The erythroid system Flashcards

Question

Codocytes or 'Target cells' - what are they? what do they look like? what are they seen in?

Answer 1

Appearance of a target with a bullseye - central, haemoglobinised area surrounded by an area of pallor, periphery of the cell contains a band of haemoglobin - lacking normal biconcave cross section due to folding of cell membrane Seen in - iron deficiency anaemia - liver dz with cholestasis - after splenectomy in dogs Often of little significance

Answer 2

Rounded projections of variable diameter & length, unevenly distributed Due to increase in membrane cholesterol or in association with RBC fragmentation Seen in - diffuse liver dz - splenic haemangioma - haemangiosarcoma - portosystemic shunts - high cholesterol diet

Answer 3

Small, densely stained spherical RBCs, lack central pallor Small portions of the cell membrane may have been phagocytose by mononuclear phagocytes; residual cellular tissue resumes the smallest shape possible - a sphere Rarely recognised in cats as normal RBCs have less central pallor than in dogs. Presence implies that erythrocytes have surface bound antibodies or complement - indicator of IMHA (when increased number) - can happen in a normal healthy spleen as macrophages recognise they're old Will be present in animals that have received transfusions - cells are damaged and foreign

Answer 4

Irregular, fragmented erythrocytes Through mechanical trauma to circulating erythrocytes Markers of disseminating intravascular coagulation (DIC) and other angiopathies. Seen in immune mediated anaemia, thrombosis, splenic haemangiosarcoma, glomerulonephritis, congestive heart failure, valvular heart disease, doxorubicin toxicosis and myelofibrosis

Answer 5

RBCs with spiked projections of more uniform length 'Echinocytes' Some normal in ruminants & rabbits Rarely snake envenomation Occasionally in dehydration Mostly artifactual (exposure to anticoagulant)

Answer 6

To confirm agglutination: mix 1 drop of blood with 4 drops of saline -> agglutination will persist, rouleaux formation will disperse

Answer 7

Clustering, sticking, piling of RBCs Normal finding in horses Indicates inflammation in small animals Related to increased 'stickiness' of plasma with increased globulin content

Answer 8

Grossly grainy appearance IMHA Mismatched blood transfusion

Answer 9

(HgB) Oxidative damage - Heinz bodies Signs of regeneration - basophilic stippling - nucleated erythrocytes - Howell-Jolly bodies Infectious agents - parasites - bacteria - viral inclusions

Answer 10

Irregular shaped, refractile inclusions Consisting of oxidative denatured haemoglobin Increased numbers in paracetamol and onion toxicity and other oxidative compounds, more common in cats than in dogs (as cats are more sensitive to oxidative damage) Up to 10% of RBCs in normal cats In cats also commonly associated with DM, lymphoma and hyperthyroidism (but also wide range of other diseases including CKD)

Answer 11

Multiple, small, dark blue, punctate aggregates in RBC (i.e. tiny diffuse dark dots of the surface) in vivo aggregation of ribosomes into small basophilic granules Caused by low levels of pyrimidine 5'-nucleotidase (P5N), enzyme that catabolises ribsomes In cats (more common) & dogs associated with intensely regenerative anaemia. Associated with lead poisoning (reduced P5N activity) Normal in immature erythrocytes in ruminants (low levels of P5N are normal).

Answer 12

nRBCs / metarubricytes / normoblasts Erythrocytes with remains of a nucleus Regenerative anaemia - early release of RBcs from bone marrow and extra-medullary haematopoiesis sites in response to hypoxia In absence of anaemia - non-functioning spleen - marrow damage - in cats, in absence of polychromasia, indication of myelodysplasia or myeloproliferative dz

Answer 13

Refractile, single dark blueish bodies in RBCs of variable Representing nuclear remnants Indicates: - regenerative anaemia - splenectomy - suppressed splenic function - higher % seen in normal cats

Answer 14

- tick born dz - intracellular - endemic in cattle - dogs: Babesia canis or B. gibsoni, rare in UK, imported - pear shaped inclusions, often occur in pairs of 4 Uncomplicated or complicated forms: - haemolytic anaemia - SIRS, MODS

Answer 15

- highly pleomorphic, appearing as chains, discs or rods - on surface or embedded into RBC membranes - worldwide distribution - diagnosis confirmed by PCR - haemobartonellosis or feline infectious anaemia - variable CS including regenerative anaemia, pyrexia and malaise

Answer 16

RBCs miscounted - mistaken for platelets - aggregated into pairs and triplets MCV misleading - cell shrinkage of swelling due to transport, tube filling or osmotic effects in machine

Answer 17

High MCHC - not physiological to cram more Hgb into red cells than they will take - haemolysis (sample handling or intravascular) - lipaemia MCV - swelling of transport - misidentification (pairs and triplets, cross over with large platelets) - cell shrinkage or expansion in sample e.g. hyperosmolar - will impact on calculated PCV/HCT

Answer 18

PCV (Hct), RBCc and Hgb - all 3 measures of red cell mass and oxygen carrying capacity - usually interpret them as a block - all equally affected by haemoconcentration - will usually increase and decrease in line with another - therefore, when they are discordant -> find out why

Answer 19

Based on MCV and MCHC - blunt measure - microscope visible findings may not be sufficient to push parameter out of reference range - machine dot-plots and histograms more sensitive Normocytic normochromic - often anaemia of illness or pre-regenerative or occasionally non-regnerative Macrocytic hypochromic - classically highly regenerative - [sometimes could just be cell swelling of transport] Microcytic hypochromic - classic iron deficiency -> chronic external blood loss - without anaemia -> portosystemic shunts

Answer 20

- increase in PCV, Hgb concentration and RBCc Term polycythaemia implies increased number of several haemopoeitc cell lines (human), but dogs and cats with polycythaemia vera usually have normal neutrophil & platelet counts

Answer 21

Relative - apparent increase in RBC due to a decrease in fluid in circulation - often increased total protein and albumin Absolute - true increase in RBC mass due to increased RBC production/release - usually polychromasia, anisocytosis and reticulocytes

Answer 22

= increased PCV but no increase in RBC production Dehydration - water or acellular fluid loss - e.g. v+, d+, PU, extensive burns, adipsia, water deprivation Exercise, fear, excitement, severe pain - stress - adrenaline secretion, splenic contraction and transient redistribution of RBC from the spleen to the circulation Resolves after rehydration or removal of cause of splenic contraction

Answer 23

= increase in RBC production Primary polycythaemia (polycythaemia vera) - rare myeloproliferative disorder - abnormal response to RBC precursors - normal EPO levels Secondary polycythaemia - chronic tissue hypoxia of renal tissues (low arterial pO2) due to: heart/lung dz, high altitude, thrombosis, constriction of renal vessels - renal tumour or cysts (increased intra-capsular pressure) - increased EPO

Answer 24

RBCs with a ragged appearing, poorly haemoglobinised fringe of cytoplasm along 1 side of the cell. Also known as 'hemi-ghost' cells and 'pseudo-spherocytes' Form under conditions of excess oxidant stress to the erythrocytes, which induces cross linking of membrane proteins Spheroid & rigid - become trapped and removed by extravascular haemolysis Often, they're seen in association with Heinz bodies, which provide evidence of an oxidant effect on haemoglobin Seen in animals with inherited glucose-6-phosphae deficiency: increased susceptibility to oxidant-induced erythrocyte injury; oxidative damage (dogs, onion poisoning)

The erythroid system Flashcards

(48 cards)