45 Anaemia + thrombocytopenia Flashcards
Simply, what are the causes of a macrocytic anaemia? (3).
B12/folate, metabolic.
Marrow damage.
Haemolysis (new RBC’s are larger).
What causes normocytic anaemia?
Anaemia of chronic disease/inflammation.
What causes a microcytic anaemia? (3).
Iron deficiency.
Haemoglobin disorders.
(Sometimes chronic disease).
Describe how iron is balanced in the body.
No excretion, limited absorption.
Controlled by gut mucosa, absorbed in duodenum.
What is iron transported by?
Transferritin.
What is iron stored in? (2)
Ferritin.
Haemosiderin.
Which lab tests are used to establish low iron? (3).
FBC, indices and film.
Ferritin.
% hypochromic cells.
What are the three main causes of low iron in children?
Diet.
Growth.
Malabsorption.
What are the three main causes of low iron in young women?
Menstrual loss/problems.
Pregnancy (body can’t increase uptake).
Diet.
What are the main causes of low iron in older people? (1,6)
Bleeding.
GI problems: ulcer, gastritis, malignancy, aspirin, diverticulitis, GI surgery.
How is low iron treated?
Oral iron (if it doesn't work give IV). Treat cause.
What do RBC’s look like in iron deficiency?
Microcytic.
Hypochromic.
What do RBCs look like in megaloblastic anaemia?
Macrocytic.
What are the causes of megaloblastic anaemia? (5).
B12/folate deficiency. Alcohol. Drugs: cytotoxics, folate antagonists, NO2. Haematological malignancies. Congenital: transcobalamin deficiency, orotic aciduria.
How does low B12/folate cause anaemia?
B12 needed to make folate. Folate needed to make purines. Purines needed for DNA synthesis.
Describe the sources of B12, its absorption and storage:
Animal sources only.
Gastric parietal cells, intrinsic factor and receptors in terminal ilium.
Stores sufficient for years.
What can cause B12 deficiency? (1,2,5)
Veganism.
Gastric: pernicious anaemia, gastrectomy.
Small bowel problems: resection, corns, diverticulosis, fish tapeworm, tropical sprue.
Describe the sources of folate:
Absorption site?
Storage:
Green vegetables, beans, peas, nuts, liver.
Absorbed in upper small bowel.
Body stores 4 months worth.
What causes folate deficiency? (8)
Mainly dietary.
Malabsorption.
Increased usage: pregnancy, haemolysis, inflammation.
Drugs/alcohol/ITU.
What are the features of B12/folate deficiency? (6).
Megaloblastic anaemia. If severe: pancytopenia. Mild jaundice. Glossitis. Anorexia/weight loss. Sterility.
What is the cause of pernicious anaemia?
Autoimmune attack on parietal cells making intrinsic factor.
What is SACDC?
Sub-acute combined degeneration of the cord.
Any cause of B12 deficiency will cause this.
How is B12/folate deficiency treated?
B12 and folate until B12 excluded.
Folic acid daily to build stores.
Potassium + iron supplement needed initially.
What are the common causes of haemolysis? (7).
Haemoglobinopathy (sickle cell). Enzyme defects (G6PD). Hereditary sphero/eliptocytosis. Antibodies. Drugs/toxins. Heart valves (fragmentation). Vasculitis.
How is autoimmune haemolytic anaemia managed?
Steroids/immunosuppression.
What is anaemia of chronic disease due to? (3).
Abnormal iron metabolism.
Poor erythropoetin response.
Blunted bone marrow response.
What is anaemia of chronic disease mediated by?
Release of Il-1, Il-6 and TNF-α.
Hepcidin (regulates iron release form macrophages).
What are the features of anaemia of chronic disease? (4).
Mild anaemia, normal MCV.
Raised inflamm markers: CRP, ESR, PV.
Normal/high ferritin + low serum iron.
Normal % transferrin saturation.
What are the two classical presentations of immune thrombocytopenia purpura?
Kids: acute, post viral, self limiting.
Adults: chronic, relapsing/remitting.
How is immune thrombocytopenia purpura treated? (4)
Steroids.
IV immunoglobulin (to overload spleen).
Immunosuppressives/splenectomy.
Thrombo-mimetics: Eltrombopag, romiplostin.
When should thrombotic thrombocytopenia purpura be suspected?
Thrombocytopenia with fever, neurological problems, haemolysis.
What is the immune basis of TTP? (2).
ADAMTS-13.
VWD.
How is TTP treated? (4).
Plasma exchange.
Steroids.
Vincristine.
Rituximab.
