Anaemia in Adult Males is considered as an Hb Value less than what?
Anaemia in Adult Females is considered as an Hb Value less than what?
Hb <11.5 g/dl
What is an Erythrocyte?
This is a fully developed red blood cell.
How many new Erythrocytes are made each day?
1012 New Erythrocytes
What is the primary site of EPO synthesis?
The peritubular cells of the kidneys (Renal cortex).
How is EPO production triggered?
EPO is not stored. Like most physiological cycles, it is a negative feedback cycle. The production of EPO is triggered by tissue hypoxia (oxygen tension in the tubules of the kidney).
What is the major stimulant for EPO production?
Chronic renal disease/Bilateral nephrectomy will stop or reduce the production of which growth factor?
A failure of production of EPO causes what type of Anaemia?
Normacytic anaemia. The red cells will be a normal shape and size, but there will be less of them.
In cases of chronic haemolysis, as in thalassaemia, EPO production rises as a result of chronic hypoxia. What effect(s) does this have?
An increase in EPO eads to an increase in the numbers of erythrocytes (red blood cells), resulting in expansion and eventually fatty deposition within the bone marrow. In children, this can cause growth deformities like Frontal Bossing.
When do reticulocyte counts rise?
- Haemolytic anaemia
- Treatment of a haemotinic deficiency
What is the ratio of reticulocyte to red blood cell count in a normal human being?
1:100 Reticulocyte:Red blood cell
What is a pronormoblast?
This is the earliest stage of the erythrocyte, formed from stem cells. They have a large nucleus, and no haemoglobin.
What are normoblasts?
A precursor to red blood cells. There is still a nucleus, but through the many variations of normoblasts, this gradually decreases. Eventually it is extruded from the cell and released into the blood.
What % of the final Haemoglobin do reticulocytes contain?
What is anaemia of chronic disease?
Anaemia of chronic disease. Within any individual who lives with a chronic disease (eg rheumatoid arthritis),a complex interaction of
inflammatory cytokines interferes with the red cell lifecycle by
impairing iron metabolism and inhibiting red cell precursors.
The end result is a normocytic anaemia.
If asked to "check the haemotinics", what do you look at?
Iron content is rate-limiting for erythropoiesis. So, in iron deficiency anaemia, the cells are ___. This is known as ______ ______.
The red cells are smaller in size This is known as microcytic anaemia.
What is the term used to describe low haemoglobin?
Vitamin B12 and Folate are used for which two important processes?
DNA Synthesis and Cell Mitoses.
A Vitamin B12 or a folate deficiency leads to what?
These are important for DNA production and cell mitosis. A Lack means that cell formation and production happens more slowly. It leads to the productino of magaloblasts (enlarged, misshapen cells)!
How much Ferrous Iron is absorbed from the small intestine every day in a healthy adult?
Which protein does Iron attach to in the serum, and what is its function?
The protein is called Transferrin. It binds to iron, and transports it to the bone marrow.
Which receptors are increased in iron deficiency?
Soluble Transfferin receptors. sTfR.
What is ferritin?
It is a storage compound. Stored in the liver.
Where are dying red blood cells recycled?
The spleen. This is where iron is recycled into the plasma for future use.
Describe the iron deficieny PROFILE.
- Serum Iron is reduced
- Serum total iron binding capacity is increased. The body is working hard to bind any iron that is left.
- Serum ferritin is reduced since iron stores are low.
- Serum soluble transferrin receptors are increased since any iron in the system is being used up.
Give causes of Vitamin B12 deficiency
- Pernicious anaemia
- Inadequate intake
- Poor absorbtion
What is the leading cause of B12 deficiency?
- Igg autoantibodies target parietal cells, and its product (intrinsic factor IF)
- This basically means that less B12-IF is absorbed in the terminal ileum. BAD TIMES.
What are the four proteins of importance in red blood cells?
Defects in the structural proteins that form red blood cells can cause what?
These cells cannot withstand the shear forces of the microcirculation. Their shape changes (eg they become elliptical). These then get destroyed within the spleen by macrophages. This is haemolytic anaemia.
Hereditary spherocytosis and elliptocytosis are examples of what?
Haemolytic anaemia. These are both due to defets in the Spectrin, one of four major protein components in the red blood cell.
What is Thalassaemia?
There is a reduced rate of synthesis of either alpha or Beta globin chains. Within this group of inherited conditions, there may be both ineffective erythropoiesis, and haemolysis, leading to hypochromic (low iron) normacytic (normal size) anaemia.
What is sickle-cell disease?
There is an inheritance of two abnormal Beta chains (HbSS). The abnormality is a point mutation. This causes insolubility in the cells deoxygenated state, and crystalisation within the red blood cell. This...leads to sickle cell deformity, and vascular occlusion. Most often seen in Afro-Carribean populations.
What is 2,3 - diphosphoglycerate?
This sits in between beta chains in haemoglobin, and helps to offload oxygen.
The change from foetal to adult haemoglobin occurs at 3-6 months. What is the difference between adult and foetal haemoglobin?
Foetal Haemoglobin has a higher affinity for oxygen than adult haemoglobin.
In metabolic alkalosis, what happens to the oxygen dissociation curve?
With an increased pH, CO2 is decreased, and the curve shifts to the LEFT. This means there is a higher affinity for oxygen in the lungs, and it is "harder" to release oxgen to tissues. This also occurs with foetal haemoglobin.
How is the oxygen dissociation curve affected in metabolic acidosis?
Decreased pH, raised concentration of 2,3-DPG H+ ions. Shift to the right. This means greater release of O2 into the tissues.
What is the role of the reticuloendothelial system?
Simply? This cleans up dead and dying/out of date cells.
What are haemolytic anaemias?
A group of anaemias that lead to a shorteneed life span of red cells.
What is LDH, and why is it useful?
This is a nucleic enzyme, released on red cell destruction. It's measurable in a blood sample, and is a useful indicator of haemolysis.
When investigating haemolysis, what three things do you assess?
- Lactic acid dehydrogenase (LAD)
- Reticulocyte count
How does haemolysis cause Jaundice?
Excess uncojugated billirubin can occur from the breakdown of haem groups.
What are the defining levels of Haemoglobin, for anaemia in Males and Females?
Males: 13.5 g/dl
Females: 11.5 g/dl
How is the total circulating haemoglobin concentration determined?
- The circulating plasma volume
- The total circulating haemoglobin mass
How may pregnancy or splenomegaly cause anaemia?
These can cause in increase in plasma volume, effectively reducing heaemoglobing concentration, though circulating levels may appear normal.
What is the end result of anaemia?
Tissue hypoxia is the end result of reduced oxygen carrying capacity in the red blood cells.
What are the two key compensatory mechanisms in place that act in response to tissue hypoxia from anaemia?
- Cardiac compensation. This is the major adapter. Both Stroke volume and heart rate increase to bring about a subsequent increase in cardiac output. This can present as palpatations or heart murmurs.
- Commonly, a generalised pallor is observed. This is generally due to a vasoconstriction, with redistribution of blood to key areas.
Name some of the general clinical signs and symptoms of anaemia.
- Confusion and symptoms of cardiac failure
- Weakness and lethargy
- Angular Stomitis
- Dysphasia/Pharayngeal web
Name some causes of microcytic, hypochromic anaemia.
What causes Normocytic normochromic anaemia?
What causes Macrocytic megaloblastic anaemia?
G6PD deficiency and hereditary spherocytosis cause what type of anaemia?
A Microcytic RBC has a MCV of what?
An MCV of LESS than 80fl
Is a macrocytic blood film an indicator of excess alcohol consumption or liver disease?
Yes it is!
Name three conditions in which target cells are found in peripheral blood films.
- Liver disease (obstructive jaundice)
- Thalassaemia major
- Sickle cell anaemia
In which conditions do you observe fragmented RBC's on peripheral blood film?
Cardiac Valve (synthetic)
In which conditions does peripheral blood film show tear drop poikilocytes?
- Extramedullary haemopoiesis
Ringed RBC's on peripheral blood film are a sign of which condition?
Malaria infection from P falciparum.
Prickle type RBC's pn peripheral blood film are indicative of which condition?
Pyruvate Kinase deficiency
What is the most COMMON cause of IRON DEFICIENT anaemia?
What is Beta-Thallasemia?
This is a microcytic hypochromic anaemia. It is one of the most common autosomal inerited disorders.
Pathology is reduced beta globin production, from ineffective erythropoiesis and haemolysis.
What is the fundamental difference between warm and cold autoimmune haemolytic anaemias?
- Warm is associated with production of IgG
- Cold is associated with production of IgM
What are the functions of the haemopoietic system?
Transport: cells, oxygen, hormones, drugs
Surveilence: Cells, cytokines, proteins
Temperature regulation: Blood flow control
What are the component parts of the haemopoietic system?
Bone: Scaffold (medulla protected by cortical bone) and cells (stroma)
Blood: vessels (endothelium) and cells (circulating)
Lymph: vessels and cells (circulating, nodes and extra lymphatic tissues,Spleen, Thymus
The bone marrow produces which two elements of the haemopoietic system?
Cells, and stroma (connective tissue)
What do plasma cells produce?
What are the sites of prenatal blood production?
- Yolk sac
- bone marrow
- Bone marrow
What are the main sites of postnatal blood production?
- Vertebra and pelvis
B and T lymphocytes, and Natural Killer cells are derived from which earlier cell?
Lymphoid stem cell
Granulocyte monocyte progenitor cells produce which cell types?
Erythroid progenitors produce which type of cell?
Red blood cell
Megakaryocyte progenitor cells produce what?
In a patient with acute renal failure, which agents would use to ensure adequate production of red blod cells?
Erythropoietin stimulating agents (ESA)
Monitor haemoglobin to find appropriate dose. Aim for increase of no more than 20g/l over 4 weeks
What is Hydroxocobalamin?
IM injection suitable B12 supplement.
What does stem cell factor cause?
An increase in haemopoietic stem cell reproduction.
(Granulocyte-Monocyte Colony Stimulating Factor) -
↑MPC (myeloid progenitor cell)
differentiation into granulocyte & monocyte lineage
Where is Thrombopoietin produced, and what is it's effect?
liver & kidneys
megakaryocyte → platelet
- Granulocyte Colony Stimulating Factor -
What does it do?
maturation of neutrophils
(+ inhibits neutrophil apoptosis
Neutrophils take 12 days to produce - but how long do they spend in circulation?
Just 12 hours!
A trephine is usec as part of which invasive investigatory procedure?
Bone marrow biopsy
What (physiologically) hapens to cause
Idiopathic Thrombocytopenic Purpura?
Autoantibodies opsonise platelets, causing their lysis in the spleen.
Name two drugs that are known triggers for idiopathic thrombocytic purpura.
What wil the FBC show in
Idiopathic Thrombocytopenic Purpura?
Isolated thrombocytopaenia (often a compensatory increase in megakaryocytes too).
A 30 year old man with:
- Signs of Anaemia
- Altered mental state,
- focal pathologies
- Haematuria --->Acute Renal Failure,
- Anaemia, RBC Fragments
- Unconj Bilirubinaemia
I have given every possible symptom here -- so what does the poor fellow have?
Thrombotic Thrombocytopenic Purpura
WHat is the pathophysiology of thrombotic thrombocytopenic purpura?
- von Willebrand Factor Multimers circulate in blood
- Congenital form - Pts lack ADAMTS13 enzyme which cleaves vWF multimers
- Acquired forms (more common) - Autoantibodies antagonise enzyme -->Platelets clump & cause ‘white’thromboses in small vessels -Mostly platelets content, little fibrin/RBCs
- Thromboses & deposition damages organs incl. kidneys, CNS
- Adults predominantly affected
What is the pathophysiology of Haemolytic Uraemic Syndrome?
- Entero-haemorrhagic E-Coli 0157- Produces
- shiga-like toxin which Causes platelet-agglutination & "white thromboses" in small vessels
- Similar pathology to TTP
- Young Children mostly affected, but does occur in adolescents & adults
In severe B12 deficiency, IM injection of which drug (every 3 months) is used?
(1mg 3xweekly for 2 weeks, maintenance dose 4xyr)
Can cause; Rash, chills, and hypokalaemia
Which important vitamin is required to convert folic acid into folate?
When is Folic acid given (OTHER THAN PREGNANCY)?
In megaloblastic anaemia, and when Methotrexate is given (it reduces the side effects)
Name two iron chelators, that can be used in cases of iron overload or iron poisoning.
- Desferrioxamine - IV or subcut. IV for poisoning, SC for overload
- Desferasirox - This is given ORALLY. Causes gut irritation, so take on empty stomach, and avoid other irritants like NSAIDS.
Hearing and visual disturbances occur with both
Name two Erythropoiesis Stimulating Agents.