Pathology Flashcards
What is inheritance and genotype of sickle cell anaemia?
Autosomal recessive
Sickle cell anaemia - HbSS
Sickle cell trait - HbAS
What is the management of transfusion related acute lung injury?
STOP THE TRANSFUSION.
Oxygen should be administered. Approximately 75% of patients require aggressive respiratory support.
Diuretic usage should be avoided
What transfusion product is most likely to result in bacterial infection?
What is the most common bacteria to be associated with transfusion infections?
Platelets - as stored at room temp
The most common bacterial organism associated with transfusion is Yersinia enterocolitica. This organism is capable of multiplying at low temperatures and using iron as a nutrient.
In Polycythaemia vera is arterial or venous thrombosis more common?
Arterial
What are the criteria for a diagnosis of Polycythaemia vera?
The diagnosis of PCV requires two major criteria and one minor criterion, or the first major criterion and two minor criteria:
Major criteria:
HB > 18.5 g/dl in men, 16.5 g/dl in women
Elevated red cell mass > 25% above mean normal predicted value
Presence of JAK2 mutation
Minor criteria:
Bone marrow biopsy showing hypercellularity with prominent erythroid, granulocytic and megakaryocytic proliferation
Serum erythropoietin level below normal range
Endogenous erythroid colony formation in vitro
What is poikilocytosis?
Abnormalities of red cell shape are referred to as poikilocytosis.
What are Heinz bodies?
List 5 conditions where they are seen?
‘Heinz bodies’ are denatured haemoglobin caused by oxidative damage. They appear as small, round inclusions within the red cell body.
They are never seen in normal, healthy individuals because they are removed by the spleen.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency NADPH deficiency Chronic liver disease Alpha thalassaemia Hyposplenism or asplenia
What is the mutation causing sickle cell disease?
A point mutation in the beta-globin chain of haemoglobin, causing glutamic acid to be replaced by valine at the sixth position.
The beta-globin gene is found on chromosome 11.
What are Target cells?
In what conditions might they be seen?
‘Target cells, which are also known as codocytes or ‘Mexican hat cells’ have the appearance of a shooting target with a bullseye.. These cells are characterized by a disproportional increase in the ratio of the surface membrane area to volume.
Liver disease Alpha thalassaemia Beta thalassaemia Haemoglobin C disease Post-splenectomy Autosplenectomy caused by sickle-cell disease
Sickle cell disease patient presents with pleuritic pain in left hypochondrium radiating to left shoulder, audible rub over the area.
What is the complication he has?
Splenic infarction
What is the inheritance pattern of the Thalassaemias?
Which populations tend to have them?
Autosomal recessive
They are commonest in people of Mediterranean and Asian origin
What are Howell-Jolly bodies?
When are they seen?
Nuclear remnants found in red blood cells that are normally removed by the spleen.
Appears as a basophilic (purple) spot on the otherwise eosinophilic (pink) erythrocyte.
They are usually seen in conditions where splenic function has been markedly decreased: Post-splenectomy Splenic trauma Autosplenectomy secondary to sickle-cell disease Amyloidosis Severe haemolytic anaemia Severe megaloblastic anaemia Myelodysplastic syndrome
What is Glanzmann’s thrombasthenia
Glanzmann’s thrombasthenia is a rare platelet disorder in which platelets contain defective or low levels of glycoprotein IIb/IIIa.
Glycoprotein IIb/IIIa is a receptor for fibrinogen
What kind of anaemia are pencil cells typical of?
Iron deficiency anaemia
What are cigar cells otherwise known as?
In what conditions are they seen?
‘Cigar cells’, also known as elliptocytes, are red blood cells that have an oval or elongated stretched out shape.
Most commonly associated with hereditary elliptocytosis but may also be seen in iron deficiency anaemia, myeloproliferative disorders and myelodysplastic syndromes.
What is the inheritance pattern of G6PD deficiency?
What can trigger a haemolytic crisis?
X-linked recessive
Illness, most notably infection and DKA
Drugs including certain antibiotics, antimalarials, sulphonamides and aspirin
Foods, most notably fava beans
What antibiotics can trigger a haemolytic crisis in G6PD deficiency?
Nitrofurantoin
Quinolones (such as ciprofloxacin)
Trimethoprim
Chloramphenicol
The use of penicillins and cephalosporins is safe however, and does not trigger haemolysis.
Can girls be affected by G6PD deficiency?
Symptomatic patients are almost exclusively male but females can occasionally be affected due to unfavourable lyonisation.
Lyonization theory states that in the somatic cells of female mammals, one of the two X chromosomes is randomly inactivated early in development
What is the most common type of transfusion reaction?
Febrile transfusion reaction
What factor is deficient in Haemophilia A?
What inheritance pattern does it have?
Factor VIII
Usually X-linked recessive
How does ITP present?
What causes it?
Immune mediated reduction in platelet count.
Antibodies target glycoprotein IIb-IIIa or Ib complex.
Acute ITP is more common in children and has an equal sex distribution. Chronic ITP is more common in young to middle aged women.
ITP tends to present with epistaxis, oral bleeding, purpura or petechiae and not usually with haemarthrosis.
It is also not an inherited disorder.
What is the most common hereditary coagulation disorder?
Von Willebrand disease (vWD) is the most common hereditary coagulation disorder occurring in approximately 1 in 100 of the population.
Deficiency in Von Willebrand factor (vWF)
This causes a reduction in factor VIII levels as vWF binds to factor VIII to protect it from rapid breakdown within the blood.
vWF is also required for platelet adhesion and a deficiency of it will also result in abnormal platelet function.
Prolongs both the APTT and the bleeding time
If symptomatic the most common symptoms are easy bruising, epistaxis and menorrhagia.
What inheritance is shown by Factor V Leiden mutation?
Autosomal dominant
Results in a hypercoagulable state
Trisomy 21 is associated with which leukaemia?
ALL