meh haem bb quiz and SM Flashcards
How much folic acid should the woman take each day
400 micrograms
A 65 year old woman is prescribed indapamide (a diuretic drug) to treat hypertension. At her 6 month medication review the doctor notes from her blood results that an apparent polycythaemia has been reported by the lab.
What would the haematocrit and plasma volume be in this patient?
High haematocrit, low plasma volume
Correct. Well done!
Polycythaemia, also known as erythrocytosis, simply means a high concentration of red blood cells in blood.
“Apparent polycythaemia” is where the absolute number of red cells is normal but a reduced volume of plasma means that the concentration of red cells is elevated. Apparent polycythaemia can be caused by obesity, smoking, drinking too much alcohol or certain medicines such as diuretics. A low plasma volume in this patient is caused by the diuretic which would increase urine volume output, reducing plasma volume as less water is reabsorbed in the kidneys.
Chronic myeloid leukaemia impact on neutrophil number
increase
sepsis can result in
neutropenia
A 22 year old man with Haemoglobin H disease attends the haematology clinic for a routine red cell transfusion to help manage his condition.
What is the genetic basis of this man’s disease?
3 mutated α-globin alleles
Correct. Well done! This was a distinction level question.
Disease causing mutations in 3 of the 4 α-globin genes results in haemoglobin H disease which to leads to moderately severe anaemia. A blood film will show microcytic and hypochromic anaemia with the presence of target cells and Heinz bodies.
A full blood count is performed on a blood sample from a 23 year old woman with iron deficiency anaemia.
What results would likely be evident in this test?
Red blood cell count would be low as she does not have the iron available for bone marrow to produce RBCs, mean cell volume is lower as RBCs are smaller (microcytic anaemia), mean cell haemoglobin is reduced as there is less iron available to make haem groups. Increased red cell distribution width is increased as iron stores have fallen so there may be some normal RBCs and some that are smaller hence a greater variety in size.
The peptide hormone hepcidin is a key regulator of iron homeostasis.
Which cytokine would increase the production of this hormone by the liver?
Interleukin 6
Correct. Interleukin 6 released as a consequence of chronic inflammatory diseases stimulates hepcidin release from the liver and can cause anaemia of chronic disease
The peptide hormone hepcidin is a key regulator of iron homeostasis.
Which cytokine would increase the production of this hormone by the liver?
Interleukin 6
Correct. Interleukin 6 released as a consequence of chronic inflammatory diseases stimulates hepcidin release from the liver and can cause anaemia of chronic disease
A 64 year old man visits his GP complaining of loss of appetite, recent weight loss and fatigue. Examination shows he has splenomegaly and hepatomegaly and further investigations lead to a diagnosis of primary myelofibrosis.
What feature would be expected on a blood film from this patient as a consequence of his disease?
Teardrop cells
Correct. Well done! Teardrop cells (also called dacrocytes) are a type of poikilocyte (abnormally shaped red blood cell) that is shaped like a teardrop. They are common in myelofibrosis and thought to be formed due to mechanically squeezing out from the bone marrow as a result of the infiltrative process.
A 65 year old man has developed microangiopathic haemolytic anaemia due to aortic valve stenosis.
What change would be observed as a consequence of this anaemia?
Haemoglobinaemia
Correct. Haemoglobinaemia = excess haemoglobin in the blood. If the normal reticuloendothelial pathway for removal of red blood cells is overwhelmed or haemolysis is very severe (e.g. due to incompatible blood transfusion), a direct breakdown of red blood cells results in release of haemoglobin into the circulation. Normally free haemoglobin in the blood is picked up by the protein haptoglobin (produced by liver), but there is a limited amount of this protein and it can become saturated very quickly.
what causes different shifts of the oxygen curve
Name two intracellular protein-iron complexes that are used to store iron.
ferritin and haemosiderin
Ferritin is a universal intracellular protein that stores iron and releases it in a controlled fashion. Ferritin is found in most tissues as a cytosolic protein, but small amounts are secreted into the serum where it functions as an iron carrier. A ferritin blood test is therefore a useful diagnistic. Haemosiderin is also an iron-storage complex and is only found within cells. Haemosiderin is complex of ferritin, denatured ferritin and other material. Unlike ferritin, the iron within deposits of haemosiderin is very poorly available.
A blood film from a 66 year old man with advanced prostate cancer shows the presence of nucleated red blood cells and granulocyte precursors. Metastatic bone marrow infiltration has occured as a result of his cancer.
What term would be used to describe this blood film?
This would be called a Leucoerythroblastic film
Leukoerythoblastosis is essentially the ‘Spilling’ out of blast cells from the marrow into blood when the marrow is under stress. The most common causes include bone marrow infiltration by metastatic carcinoma or primary myelofibrosis, severe infection and sepsis/shock.
A 60 year old woman who suffered a stroke 3 years ago presents to her GP with varicose veins. Upon questioning, the patient says that she often feels itchy all over and that this gets worse when showering. Subsequent investigations reveal that the woman has Polycythaemia Vera.
What type of polycythaemia is this?
Absolute Primary Polcythaemia
Correct. Well done! In Polycythaemia Vera haematocrit increases because there is an increase in erythrocytes rather than decrease in plasma volume so it has to be absolute and not relative. This abnormality arises in the bone marrow and so it is primary and not secondary. Secondary would be due to an increase in erythropoietin.
After injury to her uterus during a difficult delivery of a 4.0 kg baby boy, a 22 year old woman has postpartum hemorrhage. She has lost 1 litre of blood since giving birth 6 hours ago and now has an increased heart rate, increased breathing rate and feels faint upon standing.
What finding would be likely in a full blood count from this woman in her current condition?
Neutrophilia
Correct. A full blood count can only measure the circulating pool of neutrophils. An acute haemorrhage brings more neutrophils from the marginated pool and into the circulating pool thus leading to neutrophilia.
A 19 year woman presents to her GP complaining of fatigue, shortness of breath, and cold hands and feet. A full blood count was requested from the lab which gave the following results.
What is the most likely cause of this patient’s symptoms?
Iron deficiency
Correct. Well done! Anaemia is clear from the haemoglobin level and the microcytosis would be consistent with iron deficiency anaemia. The reticulocyte cout here is “abnormally normal” as you would expect an increase in reticulocytes given the haemoglobin level. The deficiency in iron however is limiting the bone marrow’s capacity to produce ne red blood cells.
A 62 year old man with primary myelofibrosis has developed hepatomegaly.
Which factor is driving this enlargement?
Extramedullary haemopoiesis
Extramedullary haemopoiesis (i.e. the production of blood cells outside the bone marrow). Primary myelofibrosis is a myeloproliferative neoplasm where the proliferation of mutated haematopoietic stem cells results in reactive bone marrow fibrosis eventually leading to the replacement of marrow with scar tissue. Mobilisation of mutated progenitor cells from bone marrow can also occur and these cells can colonise the liver and spleen leading to extramedullary haemopoiesis and enlargement of these organs.
A 45 year old man with a history of cirrhosis, diabetes mellitus, arthropathy and increased skin pigmentation is referred for genetic testing and a diagnosis of hereditary haemochromatosis is confirmed.
What biochemical change would be present in this patient as a result of his inherited disease?
Increased transferrin receptor activity
Correct. Well done! hereditary haemochromatosis is an autosomal recessive disease causing too much iron to enter cells and accumulate in end organs causing damage. The affected gene is called HFE. The HFE protein normally interacts with the transferrin receptor reducing its affinity for iron-bound transferrin. HFE also promotes hepcidin expression through the activation of signalling pathways in the liver. Mutated HFE therefore results in a loss of negative influences on iron uptake and absorption resulting in iron overload and organ damage (e.g damage to the pancreas would reduce insulin secretion leading to diaetes mellitus).
A 65 year old man with a history of recent weight loss, swollen ankles, shortness of breath and blood in his urine is diagnosed with chronic kidney disease
What could contribute to the development of anaemia in this patient?
Uraemia
Correct. Kidney dysfunction can result in uraemia (as they can’t excrete urea as efficiently) an increase in urea concentration in blood acts to inhibit erythropoiesis and reduces the lifespan of existing red blood cells as well as inhibiting platelet function, which can cause chronic bleeding from the gastrointestinal tract.
A 7 year old girl is admitted to A&E with a sudden onset of fever, sensitivity to light and widespread bruising. An assessment of the patient shows a temperature of 38.8 °C, respiratory rate of 23/min and a non blanching rash. Blood tests show low platelet count, prolonged clotting time and increased concentration of D-dimer and fibrin degradation products. The patient has no other pre-existing medical conditions.
Which of the following could you expect to see in a peripheral blood film from this patient?
Schistocytes
Correct. Well done!
Schistocytes on the peripheral blood film is a characteristic feature of microangiopathic hemolytic anemia (MAHA) often seen in disseminated intravascular coagulation (DIC). The shistocytes result from trauma as red cells get snagged as they try to pass through small vessels laden with fibrin strands due to increased activation of the coagulation cascade. DIC is often seen during sepsis. The sudden onset fever, tachypnea alongside the rash and sensitivity to lights are suggestive of potential sepsis after meningococcal infection. Bruising, thrombocytopenia, prolonged clotting time and increased D-dimers are suggestive of DIC.
A 60 year old man presents to his GP with haematuria, flank pain and an abdominal mass. Subsequent investigations show that he has a renal cell carcinoma. His plasma erythropoietin is measured at 95 IU/L (normal: 4.3 – 29.0 IU/L).
What blood abnormality would likely be present in this man as a consequence of his carcinoma?
Secondary polycythaemia
Correct. Well done! The increased release of erythropoietin from his carcinoma would give rise to a secondary polycythaemia by promoting the production of excess red blood cells.
A 50 year old man with a 30 year history of chronic alcohol dependence develops cirrhosis.
What haematological abnormality would most likely be present in this patient?
Thrombocytopenia
Correct. Well done! This is found in 75% of patients with liver disease. This occurs because of splenomegaly and therefore increased splenic pooling. Also the damage to the liver causes reduced thrombopoietin production.
A 7 year old boy is diagnosed with hereditary spherocytosis?
What is the underlying pathophysiology of this disease?
Increased red cell rigidity
Correct. Mutations resulting in loss of function of proetins (ankyrin, spectrin, band 3, Protein 4.2) involved in vertical interactions between the cytoskeleton and the lipid bilayer of the plasma membrane result in hereditary spherocytosis. Disruption of this interaction causes a local disconnection of the cytoskeleton and membrane resulting in vesiculation of unsupported membrane components and progressive reduction in membrane surface area.This causes the red cells to adopt a spherocyte shape which is more rigid compared to the normal biconcave shape and therefore less deformable. Spherocytes haemolyze as they pass through the small diameter blood vessels of the spleen. The poor deformability of spherocytes only appears to be a problem in the spleen since these cells have a nearly normal lifespan following splenectomy.
A 19 year old woman presents to her GP by with constant burning pains in her hands and feet. She also reports frequent headaches and ringing in her ears as well as bruising very easily. The GP orders a full blood count which shows a platelet count of 706 × 109/L (140-400 × 109/L). Further investigations confirm a diagnisis of essential thrombocythaemia.
What would be the most appropriate first line drug treatment to help mange this patient’s condition?
Aspirin
Correct. Well done! Aspirin has antiplatelet actions and would be prescribed to help reduce the likelihood of blood clots. Aspirin irreversibly inhibits cyclooxygenase-1 in platelets and megakaryocytes and thereby blocks the formation of thromboxane A2 (which is a potent vasoconstrictor and platelet aggregant). Low dose aspirin would be used due to the irreversible nature of the inhibition (platelets do not have a nucleus so could not make more cyclooxygenase once irreversibly inhibited).
