Common Causes of Anaemia and Thrombocytopenia Flashcards
What are examples of Macrocytic anaemia?
B12, Folate, metabolic (e.g. thyroid/liver disease)
Marrow damage (alcohol, drugs, marrow diseases)
Haemolysis (due to reticulocytosis)
What are examples of normocytic anaemia?
Anaemia of chronic disease / inflammatory
What are examples of microcytic anaemia?
Iron deficiency
Haemoglobin disorders
(sometimes chronic disease)
What lab tests can be used to establish low iron?
FBC
Fettitin
% hypochromic cells
What are the main causes of iron deficiency?
Blood loss from anywhere
Increased demand - pregnancy/growth
reduced intake- diet/malabsorption
What are the main causes of iron deficiency in children?
diet
growth
malabsorption
What are the main causes of iron deficiency in young women?
Menstrual loss/problems
Pregnancy
Diet
What are the main causes of iron deficiency in older people?
Bleeding
GI problems e.g. ulcer, malignancy, diverticulitis
What forms of iron treatment are available?
Oral iron - Often unreliable
IM iron - painful,out of date
IV iron - increasingly used
What is megaloblastic anaemia caused by?
characteristic cell morphology caused by impaired DNA synthesis
How do B12 + Folate cause anaemia?
DNA consists of purine/pyrimidine bases
folates are required for their synthesis
B12 is essential for cell folate generation
So low Folate or B12 starves DNA of bases
What are food sources of B12?
animal sources
Where is B12 absorbed in the body?
vitamin B12 binds to haptocorrin - produced by the salivary glands and the parietal cells in the stomach
in duodenum, pancreatic proteases degrades the haptocorrin and vitamin B12
Then binds to Intrinsic Factor produced by parietal cells
in the mucosal cells of the distal ileum the vitamin B12-Intrinsic Factor complex is recognised by special receptors
Vitamin B12 then enters the blood bound to transcobalamin = active B12
Can B12 be stored and for how long?
Yes can store
sufficient for some years
Who tends to suffer from B12 deficiency?
Nutritional - vegans
Gastric problems - Pernicious anaemia,
gastrectomy
Small bowel problems - Terminal ileal resection, Crohns, stagnant loops, jejunal diverticulosis, tropical sprue, Fish tapeworm
What sources of food contain lots of folic acid?
Must be consumed! green vegetable beans peas nuts liver
Where is folic acid absorbed?
upper small bowel
How long does the body store folic acid?
4 months
What can cause folic acid deficiency?
Mainly dietary/malnutrition
Malabsorption/small bowel disease
Increased usage: pregnany, haemolysis, inflammatory disorders
Drugs/alcohol/ITU (intensive therapy unit)
What clinical features are present in someone with B12/folate deficiency?
Megaloblastic anaemia
Can have pancytopenia if more severe - deficiency of red cells, white cells and platelets
Mild jaundice
Glossitis (inflammation of the tongue)/angular stomatitis (inflammation of corners of the mouth)
anorexia/weight loss
sterility - incapability to reproduction
What are the lab features B12/folate deficiency?
Blood count and film, marrow sometimes Bilirubin and Lactate Dehydrogenase B12 and folate levels Antibodies B12 absorption tests +/- IF GI investigations e.g. crohns, blind loop
What is pernicious anaemia?
Autoimmune disease
Antibodies to parietal cells/intrinsic factor
Atrophic gastritis with achlorhydria - absence of hydrochloric acid in the gastric secretions
Don’t form intrinsic factor
Incidence of stomach cancer
What is subacute combined degeneration of the cord (SACDC)?
Any cause of severe B12 deficiency - Anaemia not an absolute requirement
Demyelination of dorsal + lateral columns
Peripheral nerve damage
How does subacute combined degeneration of the cord (SACDC) present?
Peripheral neuropathy/Paraesthesiae
Numbness and distal weakness
Unsteady walking
Dementia
What is the treatment for B12 and folate deficiency?
Give both B12 + Folate until B12 deficiency excluded
B12 x5 then 3 monthly for life
Folic acid 5mg daily to build stores
What are the causes of haemolysis (simply)?
Things wrong inside the red cell
Things wrong with the red cell membrane
Things wrong external to the red cell
What are common causes of haemolysis inside the cell?
Haemoglobinopathy (Sickle cell) Enzyme defects (G6PD)
What are common causes of haemolysis with the membrane?
Hereditary Spherocytosis/elliptocytosis (RBC the wrong shape)
What are common causes of haemolysis outside the cell?
Antibodies (warm/cold)
Drugs/toxins
Heart valves
Vascular/vasculitis/‘microangiopathy
What tests show the presence of haemolysis?
Anaemic (can be compendated for)
High MCV, macrocytic
High Reticulocytes - an immature red blood cell without a nucleus having a granular appearance
Blood film (fragments/spherocytes)
Raised bilirubin, LDH (lactate dehydrogenase)
Low haptoglobins - protein that binds to haemoglobin
Urinary Haemosiderin - brown urine
What is the treatment for autoimmune haemolytic anaemia?
steroids
immunosuppression
Transfusion can be tricky as hard to cross match
Why is there reduced red cell production in anaemia of chronic disease?
Inflammatory cytokines control mechanism of absorption of iron - Hepcidine is the key regulator of iron absorption and release from macrophages
Abnormal iron metabolism
poor erythropoetin response
blunted marrow response
What are the features of anaemia of chronic disease?
No other causes of anaemia - diagnosis of exclusion A suitable medical history Usually mild anaemia, normal MCV Often raised inflammatory markers Normal/high ferritin + low serum iron Normal % Saturation transferrin
What is the treatment for anaemia of chronic disease?
The cause if possible
Erythropoetin
Iron? IV?
Transfusion?
What is immune thrombocytopenic purpura (ITP)?
isolated low platelet count characteristic purpuric rash increased tendency to bleed immune disorder Occurs on its own or as part of: Other autoimmune diseases, Lymphomas, CLL, HIV Can be acute/chronic/relapsing
What are the clinical features of immune thrombocytopenic purpura (ITP)?
Bruising characteristic purpuric rash increased tendency to bleed low platelet count No definitive test
What is the treatment for immune thrombocytopenic purpura (ITP)?
Steroid - first line IV immunoglobulin Other immunosuppressives splenectomy Newer thrombo-mimetics: Eltrombopag, Romiplostin
What is the outcome after treatment for immune thrombocytopenic purpura (ITP)?
Usually rapid responses
Can relapse after therapy
Rarely life-threatening
commonly recurrent
What is Thrombotic thrombocytopenia purpura (TTP)?
blood clots form in small blood vessels throughout the body
Rare but urgent diagnosis
Most are immune
Apart from thrombosis forming, what other symptoms are present in thrombocytopenia?
Fever
Neurological symptoms
Haemolysis
What urgent therapy is used in Thrombotic thrombocytopenia purpura (TTP)?
Plasma exchange with FFP/plasma
Steroids
Outcomes vary – can see relapses
