Myelomonocytic myeloproliferative diseases in a horse.
Abstract: Myelomonocytic myeloproliferative disease in a horse was diagnosed on the basis of hematologic, enzymatic, and histopathologic findings. It was characterized clinically by depression, weight loss splenomegaly, lymphadenopathy, coagulopathy, and bacteremia. Hematologic findings included severe refractory anemia, thrombocytopenia, monocytosis, and pleomorphic leukocytes, with a left shift of the myeloid series. The serum lysozyme concentration was 14.5 microgram/ml (normal, less than 5 microgram/ml). The bone marrow contained many immature cells of the myeloid series and had a myeloid-to-erythroid ratio of 30.5 to 1. The horse died after brief hospitalization. Necropsy revealed generalized lymphadenopathy and hemorrhages throughout the body. Histopathologically, primitive cells were seen in several tissues. Cells that proliferated in the bone marrow were primarily myeloblastic, with some additional erythropoietic cells. Myeloblastic cells with evidence of normal erythropoiesis were seen in numerous lymph nodes and in the spleen, whereas primarily normal erythropoietic cells proliferated in the adrenal glands. Myeloid blast-type cells predominated in the lungs, myocardium, liver, and kidneys.
Publication Date: 1982-02-01 PubMed ID: 7056685
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Summary
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The research article details a case of Myelomonocytic myeloproliferative disease in a horse, highlighting the symptoms, diagnostic findings, and eventual death of the animal. The disease was determined through various tests including hematologic, enzymatic, and histopathologic evaluations.
Clinical Signs and Hematologic Findings
- The horse exhibited noticeable signs of depression and weight loss as well as observable physical abnormalities such as enlarged spleen (splenomegaly), enlarged lymph nodes (lymphadenopathy) and clotting disorders (coagulopathy). It was also found to have bacteria in its blood (bacteremia).
- Hematologic findings revealed severe unresponsive anemia, a decrease in the number of platelets (thrombocytopenia), an increase in monocytic white blood cells (monocytosis), and a variety of shapes and sizes in leukocytes, typically indicating an immune response to infection or disease. There was a marked rise in the number of immature white blood cells, namely in the myeloid series (cells that give rise to granulocytes and monocytes).
Enzymatic and Histopathologic Findings
- The serum lysozyme concentration, an enzyme that can break down bacterial cell walls, was significantly higher than the normal level. This could be an indicator of bacterial infection or a reaction to inflammation caused by the disease.
- The bone marrow had an unusual amount of immature myeloid series cells leading to an imbalanced myeloid-to-erythroid ratio (30.5:1) when the normal ratio is closer to 1:1 or 3:1. This phenomenon strongly suggested proliferation of myeloid cells.
- The autopsy showed generalized lymphadenopathy, which is a condition where the lymph nodes throughout the body are abnormal in size, number or consistency. Also, hemorrhages were found throughout the body, indicating severe bleeding.
- Microscopic examination of various tissues revealed presence of immature cells. Cells proliferating in the bone marrow were mainly myeloblastic, with some erythropoietic cells. These cells were also observed in numerous lymph nodes and in the spleen. The predominant cells in the lungs, myocardium, liver, and kidneys were of the myeloid blast-type.
Cite This Article
APA
Brumbaugh GW, Stitzel KA, Zinkl JG, Feldman BF.
(1982).
Myelomonocytic myeloproliferative diseases in a horse.
J Am Vet Med Assoc, 180(3), 313-316.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Horse Diseases / blood
- Horses
- Myeloproliferative Disorders / pathology
- Myeloproliferative Disorders / veterinary
Citations
This article has been cited 5 times.- Satué K, Gardon JC, Muñoz A. A review of current knowledge of myeloproliferative disorders in the horse. Acta Vet Scand 2021 Feb 23;63(1):8.
- Morosco DT, Cline CR, Owston MA, Kumar S, Dick EJ Jr. Spontaneous mediastinal myeloid sarcoma in a common marmoset (Callithrix jacchus) and review of the veterinary literature. J Med Primatol 2017 Apr;46(2):42-47.
- Muñoz A, Riber C, Trigo P, Castejón F. Hematopoietic neoplasias in horses: myeloproliferative and lymphoproliferative disorders. J Equine Sci 2009;20(4):59-72.
- Bruhn O, Grötzinger J, Cascorbi I, Jung S. Antimicrobial peptides and proteins of the horse--insights into a well-armed organism. Vet Res 2011 Sep 2;42(1):98.
- Bienzle D, Hughson SL, Vernau W. Acute myelomonocytic leukemia in a horse. Can Vet J 1993 Jan;34(1):36-7.
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