Polycythaemia Flashcards
What is a pathological fracture?
A pathological fracture occurs in abnormal bone due to insignificant injury.
What are some causes of pathological fractures?
Causes include metastatic tumours, bone disease, local benign conditions, and primary malignant tumours.
What types of metastatic tumours can cause pathological fractures?
Breast, lung, thyroid, renal, and prostate tumours.
What bone diseases can lead to pathological fractures?
Osteogenesis imperfecta, osteoporosis, metabolic bone disease, and Paget’s disease.
What local benign conditions can cause pathological fractures?
Chronic osteomyelitis and solitary bone cyst.
What primary malignant tumours are associated with pathological fractures?
Chondrosarcoma, osteosarcoma, and Ewing’s tumour.
What are the types of polycythaemia?
Polycythaemia may be relative, primary (polycythaemia rubra vera), or secondary.
What are the relative causes of polycythaemia?
Relative causes include dehydration and stress (Gaisbock syndrome).
What is the primary cause of polycythaemia?
The primary cause is polycythaemia rubra vera.
What are the secondary causes of polycythaemia?
Secondary causes include COPD, altitude, obstructive sleep apnoea, and excessive erythropoietin due to conditions like cerebellar haemangioma, hypernephroma, hepatoma, and uterine fibroids.
How can true polycythaemia be differentiated from relative polycythaemia?
Red cell mass studies are sometimes used. In true polycythaemia, the total red cell mass in males is > 35 ml/kg and in females > 32 ml/kg.
What is a potential complication of uterine fibroids related to polycythaemia?
Uterine fibroids may cause menorrhagia, which can lead to blood loss; polycythaemia is rarely a clinical problem.
What is polycythaemia vera?
A myeloproliferative disorder caused by clonal proliferation of a marrow stem cell leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets.
What mutation is present in approximately 95% of patients with polycythaemia vera?
A mutation in JAK2.
When does the incidence of polycythaemia vera peak?
In the sixth decade.
What are common features of polycythaemia vera?
Pruritus after a hot bath, splenomegaly, hypertension, hyperviscosity, arterial thrombosis, venous thrombosis, haemorrhage, and low ESR.
What tests does the BCSH recommend following history and examination?
Full blood count/film, JAK2 mutation, serum ferritin, renal and liver function tests.
What tests are suggested if the JAK2 mutation is negative?
Red cell mass, arterial oxygen saturation, abdominal ultrasound, serum erythropoietin level, bone marrow aspirate and trephine, cytogenetic analysis, erythroid burst-forming unit (BFU-E) culture.
What other features may be seen in polycythaemia vera?
Low ESR and raised leukocyte alkaline phosphatase.
What are the diagnostic criteria for JAK2-positive polycythaemia vera?
Requires both criteria A1 and A2 to be present.
What is criterion A1 for JAK2-positive polycythaemia vera?
High haematocrit (>0.52 in men, >0.48 in women) OR raised red cell mass (>25% above predicted).
What is criterion A2 for JAK2-positive polycythaemia vera?
Mutation in JAK2.
What are the diagnostic criteria for JAK2-negative polycythaemia vera?
Requires A1 + A2 + A3 + either another A or two B criteria.
What is criterion A1 for JAK2-negative polycythaemia vera?
Raised red cell mass (>25% above predicted) OR haematocrit >0.60 in men, >0.56 in women.
What is criterion A2 for JAK2-negative polycythaemia vera?
Absence of mutation in JAK2.
What is criterion A3 for JAK2-negative polycythaemia vera?
No cause of secondary erythrocytosis.
What is criterion A4 for JAK2-negative polycythaemia vera?
Palpable splenomegaly.
What is criterion A5 for JAK2-negative polycythaemia vera?
Presence of an acquired genetic abnormality (excluding BCR-ABL) in the haematopoietic cells.
What is criterion B1 for JAK2-negative polycythaemia vera?
Thrombocytosis (platelet count >450 * 10^9/l).
What is criterion B2 for JAK2-negative polycythaemia vera?
Neutrophil leucocytosis (neutrophil count > 10 * 10^9/l in non-smokers; > 12.5 * 10^9/l in smokers).
What is criterion B3 for JAK2-negative polycythaemia vera?
Radiological evidence of splenomegaly.
What is criterion B4 for JAK2-negative polycythaemia vera?
Endogenous erythroid colonies or low serum erythropoietin.
What is polycythaemia vera?
A myeloproliferative disorder caused by clonal proliferation of a marrow stem cell leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets.
What are the typical features of polycythaemia vera?
Hyperviscosity, pruritus, and splenomegaly.
What is the first-line treatment for polycythaemia vera?
Venesection to keep the haemoglobin in the normal range.
What role does aspirin play in the management of polycythaemia vera?
It reduces the risk of thrombotic events.
What chemotherapy agent is used in polycythaemia vera?
Hydroxyurea, which has a slight increased risk of secondary leukaemia.
What is phosphorus-32 therapy used for?
It is one of the treatment options for polycythaemia vera.
What is a significant cause of morbidity and mortality in polycythaemia vera?
Thrombotic events.
What percentage of patients with polycythaemia vera progress to myelofibrosis?
5-15%.
What percentage of patients with polycythaemia vera progress to acute leukaemia?
5-15% (risk increased with chemotherapy treatment).
