Formative Flashcards
A 58 year old lady with a family history of hypothryoidism and atrophic gastritis presents with fatigue, macrocytosis and pancytopenia. What is the likely diagnosis?
- Pernicious anaemia
- B12 deficiency in patients with pernicious anaemia can present with pancytopenia and not just an isolated macrocytic anaemia. It is not uncommon to elicit a personal or family history of other autoimmune disorders
A 25 year old male has recurrent admissions to hospital with pain in his legs and chest wall. On one occasion he became extremely breathless and required a red cell exchange transfusion. What is the likely diagnosis?
- Sickle cell anaemia
- Patients with sickle cell disease can have uncomplicated vaso-occlusive crisis in their musculoskeletal system. Sickle cell crisis in the pulmonary vasculature is a life-threatening emergency that requires prompt therapy with exchange transfusion
A 21 year old girl has a history of heavy periods and investigations indicate a defect in primary haemostasis. Her blood count is normal. What is the likely diagnosis?
- Von Willebrand’s disease
- Disorder of primary haemostasis due to deficiency of von Willebrand factor which bridges platelets to sub-endothelial collagen following endothelial injury. This affects platelet adhesion at the site of injury
Name an example of an ADP antagonist and describe its mechanism of action
Clopidogrel - selectively inhibits the binding of ADP to its platelet receptor and the subsequent ADP-mediated activation of the glycoprotein GPIIb/IIIa complex, thereby inhibiting platelet aggregation. This action is irreversible
Name an example of a drug that irreversibly inactivates cyclooxygenase 1 and describe how it does this
Aspirin - this irreversibly stops production of thromboxane which is an important initiator of platelet aggregation
Name a drug that is a highly selective direct inhibitor of activated factor X and describe how it does this
Riveroxiban - competitively inhibits factor Xa. Factor Xa along with factor Va for the prothrombinase complex which converts prothrombin to thrombin
What is the protein target for Rituximab and what is this drug used for?
- CD20
- Rituximab is a monoclonal antibody directed against CD20 expressed on B cells an B cell lymphomas
What is the protein target for Imatinib and what is this drug used for?
- BCR-ABL1 tyrosine kinase
- Imatinib is a tyrosine kinase inhibitor that inhibits the BCR-ABL-1 protein unique to CML
A 67 year old man with chest pain and STEMI is treated with aspirin in the ambulance on the way to hospital. What is the protein target for aspirin?
- Cyclooxygenase
- Aspirin is an irreversible inactivator of cyclooxygenase that is required for the production of prostaglandins and thromboxanes for platelet aggregation
What is the name for an abnormally low platelet count?
Thrombocytopenia
What is the name for an abnormally high neutrophil count?
Neutrophilia
If a patient has a normal prothrombin time, prologned APTT, normal platelet count and normal fibrinogen,what is the most likely cause?
- Factor VIII deficiency
- Isolated prolonged APTT reflects deficiency of factors involved in the intrinsic pathway of coagulation (factors VIII and IX) or the presence of an anti-phospholipid antibody that is not associated with a bleeding phenotype
If a patient has a prolonged PT, normal APTT, normal platelet count and normal fibrinogen, what is the likely cause?
- Factor VII deficiency
- An isolated prolonged PT reflects deficiency of factors involved in the extrinsic pathway of coagulation and the only coagulation factor involved is therefore factor VII.
- Deficiencies of common pathway factors (II, V, X) will cause prolongation of both PT and APTT
If a patient has a prolonged PT, prolonged APTT, low platelet count and low fibrinogen, what is the likely cause?
Disseminated intravascular coagulation is a consumptive coagulopathy due to abnormal activation of the coagulation system with deposition of thrombi in micro and macro vasculature. The consumptive nature of the process is reflected by an acquired reduction in coagulation factors causing the prolonged clotting times and thrombocytopenia
Uncontrolled production of essentially normally functioning blood cells. What is this?
Polycythaemia rubra vera
Uncontrolled production of immature blood cells in the bone marrow. What is this?
- Acute myeloid leukaemia
- Bone marrow based malignancy where there is a block in differentiation and an excess of primitive cells accumulate rapidly
Clonal B cell disorder usually resulting in a large number of circulating malignant cells. What is this?
- Chronic lymphocytic leukaemia
- Unlike AML there is not a block on early differentiation but failure of cell death and so a steady accumulation of cells over time.
- They are produced in bone marrow and seen circulating as an excess of small mature lymphocytes in the blood.
- Diagnosis is confirmed by peripheral blood immunophenotying