Epidemiology + Risk Factors
What is the patient's name?
Pete Weddle, 62, M
Explain the name "kala-azar" (Hindi for black fever)
The disease often causes hyperpigmentation in individuals of South Asian ancestry
Freebie
urwelcom
List prevention strategies against Leishmaniasis
Avoid sandfly bites: limit outdoor activities at dawn/dusk/night in endemic areas, wear protective clothing, apply insect repellant
How is Leishmaniasis spread?
Through sandfly bites
What are the different types of Leishmaniasis?
(diffuse) cutaneous, mucocutaneous, and visceral
What immune cell is needed to mount an effective immune response to Leishmania spp.?
Parasite-specific CD4+ Th1 cells
List laboratory methods for diagnosing Leishmaniasis
Biopsy microscopy, culture medium, serology
Name different species of Leishmania (at least 4)
Old World: L. major, L. tropica, L. donovani, L. infantum
New World: L. mexicana, L. braziliensis, L. chagasi
What is the usual timeline for symptom development in Leishmaniasis
Symptoms usually arise a few weeks to months after infection for cutaneous Leishmaniasis and a few months to years for visceral
How does Leishmania survive within macrophages? (an acidic environment)
Amastigotes express a proton-transporting ATPase which maintains the pH at ~6.5
Daily Double!
If anyone can explain to me treatment differences, if any, between L. donovani species complex and L. infantum, I'll give double points. Specifically treatment with miltefosine (IMPAVIDO)
Describe the life cycle of Leishmania spp.
(picture on separate tab)
What are typical symptoms of Leishmaniasis
Fever, cachexia, hepatosplenomegaly, pancytopenia, hypergammaglobulinemia
Leishmania requires iron for survival, how does the host combat this?
Uses proinflammatory cytokines to repress iron absorption (upregulating hepcidin, ferritin, and downregulation of transferrin in the macrophage)
What is the MoA for leishmanicidal liposomal amphotericin B?
It is thought that the drug binds to parasitic ergosterol precursors (lanosterol), disrupting the parasite membrane
What are the implications of anthroponotic transmission?
As humans are the sole reservoir, control of the disease in the individual can help control the spread of the disease in the population
Compare-contrast clinical manifestations of VL-HIV coinfections
Classical features not significantly different. Prognosis, cure rate, relapse rate, AIDS progression are much worse especially with untreated HIV coinfection
Leishmania promastigotes express 2 major virulence factors: Lipophosphoglycan and Gp63. Explain their MoA
Lipophosphoglycan: Forms dense glycocalyx that activates and inhibits complement while targeting the cell for phagocytosis by macrophages
Gp63: Binds to fibronectin to promote adhesion to macrophages. Cleaves complement and lysosomal enzymes.
Mr. Weddle expressed concern over the bone marrow aspiration. How would you ease the patient's fears and contrast bone marrow aspiration to the more diagnostically sensitive splenic aspiration?
(Answers vary)
Splenic aspiration carries a high risk of life-threatening hemorrhage.