Microcytic anaemia - vWD Flashcards
(77 cards)
Define microcytic anaemia
Anaemia associated with a low MCV (< 80 fl).
2 main mechanisms devolving into microcytic anaemia
Defects in either haem or globin synthesis
Causes of microcytic anaemia (4)
• Defects in haem synthesis
Iron deficiency – most common
Can be caused by blood loss (e.g. GI – in Tropics, hookworm is the most common cause of GI blood loss), reduced absorption (e.g. small bowel disease), increased demands (e.g. growth/pregnancy), reduced intakes (e.g. vegans)
Anaemia of Chronic Disease – 2nd most common
Due to poor use of iron in erythropoiesis, cytokine-induced shortening of RBC survival, and reduced production of and response to erythropoietin.
Hepcidin plays a key role
Can occur in many chronic diseases e.g. chronic infection, vasculitis, rheumatoid arthritis, malignancy, renal failure
Sideroblastic Anaemia
Abnormality of haem synthesis
Can be inherited or secondary (e.g. to alcohol/drugs)
• Defects in globin synthesis
o Thalassemia
Explain anaemia of chronic disease
Due to poor use of iron in erythropoiesis, cytokine-induced shortening of RBC survival, and reduced production of and response to erythropoietin.
Hepcidin plays a key role
Can occur in many chronic diseases e.g. chronic infection, vasculitis, rheumatoid arthritis, malignancy, renal failure
S/s of microcytic anaemia (14)
• Non-Specific o Tiredness o Lethargy o Malaise o Dyspnoea o Pallor o Palpitations o Exacerbation of ischaemic conditions (e.g. angina, intermittent claudication)
• Signs of anaemia o Pallor o Brittle nails and hair o Koilonychia (if severe) • Glossitis • Angular stomatitis • Signs of thalassemia
What can lead poisoning cause and what are the s/s 9`10)
• Lead Poisoning - can cause microcytic anaemia Symptoms of lead poisoning o Anorexia o Nausea/Vomiting o Abdominal pain o Constipation
o Blue gumline o Peripheral nerve lesions (causing wrist or foot drop) o Encephalopathy o Convulsions o Reduced consciousness
Ix for microcytic anaemia (9)
Bloods
• FBC: decreased Hb, decreased MCV, Reticulocytes
• Serum iron and serum ferritin (decreases in iron deficiency)
• Total iron binding capacity (increases in iron deficiency)
Blood Film
• Iron deficiency anaemia: Microcytic, Hypochromic (central pallor <1/3 cell size), Anisocytosis (variable cell size), Poikilocytosis (variable cell shape)
• Sideroblastic anaemia: Dimorphic blood film, Hypochromic microcytic cells
• Lead poisoning: Basophilic stippling (coarse dots represent condensed RNA in cytoplasm)
Hb Electrophoresis
• Checking for Hb variants and thalassemia
- Special investigations for iron deficiency anaemia if > 40 years and post-menopausal
- These are considered if no obvious cause of blood loss is identified: Upper GI endoscopy, Colonoscopy, investigations for haematuria
Mx for microcytic anaemia (think 3 main causes)
• Iron Deficiency - oral iron supplements – ferrous fumerate, IV iron can be used if oral ineffective or SEs too much • Sideroblastic Anaemia o Treat the cause o Pyridoxine used in inherited forms o Blood transfusion and iron chelation can be considered if there is no response to other treatments • Lead Poisoning o Remove the source o Dimercaprol o D-penicillinamine
Complications of microcytic anaemia
High output cardiac failure and other complications related to the cause
Define myelodysplasia
A series of haematological conditions characterised by chronic pancytopenia (anaemia, neutropenia, thrombocytopaenia) and abnormal cellular maturation.
There are FIVE subgroups:
- Refractory anaemia (RA)
- RA with ringed sideroblasts (RARS)
- RA with excess blasts (RAEB)
- Chronic myelomonocytic leukaemia (CMML)
- RAEB in transformation (RAEB-t)
What are the five subgroups of myelodysplasia
A series of haematological conditions characterised by chronic pancytopenia (anaemia, neutropenia, thrombocytopaenia) and abnormal cellular maturation.
There are FIVE subgroups:
- Refractory anaemia (RA)
- RA with ringed sideroblasts (RARS)
- RA with excess blasts (RAEB)
- Chronic myelomonocytic leukaemia (CMML)
- RAEB in transformation (RAEB-t)
Explain the pathophysiology of myelodysplasia
- It may be PRIMARY (intrinsic bone marrow problem)
- Or it may arise in patients who have received chemotherapy or radiotherapy for previous malignancies
- Patients may have chromosomal abnormalities
RF of myelodysplasia (5)
- Age > 70 years
- Alkylating Agents
- Topoisomerase Inhibitors
- Prior Haematopoietic Stem Cell Transplantation
- DNA Repair Deficiency Syndromes
Epidemiology of myelodysplasia
- Mean age of diagnosis: 65-75 years old
- More common in MALES
- Twice as common as AML
S/s of myelodysplasia (15)
- Anaemia (fatigue, dizziness)
- Neutropoenia (recurrent infections)
- Thrombocytopaenia (easy bruising, epistaxis)
- Anaemia (pallor, cardiac flow murmur)
- Neutropoenia (infections)
- Thrombocytopaenia (purpura or ecchymoses)
- Gum hypertrophy
- Splenomegaly, Hepatomegaly, Lymphadenopathy (RARE except in chronic myelomonocytic leukaemia CMML)
Ix for myelodysplasia (3)
Bloods
• FBC: pancytopenia
Blood Film • Normocytic or macrocytic Red Cells • Variable microcytic Red Cells in RARS • Low granulocytes • Granulocytes are not granulated • High monocytes in CMML
Bone Marrow aspiration or biopsy • Hypercellularity • Ringed siderblasts • Abnormal granulocyte precursors • 10% show marrow fibrosis
Define myelofibrosis
• Disorder of haematopoietic stem cells characterised by progressive bone marrow fibrosis associated with extramedullary haematopoiesis and splenomegaly
Explain the pathogenesis of myelofibrosis
o There is hyperplasia of megakaryocytes
o Abnormal megakaryocytes release cytokines, like platelet-derived growth factor, that stimulate fibroblast proliferation and collagen deposition in bone marrow
o This results in extramedullary haematopoiesis in the spleen and liver – causing massive hepatosplenomegaly
Epidemiology of myelofibrosis
- RARE
* Peak onset: 50-70 yrs
Associations with what other disease does myelofibrosis have
30% have previous Hx with polycythaemia rubra vera or essential thrombocytopaenia
RF of myelofibrosis (3)
- Radiation Exposure
- Industrial Solvents Exposure
- Age > 65 years
S/s of myelofibrosis (18)
o COMMON: • Weight loss • Anorexia • Fever • Night sweats • Pruritis • Abdominal discomfort o UNCOMMON: • LUQ pain • Indigestion (due to massive splenomegaly) • Bleeding • Bone pain • Gout • Infections
- SPLENOMEGALY
- Hepatomegaly (present in 50-60%)
- Pallor, petechiae, haemarthrosis, blood on PR
Ix for myelofibrosis (5)
Bloods
• FBC: Initially variable Hb, WCC and platelets.
• Later stage FBC: Anaemia, Leukopaenia, thrombocytopaenia
• LFTs - abnormal
Blood Film
• Leucoerythroblastic changes (red and white cell precursors in the peripheral blood)
• ‘Tear drop’ poikilocyte red cells
Bone Marrow Aspirate or Biopsy
• Aspiration usually unsuccessful - ‘dry tap’ (due to fibrosis)
• Trephine biopsy shows fibrotic hypercellular marrow, (dense reticulin fibres on silver staining)
Define normocytic anaemia
Anaemia with a normal MCV (80-100fl).