Haematology Flashcards
What are acanthocytes (Spur/spike cells)?
- RBCs show many spicules
What are underlying conditions of acanthocytes?
- Abetalipoproteinaemia,
- Liver disease
- Hyposplenism
What is basophilic RBC stippling?
- Accelerated erythropoiesis or defective Hb synthesis
- Small dots at the periphery are seen (rRNA)
What are underlying conditions of basophilic RBC stippling?
- Lead poisoning,
- Megaloblastic anaemia
- Myelodysplasia
- Liver disease
- Haemoglobinopathy e.g. thalassaemia
What are burr cells? (Echinocytes)
- Irregularly shaped cells
What are underlying conditions of burr cells?
- Uraemia
- GI bleeding
- Stomach carcinoma
What are Heinz bodies?
- Inclusions within RBCs of denatured Hb
What are underlying conditions of Heinz bodies?
- Glucose-6-phosphate dehydrogenase deficiency
- Chronic liver disease
What are Howell-Jolly bodies?
- Basophilic (purple spot) nuclear remnants in RBCs
What are underlying conditions of Howell-Jolly bodies?
- Post-splenectomy or hyposplenism
(e. g. sickle cell disease, coeliac disease, congenital, UC/Crohn’s, myeloproliferative disease, amyloid) - Megaloblastic anaemia, hereditary spherocytosis
What is leucoerythroblastic (myelophthisic) anaemia?
- Marrow infiltration- nucleated RBCs and primitive WBCs into peripheral blood
What are underlying conditions of leucoerythroblastic (myelophthisic) anaemia
- Marrow infiltration i.e. myelofibrosis, malignancy
What are Pelger Huet Cells?
- Hyposegmented neutrophil
What are underlying conditions of Pelger Huet cells?
- Congenital (lamin B Receptor mutation)
- Acquired (myelogenous leukaemia and myelodysplastic syndromes)
What is polychromasia? (Signs of reticulocytes)
- Red Blood cells of multiple colours (particularly grey-blue), due to differing amounts of Hb in RBC
What are underlying conditions of polychromasia?
- Premature/inappropriate release from BM
What are reticulocytes?
- Immature RBCs (mesh-like network of ribosomal RNA
becomes visible with certain stains i.e. new methylene blue)
What are underlying conditions of reticulocytes?
- ↑in haemolytic anaemias
- ↓aplastic anaemia
- chemo
What is right shift?
- Hypermature white cells - hypersegmented polymorphs (>5 lobes to nucleus)
What are underlying conditions of reticulocytes?
- Megaloblastic anaemia, uraemia, liver disease
What is Rouleaux formation?
- Red cells stacked on each other
What are underlying conditions of Rouleaux formation?
- Chronic inflammation
- Paraproteinaemia
- Myeloma
What are Schisocytes?
- Fragmented parts of RBCs – typically irregularly shaped, jagged and asymmetrical
What are underlying conditions of schisocytes?
- Microangiopathic anaemia, e.g. DIC, haemolytic uraemic syndrome, thrombotic thrombocytopenic
purpura, pre-eclampsia
What are Spherocytes?
- Sphere shaped RBC
What are underlying conditions of spherocytes?
- Hereditary spherocytosis,
- Autoimmune Haemolytic Anaemia
What are Stomatocytes?
- Central pallor is straight or curved rod-like shape. RBCs appear as ‘smiling faces’ or ‘fish mouth’
What are underlying conditions of spherocytes?
- Hereditary stomatocytosis
- High alcohol intake
- Liver disease
What are Target cells? (Codocytes)
- Bull’s-eye appearance in central pallor
What are underlying conditions of Target cells?
- Liver disease
- Hyposplenism
- Thalassaemia
- IDA
What is anaemia in men and women defined by?
- Men: <135g/L (13.5g/dL)
- Women: <115g/L (11.5g/dL)
What are causes of anaemia?
- Reduced production of RBCs or increased loss of RBCs (haemolytic anaemias)
- Increased plasma volume (pregnancy)
What are symptoms of anaemia?
- Fatigue
- Dyspnoea
- Palpitations
- Faintness
- Headache
What are signs of anaemia?
- Pallor, in severe anaemia (Hb < 80g/L) → hyperdynamic circulation e.g. tachycardia, flow
murmurs (ejection-systolic loudest over apex) → heart failure.
What are causes of microcytic anaemia? (FAST)
FAST
- Fe deficiency
- Anaemia of chronic disease
- Sideroblastic anaemia
- Thalassaemia (in the absence of anaemia)
What are the causes of normocytic anaemia?
- Acute blood loss
- Anaemic of chronic disease
- Bone marrow failure
- Renal failure
- Hypothyroidism
- Haemolysis
- Pregnancy
What are causes of macrocytic anaemia? (FATRBC)
FATRBC
- Fetus (pregnancy)
- Antifolates (e.g. phenytoin)
- Thyroid (hypothyroidism)
- Reticulocytes (release of larger immature cells e.g. with haemolysis)
- B12 or folate deficiency
- Cirrhosis (alcohol excess or liver disease)
- Myelodysplastic syndromes
What are the signs of iron deficiency anaemia?
- Koilonychia
- Atrophic glossitis
- Angular cheilosis
- Post-cricoid webs (Plummer-Vinson syndrome)
- Brittle hair and nails
What is on the blood film of iron deficiency anaemia?
- Microcytic
- Hypochromic
- Anisocytosis (varying size)
- Poikilocytosis (shape) pencil cells
What are gastroinestinal causes of iron deficiency anaemia?
Blood loss due to
- Meckel’s diverticulum (older children)
- Peptic ulcer/Gastritis (chronic NSAID use)
- Polyps/Colorectal cancer (most common cause in adults >50 years)
- Menorrhagia (women <50 years)
- Hookworm infestations (developing countries)
Apart from GI losses, what are other causes of IDA?
- Increased utilisation due to Pregnancy/lactation AND Infants/children- growth
- Decreased intake: Prematurity, Infants/children/elderly
- Loss of Fe each day fetus is not in utero
- Suboptimal diet
- Decreased absorption: Coeliac, Post-gastric surgery
- Absence in villous surface in duodenum
- Rapid transit, ↓ acid which helps Fe absorption
- Microangiopathic Haemolytic anaemia, PNH
- Chronic loss of Hb in urine → Fe deficiency
What are investigations for IDA (NICE Guidelines)?
- If no obvious cause
- OGD + colonoscopy, urine dip, coeliac investigations
What is the treatment of IDA?
- Treat the cause.
- Oral iron (SE: nausea, abdominal discomfort, diarrhea/constipation, black stools).
- With severe symptomatic anaemia: IV iron such as Ferrinject / Monofer (anaphylaxis risk)
What is anaemia of chronic disease?
- Cytokine driven inhibition of red cell production
What are causes of anaemic of chronic disease?
- Chronic infection (e.g. TB, osteomyelitis)
- Vasculitis
- Rheumatoid arthritis
- Malignancy etc.
Why is Ferritin high in ACD?
- Ferritin is an intracellular protein, iron store
- Fe sequestered in macrophage to deprive invading bacteria of Fe (unless the patient has co-existing iron deficiency anaemia)
What is ACD in renal failure due to?
- EPO deficiency
What is the pathophysiology of ACD?
- Inflammatory markers like IFNs, TNF and IL1 reduce EPO receptor production (and thus EPO synthesis) by kidneys.
- Iron metabolism is dysregulated.
- IL6 and LPS stimulate the liver to make hepcidin, which decreases iron absorption from gut (by
inhibiting transferrin) and also causes iron accumulation in macrophages.
What is sideroblastic anaemia?
- Ineffective erythropoiesis → iron loading (bone marrow) causing haemosiderosis (endocrine, liver and cardiac damage due to iron deposition)
How is sideroblastic anaemia diagnosed?
- Ring sideroblasts seen in the marrow (erythroid precursors with iron deposited in mitochondria in a ring around the nucleus).
What are causes of sideroblastic anaemia?
- Myelodysplastic disorders
- Following chemotherapy
- Irradiation
- Alcohol excess
- Lead excess
- Anti-TB drugs
- Myeloproliferative disease
What is the treatment of sideroblastic anaemia?
- Remove the cause
- Pyridoxine (vitamin B6 promotes RBC production)
What are the plasma iron studies of iron deficiency?
- Iron ↓ TIBC ↑ Ferritin ↓
What are the plasma iron studies of anaemia of chronic disease?
- Iron ↓ TIBC ↓ Ferritin ↑
What are the plasma iron studies of chronic haemolysis?
- Iron ↑ TIBC ↓ Ferritin ↑
What are the plasma iron studies of haemochromatosis?
- Iron ↑ TIBC ↓ (or N) Ferritin ↑
What are the plasma iron studies of pregnancy?
- Iron ↑ TIBC ↑ Ferritin N
What are the plasma iron studies of sideroblastic anaemia?
- Iron ↑ TIBC N Ferritin ↑
What are causes of macrocytosis?
- Megaloblastic: B12 deficiency, folate deficiency, cytotoxic drugs.
- Non-megaloblastic: Alcohol (most common cause of macrocytosis without anaemia), reticulocytosis (e.g. in haemolysis), liver disease, hypothyroidism, and pregnancy.
- Other haematological disease: Myelodysplasia, myeloma, myeloproliferative disorders, aplastic anaemia.
What are features of a megaloblastic blood film?
- Hypersegmented polymorphs
- Leucopenia
- Macrocytosis
- Anaemia
- Thrombocytopenia
What are sources of Vitamin B12?
- Meat and Dairy products
- We have large stores
What are causes of Vitamin B12 deficiency?
- Dietary (e.g. vegans)
- Malabsorption
- Stomach (lack of intrinsic factor which is produced by gastric parietal cells) → Pernicious anaemia, post gastrectomy
- Terminal ileum (absorption) due to ileal resection, Crohn’s disease, bacterial overgrowth, tropical sprue and tapeworms
What are clinical features of Vitamin B12 deficiency?
- Mouth: Glossitis, angular cheilosis
- Neuropsychiatric: Irritability, depression, psychosis, dementia
- Neurological: Paraesthesiae, peripheral neuropathy (loss of vibration and proprioception first, absent ankle reflex, spastic parapereisis, subacute combined degeneration of spinal cord)
What is pernicious anaemia?
- Autoimmune atrophic gastritis → achlorhydria and lack of gastric intrinsic factor
- Most common cause of a macrocytic anaemia in Western countries (Usually >40yrs)
What are specific tests for pernicious anaemia?
- Parietal cell antibodies (90%)
- Intrinsic factor antibodies (50%)
- Schilling test (outdated)
What is the treatment of Vitamin B12 deficiency?
- Replenish stores with IM hydroxocobalamin (B12)
What are sources of folate?
- DIET - green vegetables, nuts, yeast & liver, synthesized by gut bacteria (low body stores,
cannot produce de novo)
What are causes of folate deficiency?
- Poor diet
- Increased demand: pregnancy or ↑ cell turnover (haemolysis, malignancy, inflammatory disease and renal dialysis)
- Malabsorption: coeliac disease, tropical sprue.
- Drugs: alcohol, anti-epileptics (phenytoin), methotrexate, trimethoprim.
What is the treatment of folate deficiency?
- Give oral folic acid.
- If cause of anaemia is not known then folic acid must not be given, as this will exacerbate the neuropathy of B12 deficiency
What is haemolytic anaemia?
- Breakdown of RBCs before their normal lifespan of ~120 days
What are signs of all haemolytic anaemias?
- ↑bilirubin (unconjugated)
- ↑urobilinogen
- ↑LDH
- Reticulocytosis (↑ MCV and polychromasia)
- May have pigmented gallstones
What are signs of intravascular haemolytic anaemias?
- ↑ free plasma Hb
- ↓haptoglobin (binds free Hb)
- Haemoglobinuria (dark red urine)
- Methaemalbuminaemia (Haem + albumin in blood)
What are signs of extravascular haemolytic anaemias?
- Splenomegaly
What are erythroid hyperplasia states susceptible to?
- Parvovirus B19 (aplastic crisis)
- Iron overload
- Osteoporosis
How does haemolytic anaemia affect reticulocyte count?
- if the patient is acutely anaemic, you would expect a high reticulocyte count as this means the bone marrow is responding and working harder to produce more red cells
What are inherited causes of haemolytic anaemia?
- Membrane defect
- Hereditary spherocytosis
- Hereditary elliptocytosis
- Enzyme defect
- G6PD deficiency
- Pyruvate kinase deficiency
- Haemoglobinopathies
- Sickle Cell Disease
- Thalassaemias
What are acquired causes of haemolytic anaemia?
- Immune
- Autoimmune - warm or cold
- Alloimmune - Haemolytic transfusion reactions
- Non-immune
- Mechanical e.g. metal valves, trauma
- PNH, MAHA
- Infections (e.g. Malaria), Drugs