Nutritional Anaemia Flashcards
Define anaemia
Insufficient oxygen carrying capacity is due to reduced haemoglobin concentration as seen with insufficient RBC.
What is haemoglobin?
Iron containing oxygen transport metalloprotein within RBCs
What are the haemoglobin levels bellow which you are diagnosed with anaemia?
Women: >120
Men: >130
Pregnant women: >110
What is required for the maturation of red blood cells?
Vitamin B12 (to make DNA)
Iron (to make haemoglobin
What are the three causes of anemia?
Faliure of production (hypoproliferation, reticulocytopenic)
Ineffective erythropoiesis
Decreased survival (blood loss, haemolysis, reticulocytosis)
What are reticulocytes?
Red blood cells that are still developing
What causes low haemoglobin level using MCV?
Microcytic (small RBC)
- Iron deficiency (heme deficiency)
Normal
- Sickle cell disease
Macrocytic (large RBC)
- B12 deficiency (folate deficiency)
What is the importance of iron?
Essential for oxygen transport
Most abundant trace element in the body
Daily requirement for iron for erythropoiesis varies depending on gender and physiological needs
What is the main source of iron?
Meat sources and seafood
Describe the distribution of iron in adults.
- Dietary iron is consumed
- Duodenum produces plasma transferrin
- Transferring takes iron to where it’s most needed (bones marrow and muscle and stored in liver)
- Iron loss through menstruation and sloughed mucosal cells
How is iron metabolised?
Most iron in the body is circulating as Hb
Remain as storage proteins and transport proteins (found in liver, spleen and bone marrow)
Stable forms of iron are:
Ferric states (+3)
Ferrous states (+2)
How is iron absorption regulated?
Regulated by
- GI mucosal cells and hepcidin
- Duodenum And proximal jejunum
Via ferroportin receptors on enterocytes
Transferred into plasma and binds to transferrin
What determines the amount of iron absorbed?
Depends on the type ingested
Heme Ferrous (red meat) > non-heme ferric forms
- Other foods
- GI acidity
- State of iron storage levels
- Bone marrow activity
How does hepcidin regulate iron?
Causes ferroportin internalisation and degradation
Thereby increasing iron transfer into blood plasma from the duodenum
Feedback regulates by iron containing concerntion in plasma, liver, and erythropoietin demand for iron.
How is iron stored?
Stored as ferritin in liver
A state of iron deficiency will see reduced feratin stores and then increased transferrin
How is iron transported around the body?
In plasma: attaches to transferrin and then transported to bone marrow where is binds to receptors on RBC precursors
What do laboratory iron studies show?
Serum Fe
Ferritin
Transferrin saturation
Transferrin
Total iron binding capacity
What laboratory results would indicate anaemia?
Ferritin - LOW
transferrin saturation - LOW
TIBC - HIGH
serum iron - LOW/NORMAL
What are iron deficiency causes?
NOT ENOUGH:
Poor diet
Malabsorption
Increased physiological needs
LOOSING TOO MUCH:
Blood loss
Gi tract loss
Menstruation
What are iron deficiency investigations?
Full blood count: Hb, reticulocyte count
Iron studies: ferritin, transferrin saturation
Blood film
What are the stages in development of iron deficiency anaemia (IDA)?
Normal - iron depletion - pre-latent iron deficiency - latent iron deficiency - iron deficient erythropoiesis insist - early iron deficiency anaemia - late iron deficiency anaemia
What are some symptoms of anaemia?
Tired/fatigue
Dizzy
Pale
Cardio problems
What is vitamin B12 and folate deficiency?
Both have similar laboratory findings and clinical symptoms
Cause MACROCYTIC ANAEMIA
What is macrocytic anaemia?
Low Hb
High MCV (mean cell volume)
Normal MCHC (mean cell haemoglobin concerntration)
Megaloblastic: caused by vitamin B12/folic acid deficiency
Non megaloblastic: caused by alcoholism, hypothyroidism, liver disease, reticulocytosis
What is the source of B12?
Animal and dairy produce
Adult daily intake usually more than required due to average diet
Absorption site: ileum vie intrinsic factor
What is the source of folate?
Vegetables and liver
Daily adult intake is a bit more then we normal need
Absorption site: duodenum and jejunum
What is the function of vitamin B12 (cobalamin) and folic acid?
Important for the final maturation of RBCs and for synthesis of DNA
BOTH needed for thymidine triphosphate synthesis
What is folate used for?
DNA synthesis
Adenosine, guanine and thymidine synthesis
What are some causes of folate deficiency?
Increased demand:
- pregnancy/ breast feeding
- haemolysis and rapid cell turn over
- infancy and growth spurs
Decreased intake:
- poor diet
- elderly
- chronic alcohol intake
Decreased absorption:
- medication
- coeliac
What is the function of vitamin B12?
Essential for methylation in DNA and cell metabolism
Intracellular conversion to 2 active coenzymes necessary for the homeostasis of methylmalonic acid (MMA) and homocysteine
What is the source of vitamin B12?
Animal sources: fish, meat, dairy
How is vitamin B12 absorbed?
Requires intrinsic factor for absorption in terminal ileum
IF made in parietal cells in stomach transcobalamin 1+2 transport vitB12 to tissues
What are some causes of B12 deficiency?
Impaired absorption:
- Pernicious anaemia
- Parasites
Decreased intake:
- malnutrition
- vegan diet
Conginental causes:
- intrinsic factor receptor deficiency
- cobalamin mutation
Increased requirement:
- pregnancy
- growth spurts
- haemolysis
- HIV
Medication
- alchohol
- NO
- metformin
What is pernicious anaemia?
Autoimmune disorder - antibodies made for intrinsic factor in gastric parietal cells
Lack of Intrinsic factor
Lack of B12 absorption
What are the treatments for iron deficiency?
Diet
Oral
Stopping the bleeding
Parietal iron Supplementation
How is folic acid deficiency treated?
Oral supplements
How is B12 deficiency treated?
Oral
Inter muscular treatment
What are the clinical consequences of B12 deficiency?
Brain:
- cognition
- depression
- phycosis
Neurology:
- Myelopathy
- Ataxia
- Sensory changes
- spasticity (SACDC)
Infertility
Cardia cardiomyopathy
Tongue:
- taste impairment
- glossitis
Blood: pancytopenia
