Haematology Flashcards

Question

Risk factors for VTE - pre-existing

Answer 1

``` Thrombophilia Medical co-morbidities (e.g. cancer, heart failure, SLE, diabetes) >35y Obesity Parity >3 Smoker Paraplegia Varicose veins ```

Answer 2

``` Multiple pregnancy PET CS Prolonged labour Stillbirth PTB PPH Placental abruption ART ```

Answer 3

``` Hyperemesis OHSS Immobility Sepsis Long distance travel ```

Answer 4

Recommendations based on consensus /expert opinion rather than good evidence 50% of antenatal VTE occurs in 1st and 2nd trimester Lower threshold for commencement of prophylaxis post-partum Antenatal - assess for VTE risk - If >/= 3 of the risk factors, prophylaxis from first trimester - If >2 risk factors, prophylaxis if inpatient

Answer 5

Low SES Short interpregnancy interval Previous anaemia or PPH <18y

Answer 6

Most common cause of anaemia Increased iron requirements in pregnancy due to expanding red cell mass and increasing fetal requirements Increased demands for iron --> increased intestinal absorption + iron mobilised from Hb of circulating red cells Many women enter pregnancy with deplete iron stores More common in multiple pregnancy In women from developing countries, consider intestinal infestations (e.g. Hookworm, Giardia, Tapeworm, Schistosomiasis) Effect of iron deficiency on pregnancy: - LBW - PTB - Increased blood loss at delivery

Answer 7

Macrocytic anaemia with megaloblastic change in bone marrow - Normal dietary folate is inadequate to prevent changes in ~25% Requirements increase in pregnancy due to: - Increased red cell mass - Expanding feto-placental unit - Increase in cell replication taking place in the fetus, uterus and bone marrow Incidence variable depending on the SES and nutrition More common if taking anti-epileptic drugs or other folate antagonists (e.g. sulfasalazine)

Answer 8

``` Iron deficiency Folate deficiency Vitamin B12 deficiency Haemoglobinopathies Chronic disease Haemolysis ```

Answer 9

- Women with NTD or with previous child with NTD - Meds - sodium valproate, AEDs, sulfasalazine - Women with congenital / hereditary spherocytosis, sickle cell disease, haemolytic anemia, thalassaemia - Known malabsorption syndrome - Proven folate deficiency

Answer 10

Macrocytic anaemia with megaloblastic change in bone marrow Vitamin B12 decreases in pregnancy - But rarely ever biochemical vitamin B12 deficiency Less common Most commonly due to dietary deficiency, IBD, pernicious anaemia

Answer 11

Acts to stimulate the bone marrow to make red cells Mainly used in IDA a/w renal failure Can be used where blood transfusion has been declined Need to give with iron

Answer 12

Sickle cell - disorder of haemoglobin structure | Thalassaemia - disorder of Hb synthesis

Answer 13

Point mutation in beta-globin gene --> defective HbA RBCs can take the shape of a crescent (sickle) when in de-oxygenated state - Can more easily be destroyed --> anaemia - aggregates with other HbS --> sickling Sickling promoted by: - Acidosis - Low flow vessels Repeated sickling --> weakened cell membrane --> intravascular haemolysis - low haptoglobin level as sign of haemolysis - Increased unconjugated bilirubin Sickle blood cells --> vaso-occlusion Infarcts spleen --> susceptible to encapsulated bacteria

Answer 14

Inheritance - Autosomal recessive Sickle cell carrier / trait - No health problems unless exposure to extreme conditions, e.g. altitude or dehydration - Decreases severity of some malaria = beneficial Homozygous - chronic haemolytic anaemia - periods of sickling crisis - premature death

Answer 15

``` Increased risk: - FGR - VTE / PE - Miscarriage - PET - Abruption - CS - Infection / sepsis - hyposplenism Sickling infarcts in the placenta Crises occur more commonly in pregnancy 35% of women who are pregnant with SCD ```

Answer 16

Evaluate risk - Screen for end organ damage. Counsel on outcomes - Partner needs to be screened and genetic counselling Optimise before pregnancy - Hydroxycarbimide used to prevent crises is teratogenic so should be stopped prior to pregnancy - Check for iron overload Advice re avoiding crises - cold, hypoxia, over-exertion and stress Aspirin in pregnancy Supplements Folic acid 5mg OD Routine antenatal care - Booking bloods and vaccines - Vaccination advice as per hyposplenic patients - Hep B, influenza, meningococcal, H influenzae

Answer 17

``` MDT care Uterine artery dopplers + serial growth scans BP and urinalysis with every visit. Penicillin prophylaxis (250mg BD) MSU at every visit ``` Increased risk of VTE Monitor for anaemia with Hb at every visit Avoid precipitating factors to crises such as cold, dehydration, stress. Crises should be managed aggressively - Admission, analgesia, rehydration, early use of antibiotics, kept warm and well-oxygenated. Severe anaemia, acute chest, stroke or splenic sequestration should be treated with blood transfusion or exchange transfusion - Routine exchange transfusion not recommended Deliver by 38-40 weeks Deliver in tertiary unit with appropriate specialist support CEFM - Increased risk of c-section and abruption

Answer 18

Autosomal recessive Reduced globin chain synthesis (beta in beta-thalassaemia with excess of faulty alpha, and alpha in alpha-thalassaemia with excess of faulty beta) --> red cells with insufficient haemoglobin levels Ineffective red cell production --> release of damaged red cells into the peripheral circulation --> extravascular haemolysis

Answer 19

Severity correlates with the number of affected alpha globin genes 1 - alpha thalassaemia trait 2 - alpha thalassaemia minor - Mild microcytic hypochromic anaemia - In pregnancy, can give po iron if iron deficient 3 - haemoglobin H disease - Microcytic hypochromic anaemia - Heinz bodies - Pregnancy:- Folic acid 5mg/day, Transfusions may be offered to correct anaemia 4 - Haemoglobin Barts --> IUFD

Answer 20

Beta globin chain deficiency --> clumping of free alpha chains --> damage RBC membrane --> - Haemolysis --> iron (causes secondary haemochromatosis) and unconjugated bilirubin (causes jaundice) - Extravascular haemolysis in the spleen Thalassaemia trait or minor Thalassaemia intermedia Thalassaemia major

Answer 21

Most common and most severe form of beta thalassaemia Iron overload Haemochromatosis --> arrhythmias, pericarditis, cirrhosis, hypothyroidism, diabetes Diagnosis: - Low Hb, MCV - Blood smear - microcytic, hypochromic, target cells - Diagnosis confirmed with Hb electrophoresis = low HbA, increased HbF and HbA2 Present within first 2y of life - Usually at 3-6 months when switch from HbF to HbA occurs Treatment: - Requires lifelong blood transfusion - chelation therapy - Splenectomy

Answer 22

Chelating agents are contraindicated in pregnancy Require extra transfusions when pregnant --> increased risk of iron overload ``` Assess organ damage Folic acid 5mg/day MDT - obs, haematology Partners should be tested Avoid iron supplementation Monitor feta growth Increased incidence of red cell antibodies because of number of previous transfusions (~15%) Check TFTs - frequently hypothyroid VTE prophylaxis Cardiac failure is the primary cause of death ``` Most women subfertile - require OI ECHO at 28/40 - risk of cardiomyopathy

Answer 23

Daughters are obligate carriers May have reduced levels of factor VIII or IX - 1/3 May have bleeding tendency - e.g. dental work, surgery During pregnancy, FVIII levels rise, therefore no bleeding problems occur - However fall dramatically within 48h of delivery, therefore risk of secondary PPH FIX levels do not rise, therefore may need factor replacement during labour Consider cfDNA to reduce need for invasive testing Factor VIII levels should be checked before invasive procedures If male fetus - Deliver at tertiary centre for NICU support - Avoid FBS, forceps, ventouse, FSE - Elective CS does not eliminate risk of ICH If female fetus Delivery at tertiary centre if women is a carrier of severe factor VIII or IX deficiency

Answer 24

Affects up to 1% of population Autosomal dominant vWF = plasma protein - Stabilises factor VIII - Adheres platelets to injured vessel walls Diagnosis - prolonged APTT and low vWF - vWF and FVIII both increase in pregnancy, therefore difficult to diagnose - Refer to haem PP

Answer 25

Pre-conception - Assess type of vWD and if they respond to desmopressin (DDAVP) - Genetic counselling - Discuss potential risks of pregnancy and delivery Antenatal: - Prenatal testing (with haemostatic cover if required) - Von Willebrand screen in 1st and 3rd trimester - Anaesthetic assessment - Consider haemostatic correction before invasive testing Intrapartum - Avoid FSE, FBS, ventouse, rotational forceps - CS only for normal obstetric reasons - Baby's vWF levels increase at delivery / in response to stress - IV access, FBC, G&H - Avoid IM infections if abnormal vWF levels - Liaise with haematology - DDAVP, factor support, TXA (TXA 5/7 PP) - Active third stage Neonatal alert - Cord blood to diagnose vWD

Answer 26

``` Spurious result - repeat the test Gestational thrombocytopenia (75%) PET (15-20%) Infection DIC Thrombotic thrombocytopenia purpura Acute fatty liver APS / SLE Idiopathic immune thrombocytopenic purpura (ITP) ```

Answer 27

Isolated low plt count with normal bone marrow and absence of other causes of thrombocytopenia Autoantibodies against platelet surface antigen cause peripheral platelet destruction 2 in 10,000 pregnancies Purpuric rash Increased tendency to bleeding

Answer 28

``` Diagnosis of exclusion Examination of peripheral blood film U&E, urate LFTs +/- LDH, reticulocytes and direct Coombs test if haemolysis is suspected Coags Lupus anticoagulant, anticardiolipin antibodies, antinuclear antibodies Virology screen - TORCH, EBV, HIV +/- malaria ``` Thrombocytopenia in the first half of pregnancy is more likely to be ITP

Answer 29

``` Usually conservative / observation If very low: - Corticosteroids - IV immunoglobulin - Immunosuppressive drugs (cyclosporin) ``` Refractory ITP may require splenectomy - If have had, then should have penicillin prophylaxis in pregnancy Aim for plt >80x109/l at delivery - >50x109/l - safe of CS or normal delivery, but >80 required for epidural / spinal (d/w anaesthetics) Avoid ventouse Caution with FBS and forceps Cord bloods for platelet count - Avoid IM vitamin K if low Small risk of PPH f/u as per haematology

Answer 30

Risk of neonatal platelet count <50 is 5-15% Non-immune thrombocytopenia (NAIT) Neonatal autoimmune thrombocytopenia - Occurs if mothers have ITP or SLE - Antibodies directed against platelets - Clinical manifestations less severe than NAIT - NB: Platelet nadir occurs at day 5

Answer 31

Both are manifestations of microvascular platelet aggregation Common features are thrombocytopenia and microangiopathic haemolytic anaemia Thrombotic thrombocytopenic purpura - systemic and extensive, particularly CNS involvement Haemolytic Uraemic syndrome - Predominantly affects kidneys No effect on foetus Similar presentation to PET but no HTN Treatment = supportive +/- steroids +/- plasmaphoresis Don't deliver foetus

Answer 32

Benign, self-limiting condition Most common at delivery, can occur at any time Mild thrombocytopenia - Rarely <70x109/l Diagnosis confirmed when plt normalises outside of pregnancy

Answer 33

incidence of non-fatal DVT and PE in pregnancy is 0.1% - 75% DVT, 25% PE - RR of VTE in pregnancy is increased 4-6 fold (further increase PP - up to 20-fold) Risk of DVT after CS 1-2% If DVT remains untreated, ~20% will develop PE PE may be fatal in almost 15%

Answer 34

Those with prior VTE and - Anti-thrombin deficiency - APS - Recurrent unprovoked VTE --> treatment dose clexane AN + 6 weeks PN Also FHx of VTE but no personal Hx with antithrombin deficiency Others - standard prophylactic dose AN + 6 weeks PN - prev VTE, recurrent provoked VTE, single unprovoked VTE FHx of VTE but no PMHx, with weak lab thrombophilia (FVL heterozygous, Prothrombin heterozygous) - observe, consider PN prophylaxis FHx of VTE but no PMHx, with significant thrombophilia (FVL homo, protein C or S deficiency, FVL + PT mutation) - consider AN prophylaxis if risk factors, given PN

Answer 35

5 days - All women who have emergency CS - 2 major risk factors or 1 major + 2 minor Major - CS - BMI >30 - Immobile - comorbidity - PET - Sepsis Minor - >35y - Prolonged labour - Smoker - PPH - Extensive perineal trauma - Varicose veins BMI >40 should have 10 days

Answer 36

Lumps and itching at the injection site - May be due to technique or allergy Heparin induced thrombocytopenia --> pro-thrombotic state - Check FBC on commencement and 7-10 days later - HIT risk is substantially lower than with UFH Osteoporosis - Only reported with therapeutic doses - More common with UFH

Answer 37

Full length compression stockings Should be worn in the acute period and for 12/12 after the event to reduce the incidence of post-thrombotic syndrome LMWH - Consider BD dosing because increased renal clearance in pregnancy - Treatment should continue for the remainder of pregnancy and at least 6/52 PN and until at least 3/12 of treatment has been given in total It takes 2-3 weeks for a clot to organise - Consider insertion of IVC filter if birth is imminent and risk of bleeding is significant and would contraindicate LMWH / UFH If women very high risk of thrombosis, can use UFH peripartum

Answer 38

LMWH is preferred as: - It has a lower risk of heparin-induced thrombocytopenia - It doesn’t require routine monitoring, unlike UFH - Patient can be taught to self administer - Lower risk of osteoporosis and bone fractures - LMWH has a longer half life than UFH so can be OD or BD dosing

Haematology Flashcards

(62 cards)