Anemia Flashcards
What is anaemia?
A finding that indicates significant reduction in volume of red blood cells and Hb concentration, resulting in levels lower than normal (range depends on patient’s sex and age).
What are common symptoms of anaemia?
Fatigue, feeling Tired All The Time (TTAT), weakness, dizziness/light-headedness, dyspnea (shortness of breath), cold hands and feet.
What are less common and more severe symptoms of anaemia?
Tachypnea, tachycardia, muscle aches and cramps, angina or heart failure, pallor, hypotension, reticulocytosis, bruising more easily, dizziness when standing up, pale mucous membranes.
What is reticulocytosis?
Occurs when there is destruction/loss of RBCs or increased production by bone marrow.
There are 3 common reasons why anaemia occurs:
- Reduced number of erythrocytes
- Reduced total concentration of Hb
- Haematocrit/packed cell volume (volume
percentage/ratio of erythrocytes in blood) is
abnormally low
→ Caused either by reduced
erythrocytes
increased plasma
both
Classification systems of anaemia: Haemoltyic
anaemia (due to reduced erythrocyte production or
increased destruction)
aplastic anaemia (bone
marrow failure/damage that causes pancytopenia)
→ Aplastic anaemia can be confirmed with
bone marrow biopsy
Eg. Diamond-Blackfan anaemia: Rare
congenital type of aplastic anaemia with is
characterised by defective stem cells
Eg. Acquired defective stem cells due to
use of drugs
alcohol or infections
Eg. Unhealthy microenvironment due to
damage from radiation
infections or lack of
space due to scar tissue (fibrosis)
primary
or secondary tumours
Anaemia can be classified by MCV value into
macrocytic
normocytic
→ MCV is found by comparing patient’s blood
film to another blood film of cells that are
similar size to normocytic RBCS
What are the common reasons why anaemia occurs?
- Reduced number of erythrocytes
- Reduced total concentration of Hb
- Abnormally low haematocrit/packed cell volume
Haematocrit is the volume percentage/ratio of erythrocytes in blood.
What are the classification systems of anaemia?
- Haemolytic anaemia (due to reduced erythrocyte production or increased destruction)
- Aplastic anaemia (bone marrow failure/damage causing pancytopenia)
Aplastic anaemia can be confirmed with bone marrow biopsy.
What is Diamond-Blackfan anaemia?
A rare congenital type of aplastic anaemia characterized by defective stem cells.
What can cause acquired defective stem cells?
Use of drugs, alcohol, or infections.
What factors can lead to an unhealthy microenvironment for stem cells?
Damage from radiation, infections, or lack of space due to scar tissue (fibrosis) and primary or secondary tumours.
How can anaemia be classified by MCV value?
Anaemia can be classified into macrocytic, normocytic, and microcytic.
MCV is found by comparing the patient’s blood film to another blood film of cells that are similar in size to normocytic RBCs.
What is macrocytic anaemia?
Macrocytic anaemia is characterized by an MCV higher than the upper limit of the normal range.
How can macrocytic anaemia be classified?
It can be classified into megaloblastic and non-megaloblastic anaemia.
What characterizes megaloblastic anaemia?
Megaloblastic anaemia is characterized by unusually large, structurally abnormal blood cells (megaloblasts) due to impaired DNA synthesis.
What tests are used to diagnose macrocytic anaemia?
Blood count, blood smear, bone marrow analysis, reticulocyte count, serum B12 and folate, RBC folate, serum homocysteine, and methylmalonate.
What are the types of reticulocyte count in macrocytic anaemia?
Reticulocytosis and reticulocytopenia.
What are the causes of B12 deficiency?
Intrinsic factor antibody, gastric parietal antibody, and conditions like myelodysplastic syndrome.
What are the causes of folate deficiency?
Dietary deficiency, malabsorption, and increased requirements due to conditions like liver disorders, drugs, and pregnancy.
What is myelodysplastic syndrome (MDS)?
MDS is a group of blood cancers characterized by impaired blood cell maturation.
What happens to erythrocytes in B12 or folate deficiency anaemia?
Lack of B12 or folate can cause impaired erythrocyte maturation, leading to a decrease in erythrocyte size as they mature.
What is normocytic anaemia?
MCV is within normal range.
Examples include ACD, acute blood loss, mixed B12/folate and iron deficiency, and bone marrow disorders.
What causes chronic renal failure related to anaemia?
Reduced erythropoietin level, which is a growth factor for erythrocytes, leading to a lack of stimulation.
What is microcytic anaemia?
MCV is less than the lower limit of normal range.
Examples include IDA, thalassaemia, ACD, lead poisoning, and sideroblastic anaemia.
What is sideroblastic anaemia?
A disorder where the body produces enough iron but is unable to incorporate it into haemoglobin.
What are the types of sideroblastic anaemia?
Congenital is usually microcytic; acquired is usually macrocytic.
What is the hallmark bone marrow biopsy finding in sideroblastic anaemia?
Ringed sideroblasts (immature red blood cells with nuclei or centres surrounded by rings of iron).
What is the hallmark blood film finding in sideroblastic anaemia?
Erythrocytes with basophilic stippling and Pappenheimer bodies.
What are Pappenheimer bodies?
Cytoplasmic granules of iron found in erythrocytes.
What is normocytic anaemia?
MCV is within normal range.
Examples include ACD, acute blood loss, mixed B12/folate and iron deficiency, and bone marrow disorders.
What causes chronic renal failure related to anaemia?
Reduced erythropoietin level, which is a growth factor for erythrocytes, leading to a lack of stimulation.
What is microcytic anaemia?
MCV is less than the lower limit of normal range.
Examples include IDA, thalassaemia, ACD, lead poisoning, and sideroblastic anaemia.
What is sideroblastic anaemia?
A disorder where the body produces enough iron but is unable to incorporate it into haemoglobin.
What are the types of sideroblastic anaemia?
Congenital is usually microcytic; acquired is usually macrocytic.
What is the hallmark bone marrow biopsy finding in sideroblastic anaemia?
Ringed sideroblasts (immature red blood cells with nuclei or centres surrounded by rings of iron).
What is the hallmark blood film finding in sideroblastic anaemia?
Erythrocytes with basophilic stippling and Pappenheimer bodies.
What are Pappenheimer bodies?
Cytoplasmic granules of iron found in erythrocytes.
What is haemolysis?
Erythrocyte breakdown before their normal 120-day lifespan.
What is haemolytic anaemia?
Form of anaemia that occurs when erythrocyte destruction happens at a faster rate than erythropoiesis.
What stimulates erythropoietic hyperplasia in haemolytic anaemia?
Increased breakdown or reduced erythrocyte production.
What is the rate of RBC production in erythropoietic hyperplasia?
6-8 times the normal rate.
What are the laboratory findings in haemolytic anaemia?
- Elevated reticulocyte count (reticulocytosis)
- Elevated lactate dehydrogenase (increased cell turnover)
- Low haptoglobin
- Elevated unconjugated bilirubin
- Blood film: polychromasia, nucleated erythrocytes.
What does low haptoglobin indicate?
It is a protein produced in the liver that binds to free Hb released from dead/damaged erythrocytes. Level decreases as haptoglobin is used up faster than the liver can produce it.
What are common signs of haemolysis?
Common haemolysis signs include dark urine, jaundice, gallstones with RBC pigment, and anaemic signs.
What does dark urine indicate in haemolysis?
Dark urine occurs due to bilirubin being converted into urobilinogen, making urine and stool look more yellow/brown.
Blood test will show elevated unconjugated bilirubin.
What is jaundice and how is it related to haemolysis?
Jaundice is characterized by yellow sclera (whites of eyes) and yellow-tinged skin.
What is a common complication of chronic haemolysis?
Gallstones with RBC pigment are more common in chronic haemolysis.
What signs are more common in acute haemolysis?
Anaemic signs are more common in acute haemolysis.
What does a blood film show in haemolysis?
A blood film will show normocytic or macrocytic cells due to raised reticulocyte count.
What is paroxysmal nocturnal haemoglobinuria?
It is an acquired, rare form of intravascular haemolysis due to absence of glycosylphosphatidylinositol (GPI), leading to absence of anchored surface proteins that protect erythrocytes from lysis by the complement system.
What are the symptoms of paroxysmal nocturnal haemoglobinuria?
Patients have high levels of free Hb in blood, presenting with dark urine and increased risk of clot formation in unusual areas.
What are Haemaglobinopathies?
Inherited abnormalities of hemoglobin structure or function.
What are Membranopathies?
Inherited abnormalities characterised by erythrocytes that can’t maintain biconcave shape, making them more susceptible to damage and resulting in a shorter lifespan due to early macrophage removal in the spleen.
What is Hereditary Spherocytosis (HS)?
A type of membranopathy treated with folic acid supplementation and splenectomy.
What is Hereditary Elliptocytosis (HE)?
A type of membranopathy.
What is Hereditary Stomatocytosis?
A type of membranopathy.
What investigations are included for membranopathies?
Family history and genetic testing (usually autosomal dominant), abnormal blood film, haemolysis screen, and specialist tests.
What are the specialist tests for membranopathies?
Bilirubin elevated, elevated reticulocyte count, LDH elevated, negative Coombe’s test/direct antibody screen test.
What does a negative Coombe’s test indicate?
Indicates that erythrocytes aren’t coated in antibody.
What is the clinical presentation of membranopathies?
Prolonged neonatal jaundice, mild anaemia presenting at any age, fluctuating jaundice worse during infection periods, pigment gallstones, aplastic crisis caused by parvovirus (B19).
What is the most common enzymopathy?
G6PD deficiency
G6PD deficiency is usually X-linked recessive.
In which populations is G6PD deficiency most common?
Common in people with Mediterranean and African ancestry.
What is the effect of G6PD deficiency on erythrocytes?
Erythrocytes can’t produce much NADPH for glutathione regeneration, making RBC membranes unstable against oxidative stress.
What triggers haemolysis episodes in G6PD deficiency?
Haemolysis episodes are usually triggered after oxidative stress caused by drugs, infections, mothballs, or fava beans.
