USMLE

Leishmania

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Parasites
  1. Giardia lamblia
  2. Toxoplasma gondii
  3. Entamoeba histolytica
  4. Cryptosporidium
  5. Naegleria fowleri
  6. Trypanosoma brucei
  7. Plasmodium Overview
  8. Plasmodium Disease (Malaria)
  9. Babesia
  10. Trypanosoma cruzi
  11. Leishmania
  12. Trichomonas vaginalis
  13. Enterobius vermicularis (pinworm)
  14. Ascaris lumbricoides (giant roundworm)
  15. Strongyloides stercoralis (threadworm)
  16. Ancyclostoma and Necator
  17. Trichinella spiralis
  18. Trichuris trichiura (whipworm)
  19. Toxocara canis
  20. Onchocerca volvulus
  21. Loa loa
  22. Wuchereria bancrofti
  23. Taenia solium
  24. Diphyllobothrium latum
  25. Echinococcus granulosus
  26. Schistosoma
  27. Clonorchis sinensis
  28. Sarcoptes scabiei (Scabies)
  29. Pediculus humanis and Phthirus pubis (Lice)

Summary

Leishmania is a family of protozoan intracellular parasites that infect and replicate inside the macrophages of their host. These parasites are transmitted through sandfly bites and can cause patients to present with either cutaneous or visceral forms of disease. While patients with cutaneous leishmaniasis may experience painless skin ulcers, those with visceral leishmaniasis tend to have more severe multi-organ involvement. For example, these patients might experience symptoms like darkened skin, hepatomegaly, splenomegaly, and pancytopenia. Leishmaniasis is commonly diagnosed through biopsies that reveal amastigotes inside the macrophages of infected patients. For treatment, amphotericin B is the primary drug used for both types of the disease, while stibogluconate is commonly prescribed for those with visceral leishmaniasis. 

Key Points

  • Leishmania spp.
    • Characteristics
      • Family of obligate intracellular protozoan parasites
    • Transmission
      • Transmitted by bite of sandfly
    • Presentation: Leishmaniasis
      • Visceral leishmaniasis
        • Darkened skin
        • Splenomegaly
        • Hepatomegaly
        • Pancytopenia
      • Cutaneous leishmaniasis
        • Painless ulcers
    • Diagnosis
      • Biopsy of lesions or infected organs
        • Macrophages filled with amastigotes (FA)
    • Treatment
      • Amphotericin B
      • Paromomycin, Pentamidine
        • Mainly used for cutaneous leishmaniasis
      • Stibogluconate, miltefosine
        • Mainly used for visceral leishmaniasis