MPD 2 Flashcards
Define what essential thrombocythaemia is and what can the abnormal function of the cells produce cause?
Uncontrolled production of abnormal platelets
The abnormal function of the cells can cause:
- Bleeding (due to aquired von williebrand disease) or arterial thrombosis
What are the clinical features of essential thrombocytopenia ?
- Clinical features common to MPD
- Particularly vasoocclusive complications - causing headache, atypical chest pain, light headedness, erythromyalgia - redness, swelling or pain in the hands and feet (more so then PVR I think)
- Bleeding (unpredictable risk especially at surgery)
How is essential thrombocythaemia diagnosed ?
- You need to exclude reactive thrombocytosis!
- Then need to exclude CML
- Then you look for genetic mutations - main one being JAK2 present in 50%, if this is negative then check for CALR mutation and again if negative check for MPL mutation
Bone marrow will show to many megakaryocytes (platelet precursors)
What are some of the potential causes of reactive thrombocytosis?
- Bleeding
- Infection
- Malignancy
- Trauma/post-surgery
- Iron deficiency
Pic on the left shows patient with ET and pic on R shows patient with a reactive thrombocytosis post-op for AAA
What is the treatment of ET?
- Low dose aspirin to reduce thrombosis risk
- Hydroxycarbamide to decrease platelets if >60 or had a previous thrombosis
- anagrelide, interferon alpha secondary options to hydroxycarbamide
What is myelofibrosis and how can it arise?
Myelofibrosis is a serious bone marrow disorder that disrupts your body’s normal production of blood cells. The result is extensive scarring in your bone marrow which results in extramedullary haematopoiesis in the spleen and liver which causes massive hepatosplenomegaly
It can be idiopaathic or arise secondary to ET or post-polycythaemia
What are the key clinical features of myelofibrosis ?
- Bone marrow failure - anaemia, infections, bleeding
- Massive hepatosplenomegaly - causes abdo discomfort
- Hypermetabolic symtpoms - night sweat, fever, weight loss
What are the 2 characteristic cell types seen in myelofibrosis ?
- Teardrop RBC’s - poikilocytes - formed as they squeeze through the fibrosis in the bone marrow
- and leucoerythroblastic cells - nucleated RBC’s and immature WBC’s e.g. myelocytes
What characterisitic cell appearance is shown and what condition is it associated with ?
Teardrop poikilocytes - seen in myelofibrosis
How is myelofibrosis diagnosed ?
- FBC
- Typical blood film (tear-drop shaped RBC and leucoerythroblastic)
- Bone marrow aspiration - results in a dry tap, the inability to aspirate marrow from a properly placed needle
- Bone scarring/fibrosis on trephine biopsy - for definite diagnosis
- JAK2 or CALR mutation in a proportion
Shows the characteristic bone marrow appearance of myelofibrosis vs normal bone marrow
What characteristic film appearance is shown and what conditions is it associated with ?
Leucoerythroblastic film associated with:
- Reactive (sepsis)
- Marrow infiltration
- Myelofibrosis
What is the treatment of myelofibrosis ?
Bone marrow support for the marrow failure - blood transfusion, platelets, antibiotics
Allogenic stem cell transplantation may be considered for cure in young patients but carries a high risk of mortality
- JAK2 inhibitor ruxolitinib 1st line drug given
- hydroxycarbamide 2nd line
What is the most common cause of high blood counts ?
Reactive causes not MPD
What are the reactive causes which can cause a high granulocyte count ?
- Infection: eg pyogenic bacteria causing neutrophilia
- Physiological eg post-surgery (recall the AAA patient earlier), steroids
What are the reactive causes which can cause a high RBC?
- Dehydration (diuretics): pseudopolycythaemia
- Secondary polycythaemia (eg hypoxia-induced)
