45 - Anaemia and Thrombocytopenia Flashcards
Causes of anaemia
Haematinic deficiencies 2° to chronic disease Haemolysis Alcohol, drugs, toxins Renal impairment - EPO Primary haematological/marrow disease
Macrocytic anaemia causes
B12, folate, metabolic (liver, thyroid)
Marrow damage
Haemolysis
Normocytic anaemia causes
Anaemia of chronic disease/inflammatory
Microcytic anaemia causes
Iron deficiency
Hb disorders
Iron balance maintained by:
No excretion but limited absorption Controlled at level of gut mucosa Most iron is recycled Absorbed in duodenum Transported by transferrin Stored in ferritin/haemosiderin
Lab tests for Fe deficiency
FBC, indices and film Ferritin %hypochromic cells Serum iron/TIBC Marrow
Appearance of iron deficient cells
Small pale red cells (low MCV, low MCH)
Main causes of iron deficiency
Blood loss from anywhere
Increased demand i.e. pregnancy or growth
Reduced intake e.g. diet / malabsorption
Main causes of iron deficiency in children
Diet
Growth
Malabsorption
Main causes of iron deficiency in young women
Menstrual loss/problems
Pregnancy (can be v. long after pregnancy)
Diet
Main causes of iron deficiency in older people
Bleeding
GI problems
Iron therapy
Oral - unreliable
IM - painful, out-of-date
IV - increasingly used
Megaloblastic anaemia - why? in general
A characteristic cell morphology caused by impaired DNA synthesis
Causes of megaloblastic change
B12/folic acid deficiency
Alcohol
Drugs - cytotoxics, folate antagonists, N2O
Haematological malignancy
Congenital rarities - transcobalamin deficiency, orotic aciduria
How does B12 + folate cause anaemia?
DNA consists of purine/pyrimidine bases
Folates req. for synthesis
B12 essential for cell folate generation
Low folate therefore = B12 starves DNA of bases
Vit B12 in all diets in high numbers except…
Vegan
Where is vit B12 absorbed
Gastric parietal cells
Intrinsic factor
Receptors in terminal ileum
Stores sufficient for some years
B12 deficiency - effects
Pernicious anaemia (autoimmune) Gastrectomy
Small bowel problems (Crohn’s, jejunal diverticulosis, tapeworm)
What foods are folic acid in
Green veg Beans Peas Nuts Liver
Folic acid is absorbed where and what food reqs.
Needs daily intake
Absorbed in upper small bowel
Body stores four months worth
B12 or folate deficiency features
Megaloblastic anaemia Pancytopenia if more severe Mild jaundice Glossitis/angular stomatitis Anorexia / weight loss Sterility
Labs for B12 + folate deficiency
Blood count + film (sometimes marrow) Bilirubin + LDH B12&folate Antibodies B12 absorption tests
GI investigations - Crohn’s, malabsorption, blind loop
What is the classic cause of B12 deficiency
Pernicious anaemia
What is pernicious anaemia
Igs to parietal cells/intrinsic factor
Autoimmune associations
Atrophic gastritis with achlorhydria
Incidence of Ca stomach
What does SACDC stand for?
Subacute combined degeneration of the cord
SACDC features
Any cause of severe B12 deficiency
Anaemia not absolute req.
Demyelination of dorsal + lateral columns
Peripheral nerve damage
SACDC presentation
Peripheral neuropathy / paraesthesiae
Numbness and distal weakness
Unsteady walking
Dementia
SACDC treatment
B12+folate until B12 excluded
B12 x 5 then 3 months for life
Folic acid 5mg daily to build stores
Need for K+ and Fe initially
Haemolysis causes
Haemoglobinopathy
G6PD
Hereditary spherocytosis / elliptocytosis
Antibodies
Drugs, toxins
Heart valves
Vascular / vasculitis / microangiopathy
Tests for haemolysis
Anaemia High MCV, macrocytic High reticulocytes Blood film (fragments/spherocytes) Raised bilirubin, LDH Low haptoglobins Urinary haemosiderin
Anaemia of chronic disease
Common
Normal MCV
Reduced RBC production due to: abnormal iron metabolism, poor EPO response and blunted marrow response
Effects of ACD mediated by
Cytokine release - IL1,IL6, TNF-alpha
Hepcidin in particular -> regulator of iron absorption and release from macrophages
Features of ACD
Usually normal MCV, ferritin, % saturation of transferrin
Low serum iron + raised inflammatory markers
Treatment of ACD
Cause if possible
EPO/ IV Fe
Transfusion
All possible but need to check symptoms first
Causes of thrombocytopenia
Drugs, alcohol, toxins ITP Autoimmune diseases Liver/hypersplenism Pregnancy Haematological / marrow issues Infections DIC Congenital
ITP stands for?
Immune thrombocytopenia purpura
ITP features
Common - distinguishes kids + adults
Immune disorder
Can be acute/chronic/relapsing
ITP - clinical presentation
Bruising or petechiae or bleeding
Platelet count can be anywhere
ITP - therapy
Steroids are first line IV Ig Immunosuppressives or splenectomy Thrombo-mimetics Thrombopoetin
TTP stands for?
Thrombotic thrombocytopenia purpura
TTP - features
rare but urgent diagnosis needed
Most are immune (ADAMTS-13 / VWD)
TTP - clinical presentation
Fever
Neurological symptoms
Haemolysis (retics/LDH)
TTP - tests
Microangiopathy
Blood film fragments
TTP - therapy
Plasma exchange with FFP/plasma Steroids Vincristine Rituximab Outcomes vary Monitor ADAMTS-13
