • observation
        • indication
          • in immunocompetent patients with strictly cutaneous (no visceral, mucosal, or systemic involvement) disease that is spontaneously healing and known to be caused by Leishmania species
    • Medical
      • liposomal amphotericin B
        • indication
          • first-line treatment for visceral leishmaniasis
  • Complications
    • Complications from pancytopenia
      • leukopenia
        • secondary bacterial infection
        • sepsis
      • anemia
        • fatigue
        • pallor
      • thrombocytopenia
        • bleeding
  • Prognosis
    • Cutaneous leishmaniasis
      • typically self-resolves in 3-6 months without therapy
    • Visceral leishmaniasis
      • a seriously progressive condition that can be lethal without treatment
      • if untreated, death can occur within 2 years
    • Co-infection with HIV leads to a severe and rapidly progressive fatal outcome
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