Haemotology Flashcards
Blood film: hyposplenism
- target cells
- Howell-Jolly bodies
- Pappenheimer bodies
- siderotic granules
- acanthocytes
Blood film:iron-deficiency anaemia
- microcytic, hypochromic
- target cells
- ‘pencil’ poikilocytes
- if combined with B12/folate deficiency a ‘dimorphic’ film occurs with mixed microcytic and macrocytic cells
Blood film:myelofibrosis
‘tear-drop’ poikilocytes
Blood film:intravascular haemolysis
schistocytes
Blood film: Megaloblastic anaemia
hypersegmented neutrophils
Target cells/ codocytes
Sickle-cell/thalassaemia
Iron-deficiency anaemia
Hyposplenism
Liver disease
due to increase in surface membrane area to volume ratio. either by increased membrane surface area or decreased intracellular haemoglobin
‘Tear-drop’ poikilocytes/ dacrocytes
Myelofibrosis
Due to compression of RBCs during release either from a fibrosed bone marrow or extramedullary haemopoiesis (RBCs produced outside the bone marrow e.g. Spleen)
Spherocytes
Hereditary spherocytosis
Autoimmune hemolytic anaemia
Rounded RBCs that have lost their biconcave shape due to membrane loss (usually in the spleen) and become spheres.
* This usually indicates active haemolysis.
* As a result of the shape, they cannot bend through capillaries as easily.
Basophilic stippling
Lead poisoning
Thalassaemia
Sideroblastic anaemia
Myelodysplasia
Describes the presence of small granular bodies (denatured RNA fragments) within the RBC cytoplasm due to disordered/accelerated erythropoiesis meaning RBCs with immature cytoplasm are released from the bone marrow.
Howell-Jolly bodies
Hyposplenism
Nuclear remnant found in RBCs, normally excluded before becoming reticulocytes and removed by the spleen
Heinz bodies
G6PD deficiency
Alpha-thalassaemia
Denatured Haemoglobin due to oxidative damage/unstable Hb.
* Normally removed by the spleen (becoming a bite/blister cell).
* Appears as “nose” or pale circle with specific staining.
Schistocytes (‘helmet cells’)
Intravascular haemolysis
Mechanical heart valve
Disseminated intravascular coagulation
Fragmented RBCs – caused by intravascular strands of fibrin or spleen dysfunction as the spleen removes RBCs from circulation.
* Small amounts can be seen in a normal individual.
‘Pencil’ poikilocytes
Iron deficency anaemia
Burr cells (echinocytes)
Uraemia
Pyruvate kinase deficiency
Describes cells with many (10-30) regular spicules.
a) Burr Cells:type of Echinocyte, found in patients with uraemia
Acanthocytes (spur cells)
Abetalipoproteinemia
These cells form from changes in the fats and proteins on red blood cells’ outer layers
Causes of iron deficiency
- Blood loss (e.g. GI, menorrhagia )
- Reduced absorption (e.g. small bowel disease (coeliac), hookworm infestation)
- Increased demands (e.g. growth, pregnancy)
- Reduced intake (e.g. vegans)
causes of microcytic anaemia
iron deficiency
thalassemia
sideroblastic anaemia
lead poisoning
presentation of anaemia
tiredness
dyspnea, esp on exertion
lethargy
pallor
exacerbation of ischemic conditions (angina, intermittent claudication)
palpitations
presentation of iron deficiency anaemia
anaemia presentation
- Pica
- restless legs syndrome
- Pallor
- Brittle nails and hair loss
- post cricoid webs→ plumber vinson syndrome
- Koilonychia (if severe): thinning, flattening, and then spooning of the nails
- glossitis
angular stomatitis
specific signs of lead poisoning
- Blue gumline
- Peripheral nerve lesions (causing wrist or foot drop)
- Encephalopathy
- Convulsions
- Reduced consciousness
- abdominal pain
- N&V
- constipation
Iron deficiency anaemia iron studies result
low serum iron
high TIBC
low transferrin saturation
low serum ferritin (raised ferritin does not necessarily rule out iron deficiency anaemia if the is co-occurring inflammation- high ferritin in anaemia of chronic disease)
Other: thrombocytosis. thrombocytopenia is severe, high RDW (anisocytosis), low MCHC & MCH, low Reticulocytes
anaemia of chronic disease iron study results
low TIBC
low serum iron
low transferrin saturation
high ferritin
anaemia of chronic disease iron study results
low TIBC
low serum iron
low transferrin saturation
high ferritin
lead poisoning blood film
basophilic stiplling
clover leaf morphology
when should you refer in anaemia
-
**2ww colorectal suspected cancer pathway referral
- Anaemia (iron-deficiency), 60 and over
- Anaemia (iron-deficiency, unexplained) with rectal bleeding in adults under 50
- post-menopausal women with a haemoglobin level ≤10 dg/L and men with a haemoglobin level ≤11 dg/L should be referred to a gastroenterologist within 2 weeks.These are considered if no obvious cause of blood loss is identified
- Upper GI endoscopy
- Colonoscopy
- Haematuria
- Offer testing for occult blood in faeces (FIT)
- Anaemia (iron-deficiency) without rectal bleeding in adults under 60
- Anaemia (even in the absence of iron-deficiency) without rectal bleeding, 60 and over - Offer testing for occult blood in faeces (FIT)
treatment of iron deficiency anaemia, common side effects
underlying cause
- oral iron supplements (ferris sulphate)
- ( Absorption is enhanced by ascorbic acid (vitamin C) & meat, and inhibited by calcium, fibre, tea, coffee, and wine )
- continue taking iron for 3 months after the iron deficiency has been corrected in order to replenish iron stores.
- Common side effects of iron supplementation include nausea, abdominal pain, constipation, diarrhoea
- Iron-rich diet: this includes dark-green leafy vegetables, meat, iron-fortified bread
-
2nd line if oral not working or intolerant :
- IV iron replacement
- red cell transfusion (esp, if cardiovascular compromise→ dyspnoea at rest, chest pain, or lightheadedness)
Lead poisoning treatment
- Remove the source
- various chelating agents are currently used:
- dimercaptosuccinic acid (DMSA)
- D-penicillamine
- EDTA
- dimercaprol
complications of anaemia
High-output cardiac failure
anaemia diagnostic values hb
<13.5 g/dL in men, <12 g/dL in women, and <11 g/dL in pregnant women
main points - Pathophys anaemia of chronic disease
Chronic disease precipitates the formation of inflammatory cytokines such as IL-1 and IL-6. High levels of IL-6 stimulates hepcidin release (from the liver) which is inhibitory in iron absorption as it decreases the activity of ferroportin.
Ferroportin is an iron export channel of the basolateral surface of gut (duodenal) enterocytes and the plasma membrane of reticuloendothelial cells (macrophages). Therefore, haemoglobin production decreases and anaemia of chronic disease precipitates. Also increased uptake of iron by macrophages
Anaemia is mainly due to decreased red blood cell production; may be aggravated by shortened red blood cell survival.
treatment of anaemia of CD
primarily treatment of the underlying disorder
if needed, adjunct with: red blood cell transfusion, erythropoises-stimulating agents (epoetin alfa or darbepoetin alfa SC), supplemental iron
- RBC transfususion if severe (<80g/L) or life threatening anaemia (<65g/L), heart failure, significant pulmonary disease, or cerebral vascular disease.
what is sideroblastic anaemia
red cells fail to completely form haem, whose biosynthesis takes place partly in the mitochondrion.
This leads to deposits of iron in the mitochondria that form a ring around the nucleus called a ring sideroblast. It may be congenital or acquired.
hemosiderosis of the liver, heart and endocrine organs (similar to that seen in hereditary haemochromatosis).
features of sideroblastic a
microcytic anaemia refractory to intensive iron therapy, associated with an atypically high serum ferritin and iron.
sideroblastic A: causes
Congenital cause: delta-aminolevulinate synthase-2 deficiency
Acquired causes
- myelodysplasia
- alcohol
- lead
- anti-TB medications - isoniazid
sideroblastic A: Ix & Tx
- full blood count
- hypochromic microcytic anaemia (more so in congenital)
- iron studies
- high ferritin
- high iron
- high transferrin saturation
- blood film
- basophilic stippling of red blood cells
- bone marrow
- Prussian blue staining will show ringed sideroblasts
- supportive
- treat any underlying cause
- pyridoxine may help
causes of B12 deficiency
Reduced absorption (e.g. post-gastrectomy, pernicious anaemia, terminal ileal resection or disease)
- Reduced intake (vegans)
- Abnormal metabolism (congenital transcobalamin II deficiency)
- Gastric causes – pernicious anaemia, chronic severe atrophic gastritis
- Pancreatic – any cause of pancreatic insufficiency
- Small bowel bacterial overgrowth (since bacteria utilize vitamin B12), terminal ileal resection, severe terminal ileal disease (i.e. Crohn’s disease)
- Tuberculosis
- Metformin therapy
- Zollinger-Ellison syndrome
- Drugs- colchicine, metformin, PPIs, H2 antagonists, anticonvulsants
pernicious anaemia
- Pernicious anaemiais an autoimmune condition involving gastritis, atrophy of all layers of the body and fundus of the stomach and loss of normal gastric glands, parietal and chief cells
- eads to alack of intrinsic factor
It commonly occurs in patients >40 years with a background of auto-immune thyroid disease, vitiligo, T1DM and Addison’s disease. In addition, patients have a 3x increased risk of gastric cancer.
Dietary insufficiency, malabsorption and excessive utilisation of vitamin B12 can also precipitate megaloblastic anaemia.
Causes ofFolate Deficiency:
- Reduced intake (alcoholics, elderly, anorexia)
- Increased demand (pregnancy, lactation, malignancy, chronic inflammation)
- Reduced absorption
- Jejunal disease (e.g. coeliac disease)
- Drugs (e.g. phenytoin)
- Methotrexate (dihydrofolate reductase inhibitor)
- Hydroxyurea
- Azathioprine
- Zidovudine
Non-Megaloblastic (normoblastic) causes of megaloblastic anaemia
- Alcohol excess
- Liver disease
- Myelodysplasia
- Multiple myeloma
- Hypothyroidism
- Haemolysis (shift to immature red cell form - reticulocytosis)
- Drugs (e.g. tyrosine kinase inhibitor, cytotoxic)
- pregnancy
blood film in megaloblastic anaemia
- Megaloblasts
- Hypersegmented neutrophil nuclei
- basophilic cytoplasm
Management Plan of megaloblastic anaemia
- VB12 deficiency**Symptomatic
- IM / SC cyanocobalamin or IM hydroxocobalamin first line. Then lifelong oral or parenteral.
- IF NEEDED : Can adjunct with blood transfusion w diuretic , oral folic acid
- dietary supplementation + multivitamines
-
Pernicious Anaemia
- IM hydroxycobalamin for life
-
Folate Deficiency
- Oral folic acid + treatment of the underlying condition
- If B12 deficiency is present, it must be treated before the folic acid deficiency
causes of normocytic anaemia
- Causes:
- Decreased production of normal-sized blood cells : Hypoproliferative (reticulocyte count <2%)
- aplastic anaemia
- anaemia of chronic disease
- chronic kidney disease
- Increased production of HbS
- sickle cell disease
- Increased destruction of red blood cells (e.g. haemolysis, post-haemorrhagic anaemia): Hyperproliferative (reticulocyte count >2%)
- haemolytic anaemia
- acute blood loss
- Uncompensated increase in plasma volume
- pregnancy, fluid overload
- Vitamin B2 deficiency
- Vitamin B6 deficiency
hereditary causes of haemolytic anaemia
- Membrane Defects
- Hereditary spherocytosis
- Elliptocytosis
- Paroxysmal nocturnal haemoglobinuria
- Metabolic Defects
- G6PD deficiency
- Pyruvate kinase deficiency
- Haemoglobinopathies
- Sickle cell disease
- Thalassemia
acquired causes of haemolytic anaemia
- Autoimmune
- Antibodies attach to erythrocytes causing intravascular and extravascular haemolysis
- Isoimmune
- Transfusion reaction
- Haemolytic disease of the newborn
- Drugs
- Penicillin
- Quinine
- NOTE: this is caused by the formation of a drug-antibody-erythrocyte complex
- Trauma
- Microangiopathic haemolytic anaemia (caused by RBC fragmentation in abnormal microcirculation)
- E.g. haemolytic uraemic syndrome, DIC, malignant hypertension
- prosthetic heart valves
- Microangiopathic haemolytic anaemia (caused by RBC fragmentation in abnormal microcirculation)
- Infection
- Malaria
- Sepsis
AIHA causes
Autoimmune haemolytic anaemia (AIHA)
It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection or drugs.
warm:
- idiopathic
- autoimmune disease: e.g.systemic lupus erythematosus*
- Lymphoproliferative neoplasms
- lymphoma
- chronic lymphocytic leukaemia
- drugs: e.g. methyldopa
Causes of cold AIHA
- neoplasia: e.g. lymphoma
- infections: e.g. mycoplasma, EBV
- Post-infectious haemolytic- occurring 2-3 weeks after
- Idiopathic
warm AIHA features
Warm is the most common type of AIHA.
- usuallyIgG
- haemolysis at body temperature
- haemolysis tends to occur in extravascular sites, for example the spleen.
causes
- idiopathic
- autoimmune disease: e.g.systemic lupus erythematosus*
- Lymphoproliferative neoplasms
- lymphoma
- chronic lymphocytic leukaemia
- drugs: e.g. methyldopa
cold AIHA features
The antibody in cold AIHA
- usuallyIgM
- haemolysis best at 4 deg C.
- Haemolysis is mediated by complement
- more commonly intravascular.
Features may include symptoms of Raynaud’s and acrocynaosis. Patients respond less well to steroids
Causes of cold AIHA
- neoplasia: e.g. lymphoma
- infections: e.g. mycoplasma, EBV
- Post-infectious haemolytic- occurring 2-3 weeks after
- Idiopathic
classification of haemolytic anaemia
AIHA: warm & cold
intravascular & extravascular
autoimmune (Coombs positive) and non-autoimmune (Coombs negative) haemolytic anaemia.
intravascular causes of haemolytic anaemia
- intravascular haemolysis occurs in the blood stream, resulting in release of cellular contents (in particular haemoglobin) into the circulation.
- This excess of haemoglobin is dealt with in many ways: combines with haptoglobin, combines with albumin (methaemalbuminaemia), loss in the urine (haemoglobinuria), and stored in tubular epithelial cells as haemosiderin and shed into the urine (hemosiderinuria).
- Intrinsic cellular injury (e.g. glucose-6-phosphate deficiency - G6PD)
- Intravascular complement mediated lysis (some autoimmune haemolytic anaemias
- Paroxysmal nocturnal haemoglobinuria and acute transfusion reactions)
- Mechanical injury (Microangiopathic haemolytic anaemia and cardiac valves)
- Autoimmune haemolytic anaemia
extravascular causes of haemolytic anaemia
Extravascular haemolysis occurs in the reticuloendothelial system (the spleen and liver) and is therefore not associated with dramatic release of free haemoglobin into the circulation. Splenomegaly and hepatomegaly are typical.
Causes of Extravascular haemolytic anaemia
Causes include:
Abnormal red blood cells (sickle cell anaemia and hereditary spherocytosis)
Normal cells marked by antibodies for splenic phagocytosis.
presentation of haemolytic anaemia
symptoms
- Jaundice
- Haematuria
- Anaemia symptoms → fatigue, dyspnea
- orthostatic hypotension
Presentation - signs
- Pallor
- Jaundice
- Hepatosplenomegaly
blood & urine results in haemolytic anaemia
- Low Hb
- High reticulocytes
- High MCV, can be normal too
- High unconjugated (direct) bilirubin
- Low haptoglobin (a protein that binds to free Hb released by red blood cells)
- high LDH
- U&Es, haemoglobinurea
- Folate
- High urobilinogen
- Haemoglobinuria
- Haemosiderinuria
blood film in haemolytic anaemia
- Leucoerythroblastic picture
- Macrocytosis
- Nucleated erythrocytes or reticulocytes
- Polychromasia
- May identify specific abnormal cells such as:
- Spherocytes
- Elliptocytes
- Sickle cells
- Schistocytes
- Malarial parasites
special tests in haemolytic anaemia
-
Direct Coombs’ Test (important for differentiating immune from non-immune aetiologies)
- Tests for autoimmune haemolytic anaemia
- Identifies erythrocytes coated with antibodies
-
Osmotic fragility test or Spectrin mutation analysis
- Identifies membrane abnormalities
-
Ham’s Test
- Lysis of erythrocytes in acidified serum in paroxysmal nocturnal haemoglobinuria
-
Hb Electrophoresis or Enzyme Assays
- To exclude other causes
- Bone Marrow Biopsy(rarely performed)
management of AIHA
underlying cause
warm AIHA
- treatment of any underlying disorder
- steroids (+/- rituximab)are generally used first-line
Other
- plasmapheresis
what is hereditary sperocytosis & pathophys
- most common hereditary haemolytic anaemia
- autosomal dominant defect of red blood cell cytoskeleton- cell membrane protein
- Abnormal sections of membrane are removed by the spleen, resulting in a reduced surface area to volume ratio and causing spherical distortion of cells (seen as spherocytes on blood film)
- as more membrane is removed, the cells haemolyse (extravascular haemolysis) and are removed from circulation in the spleen.
- red blood cell survival reduced as destroyed by the spleen
RFs & epidemiology of hereditary spherocytosis
family history of anaemia, jaundice, splenectomy, or known HS; also Northern European ancestry.
presentation of of hereditary spherocytosis
presents with neonatal or childhood onset jaundice/anaemia, and splenomegaly.
- failure to thrive
- jaundice,gallstones
- splenomegaly
- anaemia, pallor
- aplastic crisis precipitated by parvovirus infection
- degree of haemolysis variable
- MCHC elevated
Ix: hereditary spherocytosis
- the osmotic fragility test was previously the recommend investigation of choice. However, it is now deemed unreliable and is no longer recommended
- ‘patients with a family history of HS, typical clinical features and laboratory investigations (spherocytes, raised mean corpuscular haemoglobin concentration [MCHC], increase in reticulocytes) do not require any additional tests
- blood smear: spherocytes present, also may be pincer cells
- elevated unconjugated bilirubin
- LFTs normal
- if the diagnosis is equivocal the BJH recommend theEMA bindingtest and the cryohaemolysis/ acidified glycerol lysis test test
- for atypical presentations electrophoresis analysis of erythrocyte membranes is the method of choice
- negative direct anti-globulin test (DAT) and an elevated reticulocyte count.
Tx: hereditary spherocytosis
depends on the severity of the haemolysis and degree of anaemia, but is generally supportive for most patients.
- acute haemolytic crisis:
- treatment is generally supportive
- transfusion if necessary
- folate replacement
- longer term treatment:
- if severe: splenectomy
what is Paroxysmal nocturnal haemoglobinuria (PNH)
disorder leading to haemolysis (mainly intravascular) of haematological cells and thrombophilia
rare acquired stem cell disorder of unknown aetiology
It is thought to be caused by increased sensitivity of cell membranes to complement (see below) due to a lack of glycoprotein glycosyl-phosphatidylinositol (GPI).
- GPI can be thought of as an anchor which attaches surface proteins to the cell membrane
- complement-regulating surface proteins, e.g. decay-accelerating factor (DAF), are not properly bound to the cell membrane due a lack of GPI
- thrombosis is thought to be caused by a lack of CD59 on platelet membranes predisposing to platelet aggregation
may be associated with other stem cell defects and increased risk of thrombosis (via an effect on complement mediated platelet aggregation)
associated with relative or absolute marrow hypoplasia- aplastic anaemia
features of Paroxysmal nocturnal haemoglobinuria (PNH)
- haemolytic anaemia
- red blood cells, white blood cells, platelets or stem cells may be affected therefore pancytopaenia may be present
- haemoglobinuria: classically dark-coloured urine in the morning (although has been shown to occur throughout the day)
- thrombosis e.g. Budd-Chiari syndrome
- aplastic anaemia may develop in some patients
Patients are more prone to venous thrombosis