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Heamatology Flashcards

1
Q

What are the normal values for heamoglobin in men and women?

A

Normal heamoglobin value
Men: 13.5-17.5 g/dL
Women: 12-15.5 g/dL

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2
Q

What are the causes of microcytic aneamia? How do you differentiate between these causes?

A

Microcytic aneamia can be caused by Iron deficiency. Rarely, it can also be caused by Thalassaemia or Sideroblastic aneamia.
Suspect Thalasseamia if the MCV is ‘too low’ for the Hb level, and the red cell count is increased.
Both Thalasseamia and sideroblastic aneamia have an accumulation of iron, therefore there is an increase in serum iron, serum ferritin, and a low total iron binding capacity.

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3
Q

What are the symptoms and signs of aneamia?

A

Pallor, lethargy, excercise intolerance, SOB, tachycardia, palpitations, tinnitus, anorexia, possible angina

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4
Q

What are the causes of normocytic aneamia?

A
  • Acute blood loss
  • Aneamia of chronic disease
  • Bone marrow failure (low WCC, and low platlets)
  • Renal Failure
  • Hypothyroidism
  • Heamolysis
  • Pregnancy
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5
Q

What are the causes of macrocytic aneamia?

A
  • Folate of B12 deficiency
  • Hypothyroidism
  • Alcohol excess/liver disease
  • Reticulocytosis
  • Cytotoxics
  • Antifolate drugs
  • Myelodysplastic syndromes
  • Marrow Infiltration
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6
Q

What are the causes of iron deficiency aneamia?

A

Blood Loss: menorrhagia, GI bleeding
Diet: Poor diet in children, veganism, poverty
Malabsoprtion: Ceoliac disease
Hookworm

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7
Q

What are the signs of iron deficiency?

A

Koilonychia (spoon shaped nails), angular cheilosis, rarely post cricoid webs.

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8
Q

What results are found when investigating Iron deficiency aneamia?

A

Blood film shows microcytic, hypochromic aneamia with poikilocytosis and anisocytosis.
Low MCV, low MCH, low MCHC. Confirmed by low ferritin, decreased serum iron and increased serum total iron binding capacity.
If no obvious cause (eg menorrhagia) then consider gastroscopy, colonoscopy, stool microscopy for ova

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9
Q

How do you treat iron deficiency aneamia?

A

Treat the cause.
Then give Oral ferrous sulfate 200mg/8h PO. Hb should rise by a g/dL/week with a modest reticulocytosis. Continue until Hb is normal and then continue to give for 3 months to replenish stores. IV iron can be used in chronic renal failure.

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10
Q

What are the side effects of oral ferrous sulfate?

A

Nausea, abdo discomfort, diarrhoea or constipation, black stools

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11
Q

Discuss sideroblastic aneamia

A

Sideroblastic aneamia all have the presence of sideroblasts (RBCs with an accumulation of iron in the mitochondria producing a perinuclear ring of iron granules) and impaired heme production. It is characterised by ineffective erythropoesis, increased iron uptake, iron loading in the marrow and heamosiderosis (endocrine, liver, and heart damage due to iron deposition). It produces a microcytic aneamia.They can be genetic, or aquired. Causes of aquired sideroblastic aneamia includes drug or ethanol induced,myelodysplasia, or caused by nutritional deficiencies.

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12
Q

What is anisocytosis? In what conditions do you see it?

A

Anisocytosis is variation in RBC size. It is seen in in thalasseamia, megaloblastic aneamia, and IDA.

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13
Q

What are acanthocytes? In what conditions do you see them?

A

Acanthocytes are spicules on RBCs that are caused by unstable RBC membrane lipid structure. Causes of acnathocytosis include splenectomy, alcoholic liver disease, abetaliproteinaemia, spherocytosis.

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14
Q

What are blasts? In what conditions do you see them?

A

Blasts are nucleated precursor cells. They are not normally in peripheral blood, but are seen in myelofibrosis, leukeamia, or malignant infiltration by carcinoma.

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15
Q

What are Howell-Jolly bodies? In what conditions do you see them?

A

Howell-Joly bodies are DNA nuclear remnants in RBCs which are normally remove by the spleen. Howell-Joly bodies are seen post splenectomy, and in hyposplenism (eg. sickle cell disease, ceoliac disease, congenital, IBD). aLso seen in myelodysplasia and megaloblastic aneamia.

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16
Q

What causes hypochromia?

A

Hypochromia is less dense staining due to decreased Hb production, seen in IDA, thalasseamia, and sideroblastic aneamia.

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17
Q

What is poikilocytosis?

A

Poikilocytosis is variation in RBC shape. It is seen in IDA, myelofibrosis, and thalasseamia.

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18
Q

When do you see spherocytes?

A

Spherocytes occur in spherocytosis and autoimmune heamolytic aneamia.

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19
Q

What causes rouleaux cells?

A

Roleaux cells are seen in chronic inflammation, paraproteinaemia, and myeloma.

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20
Q

What are schistocytes? What causes them?

A

Schistocytes are fragmented RBCs slice by fibrin bands in intravascular heamolysis. Look for microangiopathic aneamia eg. DIC, heamolytic ureamic syndrome, thrombotic thrombocytopenic purpura, or pre-eclampsia.

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21
Q

What are target cells? In what conditions do you see them?

A

Target cells are also known as Mexican Hat cells. These are RBCs with central staining, a ring of pallow, and an outer rim of staining seen in liver disease, hyposplenia, thalassemia, and, in small numbers, in IDA.

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22
Q

What causes neutrophilia?

A

Neutrophils make up 40-75% of all WBCs. If neutrophils are > 2-7.5 x 10^9/L, then neutrophilia is present.
Neutrophilia is caused by:
-Bacterial infections
-Inflammation eg. myocardial infarction, polyarteritis nodosa
-Myeloproliferative disorders
-Drugs (steroids)
-Disseminated malignancy
-Stress eg. trauma, surgery, burns, heamorrhage, seizure.

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23
Q

What causes neutropenia?

A

Neutrophils make up 40-75% of all WBCs. If neutrophils are s syndrome)
-Bone marrow failure (decreased production)

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24
Q

What are neutrophils?

A

Neutrophils ingest and kill bacteria, fungi, and damaged cells.

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25
Q

What causes lymphocytosis?

A

Lymphocytes make up 20-45% of white blood cells. If lymphocytes> 1.5-4.5 x 10^9/L, then there is lymphocytosis. Lymphocytosis is caused by:

  • Acute viral infections
  • Chronic infections eg. hepatitis, TB
  • Leukaemias and Lymphomas, especially CLL
  • EBV
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26
Q

What causes lymphopenia?

A

Lymphocytes make up 20-45% of white blood cells. If WBC’s are <1.5-4.5 x 10^9/L, then there is lymphopenia. Causes of lymphopenia include:

  • Steroid therapy
  • SLE
  • Ureamia
  • Legionaires Disease
  • HIV (particularly CD4 T lymphocytes)
  • Marrow infiltration
  • Post chemotherapy or radiotherapy
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27
Q

What is hypereosinophilic syndrome?

A

The Hypereosinophilic Syndrome (HES) is a severe disease of unknown origin in which an increased eosinophil count (skin lesions, thromboembolic disease, lung disease, neuropathy, restrictive cardiomyopathy, hepatosplenomegaly.

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28
Q

What causes eosiniphilia?

A

Eosinophils mediate allergic reactions and defend against parasites. They make up 1-6% of white blood cells. Eosinophilia is caused by:

  • Drug reactions
  • Allergies (asthma, atopy)
  • Parasitic infections
  • Skin disease (especialyl pemphigus, eczema, psoriasis, and dermatitis herpatiformis,
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29
Q

Where do we get vitamin B12 from? How long is the body able to store it for?

A

Vitamin B12 comes from meat, fish, and dairy products. The body’s stores of vitamin B12 last approximately 4 years.

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30
Q

How is vitamin B12 metabolised?

A

Vitamin B12 is protein bound and released during digestion. B12 then binds to intrinsic factor in the stomach, and this complex is absorbed into the terminal ileum. In B12 insufficiency, synthesis of thymidine, and hence DNA, is impaired, so RBC production become reduced.

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31
Q

What are the features of vitamin B12 deficiency?

A

-General symptoms of anaemia
-‘lemon tinge’ to skin due to jaundice and pallor
-glossitis (beefy red sore tongue)
-Irritability, depression, dementia, psychosis
-Parathesia,peripheral neuropathy.
-Subacute Degeneration of the spinal cord: mixture of motor and sensory UMN and LMN signs.
Typically presents with falls at nighttime.

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32
Q

What is pernicious anaemia?

A

Pernicious anaemia is caused by an autoimmune atrophic gastritis, leading to achlorhydria and a lack of gastric intrinsic factor secretion, which leads to a decrease in absorption of vitamin B12. It usually occurs in women >40yrs.

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33
Q

What is your approach to diagnosing heamolytic aneamia?

A
  1. Is there increased breakdown of RBCs (aneamia with normal or increased RBCs, increased unconjugated bilirubin, increased LDH released from RBCs.)
  2. Is there increased Red Cell Production? (increased reticulocytes, causing increased MCV and polychromasia)
  3. Is the heamolysis mainly intravascular or extravascular ?
  4. Why is there heamolysis?
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34
Q

How do you tell if heamolysis is intra or extravascular?

A

Extravascular heamolysis may lead to splenomegaly. Invtravascular heamolysis causes increased free plasma Hb that is released from RBCs, decreased plasma haptogobin (mops up Hb and is excreted by the liver), heamoglobinuria (red-brown urine, heamosideruria (occurs when haptoglobin binding capacity is exceeded, causing free Hb to be filtered by renal tubiles and stored in the tubular cells as heamosiderin)

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35
Q

What sort of things do you want to know when taking a history for heamolysis? and examination

A

Hx: family history, race, jaundice, dark urine. drugs, previous aneamia, travel.
Exam: Jaundice, hepatosplenomegaly, gallstones (pigmented, due to increased bilirubin from heamolysis), leg ulcers (due to poor blood flow).

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36
Q

What tests would you order for heamolysis?

A
  • FBC
  • Reticulocyte count
  • Bilirubin (conjugated and unconjugated)
  • LDH
  • Haptoglobin
  • Urinary urobilogen
  • Thick and thin films for malaria screeing if travel hx.
  • Blood film
  • Direct Coombs test if autoimmune cause suspected
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37
Q

What findings might you see on a blood film for heamolysis that would point to a diagnosis?

A
  • Hypochromic microcytic aneamia (Thalasseamia)
  • Sickle Cells (Sickle cell aneamia)
  • Schistocytes (microangiopathic heamolytic aneamia)
  • Spherocytes (autoimmune heamolytic aneamia or spherocytosis)
  • Elliptocytes (heriditary elliptocytosis)
  • Heinz bodies/ bite cells (Glucose-6-Phosphate Dehydrogenase deficiency)
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38
Q

What is the difference between a direct coombs test and an indirect coombs test?

A

A direct coombs test measures antibodies attached directly to the RBCs. It is used in autoimmune heamolysis. An Indirect coombs test measures antibodies against RBCs that are free in the serum. It is used in prenatal testing and before blood transfusion. Both tests are positive when agglutination occurs.

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39
Q

How is a Direct coombs test conducted?

A

A blood sample is taken from the patient. If the patient has immune mediated heamolytic aneamia antibodies will be attached to the surface of RBCs.
The patient’s washed RBCs are incubated with antihuman antibodies (Coombs reagent). The antihuman antibodies will then bind to eachother and the RBCs will agglutinate. This is a positive test and means that there is immune mediated heamolysis.

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40
Q

How is an Indirect coombs test conducted?

A

The recipients serum is obstained, and contains antibodies (Ig’s). The doners blood sample is then added to the tube with the serum. The recipients Ig’s that target the donors RBCs form antibody-antigen complexes. Antihuman Igs (Coombs antibodies) are added to the solution.
Agglutination of the RBCs occurs because human Ig’s are attached to RBCs.

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41
Q

What are the hereditary causes of haemolytic anaemia?

A 
Enzyme Defects:
- G6PD deficiency
- Pyruvate Kinase deficiency
Membrane Defects: 
- Hereditary Spherocytosis
- Hereditary Elliptocytosis
Haemoglobinopathies:
-Sickle Cell Disease
-Thalasseamia
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42
Q

What are the acquired causes of haemolytic anaemia that are immune mediated coombs positive?

A

Immune Mediated Coombs Positive: Drug induced, autoimmune haemolytic anaemia (warm or cold), Paroxysmal cold Haemolytic anaemia, Acute transfusion reaction/ haemolytic disease of the newborn.

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43
Q

What are the acquired causes of haemolytic anaemia that are immune mediated coombs negative?

A

Autoimmune hepatitis, Post flu and vaccinations, drugs 9eg. piperacillin and rituximab).

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44
Q

What are the acquired causes of haemolytic anaemia?

A
  • Immune mediated (coombs positive and negative)
  • Microangiopathic haemolytic anaemia
  • Infection eg. Malaria
  • Paroxysmal Nocturnal Heamoglobinuria
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45
Q

What is G6PD deficiency?

A

Glucose 6 Phosphate dehydrogenase deficiency.
It is a hereditary x-linked RBC defect that is common in people from a Middle Eastern/African/Far East background. They may experience an oxidative crisis due to decreased glutathione production that can be precipitated by drugs (sulphonamides, aspirin), exposure to fava beans/broad beans, illness, or henna. During the attack there is rapid anaemia and jaundice with bite or blister cells . Bite or blister cells occur when the spleen removes Heinz bodies from the RBC. May need RBC transfusion if severe.

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46
Q

What is paroxysmal nocturnal haemoglobinuria?

A

Paroxysmal Nocturnal Heamoglobinuria is a rare stem cell disorder that causes heamolysis especially at night (and heamoglobinuria). It also causes marrow failure and thrombophilia. Visceral thrombosis (hepatic, mesenteric, and CNS veins) and pulmonary emboli are a poor prognostic indicator.

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47
Q

What is Microangiopathic haemolytic anaemia (MAHA)? What are its causes?

A

Microangiopathic haemolytic anaemia is a disruption in RBC’s that causes intravascular heamolysis and schistocytes.
Microangiopathic haemolytic anaemia can be caused by Heamolytic ureamic syndrome, DIC, pre-ecclampsia, and ecclampsia.
Treat the underlying disease. Transfusion or plasma exchange may be needed.

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48
Q

What are the different types of Autoimmune Haemolytic Anaemias?

A

Autoimmune Heamolytic Aneamias are mediated by autoantibodies causing mainly extravascular haemolysis and spherocytosis. Autoimmune haemolytic aneamias are classified by the temperature that the antibodies best bind at. There is warm and cold autoimmune mediated anaemia.

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49
Q

What is warm autoimmune haemolytic anaemia?

A

Warm autoimmune haemolytic anaemia is IgG mediated (binds at 37 degrees). Treat with steroids/immunosupressants.

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50
Q

What is cold autoimmune haemolytic anaemia?

A

Cold AIHA is IgM mediated. , binding at <4 degrees, activating cell complement. IgM mediated/cold haemolytic anaemia is worse when its cold, often with Raynauds or acrocytosis.
Caused by CLL, lymphoma, drugs, SLE, EBV, mycoplasma,

51
Q

What is sickle cell anemia/trait?

A

Sickle cell anaemia is an autosomal recessive disorder that causes production of abnormal B globin chains.(glu-> Val). The mutation results in the production of HbS instead of HbA. HbA2 and HbF are still produced normally. The homozygotes have sickle cell anaemia (SS) whereas the heterozygotes have sickle cell trait, which causes no disability except in hypoxic areas.

52
Q

Describe the pathogenesis of sickle cell anaemia.

A

HbS polymerises when deoxygenated, causing RBCs to deform. This produces sickle cells, which are fragile and haemolyse, and also block small blood vessels.

53
Q

What are the various complications of sickle cell anaemia?

A
  • Vaso-occlusive ‘painful’crisis (microvascular occlusion triggered by cold, dehydration,infection, or hypoxia. May affect bone marrow, cuase strokes, seizures, cognitive defects, avascular necrosis, mesenteric ischeamia).
  • Aplastic crisis. Triggered by parvovirus B19
  • Sequestration Crisis
54
Q

What is thalasseamia?

A

The thallasaemias are genetic diseases of unbalanced Hb synthesis, as there is underproduction (or no production) of one globin chain. Unmatched globins precipitate, damaging RBC membranes leading to their heamolysis whilst they are still in the marrow. Thalassaemias are common in the Mediterranean and Far East.

55
Q

Describe the structure of heamoglobin

A

Adult heamiglobin (HbA) is a tetramer of two alpha and two beta globin chains each containing a heam group. In the first year of life, adult haemoglobin replaces featal haemoglobin (HbF)

56
Q

What are the different types of heamoglobin

A
  • HbA (a2B2) makes up 97% adults blood.
  • HbA2 (a2d2) make up 2.5% adult blood, and found in trace amount of infant blood.
  • HbF (a2,y2) makes up 50-90% of infants blood, found in trace amounts in adults.
57
Q

What is beta-thalaseamia trait?

A

Beta thalasseamia trait is also known as beta thalasseamia minor. It is the B/B+ heterozygous genotype. Beta thalasseamia trait is a carrier and is usually asymptomatic. There is mild, well tolerated anaemia that may become a complication in pregnancy. Is often confused with iron deficiency anaemia.

58
Q

What is beta thalaseamia intermedia?

A

Beta thalaseamia intermedia describes an intermediate state with moderate anaemia but not requiring transfusions.There may be splenomegaly. There are a number of cases. These include mild homozygous B thalassaemia mutations (egB+/B+), or co inheritance of beta thalaseamia trait with another heamoglobinopathy (eg. HbC thalaseamia. Sickle cell thalaseamia produces a similar picture to sickle cell anaemia.

59
Q

What is Beta Thalasseamia Major?

A 
Beta thalasseamia major is also known as Cooley's anaemia. It denotes abnormalities in both beta globin genes, and presents in the first year with severe anaemia and failure to thrive.
Extramedullary haematopoiesis (RBCs made outside the bone marrow) occurs in response to the anaemia, causing skull bossing and heptosplenomegaly (also due to heamolysis). There is also osteopenia. Lifelong transfusions are required resulting in iron overload/deposition, seen after ~10 years as endocrine failure, liver disease, and cardiac toxicity. There is increased HbF, HbA2 is variable, and HbA is absent.
60
Q

How do you treat beta thalasseamia major?

A

Promote fitness and healthy diet.
Folate (+carnitine) supplements help.
2-4 weekly blood transfusions to supress extramedullary heamotopoiesis.
Iron chelators to prevent iron overload
Large doses of ascorbic acid to increase urinary secretion of iron
Splenectomy
Hormone replacement for endocrine complications
A histocompatible marrow transplant can offer chance of cure.

61
Q

What are the alpha thalasseamias?

A

There are two separate alpha globin genes on each chromosome 16. There are four genes (aa/aa). The alpha thalasseamias are mainly caused by gene deletions. If all four genes are deleted (–/–), death is in utero (Bart’s hydrops). HbH disease occurs if three genes are deleted (–/-a). In HbH there may be moderate anaemia and features of haemolysis such as hepatosplenomegaly, leg ulcers, and jaundice.
With two genes deleted (–/aa, or -a/-a), there is an asymptomatic carrier state, with decreased MCV. With one gene deleted, the clinical state is normal.
In the blood film, there is formation of b4 tetramers (=HbH) due to excess B chains, HbBarts, HbA, and HbA2.

62
Q

After injury, what are the three factors that stop bleeding? How do disorders in these factors affect bleeding?

A

Vasoconstriction, gap plugging by platelets, and the coagulation cascade.
Vascular and platelet disorders lead to prolonged bleeding from cuts and bleeding into the skin (easy bruising and purpure), and bleeding from mucous membranes (eg. epistaxis, bleeding from gums, menorrhagia). Coagulation disorders cause delayed bleeding into joints and muscle.

63
Q

What are the bleeding disorders caused by vascular defects?

A

Bleeding disorders caused by vascular defects can be either congenital or acquired.
Congenital: Olser-Weber-Rendu syndrome, Connective tissue disease (eg. Ehlers-Danlos syndrome),
Acquired: Senile purpure, infection (meningococcal, measles, dengue fever), steroids, scurvy, henoch Schlein purpure, painful bruising syndrome

64
Q

What are the bleeding disorders caused by platelet disorders?

A

Decreased marrow production: aplastic anaemia, megaloblastic anaemia, marrow infiltration, marrow suppression
Excess destruction: immune thrombocytopenic purpura, thrombotic thrombocytopenic purpura, haemolytic ureamic syndrome, , other autoimmune causes (SLE, CLL, drugs)
Poorly functioning platelets: NSIADS, increased urea, myeloproliferative disease.

65
Q

What are the bleeding diseases caused by coagulation disorders?

A

Congential causes include Heamophilia and Von Willebrand’s Disease.
Acquired include anticoagulants, liver disease, DIC, and platelet deficiency.

66
Q

What is haemophilia a?

A

Heamophilia a is a factor VIII deficiency, an inherited x linked recessive disorder. there is a high rate of new mutations (30% have no family history). Presentation is often early in life or after surgery with bleeds into joints leading to crippling arthropathy, and into muscles causing haematomas. Ix: Increased APTT and decreased factor VIII assay. Rx: desmopressin or factor VIII

67
Q

What is haemophilia b?

A

Heamophilia b is also known as Christmas disease. It is a factor IX deficiency and behaves clinically like factor VIII.

68
Q

What is tissue plasminogen activator?

A

tissue plasminogen activator (tPa) is released from endothelial cells when fibrin is formed. tPa converts inactive plasminogen to plasmin which can then cleave fibrin, as well as several other factors.

69
Q

What is Prothrombin Time?

A

When measuring Prothrombin time, thromboplastin is added to test the extrinsic system. PT is expressed as a ratio and is compared to a control (INR).

70
Q

What clotting factors does PT test?

What causes a prolonged PT?

A

PT tests for clotting factors 1,2,5,7,and 10.

It is prolonged by warfarin, vitamin K deficiency, liver disease, and DIC.

71
Q

What is the normal value for INR?

A

The normal value for INR is 0.9-1.2

72
Q

What is an activated partial thromboplastin time?

A

In an APTT, Kaolin is added to test the intrinsic systems. APTT test for factors 1,2,5,7,8,9,10,11,12.

73
Q

What is the normal range of APTT?

A

The normal range of APTT is 35-45.

74
Q

What are the causes of a prolonged APTT?

A

APTT is prolonged by heparin, haemophilia, liver disease, and DIC

75
Q

What is thrombin time?

A

Thrombin is added to plasma to convert fibrinogen to fibrin. Normal range is 10-15 seconds. It is prolonged by heparin treatment, DIC, dysfibrinogenaemia.

76
Q

What is the bleeding time?

A

The bleeding time tests haemostasis. It is done by making two small incisions into the skin of the forearm. Normal time to haemostasis is less than 10 mins. NB: this is rarely done. Consider the PFA 100 (platelet function analyser 100) instead

77
Q

What is a d dimer?

A

D-dimers are a fibrin degradation product, released from cross linked fibrin during fibrinolysis. This occurs in DIC, or in the presence of venous thromboembolism. D dimers may also be raised in inflammation eg. with infection or malignancy.

78
Q

What results would you expect to see when investigation bleeding caused by heparin?

A 
INR: Increased
APTT: Greatly Increased
TT: Greatly Increased
Platelet Count: Normal
Bleeding Time: Normal
79
Q

What results would you expect to see when investigation bleeding caused by DIC?

A 
INR: Greatly Increased
APTT: Greatly Increased
TT: Greatly Increased
Platelet Count: Decreased
Bleeding Time: Increased
D-Dimer: Increased
80
Q

What results would you expect to see when investigation bleeding caused by liver disease?

A 
INR: Increased
APTT: Increased
TT: Normal/Increased
Platelet Count: Normal/Decreased
Bleeding Time: Normal/Increased
Increased ALT (and deranged LFTs, decreased albumin)
81
Q

What results would you expect to see when investigation bleeding caused by a platelet defect?

A 
INR: Normal
APTT: Normal
TT: Normal
Platelet Count: Normal or decreased
Bleeding Time: Normal/Increased
82
Q

What results would you expect to see when investigation bleeding caused by Heamophilia?

A 
INR: Normal
APTT: Greatly Increased
TT: Normal
Platelet Count: Normal
Bleeding Time: Normal
83
Q

What results would you expect to see when investigation bleeding caused by von Willebrands?

A 
INR: Normal
APTT: Increased
TT: Normal
Platelet Count: Normal
Bleeding Time: Increased
84
Q

What the difference between a group and hold, and crossmatching?

A

A group and Save involves determining a patients ABO blood group and screening the patients serum for antibodies to common red cell antigens that cause transfusion reactions. In addition to this, cross matching involves mixing a sample of the patients blood with the donor blood to see if a reaction occurs. A Group and hold should be ordered if it is unlikely that the patient will need blood. This will reduced the amount of time required if the patient does end up needing a blood transfusion.
NB: there are more than 12 blood group antigens eg ABO, Rhesus, Duffy, Kid, Diego MNS, Kell

85
Q

Discuss the use of RBC transfusions

A

RBCs are used to correct anaemia and blood loss. One unit increases haemoglobin by 1-1.5g/dL.. In anaemia, transfuse until Hb is 8g/dL, or 10g/dL in heart failure.
If stored for too long, there is a decrease in the amount of 2,3, DPG.

86
Q

Discuss the use of platelet transfusions.

A

Platelets are not usually needed unless the patient is bleeding, or their platelets are below <50 x 10^9 and they have microvascular bleeding.
ABO compatibility is preferred but not required when using platelets. However, rhesus compatability is necessary in children and women of childbearing age.

87
Q

Discuss the use of fresh frozen plasma.

A

Contains clotting factors, albumin, and antibodies. Fresh frozen plasma is used to correct clotting defects eg DIC, warfarin overdose where vitamin K would be too slow, liver disease, TTP.
FFP must be used immediately after thawing, and must be ABO compatible.

88
Q

What are the complications of transfusion?

A

Early: acute haemolytics reactions, bacterial contamination, febrile reactions, allergic reactions, fluid overload, transfusion related acute lung injury (TRALI , ARDS due to anti-leucocytes antibodies in donor plasma).
Delayed: Infections, iron overload, graft-versus-host disease, post transfusion purpure.

89
Q

How does low molecular weight heparin work? Give some example of LMWH

A

Low molecular weight heparin is given SC. It has a long half life. LMWH works by activating antithrombin III. It forms a complex that inhibits factors Xa. Side effects include bleeding. It has a lower risk of HITs and osteoporosis. Although it is not routinely monitored, if it is monitored it is done so using Anti-factor Xa. It is the standard heparin used for prophylaxis, acute coronary syndrome, and VTE treatment.

90
Q

How does unfractionated heparin work?

A

UFH is given via IV. It has a short half life. UFH works by activating antithrombin III. It does so by inhibiting factors Xa, IXa, XIa, XIIa. Side Effects include HITs, Bleeding and Osteoperosis. Monitor using APTT.
UFH is useful in situations where there is a high risk of bleeding as anticoagulation can be terminated rapidly.

91
Q

What are the adverse effects of using heparin?

A

There is increased bleeding (eg surgical sites, GI, intracranial), heparin induced thrombocytopenia (HIT), and osteoporosis with long term use. HIT and osteoporosis are less coming with LWMW heparin than UFH. both types of heparins can cause hyperkalaemia.

92
Q

What is the mechanism for warfarin?

A

Warfarin inhibits the reductase enzyme responsible for regenerating the active form of Vitamin K, producing a state analogous vit K deficiency.

93
Q

What are the contraindications for warfarin?

A

Preganancy, peptic ulcer, severe hypertension, bleeding disorders.

94
Q

What are Fondoparinux and dibigatran?

A

Fondaparinux is a pentasacharidde Xa inhibitor and may be used in place of LMWH for prophylaxis in certain situations. Factor Xa inhibitors (rivaroxaban and apixaban and direct thrombin inhibitors (dibigatran) are new oral anticoagulants that do not need monitoring, but they have not yet displaced warfarin.

95
Q

What is a Reed-Sternberg Cell?

A

Reed Sternberg cells are most classically associated with Hodgekin’s lymphoma, however they also occur in other conditions. They are generally clonal B cells found in the lymph node. Reed Sternberg cells are very large with abundant pale cytoplasm and two or more oval lobulated nuclei containing large nucleoli.

96
Q

What is Hodgekin’s Lymphoma?

A

Hodgekin’s Lymphoma is a malignant proliferation of lymphocytes characterised by the presence of Reed Sternberg cells. It has bimodal age distributions with the most common being in the third and seventh decade. B symptoms imply a poor prognosis:

  • Weight loss >10% is last 6 months
  • Fever >38 degrees
  • Night sweats
97
Q

What are the different types of Hodgekin’s Lymphoma?

A 
Nodular Sclerosing (most common 70%)
Mixed Cellularity (~20%)
Lymphocyte predominant (Best prognosis)
Lymphocyte depleted (Worse prognosis)
98
Q

What is tumour lysis syndrome?

A

Tumour Lysis syndrome occurs as a result of cell breakdown after chemotherapy. It releases a large amount of intracellular components such as phosphate, potassium, and uric acid, low calcium. May lead to renal impairment. Tumour lysis syndrome can be prevented with a high fluid intake and allopurinol

99
Q

What is Burkitt’s lymphoma?

A

Burkitt’s Lyphoma is a high grade B cell neoplasm. There are two types:
- Endemic (African) form: involving maxilla and mandible, rare.
- Sporadic form: Abdominal tumours (eg. ileo-ceacal) that is more common in HIV.
Management is with chemotherapy. Burkitt’s lymphoma has a high risk of Tumour Lysis Syndrome.
Associated with c-myc gene translocation.

100
Q

What is seen on blood film in megaloblastic anaemia?

A

Hypersegmented neutrophils

101
Q

What is seen on blood film post splenectomy?

A

Target cells, Howell-Jolly bodies, Pappenheimer cells, acanthocytes

102
Q

Which cancers have the Philadelphia Chromosome?

A

The Philadelphia Chromosome t(9:22) is present in 95% of CML cases, and in 25% of adult acute lymphoblastic leukeamias. It is a poor prognostic indicator in ALL.

103
Q

What is HITs? How is it treated?

A

HITs is heparin induced thrombocytopenia. Despite being associated with low platelets, HITs is actually a prothrombotic condition. It develops 5-10 days after heparin, and occurs due to antibody formation that activates the platelets. It features a 50% reduction in platelets, thrombosis and skin allergy. Treat using anticoagulants such as danaparoid.

104
Q

How do you treat a heparin overdose?

A

Treat a heparin overdose using protamine sulphate. However, this only partially reverses the effect of LMWH.

105
Q

How do you assess a patient presenting with a probable DVT?

A

Assess using Wells score (risk of DVT eg. cancer, travel, surgery, oedema, swelling > 3cm, collateral veins, tenderness, hx of DVT).
Use a proximal leg vein ultrasound scan within 4 hours to rule in, and a d-dimer to rule out.
Tx: Using warfarin and LMWH/fondaparinux. Continue LMWH/fondaparinux until warfarin reaches INR of >2. Continue warfarin for 3-6 months.

106
Q

What is polycythemia rubra vera?

A

Polycythemia rubra vera is a myeloproliferative disorder that is caused by clonal proliferation of the bone marrow stem cells leading to an increase in Red Cell volume, as well as an increase in neutrophils and platelets. JAK2 mutation is present in 95% of cases. It occurs most commonly in the sixth decade.
Features include hyperviscosity, pruritis (especially after a bath), spenomegaly, plethoric appearance, bleeding secondary to dysfunctional platelets, and hypertension in 1/3 of patients.

107
Q

How do you treat Von Willebrands Disease?

A
  • tranexamic acid for mild bleeding
  • desmopressin (DDAVP): raises levels of vWF by inducing release of vWF from Weibel-Palade bodies in endothelial cells
  • factor VIII concentrate
108
Q

What is Von willebrand’s disease?

A

Von Willebrand’s disease is the most common inherited bleeding disorder. The majority of cases are inherited in an autosomal dominant fashion and characteristically behaves like a platelet disorder i.e. epistaxis and menorrhagia are common whilst haemoarthroses and muscle haematomas are rare. Upon investigation there is a prolonged bleeding time, APTT may be prolonged, factor VIII levels may be moderately reduced, defective platelet aggregation with ristocetin
There are three types:
•type 1: partial reduction in vWF (80% of patients)
•type 2: abnormal form of vWF
•type 3: total lack of vWF (autosomal recessive

109
Q

What is the role of Von Willebrand factor?

A

Role of von Willebrand factor
•large glycoprotein which forms massive multimers up to 1,000,000 Da in size
•promotes platelet adhesion to damaged endothelium
•carrier molecule for factor VIII

110
Q

What are the causes of thrombophilia?

A

Inherited: Protein C deficiency, Protein S deficiency, antithrombin III deficiency, activated protein C resistance (factor V Leiden).
Acquired: Antiphospholipid syndrome, the pill

111
Q

What is myeloma?

A

Myeloma is a malignant proliferation of B-lymphocyte derived plasma cells. Normally, many different plasma cells produce different immunoglobins (Igs) which are polyclonal. In myeloma, a single clone of plasma cells produces identical Ig, seen as an identical monoclonal band, or paraprotein, on serum or urine electrophoresis. The peak incidence occurs in patients aged 60-70. 2/3s of cases are IgG, 1/3is IgA.

112
Q

What are the clinical features of myeloma?

A

Features of myeloma include:

  • Bone Pain, Osteoperosis, Osteolytic lesions (particularly in the vertebrae)
  • Kidney Disease (due to light chain deposition in the Tamm-Horsfall protein in the distal loop of Henle)
  • Bacterial Infection
  • Lethargy
  • Hypercalceamia (from increased osteoclast activity signalled via myeloma cells)
  • Amyloidosis (eg. macroglossia, carpal tunnel syndrome, neuropathy, hyperviscosity)
  • Aneamia, neutropenia, or thrombocytopenia from marrow infiltration.
113
Q

What are the tests for myeloma?

A

FBC: normocytic, normochromic anaemia. Film: Roleaux
Increased ESR, Urea, Creatinine, and Calcium
X rays show punched out lesion eg. pepper pot skull, vertebral collapse, osteoporosis
Serum and urine electrophoresis show monoclonal antibodies (Bence-Jones Proteins)
Increased plasma cells in bone marrow.

114
Q

What is the typical presentation of Chronic Myeloid Leukeamia? How do you treat it?

A

CML typically presents in ages 40-70 years (middle aged)
Presents with lethargy, anaemia, abdominal pain
Gross Splenomegaly
Increased myeloid cells at all stages of maturation.
Decreased leucocytes alkaline phosphatase.
t(p:22) translocation
Treat: First Line: Imatinib (tyrosine kinase inhibitor)
Also, hydroxyurea, interferon alpha, allogenic bone marrow transplant.

115
Q

What are the myeloid cells?

A

Myeloid cells are cells that are not lymphocytes. They include:

  • Megakaryoctes, thrombocytes/platelets
  • Erythrocytes/RBCs
  • Mast Cells
  • Myeloblasts: basophils, neutrophils, eosinophils, monocytes -> macrophages
116
Q

What is CLL?

A

Chronic lyphocytic Leukaemia is caused by a malignant monoclonal proliferation of a well differentiated lymphocyte which are almost always B cells. Often presents with no symptoms, but may have bleeding, anorexia, weightloss, infections, and lymphadenopathy. Smudge cells on blood film. Increased lymphocytes of FBC. Later may have decreased Hb, platelets, and neutrophils.

117
Q

What are the complications of CLL?

A

Hypogammaglobinaemia (low Ig) leading to infection (often cause of death)
Warm autoimmune heamolysis
Marrow Failure
Transformation to high grade lyphoma

118
Q

What are the complications of hereditary spherocytosis?

A
  • Gallstones
  • Jaundice
  • Splenomegaly
  • aplastic crisis precipitated by parvovirus infection
119
Q

What are the causes of polycythemia?

A

Polycythemia may either be relative, primary or secondary.
Relative: dehydration, Stress (Gaisbock syndrome)
Primary: Polycythemia rubra vera
Secondary: COPD, altitude, OSA, Increased EPO: Hepatomas, hydronephromas, uterine fibroids, cerebellar heamangioma

120
Q

What is Thrombotic Thrombocytopenic Purpura (TTP)?

A

TTP is a potential diagnosis in any patient with anaemia and thrombocytopenia. It is fatal if untreated. Symptoms of TTP are usually non specific. It is classically described as having the pentad of: Microvascular haemolytic anaemia, thrombocytopenia, neurological damage, renal damage, and fever. Blood film shows shistocytes. It is caused by the absence of ADAMS T13, which then fails to cleave Von Willebrand factor leading to large multimers that cause platelet aggregation, thrombocytopenia, and microthrombi. Tx with plasma exchange therapy.

121
Q

What is Heamolytic Ureamic Syndrome (HUS)?

A

Heamolytic ureamic syndrome is very similar to TTP, but with more severe renal involvement and generally occurs in children after an acute viral illness (eg. gastroenteritis from E.Coli).
HUS is characterised by microvascular haemolytic anaemia, thrombocytopenia, and nephropathy. Adequate hydration is necessary to minimise risk of renal impairment. Aneamia can be treated with RBC transfusion. Avoid platelet transfusions and NSAIDs.

122
Q

What is Immune Thrombocytopenic Purpura (ITP)?

A

Primary Immune Thrombocytopenic Purpura (ITP) used to be known as idiopathic. It is characterised by isolated thrombocytopenia in the absence of other causes. It is secondary to an autoimmune antibody mediated destruction of peripheral platelets, and suppression of normal megakaryocyte development. Px with petechiae, minor mucocutaneous bleeding. tx with IVIg and platelet transfusion.

123
Q

What is Henoch Schlein Purpura?

A

HSP is a common VASCULITIS of childhood that affects the small vessels. A rash of palpable purpure is present in all cases. Presents with the triad of:

  • Palpable purpuritic rash
  • Abdo pain
  • Arthalgia/arthritis
  • glomerularnephritis.

Medicine (16 decks)

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