Abnormlaities of the erythrom 2 Flashcards
How can you test for meleana?
- meat free diet (red meat) for 5d before test or will be positive
- not always visable blood
- “feacal occult blood” very sensitive but NOT specific
Causes of increased losses?
> haemorrhage (external) - meleana - UT - Epistaxis - Post-trauma/surgery > haemorrhage (internal) - bleeding tumour - trauma - into tissue (bleeding diathesis) - surgery > haemolysis - ^ internal RBC destruction - intra v extravascualr - normal erythrocytes or abnormal/damaged ?
What is the most common form of haemolyss? Dxx?
> IMHA
- anti-redcell Ab (IgG, IgM, IgA)
- red cells opsonised -> lysis (IgM) or phagocytosis
- may agglutinate
- Coombs test + (for anti RBC Ab)
- may be severe/rapid, usually strongly regenerative
What is seen microscopically with IMHA? Ddx?
> agglutination
- flaky blood macroscopicallly
- grape like bunches of RBC
- in saline agglutination test (screening)
- one drop saline one EDTA anticoagulated blood mix on slide
- look for flecking before starts to dry (will still occour if AGGLUTINATION, will get rid of ROULEUX artefact)
Ddx = Rouleaux artefact
- stack of coins
- high protein stuck on RBC
- gritty, lumpy macroscopically
- but not pathological
What causes intravascular haemolysis? How is this seen?
> complement mediated
- ghost cells (barey visable, membrane still present, Hbg gone)
What causes extravascular haemolysis?
- macrophages in liver/spleen
- takes bites out of lipid bilayer -> spherical cell (spherocytes) as membrane reforms
- smaller, and very dark (no central pallor)
- normal volume though diameter will appear less
What else may be found with IMHA? Dxxx
- ^ bilirubin (esp with extravascular breakdown)
- neutrophilia, monocytosis (marrow upregulation)
- patelets may also be affected (Evans syndrome IMHA+ platelets)
What parasites may cause haemolysis?
> mycoplasma haemofelis and M. haemominutum (formerly haemobartonella) - epicellular - large and small forms - ^ fragility and hameolysis - cyclical 3-8 weeks - not in UK > Babesia (dogs, USA, mediterranean) - tick borne dz - pyriform bodies INSDIE RBC - haemolytic > Cytauxzoon felis (US) - intracellular - prominant splenic RBC removal
Dx of mycoplasma haemofelis?
- PCR excellent
- blood smear not reliable
Tx babesia?
- Imidocarb
Which animals develop Heinz bodies more readily?
Cats
- low number unremarkable in cats
What are heinz bodies and how do they appear?
- denatured/oxidised Hbg
- Little ‘nose’ on cell, same colour of RBC
Causes of Heinz body formation?
- onions
- paracetamol
- Vit K
- propylene glycol
What are eccentrocytes?
- Hbg uneven distribution within the cell -> eccentric distribution
- oxidative damage to membrane (cf. Heinz - Hbg)
- seen most commonly in dogs, seen horses with red maple toxicosis
What are schistocytes and keratocytes?
- Shear injury products d/t microangiopathic dmage (tumours w/ narrow vessels eg. angiosarcoma) or organ inflammatory beds (severe hepatitis, DIC) d/t fibrin stranding cutting them in half
- Clue to underlying disease vs cause
> schistocytes - RBC fragments 2* to shear injury
- assoc with fibrin deposition in vessels and DIC
What are acanthocytes?
- surface prjections (spicules)
- variable length, unevenly spacd
- narrow base and blunted
> seen with splenic dz
Pre-keratocytes and Keratocytes?
- red cells with apposed and sealed membrane
- helmet shaped cells
- associated with shearing (intravascular trauma eg. vasculitis, DIC) alongside shistocytes
Spherocytes
- extravascular destruction by macrophages taking a bite out -> membrane reforms as a sphere
- darker and smaller, perfectly round
- no central pallor
Give egs of inherited hemolytic dz
> Pyruvate kinase deficiency [Basenjis and Beagles]
- Energy production deficiency
- initially may be very regnerative
- may go on to develop myelofibrosis and acute crisis (death @ 1yr)
- chronic, severe haeolysis
PFK deficiency [English springers]
- RBC sensitive to alkaline ph : low grade haemolysis with severe episodes superimposed
feline porphyria
MOst common non-regenerative anemia?
> anaemia of inflammatory/chronic disease
- normocytic, normochromic
- usually mild and lowly progressive
- Fe sequestration (bugs want iron)
- inflam mediators -> shortened erythrocyte survival
Causes of non-regenerative anaemia? FINISH
- chronic disease
- renal
- endocrine
- FeLV
How does renal anaemia occour? Tx?
- EPO production v
- normocytic, normochromic, mild - mod
- impacts quality of life
> Tx: EPO injections (though human so can => immune response)
> aim to ^ PCV (though not to normal)
Is endocrine anaemia a common problem?
Rare
- hypothyroid and hypoadrenocorticism
- normocytic, normochromic, mild
- thyroid hormone and cortisol facultative effect on RBC production
How common is FeLV anaemia? How are they linked? What type of anaemia is seen?
- FeLV subgroup C
- 70% anaemic cats!
- selective depression of erythropoeisus
- dyspalstic production
- myeloproliferative dz ‘crowding out’
> usually non-specific erythroid hypoplasia - may be normocytic/chromic but may be macrocytic
Causes of aplastic anaemia
- FeLV, estrogen tox, phenylbutazone, chemotherapy, unknown
What is missing with apastic anaemia? What remains? What is needed to dx this?
- ALL precursors (complete non-regenerative marrow)
- fat, plasma cells and mast cells left
- need core biopsy otherwise cant tell if youve just got a rubbish sample
What is myelodysplasia? What is seen in the marrow?
- type of non-regenerative anaemia (pre-leakaemia)
- adequate cellularity in marrow but abnormal maturation/proliferation of cells (ineffective haemopoiesis)
- in the marrow: erythrocyte macrocytosis, binucleates, maturation defects, giant neutrophils, hypersegmented neuts, macroplatelets
- may progress to leukaemia
What is myelopthisis?
- neoplasia crowding out the bone marrow and altering environment
- usually haematopoetic neoplasia (esp lymphoid)
What is myelofibrosis? Dxx?
- response to injury of fibrous elements of marrow -> dry taps
- may be reactive following prolonged regenerative attempts
- Need core biopsy: reticulin stains up the fibrous elements
- osteosclerosis: cortical bone ^
+- marked extramedullary haematopoiesis
Which dz are exeptions to the non-regenerative type thing..
> iron deficiency anaemia may -> non-regenerative in the long term
immune mediated attack of RBC precursors no the mature cells -> non-regenerative
Why is melena particularly bad?
- LOSS of iron (cf. haemothorax etc. where RBC will be recycled)
Main 6 questions to ask wrt anaemia?
- mild mod severe?
- regenerative/non?
- macro/microcytic?
- hypo/normochromic?
- specific morphology changes?
- does the sample give you the answer?
What is polycythaemia?
= erythrocytosis
- ^ HCT, RBC count and Hbg
> may be spurious or relative
- dehydration (volume contraction) most common
- RBC redistribution (splenic contraction) esp in horses
Causes and subgroups of absolute erythrocytosis?
> 1* (polycythemia vera) neoplasia [ in humans all cell lines, in animals RBC only] - myeloproliferative disorder of erythroid stem cells - EPO level normal/decreased - PO2 normal > 2* (appropriate or innaropriate - chronic hypoxia - EPO secreting tumours - EPO level raised
Hyperthyroid cats have ^ RBC - is this pathological?
- technically pathological but normal for the physiological state they are in (higher metabolic rates = higher oxygen demand)
What should be submitted alongside EDTA sample? How should this be stored??
Fresh blood smear
- store blood in fridge until analysis (slows changes)
- store smears at room temperature (NOT IN FRIDGE)
