L6-7 Classfication & Laboratory Diagnosis of Anaemia Flashcards
What are the four main causes for anaemia?
Decrease in production
Increase in Haemolysis
Hypersplenism
Dilution
What are the differential diagnosis when the patient has a decrease in production?
Aplastic anemia or marrow infiltrative lesions
Derease in erythropoietin (chronic renal disease)
Iron deficiency
Thalamssemia
Folic acid deficiency
Myelodysplastic syndrome
What are the cause for hemolysis?
Intracorpuscular: Haemoglobinopathy, red cell enzymopathy, membrane abnormality
Extracorpuscular: alloimmune, autoimmune , drug induced, infeciton, mechanical, burn and toxin
What are the causes for hypersplenism?
Portal hypertension
Haemolytic disease
Chronic infection
Storage disease
What are the cause for dilutional anaemia?
Preognancy
Blood loss + fluid resuscitation
What are the clinical manifestation of anaemia?
Reduced amount of haemoglobin in blood - pallor
Tissue hypoxia - easy fatiuge
Cardiopulmonary compensation - palpitation, dyspnea
What is the most common cause of iron deficiency anaemia?
Blood loss
bleeding from peptic ulcer or carcinoma of colon
What are the clinical symptoms of iron deficiency anaemia?
no symptoms
general symptoms and signs of anaemia
Epithelial changes (glossitis, angular stomatitis, brittle naisl and dysphagia)
Pica
What are the biochemical finding in iron deficiency anaemia?
Low serum iron and low ferritin level
High serum transferrin but low transferrin saturation
What is the haemoatological findings in iron deficiency anaemia?
hypochromic microcytic red cells with anisopoikilocytes
Bone marrow: poorly haemoglobinised
Decrease or absent marrow iron store
Give some examples of vitamin B12 rich food
fish, liver and dairy products
Describe the uptake of vitamin B12
It binds with intrinsic factors secreted by parietal cells and enter the terminal ileum where it binds with transcobalamine
How is vitamin B12 relate to folate?
Vitamin B12 is needed to convert metyhl THF that enters the cell from plasma to THF, from which polyglutamate forms of folate are syntesised.
What are the cause for vitamin B12 deficiency
Dietary insufficiency
Gastric cause- prenicious anaemia, post- gastroectomy
Intestinal causes - Stagnant loop syndrome, malabsorption syndrome, fish tapeworm
Give a brief outline of prenicious anaemia
Antibodies against gastric parietal cells
Loss f parietal cells and intrinsic factors needed for vitamin B12 absorption
What are the clinical features of megaloblastic anaemia
Mild jaundice
Glossitis, angular stomatitis
Vitamin B12 neuropathy - peripheral neuropathy, optic atrophy, dementia, subacute combined degneration of cord
What are the haematological finding in a patient with megaloblastic anaemia?
Oval macrocytes, hypersegmented neutrophils, mild pancytopenia
What are the biochemical finding in a patient with megaloblastic anaemia
Raised methylmalonic acid and homocysteine elvels
Indirect hyperbilirubinaemia, increased lactate dehydrogenase level
How can we know whether it is a vitamin B12 or folate acid deficiency
Vitamin assay
What are the laboratory investigations in haemolytic anaemia
Increase in conjugated and unconjugated bilirubin
Abnormalities of RBC shape in the peripheral blood smear
Erythroid hyperplasia
What is the destiny for the haem in intravascular haemolysis
Taken up by haptoglobin
Forming methaemalbumin
Haemolgobinaemia and haemoglobinuria may result
Outline the pathogenesis in haemolytic anaemia
Deficiency or dysfunction in red cell membrane skeletal proteins cause membrane loss, decreased surface area to volume ratio, reduced deformability and inability to pass through microcirculation
