Haematology Flashcards
What are the characteristic blood test results in iron-deficiency anaemia?
Microcytic anaemia (low MCV), low ferritin (however an acute phase reactant so can’t always rely on), raised transferrin, raised total iron binding capacity.
What are the most common causes of iron-deficiency anaemia in different age categories?
Menstruating women - 2ndary to menstruation
Men + post-menopausal women - GI bleeding
Pre-school children have the greatest prevalence of iron-deficiency anaemia - increased iron requirement during growth. For similar reasons, iron-deficiency anaemia also becomes more prevalent during pregnancy.
Iron absorption is impaired in coeliac disease so consider serological testing if unexplained (total IgA and IgA TTG / tissue transglutaminase)
What are the main causes of micro, normo and macrocytic anaemia?
Microcytic: Iron-deficiency, Beta thalassaemia (inherited, absent or decreased synthesis of beta-globin chain, depending on whether homo or heterozygous can be anywhere on the spectrum from transfusion-dependent to asymptomatic. Excess iron replacement can harm)
Normocytic: anaemia of chronic disease, EPO deficiency (eg in chronic kidney disease), bone marrow insufficiency
Macrocytic: Folate or Vitamin B12 deficiency, Haemolytic anaemia.
What are common examples of intravascular versus extravascular haemolysis?
Intravascular haemolysis: microangiopathic haemolytic anaemia (breakdown in small blood vessels and includes DIC, HELLP syndrome, Haemolytic uraemic syndrome (following E.coli GI infection), ABO incomptability, Rhesus disease. Extravascular haemolysis (breakdown of RBCs in spleen + liver): divided into those with normal RCCs (malaria, autoimmune haemolytic anaemia) and deformed RCCs (sickle cell anaemia, thalasaemia, G6PD deficiency)
What is the characteristic presentation of polycythaemia vera?
- Itchiness (especially after baths/showers)
- Tingling / burning / numbness in limbs and hands/feet
- Splenomegaly
- ^ Hb on FBC
= neoplastic expansion of haemtopoetic cells in the bone marrow. Peak incidence is in people in their 60’s.
2-8% will progress into myelopfibrosis (malignant) and 1-3% will progess into acute myeloid leukaemia
What is the genetic mutation associated with most cases of polycythaemia vera?
V617F mutation on JAK2
What is the 1st line management of polycythaemia vera?
Repeat blood tests every 3-6 months and if haematocrit > 0.45 on 2 or more occasions then refer to haematology for a venesection programme.
What is the inheritance pattern of haemophilia A and B?
X-linked recessive
What is NICE guidance on management of a supected DVT
Clinical suspicion of a DVT = calculate a Wells Score.
If Wells score 2 or more = DVT likely = get a doppler USS within 4 hours OR if not possible then take a D-Dimer, commence anticoagulation and arrange USS within 24 hrs.
If scan is negative then take a D-Dimer (if haven’t already) -> if scan and d-dimer negative = v unlikely. if scan neg and D-Dimer positive then offer repeat USS in 6-8 days
If Wells score 0 or 1 - DVT unlikely = D-Dimer within 4 hours OR if not possible then commence anticoagulation and arrange D-Dimer within 24 hours. If D-Dimer is positive then USS within 4 hours / or commence anticoagulation and USS within 24 hrs.
Causes of microcytic anaemia?
1) Iron deficiency -> low iron, low ferritin, high TIBC
2) Thalassaemia -? high iron + ferritin, low TIBC
What is the typical presentation of hereditary spherocystosis?
Inherited haemolytic anaemia
= macrocytic anaemia, ^ reticulocytes, ^ LDH, ^ urinary urobilinogen, ^ mean corpuscular haemoglobin concentration, decreased haptoglobin
What antibody is associated with pernicious anaemia
Intrinsic factor antibodies
- > Vit b12 deficiency
- > macrocytic anaemia
Typical presentation of beta thalassaemia major?
in CHILDHOOD with failure to thrive and severe microcytic anaemia with high iron/ferritin + frontal bossing (=bossing in the skull) + hepatosplenomegaly
Tx = Desferrioxamine (iron-binder) + lifelong blood transfusions
Typical presentation of infective mononucleosis?
Sore throat symptoms + cervical lymphadenopathy + splenomegaly
Dx = monospot test -> heterophile antibodies
Causative agent = EPV
Which chromosomal abnormality is associated with chronic myeloid leukaemia?
Philadelphia chromosome (chromsome 9 and 22 translocation) = presents INSIDIOUSLY with MASSIVELY raised WCC count (>100)
Which clotting factor is deficient in haemophilia A?
Factor 8 (A for 8!!)
Which clotting factor is deficient in haemophilia B?
Factor 9
What investigations are suggestive of haemophilia?
^ APTT + factor 8 / 9 deficiency on assay
Desmopressin = can ^ factor 8 levels in haemophilia A
How should an abnormal INR be managed in a patient on warfarin?
If major bleeding on warfarin -> stop warfarin, give IV Vit K + IV prothrombin complex concentrate (or FFP if PCC not available)
If minor bleeding + INR > 5 -> stop warfarin + give IV Vitamin K. Resume warfarin when INR <5.
If no bleeding + INR >8 = stop warfarin + give oral Vitamin K
If no bleeding + INR 5-8 = suspend warfarin for 1-2 doses and then reduce ongoing maintenance dose
In what conditions are target cells seen on blood film?
iron deficiency anaema
Thalassaemia
Liver disease
after splenectomy
What condition shows Auer rods on bone marrow biopsy?
AML (acute myeloid leukaemia)
When are Rouleux formations seen on blood film?
Rouleux formations = clumps of red cells, seen in conditions associated with a high CRP/ESR
- infection
- Chronic inlammation / autoimmune disorders
- Myeloma