Haematological Presentations Flashcards
Anaemia is defined as a haemoglobin concentration of less than
13.5 g/dL in men and 11.5 g/dL in women
MICROCYTIC (MCV <80 fL) Anaemia
DDX
- Iron deficiency
- Anaemia of chronic disease
- Thalassaemia (more common in certain groups)
NORMOCYTIC (MCV 80–95 fL) Anaemia DDX
Acute blood loss
Haemolytic anaemia
• Hereditary spherocytosis
• Sickle cell disease (most common in sub-Saharan Africa)
• G6PD deficiency (varies with ethnicity)
• Autoimmune haemolytic anaemia
• Malaria (geographic variability)
• Drugs (e.g. dapsone, quinine, sulphonamides)
• Red cell trauma (burns, mechanical heart valves)
Mixed deficiencies
Secondary anaemia (liver and renal disease)
Bone marrow failure
Pregnancy
MACROCYTIC (MCV >95 fL) Anaemia DDX
- Megaloblastic anaemia
- Pernicious anaemia
- Vitamin B12 deficiency
- Folate deficiency
- Alcoholism
- Liver disease
- Hypothyroidism
- Hyperthyroidism (Graves)
- Addison’s disease
- Marrow infiltration
- Drugs e.g. azathioprine, methotrexace.
SPECIFIC INVESTIGATIONS
Microcytic anaemia
■■ FBC and blood film
Low haemoglobin concentration occurs with microcytosis (MCV
<80 fL) and hypochromia (MCH <27 pg). The platelet count may
be raised when anaemia is associated with acute bleeding.
Microcytic, hypochromic red blood cells with accompanying
pencil cells may also be seen on the blood film.
■■ Serum iron and TIBC
Serum iron reduced and TIBC raised with iron deficiency. With
chronic disease both are reduced, and with thalassaemia both
are normal.
■■ Serum ferritin
Concentration of serum ferritin, a protein–iron complex, will be
reduced with iron deficiency. It is not affected by chronic disease
or thalassaemia.
■■ Faecal occult blood and faecal microscopy
Detects blood loss from the gastrointestinal tract. Hookworm
ova can be identified on microscopy.
■■ Free erythrocyte protoporphyrin
Iron is added to protoporphyrin to form haem; therefore, in the
presence of iron deficiency, protoporphyrin levels will be raised.
It is a sensitive indicator of iron deficiency and is unaffected by
chronic disease or thalassaemia.
■■ Hb electrophoresis
Allows the specific diagnosis and classification of thalassaemia
and sickle cell disease.
SPECIFIC INVESTIGATIONS Normocytic anaemia
■■ FBC and film
Low haemoglobin levels are accompanied by normal red cell
indices (MCV 80–95 fL, MCH >27 pg), which can also occur in
the presence of co-existing microcytic and macrocytic anaemia
(mixed deficiency), although this will usually be picked up on the
blood film. Certain haematology laboratories report RDW, which
is increased in the presence of differing red corpuscle sizes. The
reticulocyte count will be increased with haemolytic anaemia
and following acute blood loss, and the blood film may reveal
evidence of damaged red cells or sideroblasts.
■■ Tests for haemolysis
Unconjugated bilirubin, urine urobilinogen and faecal
stercobilinogen are raised with all causes of haemolysis.
Serum haptoglobins are absent. Plasma haemoglobin is
raised specifically with intravascular haemolysis. Reference to
haematology textbooks will be required for confirmatory tests
for individual haemolytic disorders.
■■ Urinalysis
Haemosiderin and haemoglobin will be present in the urine
specifically with intravascular haemolysis
■■ Bone marrow aspiration
Aspiration of the bone marrow will reveal erythroid hyperplasia
with haemolytic anaemia; with aplastic anaemia, bone marrow
hypoplasia with fat replacement results.
SPECIFIC INVESTIGATIONS Macrocytic anaemia
■■ FBC and film
Low haemoglobin is accompanied by macrocytosis (MCV >95 fL).
The reticulocyte count is low and accompanying low platelet
and white cell counts may indicate megaloblastic anaemia.
Hypersegmented neutrophils may be seen on the blood film.
■■ Serum vitamin B12 assay
Serum levels of vitamin B12 can be estimated and deficiency
readily ascertained. If the aetiology of vitamin B12 deficiency is
not apparent, a Schilling test can be performed to clarify if the
problem lies within the stomach, terminal ileum, or is due to
intrinsic factor.
■■ Antiparietal cell antibodies and anti-intrinsic factor antibodies
Pernicious anaemia results from lack of intrinsic factor
production or blocking antibodies.
■■ Serum and red cell folate
Both of these tests are low with folate deficiency; however, in
the presence of vitamin B12 deficiency the red cell folate may
actually be increased.
■■ Bone marrow aspiration
Megaloblasts are seen in marrow aspirates with vitamin B12 or
folate deficiency.
■■ Further tests
Further tests for individual diseases responsible for macrocytosis
or secondary anaemia need to be tailored according to the
clinical presentation.
Clotting Disorders congenital causes
- Haemophilia
* von Willebrand’s disease
Clotting Disorders acquired
- Vitamin K deficiency
- Haemorrhagic disease of the newborn
- Obstructive jaundice
- Fat malabsorption
- Liver disease
- Autoimmune diseases, e.g. SLE
- Drugs – heparin, warfarin, thrombolytic therapy
- DIC
- Massive transfusion
Haemophilia labs
PT normal
APTT Increased
TT normal
von Willebrand’s
disease labs
PT normal
APTT Increased
TT normal
Liver disease labs
PT Increased
APTT Increased
TT normal
Warfarin/vitamin K
deficiency labs
PT Increased
APTT Increased
TT normal
Heparin labs
PT
APTT Increased
TTN Increased
DIC labs
PT Increased
APTT Increased
TT Increased
