Haematology Flashcards
In the treatment of MDS, what are predictors of clinical response to lenolidomide?
Predictor of GOOD response: isolated del(5q) as it suggests mild disease
Predictor of POOR response: low plts
What is the function of ADAMTS-13? What happens in TTP?
ADAMT-13 normally cuts the long vWF long multimers (secreted from endothelial cells) into shorter pieces preventing them from attaching to platelets and causing unintended clots. With TTP there is a ADAMTS-13 deficiency, so platelet clots aberrantly arise.
What is Donath-Landsteiner syndrome?
AKA PAH (paroxysmal cold haemaglobinuria), is an immune-mediated post-infective cause of haemolytic anaemia due to IgG autoantibodies to the P-antigen on RBC.
Which condition might ‘sausage links’ on fundoscopy suggest?
Hyperviscosity syndrome - most likely due to Waldenstrom’s macroglobulinaemia, although multiple myeloma is possible.
If spherocytes are noted on a blood film, which is the next test that should be conducted? What conditions are in the DDx?
DAT (direct antigen test) should be conducted to diffrentiate between:
DAT negative: hereditary spherocytosis
DAT positive: variety of immune mediated haemolytic anaemias (autoimmune, lymphoproliferative, drugs, infection)
What is the DDx for DAT positive spherocytosis?
Causes of immune-mediated haemolytic anaemias: lymphoproliferative disorders, cancers, autoimmune diseases, drugs and infection.
Which types of VWD are autosomal positive and negative?
Mild (1 / 2A / 2B / 2M) are autosomal DOMINANT
Severe (2N / 3) are autosomal RECESSIVE
What 4 parameters is the platelet functon test PFA-100 dependent upon?
- Platelet function (obviously)
- Platelet number (logical)
- Haematocrit (dilutional effects)
- vWF levels (stabilises platelets)
What are the causes of sickle cell crisis, which of these is the most common?
Aplastic crisis in sickle cell anaemia is a temporary arrest of RBC production. Most common cause is parvovirus B19, other triggers include (SHE): streptococcus, hydroxyurea, EBV.
Sickle cell anaemia is diagnosed through which 3 tests?
- Blood film: reticulocytes and signs of hyposplenism (Howell-Jolly bodies and target cells)
- Hb electrophoresis
- Sickle cell solubility test
What is Hb Barts? What condition does it cause?
Alpha-thalassaemia due to abnormalities in the gene loci for all 4 globulins of Hb. Hb Barts is a cause of non-immune hydrops foetalis (accumulation of fluid/oedema in 2 foetal compartments)
What is predictor of poor prognosis in CLL?
For CLL a chromosome 17p deletion on FISH is suggestive of poor response to chemotherapy.
In a patient with normal renal function, when should a NOAC be ceased prior to:
- Low risk procedure
- High risk procedure
Discontinuation of a NOAC (factor X1 inhibitor) in a patient with normal renal function:
- Low risk procedure = 1d
- High risk procedure = 3d
What are the 5 components of the DIC screen?
DIC screen:
Bleeding (3): low platelets, high PT/APTT, blood film (low platelet and platelet fragments i.e. schistocytes)
Clotting (2): low fibrinogen, positive D-dimer
What is the strongest predictive factor for DVT recurrence?
Obvious.
Strongest predictive factor for recurrent DVT is a previous DVT, especially if unprovoked (8% unprovoked vs. 4% provoked)
In a patient with impaired renal function (eGFR<30), when should a NOAC be ceased prior to:
- Low risk procedure
- High risk procedure
Discontinuation of a NOAC (factor X1 inhibitor) in a patient with impaired renal function:
- Low risk procedure = 3d
- High risk procedure = 4d
What elements in the FBC are prognostic in CLL?
Prognostic features for CLL in FBC: anaemia and/or thrombocytopenia (Binet or modified Rai staging)
What is the modified Rai-staging for CLL?
Modified Rai staging for CLL:
Low = elevated WCC (bone or marrow)
Intermediate = elevated WCC + LNs (anywhere)
High = anaemia/thrombocytopenia +/- LNs
What is Heyde’s syndrome?
Heyde’s syndrome:
AS
vWD (type IIa)
GI-angiodysplasia
How does scurvy cause a macrocytic anaemia?
Scurvy (vitamin C deficiency) may cause macrocytic anaemia via:
- Defective folate metabolism (co-factor for reduction of folate)
- Oxidative haemolysis as ascorbic acid is an important anti-oxidant.
True/False: Ascorbic acid is a potent oxidant.
False: Ascorbic acid is a potent reductant (i.e. anti-oxidant) and therefore donates electrons.
What is the treatment of scurvy?
Rx for scurvy – replace vitamin C, should recover in 3 months.
Which two important metals are reduced by ascorbic acid in the body?
Ascorbic acid (vitamin C) reduces iron and copper in the body.
Which type of anaemia do the following conditions cause? Hypthyroidism Scurvy Zollinger-Ellison Syndrome HRT therapy Ulcerative colitis
Macrocytic anaemia: hypothyroidism, scurvy, HRT therapy
Microcytic anaemia: Zollinger-Ellison Syndrome, Ulcerative colitis.