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.
