45 - Anaemia and Thrombocytopenia Flashcards by David Thomas

Causes of anaemia

Haematinic deficiencies
2° to chronic disease
Haemolysis
Alcohol, drugs, toxins
Renal impairment - EPO
Primary haematological/marrow disease

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Macrocytic anaemia causes

B12, folate, metabolic (liver, thyroid)
Marrow damage
Haemolysis

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Normocytic anaemia causes

Anaemia of chronic disease/inflammatory

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Microcytic anaemia causes

Iron deficiency

Hb disorders

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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

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Lab tests for Fe deficiency

FBC, indices and film
Ferritin
%hypochromic cells
Serum iron/TIBC
Marrow

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Appearance of iron deficient cells

Small pale red cells (low MCV, low MCH)

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Main causes of iron deficiency

Blood loss from anywhere
Increased demand i.e. pregnancy or growth
Reduced intake e.g. diet / malabsorption

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Main causes of iron deficiency in children

Diet
Growth
Malabsorption

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Main causes of iron deficiency in young women

Menstrual loss/problems
Pregnancy (can be v. long after pregnancy)
Diet

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Main causes of iron deficiency in older people

Bleeding

GI problems

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Iron therapy

Oral - unreliable
IM - painful, out-of-date
IV - increasingly used

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Megaloblastic anaemia - why? in general

A characteristic cell morphology caused by impaired DNA synthesis

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Causes of megaloblastic change

B12/folic acid deficiency
Alcohol
Drugs - cytotoxics, folate antagonists, N2O
Haematological malignancy
Congenital rarities - transcobalamin deficiency, orotic aciduria

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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

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Vit B12 in all diets in high numbers except…

Vegan

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Where is vit B12 absorbed

Gastric parietal cells
Intrinsic factor
Receptors in terminal ileum

Stores sufficient for some years

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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&amp;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 ```