Bone marrow assessment Flashcards
When is BM biopsy indicated?
- Non‐regenerative anaemia
- Severe thrombocytopenia
- Severe persistent neutropenia without identifiable cause
- Bi or pancytopenias
- Dysplastic circulating cells
- Elevated circulating cell counts
- Staging of lymphoma
- Unexplained hypercalcaemia
- Assessment for certain infectious diseases
- Evaluation of iron stores
- Hyperproteinaemia
What causes of erythrocytocis do no warrant BM biopsy
splenic contraction, hypovolemia, physiological induced cardiac disease, and high-altitude hypoxia
and in certain dog breeds (eg, greyhounds)
When is humerus a good site to sample?
Obese animals
DO NOT USE IN ANIMALS LESS THAN 6M due to closeness to growth plate
Where are good places to sample in thin animals?
Ileal crest
Femur
Can be done post morten but must be within 30 mins
What does a full bone marrow biopsy consist of?
a CBC, bone marrow aspirate, and bone marrow biopsy
What makes up the composition of bone marrow?
cortical and trabecular bone and stroma, vasculature, sinus wall layers, nerves, hematopoietic cells, and nonhematopoietic interstitial cells
How does bone marrow change with age?
Young animals generally present with hypercellular bone marrow, defined as having greater than 75% cellular elements with the remainder of the space occupied by adipose tissue, if present.
As the animal ages or when hematopoiesis decreases with disease, fat cells, fibrous tissue, necrosis, or metastatic tumor cells often replace normal cellular elements.
What is suggestive of acute myeloid leukaemia?
presence of greater than 20% blast cells in the bone marrow
What is myelodysplastic syndrome?
a term used to designate a group of disorders
characterized by peripheral blood cytopenias; however, the marrow is either hypercellular or normocellular for the corresponding cell lineage and there is morphologic evidence of dysplasia in one or more cell lines
It is believed that normal blood cell maturation, differentiation, function, and survival are impaired, leading to the development of peripheral
blood pancytopenia; patients may be at increased risk to transform to AML
What is aplastic anaemia?
the situation in which the marrow is devoid of
hematopoietic cells and has been replaced by fat. Destruction or suppression of multipotential hematopoietic stem cells is implicated by this finding. Causative mechanisms may include myelotoxic substances, immune-mediated mechanisms,
and some infectious diseases (eg, canine ehrlichiosis)
What is myelofibrosis?
Normally a response to damage to BM
Replacement with collagen etc
What is haemosiderosis?
when iron stores accumulate within macrophages
thus appearing as dense aggregates with large coarse granules that react strongly with Prussian blue stain. The accumulation implies increased erythrocyte destruction or ineffective erythropoiesis. This situation is present in cases with anemia of chronic disease related to decreased iron utilization or with pure red cell aplasia related to immune-mediated destruction of erythroid precursors. Increased hemosiderin levels have also been associated with feline myelofibrosis and myelodysplastic conditions.
What are the contraindications of bone marrow biopsy?
CV unstable (including v v v anaemic) Low platelets not - just ensure a very small hole secondary haemostatic disorder may be
When are aspirates and cores used?
Aspirate always Ideally also do core, but most important for non regenerative or persistent cytopaenias Assessing iron stores Infectious disease assessment Another BM suspected dz
/What are the prefered sites for animals
Cat - femoral head - care with sciatic nerve, femoral head fracture
Dog - humerus
