Blood film findings Flashcards
Basophilic stippling
megaloblastic anaemia, thalassaemias
sideroblastic anaemia alcohol abuse.
Howell Jolly Bodies - remnants of the red blood cell nucleus
Schistocytes are fragments of red blood cells seen in microangiopathic haemolytic anaemia (MAHA).
seen when
HUS
TTP
DIC
Left shift definition and causes
The number of lobes of the neutrophil nucleus can generally be used as an index of neutrophil maturity.
Left shift describes the presence of immature cells (including so-called band cells - neutrophils with an unlobed, band-shaped nucleus), compared with right shift which describes hypermature neutrophils with >5 nuclear lobes.
acute infection
more severe in leukaemias
A leukoerythroblastic film described to combined presence of immature (including nucleated) red blood cells and left shift (immature white cells).
It is suggestive of marrow fibrosis or invasion, such as: primary myelofibrosis, metastatic cancer, TB and Gaucher’s disease.
Anisocytosis is variation in red blood cell size, and quantified using the red cell distribution risk.
most common iron defieicy anemai
Cabot Rings are round red blood cell inclusions of unknown origin. They are slender loops seen in the cytoplasm of red cells in
megaloblastic anaemia, severe anaemia of any cause, lead poisoning and leukaemia.
Echinocytes or burr cells (from the Greek “echinos”, meaning “hedgehog” or “sea urchin”) are red blood cells with small, regularly distributed projections across the cell surface. They are distinct from acanthocytes (or spur cells) which appears irregularly spiked or thorny.
liver disease, vitamin E deficiency, end-stage renal disease, and the haemolytic enzyme disorder pyruvate kinase deficiency.
Reticulocytes are immature red blood cells.
haemolysis and acute bleeding
Target cells (also known as codocytes) are a relatively non-specific blood film finding. In contrast to spherocytes, which are thought to occur when the surface areas to volume ratio is reduced, target cells are thought to represent relative membrane excess.
They are seen in obstructive liver disease, haemoglobinopathies (thalassaemia and sickle cell disease), and post-splenectomy. In addition, small numbers may be seen in iron deficiency anaemia.
Rouleaux are stacks of aggregated red blood cells. They occur when the plasma protein concentration is high, such as in
myeloma
A 5 year old boy presents to the Paediatric Emergency Department with his father. He has recently been treated for a urinary tract infection with nitrofurantoin. Although his urinary symptoms have improved, his father has now noticed yellowing of the patient’s eyes and increased fatigue. The family have recently moved to the United Kingdom from Greece and his father reports the patient’s only past medical history is an episode of neonatal jaundice. On examination the patient has jaundiced sclera and appears lethargic. Blood test results are shown below.
Investigation Result Normal Range
Haemoglobin 62 g/l 135-180 g/l
White Cell Count 7.8 10^9^/l 4.0-11.0 10^9^/l
Platelets 265 10^9^/l 150-400 10^9^/l
Mean Corpuscular Volume 86 fl 82-100 fl
Bilirubin 29 umol/l 3-17 umol/l
Which of the following findings on blood film is consistent with the most likely diagnosis?
Heinz bodies and bite cells
This patient is presenting with haemolytic anaemia caused by underlying glucose-6-phosphate dehydrogenase deficiency (G6PD). G6PD is an X-linked recessive genetic disorder in which a deficiency of the glucose-6-phosphate enzyme results in free radicals destroying erythrocytes in response to oxidative stress. It occurs more commonly in patients of Mediterranean and African ethnicities. Triggers for haemolysis include intercurrent illnesses and infections, fava beans, henna and certain medications including nitrofurantoin, ciprofloxacin, sulfa-drugs and anti-malarials such as primaquine. The classic finding on blood film is Heinz bodies (denatured haemoglobin secondary to oxidative damage) and bite cells (erythrocytes with an irregular membrane caused by splenic macrophages attempting to remove Heinz bodies)
what is validity
Validity within a study describes how accurately it measures what it is intended to measure.
what can affect validity
Validity can be affected by the number of participants within a study. Where the sample size is smaller, the degree of validity decreases.
what is generalisability
Generalisability describes the extent to which the results of a study can be interpreted as representative of a wider population. Generalisability increases with sample size, but the sample size in this study has decreased.
