Haematology Flashcards
What is aplastic anaemia?
Characterised by diminished haematopoietic precursors in the bone marrow and deficiency of all blood cell elements (pancytopaenia)
What is the aetiology of idiopathic aplastic anaemia?
May be due to destruction or suppression of the stem cell by autoimmune mechanisms
What is the aetiology of acquired anaplastic anaemia?
- Drugs (chloramphenicol, gold, alkylating agents, antiepileptics, sulphonamids, methotrexate, nifedipine)
- Chemicals (DDT, benzene)
- Radiation
- Viral infection (B19 parvovirus, HIV, EBV)
- Paroxysmal nocturnal haemoglobinuria
What is the aetiology of inherited aplastic anaemia?
- Fanconi’s anaemia
- Dyskeratosis congenita (associated with reitculated hyperpigmented rash, nail dystrophy and mucosa leukoplakia)
What is the epdemiology of aplastic anaemia?
- Can occur at any age
- Slightly more common in males
What are the presenting symptoms of aplastic anaemia?
Slow (months) or rapid (days) onset
- Anaemia: Tiredness, lethargy, dyspnoea
- Thrombocytopaenia: Easy bruising, bleeding gums, epistaxis
- Leukopenia: Increased frequency and severity of infections
What are the signs of aplastic anaemia on examination?
- Anaemia: Pale
- Thrombocytopaenia: Petechiae, bruises
- Leukopenia: Multiple bacterial or fungal infections. No hepatomegaly, splenomegaly or lymphadenopathy
What are the investigations for aplastic anaemia?
- Blood: FBC (reduced Hb, platelets, WCC, normal MCV, low or absent reticulocytes)
- Blood film: Exclude leukaemia
- Bone marrow trephine biopsy:
- Criteria for severe aplastic anaemia (AA)
What is a blood transfusion?
Process of receiving blood or blood products into one’s circulation intravenously
What are the indications for a blood transfusion?
- Anaemia
- Major surgical operation
- Accidents resulting in considerable blood loss
- Cancer pts requiring therapy
- Severe burn victims
- Pts of hereditary disorders like Haemophilia and Thalassaemia
What are the possible complications of blood transfusions?
- Acute haemolytic reactions
- Delayed haemolytic reactions
- Febrile nonhaemolytic reactions
- Allergic
- Tranfusion-associated acute lung injury
What is disseminated intravascular coagulation (DIC)?
Disorder of the clotting cascade that can complicate a serious illness. May occur in 2 forms:
1) Acute overt form where there is bleeding and depletion of platelets and clotting factors
2) Chronic non-overt form where thromboembolism is accompanies by generalised activation of the coagulation system
What is the aetiology of DIC?
- Infection: Particularly Gram-negative sepsis
- Obstetric complications: Missed miscarriage, severe pre-eclampsia, placental abruption, amniotic emboli
- Malignancy: Acute promyelocytic leukaemia (acute DIC), lung, breast, GI, malignancy (chronic DIC
- Also haemolytic transfusion reaction, burns, severe liver disease , aortic aneurysms, haemangiomas
What is the aetiology of acute DIC?
- Activation of coagulation is a consequence of endothelial damage and increased release of granulocyte/macrophage procoagulant substances e.g. tissue factor
- Explosive thrombin generation depletes clotting factors and platelets while simultaneously activating the fibrinolytic system
- Leads to bleeding in subcutaneous tissues, skin and mucous membranes
- Occlusion of blood vessels by fibrin results in microangiopathic haemolytic anaemia and ischaemic organ dammage
What is the epidemiology of DIC?
Seen in any severely ill patient
What are the presenting symptoms of DIC?
If pt is severely unwell with symptoms of the underlying disease, confusion, dyspnoea and evidence of bleeding
What are the signs of DIC on examination?
Signs of underlying aetiology, fever, evidence of shock (hypotension, tachycardia)
- Acute DIC: Petechiae, purpura, echhymoses, epistaxis, mucosal bleeding, over haemorrhage. Signs of end organ damage (e.g. local infarction or gangrene), respiratory distress, oliguria caused by renal failure
- Chronic DIC: Signs of deep venous or arterial thrombosis or embolism, superficial venous thrombosis, especially without varicose veins
What are the investigations for DIC?
- Blood: FBC (reduced platelets, Hb. Clotting: Increased APTT/PT/TT, fibrin degradation products and d-dimers, reduced fibrinogen)
- Peripheral blood film: Red blood cell fragments (schistocytes). Other investigations according to aetiology
What is haemochromatosis?
Body iron overload resulting from excessive intestinal iron absorption which may lead to organ damage (particular liver, joints, pancreas, pituitary and heart)
What is the aetiology of haemochromatosis?
- Mutation in the HFE gene on chromsome 6p
- Most common mutation is C282Y, less common is H63D
What is the epidemiology of haemochromatosis?
- Carrier frequency is up to 1/10, not all express disease
- Age of presentation = 40-60 yrs typically
- Females have later onset and less severe presentation as a result of iron loss through menstruation
What are the presenting symptoms of haemochromatosis?
- May be asymptomatic
- Non specific symptoms: weakness, fatigue, lethargy and abdo pain
- Later features: small/large joint pains (most commonly 2nd/3rd MCP joints), symptoms of liver disease, DM, hypogonadism, cardiac failure
- Exclude causes of secondary iron overload (e.g. multiple transfusions)
What are the signs of haemochromatosis on examination?
May be normal, but with severe iron overload:
- Skin: Pigmentation (‘slate-grey) resulting from increased melanin deposits
- Liver: Hepatosplenomegaly
- Heart: Signs of heart failure, arrhythmias
- Hypogonadism: Testicular atrophy, loss of hair, gynaecomastia
What are the investigations for haemochromatosis?
- Blood: Increased iron, ferritin and transferrin sats, reduced TIBC
- Gene typing of HFE
- Test for complications in various organs, LFTs, fasting or random blood glucose, pituitary function test, ECG, Joint X-ray
What is haemolytic anaemia?
Premature erythrocyte breakdown causing shortened erythrocyte life span (less than 120 days) and anaemia
What is the aetiology of hereditary haemolytic anaemia?
- Membrane defects: Hereditary spherocytosis, elliptocytosis
- Metabolic defects: G6PD deficiency. Pyruvate kinase deficiencies (autosomal recessive)
- Haemoglobinopathies: Sickle cell disease, thalassaemia
What is the aetiology of acquired haemolytic anaemia?
- Autoimmune: Warm or cold antibodies attach to erythrocytes causing intravascular haemolysis and extravascular haemolysis
- Isoimmune: Transfusion reaction, haemolytic disease of the newborn
- Drugs: Penicillin, quinine
- Trauma: Microangiopathic haemolytic anaemia caused by red cell fragmentation in abnormal microcirculation (haemolytic uraemic syndrome, DIC, pre-eclampsia), artificial heart valves
- Infection: Malaria, sepsis
- Paroxysmal nocturnal haemoglobinuria
What is the epidemiology of haemolytic anaemia?
- Common
- Genetic causes prevalent in African, Mediterranean, Middle Eastern populations
- Hereditary spherocytosis is most common inherited haemolytic anaemia in Northern Europe
What are the presenting symptoms of haemolytic anaemia?
- Jaundice
- Haematuria
- Anaemia
- Ask about systemic illness, family, drug and travel history
What are the signs of haemolytic anaemia on examination?
- Pallor (anaemia)
- Jaundice
- Hepatosplenomegaly
What are the investigations for haemolytic anaemia?
- Blood: FBC (reduced Hb, raised reticulocytes, MC, unconjugated bilirubin), U&E, folate
- Blood film: Leucoerythroblastic picture, macrocytosis, nucleates erythrocytes , polychromasia
- Urine: Raised urobilirubinogen
- Direct Coombs’ test: Identifies erythrocytes coated with antibodies
- Osmotic fragility test
- Ham’s test
- Hb electrophoresis
- Bone marrow biopsy
What is haemolytic uraemic syndrome?
Triad of microagniopathic haemolytic anaemia, acute renal failure and thrombocytopaenia. 2 forms
1) D+ (diarrhoea-associated form)
2) D- (no prodromal illness identified
What is the aetiology of haemolytic uraemic syndrome?
- Aetiological factor causing endothelial injury result in platelet aggrregation, release of unusually large wVF multimers and activation of platelets and the clotting cascade
- Results in small vessel thrombosis, particularly the glomerular afferent arteriole and capillaries which undergo fibrinoid necrosis
- Followed by renal ischaemic and acute renal failure
- Thrombi promote intravascular haemolysis
What are the risk factors for haemolytic uraemic syndrome?
- Infection: Verotoxin-producing E.coli, Shigella neuraminidase-producing infections, HIV
- Drugs: Oral contraceptive pill, ciclosporin, mitomycin, 5-fluorouracil
- Others: Malignant hypertension, malignany, pregnancy, SLE, scleroderma
What is the epidemiology of haemolytic uraemic syndrome?
- Uncommon
- D+ often affects young children, occurs more often in summer in endemics and is most common cause of acute renal failure in children
What are the presenting symptoms of haemolytic uraemic syndrome?
- GI: Severe abdominal colic, water diarrhoea that becomes bloodstained
- General: Malaise, fatigue, nausea, fever, less than 38 (D+)
- Renal: Oliguria or anuria, haematuria
What are the signs of haemolytic uraemic syndrome on examination?
- General: Pallor (from anaemia), slight jaundice (from haemolysis), bruising (severe thrombocytopaenia), generalised oedema, hypertension and retinopathy
- GI: Abdominal tenderness
- CNS signs: Weakness, reduced vision, fits, reduced consciousness
What would be the blood results after investigating haemolytic uraemic syndrome?
- FBC: Normocytic anaemia, raised neutrophils, reduced platelets
- U&E: Raised urea, creatinine, urate, K+, reduced Na+
- Clotting: Normal Pit, APTT and fibrinogen levels, abnormality may indicate DIC
- LFT: Raised unconjugated bilirubin, raised LDH from haemolysis
- Blood cultures
- ABG: Reduced pH, bicarbonate, pac02, normal anion group
- Blood film: Fragmented red blood cells, raised reticulocytes, spherocytes
What are the investigations for haemolytic uraemic syndrome?
- Urine: more than 1g protein/24h
- Stool samples
- Renal biopsy: contraindicated in severe thrombocytopaenia
What is haemophilia?
Bleeding diatheses resulting from an inherited deficiency of a clotting factor
1) Haemophilia A (most common): deficiency of factor VIII
2) Haemophilia B: deficiency of factor IX (Christmas disease)
3) Haemophilia C (rare): Deficiency of factor XI
What is the aetiology of haemophilia?
- A & B exhibit X-linked recessive inheritance.
- Factor VIII is vital co-factor in intrinsic pathway of coagulation cascade. Activated factor IX activates factor X (X -> Xa)
What is the epidemiology of haemophilia?
- A= 1/5-10,000 males
- B= 1/25-30,000 males
- C more common in Ashkenazi Jews
What are the presenting symptoms of haemophilia?
- Symptoms usually begin from early childhood
- Swollen painful joints occurring spontaneously or with minimal trauma (haemarthroses)
- Painful bleeding into muscles. Haematuria. Excessive bleeding or bleeding after surgery or trauma
- Female carriers usually asymptomatic, but may have low enough levels to cause excess bleeding after trauma
What are the signs of haemophilia on examination?
- Multiple bruises
- Muscle haematomas. Haemarthroses. Joint deformity,
- Nerve palsies (nerve compression by haematoma)
- Signs of iron deficiency anaemia
What are the investigations of haemophilia?
- Clotting screen (raised APTT, reflects the activity of intrinsic and the common pathway)
- Coagulation factor assays (reduced factor VIII, IX or CI depending on condition)
- Other investigations according to complications (e.g. arthroscopy)
What is immune thrombocytopenic purpura (ITP)?
Syndrome characterised by immune destruction of platelets resulting in bruising or bleeding tendency
What is the aetiology of ITP?
- Often idiopathic
- Acute ITP usually seen after a viral infection in children, while chronic form is more common in adults
- May be associated with infections (malaria, EBV, HIV), autoimmune disease (SLE, thyroid disease), malignancies and drugs (e.e. quinine)
- Autoantibodies that bind to platelet membrane proteins results in thrombocytopenia (glycoprotein IIb/IIIa and Ib/IX)
What is the epidemiology of ITP?
- Acute ITP presents in children between 2-7 yrs
- Chronic ITP seen in adults & is 4x more common in women
What are the presenting symptoms of ITP?
- Easy bruising
- Mucosal bleeding
- Menorrhagia
- Epistaxis
What are the signs of ITP on examination?
- Visible petechiae, bruises (purpura or ecchymoses
- Typically, signs of other illness (e.g. infections, wasting, splenomegaly) would suggest other causes
What are the investigations for ITP?
- Diagnosis of exclusion: Excluse myelodysplasia, acute leukaemia, marrow infiltration
- Blood: FBC (reduced platelets), clotting screen, autoantibodies
- Blood film: Rule out ‘pseudothrombocytopenia’) caused by platelet clumping given falsely low counts
- Bone marrow: Exclude other pathology
What is acute lymphoblastic leukaemia (ALL)?
Malignancy of the bone marrow and blood characterised by the proliferation of lymphoblasts (primitive lymphoid cells)
What is the aetiology of ALL?
Lymphoblasts undergo malignant transformation and proliferation, with subsequent replacement of normal marrow elements, leading to bone marrow failure and infiltration into other tissues
What are the risk factors ALL?
- Environment (radiation, viruses)
- Genetic (Down’s syndrome
- Neurofibromatosis type 1
- Fanconi’s anaemia
- Achondroplasia
- Ataxia telangiectasia
- Xeroderma pigmentosum
- X-linked agammaglobulinaemia
- Increased risk in siblings
What is the epidemiology of ALL?
- Most common malignancy of childhood
- Peak incidence 2-5 yrs
- Second peak in elderly
What are the presenting symptoms of ALL?
- Symptoms of bone marrow failure: Anaemia (fatigue dyspnoea), bleeding (spontaneous bruising, bleeding gums, menorrhagia), opportunistic infections (bacteria, viral, fungal, protozoal)
- Symptoms of organ infiltration: Tender bones, enlarged lymph nodes, mediastinal compression (in T-cell ALL), meningeal involvement (headache, visual disturbances, nausea)
What are the signs of ALL on examination?
Signs of bone marrow failure: Pallor, bruising, infections (e.g. fever, GI, skin, respiratory systems)
- Signs of organ infiltration: Lymphadenopathy, hepatosplenomegaly, cranial nerve palsies, retinal haemorrhage or papilloedema or fundoscopy, leukaemia infiltration of the anterior chamber of the eye (mimic hypopyon), testicular swelling
What are the investigations for ALL?
- Blood: FBC (normochromic, normocytic anaemia, reduced platelets, variable WCC) raised uric acid & LDH, clotting screen
- Blood film: Lymphoblasts seen
- Bone marrow aspirate or trephine biopsy: Hypercellular with more than 30% lymphoblasts
- Immunophenotypic
- Cytogenics
- Cytochemistry
- Lumbar puncture: for CNS involvement
- CXR: mediastinal lymphadenopathy, thymic enlargement, lytic bone lesiosn
- Bone radiographs: Mottled appearance with ‘punched out’ lesions
What is acute myeloblastic leukaemia (AML)?
Malignancy of primitive myeloid lineage white blood cells (myeloblasts) with proliferation in the bone marrow and blood
What is the aetiology of AML?
Myeloblasts, arrested at early stage of development, with varying cytogenetic abnormalities, undergo malignant transformation and proliferation. Subsequence replacement of normal marrow elements, bone marrow failure
What is the epidemiology of AML?
Most common acute leukaemia in adults
Incidence increases with age
What are the presenting symptoms of AML?
- Symptoms of bone marrow failure: Anaemia (lethargy, dyspnoea), bleeding (thrombocytopenia of DIC), opportunistic or recurrent infections
- Signs of tissue infiltration: Gum swelling or bleeding, CNS involvement (headaches, nausea, diplopia), especially with M4 & M5 variants
What are the signs of AML on examination?
- Signs of bone marrow failure: Pallor, cardiac flow murmur, echhymoses, bleeding, opportunistic or recurrent infections (e.g. fever, mouth ulcers, skin infections, PCP)
- Signs of tissue infiltration: Skin rashes, gum hypertrophy, deposit of leukaemic blasts may rarely be seen in the eye (chloroma), tongue and bone- in latter may cause fractures
What are the investigations for AML?
- Blood: FBC (reduced Hb, platelets, variable WCC), raised uric acid & LDH, clotting studies
- Blood film: AML blasts may show cytoplasmic granules or Auer rods
- Bone marrow aspirate or biopsy: Hypercellular with more than 30% blasts (immature cells)
- Immunophenotyping:
- Cytogenetics
- Immunocytochemistry
What is chronic lymphocytic leukaemia (CLL)?
- Characterised by progressive accumulation of functionally incompetent lymphocytes which are monoclonal in origins
- Overlap between CLL and non-Hodgkin’s lymphomas
What is the aetiology of CLL?
- Malignant cells may accumulate as result of their inability to undergo apoptosis
- Most common chromosomal change include trisomy 12, 11q and 13q deletions
What is the epidemiology of CLL?
- 90% are over 50yes
- Males more than females
- Rare in Asians
What are the presenting symptoms of CLL?
- Asymptomatic: Almost half diagnosed on routine blood count
- Systemic symptoms: Lethargy, malaise, night sweats
- Symptoms of bone marrow failure: Recurrent infections (bacterial, viral, fungal), herpes zoster, easy bruising or bleeding (e.g. epistaxis). Assess pts performance status and comorbidites
What are the sides of CLL on examination?
Non-tender lymphadenopathy (often symmetrical), hepatomegaly, splenomegaly
- Later stages, signs of bone marrow failure: Pallor, cardiac flow murmur, purpura/echhymoses
What are the investigations for CLL?
- May be associated with autoimmune phenomena: Haemolytic anaemia, thrombocytopenia or combination of both (Evan’s syndrome)
- Blood: FBC (gross lymphocytosis, reduced platelets). Anaemia may be due to bone marrow infiltration, hypersplenism or autoimmune haemolysis. Reduced serum immunoglobulins
- Blood film: Small lymphocytes with thin rims of cytoplasm and smudge/smear cells
- Bone marrow aspirate or biopsy
What is chronic myeloid leukaemia (CML)?
Malignant clonal disease, characterised by proliferation of granulocyte precursors in the bone marrow and blood
- Distinguished from AML by its slower progression
What is the aetiology of CML?
- Malignant proliferation of stem cells with characteristic chromosomal translocation t(9;22) resulting in Philadelphia (Ph) chromosome
What are the 3 phases of CML?
- Relative stable chronic phase of variable duration (4-6 yrs)
- Transforms in accelerated phase (3-9 months)
- Then acute leukaemia phase (blast transformation)
What are the presenting symptoms of CML?
- Asymptomatic in up to 4-50% and is diagnosed on routine blood count
- Hypermetabolic symptoms: Weight loss, malaise, sweating
- Bone marrow failure symptoms: Lethargy, dyspnoea, easy bruising, epistaxis (infection is rare)
- Abdominal discomfort and early satiety
- Occasionally presents with gout or hyperviscosity symptoms (visual disturbances, headaches, priapism)
- May present during blast crisis with symptoms of AML or ALL