Conteudo

Visceral Leishmaniasis is a predominantly rural zooantroponose which is transmitted to man by a cryptozoite dipterous insect bite (DIPTERA) belonging to the Psychodidae family (Phlebotomus or Lutzomya longipalpis).

The canids (for instance, dog, fox: Lycalopex vetulus) are the most frequent animal hosts in our environment. The diagnosis was made based on the direct search for the Leishmania donovani (amastigote forms) in marrow material and through myeloculture in NNN (Mc Neal, Novy e Nicole) culture mean. The samples were obtained through aspirative punctures from the sternum (second intercostal space) and iliac crests (anterosuperior spine). Medular smears were stained with leishman.

We report here cytological alterations that occur in the bone marrow parenchima regarding morphology and cellularity. We studied 100 patients with Visceral Leishmaniasis whose bone marrow "aspirate" analysis disclosed the protozoary Leishmania donovani. The main alterations observed were the following:

Bone marrow smears are mostly thin, without "granules".
Global cellularity is frequently decreased, especially when the disease is at an advanced stage.
After gathering specific counts in bone marrow, the (Myeloid/Erythroid) Ratio is inverted or close to 1:1 values.
There is both relative and an absolute hypocellularity granulocitic.
Increased numbers of neutrophile promielocytes were present.
Decreased numbers of segmented neutrophiles.
There was an absence of eosinophiles in most cases. However, we eventually found increased eosinophiles in several patients, since they presented an association of Visceral Leishmaniasis and vermin infestations.
An elevated level of eytroblastic cellularity.
Microerytroblasts are the predominant type of erytroblasts.
Increased late normoblasts rates.
Several patients presented erytroblasts with "clover-leaf shaped" nucleus.
Presence of erytroblast clusters due the erythroid hyperplasia.
An elevated amount of mitosis in the red cell series.
A relative increase of limphocytes, sometimes more than 50%.
Increased plasmocytes, sometimes to a very large degree, example
more than 8%.
Presence of plasmocyte clusters.
Mott cells are occasionally found.
Polinuclear plasmocytes with three or more nuclei are sometimes found.
Platelet activity is always decreased, although sometimes the megakaryocytes count is normal.
A significant increase in the number and activity of macrophages.

Final Observations:

The presence of the above alterations lead us to search for protozoary in the bone marrow smears, especially in those cases where there was the diagnostic possibility of Visceral Leishmaniasis. However, even if all these alterations are found in the same suspected case, a diagnosis of Visceral Leishmaniasis cannot be determined until after the Leishmania donovani are actually found. Most of the alterations cited above have been previously described, and can be found in the international medical literature.

Our sincerest thanks to the medical staff and patients of the Infectious and Parasitic Service of Clinical Hospital of the University of São Paulo School of Medicine where most of this data was gathered.

Photo Gallery: The magnifications used were 400X, 630X and 1000X.

About the author: Nivaldo Medeiros, MD Former Director of the Hematology and Cytology Service of the Central Laboratory of the University of São Paulo School of Medicine. Former Assistant Physician of the Department of Clinical Pathology (Hematology Service) at the Cancer Hospital of São Paulo.

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Other Websites from the same author: Atlas of Hematology, Cellular Similarity and Morphologic Similarities
E-mail: nivas@earthlink.net