Haematology 2 Flashcards
What is polycythaemia?
Erythrocytosis of any cause (high red blood cell count) and increased haemoglobin and packed cell volume (PCV)
Describe the epidemiology of polycythaemia
95% of patients have the JAK2 mutation
What is the difference between absolute and relative polycythaemia?
Absolute = increased number of RBCs Relative = normal number of RBCs but reduction in plasma
What is the difference between primary and secondary absolute polycythaemia?
Primary = increased sensitivity of BM cells to EPOSecondary = more circulating EPO
What are 2 causes of primary absolute polycythaemia?
- Polycythaemia rubra vera = genetic mutation in JAK2 gene
- Primary familial and congenital polycythaemia = genetic mutation in EPO receptor gene
What are 8 causes of secondary absolute polycythaemia?
- Chronic hypoxia2. Erythropoietin producing tumour (e.g. renal carcinoma)3. High altitude4. COPD5. Sleep apnoea6. PKD7. Renal artery stenosis8. Kidney cancer
What are 3 causes of relative polycythaemia?
- Obesity2. Dehydration3. Excessive alcohol consumption
What are 2 signs of polycythaemia?
- Hypertension2. Angina
What is a sign of polycythaemia rubra vera that is not seen in secondary polycythaemia?
Hepatosplenomegaly
What are 9 symptoms of polycythaemia?
- Easy bleeding/bruising2. Fatigue3. Dizziness4. Headaches5. Blurred vision6. Plethoric complexion7. Itching especially after contact with water8. Tinnitus9. Erythromelalgia (burning sensation in fingers/toes)
What are 3 investigations for patients with polycythaemia?
- FBC2. BM biopsy3. Genetic testing for JAK2 gene
What is the difference between FBC for polycythaemia rubra vera and secondary polycythaemia?
Both = low serum EPORubra vera = raised WBC and plateletsSecondary = normal WBC and platelets
What is the treatment for polycythaemia?
- Blood letting (venesection - removal of 400-500ml of blood)- Low dose aspirin daily- Hydroxycarbamide (for those at risk of thrombus)- Treat the cause
What is thrombocytopenia?
Deficiency of platelets in the blood
Describe the epidemiology of immune thrombocytopenia (ITP)
- Mainly seen in children aged 2-6- Primary = often post-viral infections (self-limiting)- Secondary = more common in young women, malignancies and HIV
What are 3 causes of ITP?
- Reduced platelet production in BM2. Autoimmune destruction of platelets3. Problems of enlarged spleen
Describe the pathophysiology of ITP
- Autoimmune destruction of platelets due to IgG antibodies- IgG antibodies coat the platelets which are then removed by binding to Fc receptors on macrophages
What are 6 symptoms of both ITP and TTP?
- Purpura (red/purple spots on skin caused by bleeding underneath)2. Epistaxis3. Easy bruising4. Menorrhagia5. Headache6. Fatigue
What are 2 symptoms of ITP?
- Gum bleeding2. Vomiting
What are 3 investigations for ITP?
- FBC2. BM biopsy3. Platelet autoantibodies present in 70% of cases
What is the treatment for ITP?
- 1st line = corticosteroids e.g. prednisolone - IV IgG (temporarily increases no. of platelets)- Splenectomy- Immunosuppression = oral azathioprine
Describe the epidemiology of thrombotic thrombocytopenia (TTP)
- Rare- More common in adults- More common in females (3:2)- Associated with HIV, cancer and systemic lupus erythematosus
What is the cause of TTP?
Deficiency of von Willebrand Factor cleaving protein (vWF-cp) a.k.a ADAMTS 13 (responsible for the degradation of vWF)
Describe the pathophysiology of TTP
- Lack of vWF-cp results in extensive microvascular clot formation in small vessels in the body- Results in low platelet count and organ damage