define atrophic glossitis
glossitis is soreness and inflammation of the tongue, atrophic glossitis is when papillae on the tongue are worn away leaving the tongue glossy and red
define angular stomatitis
this is an inflammatory condition that affects the corners of the mouth
define intramuscular hydroxocobalamin
man made B12 that is injected into the muscle
define haemodialysis
– method of removing excess fluid and salt and wastes from the blood and thus replacing the excretion functions of the kidneys
define hypersegemented neutrophils
– this is the presence of hypersegemented neutrophils as. Diagnostic feature of megoblastic anaemia
Define anaemia
this is a condition in which there is a deficiency of red cells or of haemoglobin in the blood, the levels to define anaemia vary in men and women
what are the limits of anaemia for men and women
less that 12.2 for women
less than 13.7 for men
(measurements of haemoglobin per g/dl)
define haemoglobin
– this is a red protein that transports oxygen in the blood in red blood cells, it contains 4 proteins which contain an iron bound to a haem group
define reticulocytes
– these are immature red blood cells, they have a reticular appearance when stained with methylane blue stain
define erythropoietin
this is a hormone that is secreted by the kidneys in the interstitial cells of the proximal convoluted tubules and increases the rate of production of red blood cells in response to hypoxia
what is the EPO response to anaemia
- These can be different depending if it is due to dimished oxygen carrying capacity in the blood such as haemoglobin or a decrease in the erythrocytes
- If someone is anaemic then they could have a lack of oxygen that is circulating due to less haemoglobin if the red blood cells are microcytic, this would be noticed by the EPO in the interstitial cells of the proximal convoluted tubule and this would therefore cause an increase in the amount of red blood cells by acting on erythropoietic stem cells
- EPO is in the proximal tubule as oxygen levels remain constant and do not change with blood pressure and exercise here
what is the CVS response to anaemia
- There is also an increase in cardiac output, this is due to the amount of haematocrit decreasing therefore the afterload decreases so this increases stroke volume and thus cardiac output
- There can also be redistribution of cardiac output, the blood flow is redistributed to the tissues such as the brain and heart
- There is increased oxygen extraction, and a decrease in mixed venous oxygen saturation, less oxygen available therefore more oxygen is removed from the tissues
- Oxyhaemoglobin dissociation curve shifts to the right, this is because haemoglobin as a decreased affinity for the oxygen molecule therefore releases oxygen to the tissues at higher partial pressures
what are the basic mechanisms that lead to anaemia
- Impaired ability of the bone marrow to produce RBC
- Destruction and loss of RBC
- Lack of production of haemoglobin
describe the formation of red blood cells
- It starts with a haemotopoietic stem cell or a haemocytoblast which differentiates into a stem cell called a common myeloid progenitor or proerythroblast (ready for growth to a erythrocyte)
- The proerythroblast undergoes a series of transformations where its nucleus progressively shrinks (condenses) and its cytoplasm becomes filled with haemoglobin until it becomes a reticulocyte and is released into the blood.
- Normoblast becomes a reticulocyte,
- The proerythroblast develops into an erythroblast. The erythroblast then undergoes successive changes where its nucleus progressively shrinks and its cytoplasm becomes filled with haemoglobin.
- Finally the nucleus is expelled and it becomes a reticulocyte most of which stay in the marrow to become erythrocytes but some may be released into the blood. Reticulocytes can mature into adult RBCs in the circulation
- The final stage of development is when the mature reticulocyte expels the nucleus and the newly formed erythrocyte squeezes through pores in the marrow capillary membrane into the blood by a process known as diapedesis
describe the destruction of red blood cells
- After ~120 days old (senescent) RBCs are removed from the blood by macrophages as they pass through the spleen.
- One way the spleen detects old RBCs is by their lack of deformability. Old cells become more rigid and this enables them to become entrapped in the spleen capillaries.- monitored by the macrophages
- Trapped RBCs are engulfed by splenic macrophages and broken open by osmotic lysis.
- The haem (in USA: heme) prosthetic groups are removed from the globin proteins and the globin protines are broken down to amino acids
describe how the haem is broken down
- The haem is then broken open by the haemoxygenase enzyme. Iron atoms from haem are collected by transferrin. Transferrin carries the iron in the blood to the liver and thence the bone marrow where it can be re-used to make new haemoglobin.
- The opened porphyrin ring minus its iron atom is now called BILIVERDIN (so-called because it has a greenish colour
- Biliverdin is then reduced to BILIRUBIN (which has a yellowish colour) in the macrophage by biliverdin reductase.
- Bilirubin is more stable than biliverdin
describe how bilirubin is broken down
- Stuck to albumin in the spleen and then the albumin bilibrubin is released into the blood
- Bilirubin is not very soluble. It binds to albumin in the splenic macrophages and the complex released into the blood. This is called unconjugated bilirubin.
- When the unconjugated bilirubin reaches the liver it is attached to glucuronic acid by the hepatocytes to make it more soluble. When bound to glucuronic acid it is called conjugated bilirubin.
- Normal level of conjugated bilirubin in the blood is 0.1-0.3 mg/dL
- Conjugated bilirubin passes in the bile to the small intestine where bacteria convert it into urobilinogen.
- Most urobilinogen passes out of the body in faeces but about 10% passes back in the portal vein to the liver. The recycled urobilinogen leaves the liver in venous blood. When it passes through the kidney it is excreted in urine (giving it its yellow colour
what gives urine its yellow colour
urobilinogen
describe the size of red blood cells and how they lead to anaemia
- Red blood cell size can be used to classify anaemia
- There is microcytic anaemia which is when the red blood cells are too small <80fl
- There is macrocytic anaemia which is when the red blood cells are too large >96fl
- There is normocytic anaemia which is when the red blood cells are normal size 80-96fl
what things cause microcytic anaemia
- Iron defiency
- Anaemia of chronic disorders
- Thalassaemias and haemoglobin E train
what things cause macrocytic anaemia
- Alcohol
- Vitamin B12 or folate deficiency
- Drug intake
- Haemolysis
- Liver disease
- Thyroid disease
what things cause normocytic anaemia
- Acute blood loss
- Anaemia of chronic disorders
- Anaemia of renal failure
- Haemolytic anaemia
- Anaemia of endocrine disease
- Early iron deficiency anaemia
- Mixed iron and vitamin B12/folate deficiency
- Sickle cell disease
what are the symptoms of microcytic anaemia with lack of iron
- Tiredness – lack of oxygen
- Shortness of breath – lack of oxygen
- Increased constipation
- Blood in stools
- Pale – less haemoglobin therefore less redness towards the skin
- Atrophic glossitis – low levels of iron mean that there are low levels of myoglobin, this is a molecule that has an important role in all muscles in the body
- Angular stomatitis/cheilitis – lack of iron
- Low haemoglobin – hyperchromic – reduced haemoglobin production due to iron deficiency
- Microcytic anaemia
- Microcystic red blood cells
- Normal white blood cells
- Normal platelet count
- Normal reticulocytes
describe patient 1
- explanation
- causes
- tests
Explanation
- Lack of iron means lack of haem groups therefore the oxygen cannot bind to the haemoglobin therefore there is reduced circulation of oxygen leading to tiredness and shortness of breath
Iron deficiency – due to low iron in diet, reduced red blood cell synthesis, excess iron loss may be due to bleeding – blood in stool inflammatory disorder, high stomach pH, hookworm, - need to test ferritin, take ferrous sulphate tablets, improve diet
Causes
- Taking NSAIDS
- Stomach ulcers
- Swelling of the large intestines or food pipe
- Piles
- Cancers of the bowel or stomach but this is less common
Tests
- Blood in stools mean there is bleeding in the digestive tract
- Could be due to, piles, anal fissure, bowel cancer
