Fichas
Anaemia
Fichas del conjunto (63)
- 1Define anaemia- Decreased haemoglobin in the blood such that there is inadequate oxygen delivery to tissues
- Hb <135g/L in men
- Hb <115 in women - 2How can anaemia present?- Asymptomatic: a slowly falling Hb allows for haemodynamic compensation
- Non-specific: fatigue, weakness, headaches
- CV: dyspnoea on exertion, angina, intermittent claudication, palpitations - 3What general signs can be seen in a patient with anaemia?- Pallor
- Tachycardia
- Systolic flow murmur
- Signs of heart failure - 4Give examples of specific signs that suggest certain types of anaemia- Koilonychia: IDA
- Jaundice: haemolytic anaemia
- Leg ulcers: sickle cell disease
- Bone marrow expansion leading to abnormal facial structures/pathological fractures: thalassemia (rare) - 5Discuss anaemia and transfusion- Generally not indicated if there is no acute bleed & pt is not symptomatic
- If anaemia is severe and requires transfusion, beware of associated HF
- Transfusion should be given very slowly alongside furosemide - 6What are MCV and MCH?- MCV = size of each RBC
- MCH = amount of haemoglobin in each red blood cell - 7What are the causes of microcytic anaemia (Low MCV, <80fl)?- Iron deficiency anaemia (IDA): blood loss until proven otherwise
- Thalassemia
- Lead poisoning
- Sideroblastic anaemia (rare) - 8What are the causes of normocytic anaemia (normal MCV)?- Acute blood loss
- Anaemia of chronic disease
- Renal anaemia
- Haemolytic anaemias (can be macrocytic due to reticulocytosis
- Marrow failure
- Pregnancy
- Connective tissue diseases
- Diamorphic blood film (combined micro/macrocytic processes) - 9What are the causes of macrocytic anaemia (high MCV, >96fl)- B12 deficiency (pernicious anaemia/Crohn's)
- Folate deficiency (coeliac disease)
- Alcohol excess (or severe liver disease)
- Myelodysplastic syndromes
- Severe hypothyroidism (myxoedema, can be normocytic) - 10What investigations would help you determine the aetiology of a microcytic anaemia?- FBC
- Iron studies: serum iron, serum ferritin, total iron binding capacity, serum soluble transferrin receptors
- Blood film: microcytic anaemia generally also hypochromic (pale on blood film, represents low MCH), may also show sideroblasts/signs of thalassemia - 11What signs can indicate IDA?- Koilonychia
- Angular stomatitis
- Brittle nails/hair - 12How does IDA develop and what is the 'latent iron deficiency' period?- Inadequate iron for haemoglobin synthesis
- 'Latent iron deficiency' period is when normal Hb is maintained despite the iron deficiency - 13What are the different causes of IDA?- Blood loss: hookworm most common worldwide, heavy menstruation or GI bleeds the most common in the UK
- ↓ absorption e.g. coeliacs, pts on antacids
- ↑ demand: growth & pregnancy
- Inadequate intake: rare in developed world, premature infants/prolonged breastfeeding most at risk - 14How is IDA diagnosed?- Blood film: microcytic, hypochromic cells with poikilocytosis (shape variation) and anisocytosis (size variation)
- ↓ serum iron
- ↑ total iron binding capacity
- ↓ serum ferritin
- ↑ soluble transferrin receptor - 15What further investigations might you do for a patient with IDA?- If good Hx of menorrhagia (ask about no. of sanitary items used), start oral iron, with only further investigation necessary being coeliac serology
- Without obvious cause: check coeliac serology and refer for GI investigation
- Stool microscopy if recent foreign travel - 16Discuss the management of IDA- Address underlying cause
- Oral ferrous sulphate 200mg t.d.s, commence before results of Ix
- Advise ↑ dietary intake of dark green vegetables, fortified bread/cereals, lean red meat and prunes/raisins
- If ferrous sulphate is not tolerated, consider switch to ferrous gluconate
- Monitor for improvement after 1 month
- Continue Tx for 3 months after blood parameters return to normal - 17What is the 'Rule of 10's'?- The maximum rise in Hb concentration in 1 week is 10g/L
- If more han 10g/L decline is seen over a week, then blood is being lost
- When transfusing, 1 bag will ↑ HB concentration by 10g/L - 18Give common side effects of ferrous sulphate and how can they be ameliorated?- GI-related: cramping, bloating, nausea, vomiting, constipation and black stools
- Adverse effects can be decreased if taken with meals, offering laxatives or dose reduction - 19Anaemia of chronic disease is a top differential for IDA, how can it be differentiated using investigations?- Serum iron will be decreased (same as IDA)
- TIBC decreased (increased in IDA)
- Soluble transferrin receptor is normal (increased in IDA)
- Ferritin will be raised (decreased in IDA) - 20What is Patterson-Brown (Plummer-Vinson) syndrome and how is it treated?- Rare
- Characterised by dysphagia, odynophagia, IDA, glossitis, chelitis and oesophageal webs
- Generally occurs in post-menopausal women
- Tx: iron supplementation and mechanical widening of oesophagus - 21What is thalassemia?- Genetic disorders of Hb synthesis
- Common in the Middle/Far East
- Caused by deficient alpha or beta chains, thus resulting in α- and β-thalassemia (split into minor (trait) and major (Cooley's anaemia)) - 22Discuss β-thalassemia minor: presentation, haemoglobin- Carrier state
- Usually asymptomatic and gives a mild microcytic anaemia that may worsen in pregnancy
- Often confused with IDA
- HbA2 is raised, with slightly raised HbF also - 23Discuss β-thalassemia major (Cooley's anaemia): genetic abnormality, presentation, extra features, survival, blood film and management- Abnormality in both globin genes
- Presents within first year with severe anaemia, hepatosplenomegaly and FTT
- Extramedullary haematopoiesis results in facial deformities
- Survival is possible due to HbF
- Blood films show hypochromic microcytic cells, also target cells and nucleated RBCs
- Manage with lifelong blood transfusions - 24Discuss α-thalassemia: different genetics and their manifestations- Bart's hydrops: deletion of all 4 α-globin genes > HbBarts (γ4), death in utero
- Deletion of 3 genes: moderate microcytic anaemia with features of haemolysis
- Deletion of 2: asymptomatic carrier state with reduced MCV
- Deletion of 1: clinically normal - 25What is sideroblastic anaemia and how is it caused?- Bone marrow produces ringed 'sideroblasts' rather than erythrocytes, which can be seen in the bone marrow
- Can be a congenital disorder or, more commonly, acquired in myelodysplastic syndrome - 26Outline the approach to investigating a macrocytic anaemia- Blood film: hypersegmented neutrophils in B12/folate deficiency
- LFTs/TFTs: raised bilirubin in B12/folate deficiency
- Serum B12/folate
- If B12 is low:
> Anti-parietal cell Ab, anti-IF Ab
> Schilling test
- Bone marrow biopsy: megaloblasts suggest B12/folate deficiency - 27What is the mechanism by which B12/folate deficiency causes macrocytic anaemia?- Both involved in DNA synthesis
- Malfunctioning DNA synthesis leads to failure to 'stop' erythrocyte development leading to very large cells, which eventually are trapped and destroyed in the reticuloendothelial system - 28Outline the physiological absorption of B12- From animal: meat. eggs etc
- To be absorbed, B12 must combine with intrinsic factor (IF) produced in the stomach (parietal cells). *In complete absence of IF, 2% of B12 can still be absorbed
- B12 is absorbed in terminal ileum
- Even in total malabsorption, body stores will last for 3 years - 29What are the different causes of B12 deficiency?- Chronic low dietary intake (vegans)
- Impaired binding in the stomach: pernicious anaemia, congenital absence of IF, gastrectomy
- Small bowel disease: resection, Crohn's/backwash ileitis in US, bacterial overgrowth
*Pancreatitis, coeliac disease and metformin cause mild impairment but not enough to cause significant B12 deficiency - 30What is pernicious anaemia?- Autoimmune disease resulting in severe B12 deficiency
- There are 3 types of autoantibodies which can contribute towards disease:
> Autoantibodies against parietal cells
> Blocking antibodies
> Binding antibodies - 31Name a significant complication of B12 deficiency and describe how it presents- Subacute combined degeneration of the cord
- Simultaneous posterior column (LMN) and CST (UMN) loss due to B12 deficiency, gives both LMN & UMN signs
- Initial peripheral neuropathy
- Classic triad: extensor plantars, brisk knee jerks but absent ankle jerks
- Tone & power usually normal, gait may be ataxic - 32Give causes of folate deficiency- Poor nutritional intake: poor diet, alcohol excess, anorexia
- Malabsorption: coeliac disease
- Anti-folate drugs: trimethoprim, methotrexate, anti-convulsants
- Excess physiological use: pregnancy, lactation, prematurity
- Pathological use: excess erythrocyte production, malignancy, inflammatory disease - 33How is folate deficiency treated?- Folic acid 5mg/day PO for 4 months
- Always with combined B12 unless known to have normal B12 level - 34Outline the approach to investigating a normocytic anaemia- Is there acute blood loss?
- Is there underlying chronic disease?
- Is it haemolytic?
- Are other cell lines affected? - 35Discuss anaemia of chronic disease and its pathology- Normochromic or hypochromic
- Rarely severe
- Seen in chronic infection, malignancy, CKD and rheumatoid disorders
- Pathology involves predominant WBC production in the bone marrow - 36Discuss bone marrow failure as a cause of anaemia- Hb, reticulocytes, WBC and platelets all equally low
- Alterations on blood film, will require bone marrow biopsy
- If there are no abnormal blasts in pancytopenic marrow, diagnosis = aplastic anaemia (idiopathic or drug induced)
- Other causes apparant on marrow: haem malignancies, metastatic disease, myelofibrosis or myelodysplasia
- Parvovirus can also cause cessation of marrow erythropoiesis - 37Where does extravascular haemolysis take place?Reticuloendothelial system of the liver, spleen and bone marrow
- 38What is the normal lifespan of a RBC?120 days
- 39Give intrinsic causes of haemolytic anaemia- Haemoglobinopathies: sickle cell, thalassemia
- Membranopathies: spherocytosis, eliptocytosis
- Enzymeopathies: G6P deficiency - 40Give extrinsic causes of haemolytic anaemia- Autoimmune disease: warm or cold
- Alloimmune disease: transfusion/transplant reaction, rhesus disease
- Drug induced e.g. penicillins
- Parasites: plasmodium etc
- Microangiopathic haemolytic anaemias e.g. DIC - 41What standard investigations might help you diagnose haemolytic anaemia?- FBC: low Hb with ↑ MCV
- LFTs: ↑ unconjugated bilirubin
- Lipids: ↑ serum LDH (released from RBCs)
- Reticulocyte count: >2% or 100x10^9/L suggests ↑ RBD production, will give ↑ MCV
- Blood film - 42What different features might be picked up on a blood film of a random haemolytic anaemia, and to what conditions do they link to?- Hypochromic, microcytic cells: thalassemia
- Sickle cells: sickle cell anaemia
- Spherocytes: hereditary spherocytosis or autoimmune haemolytic anaemia
- Eliptocytes: hereditary eliptocytosis
- Heinz bodes/'bite' cells: G6PD deficiency
- Schistocytes: microangiopathic haemolytic anaemia - 43What further tests might you do to pursue a diagnosis of a haemolytic anaemia?- Coomb's test: identifies RBCs coated with antibodies or complement, indicating immune cause of haemolysis
- Hb electrophoresis: identify haemoglobinopathies
- Enzyme assays
- ↓ plasma haptoglobin and urinary haemosiderin present indicate intravascular haemolysis - 44What is sickle cell anaemia (SCA)?- Autosomal recessive disorder
- Production of abnormal β-globulin
- Results in production of HbS rather than HbA
- Much more common in patients of African origin - 45What are the different genotypes of SCA?- HbSS (phenotype)
- HbAS (trait): confers protection from malaria, rarely symptomatic but vaso-occlusive events may occur in hypoxia (e.g. flying or anaethesia) - 46Outline the pathogenesis of SCA- HbS polymerises when deoxygenated, causing RBCs to form 'sickle cells'
- Sickle cells are fragile and haemolyse, and also block small vessels - 47How is SCA diagnosed?- Usually on the 'Guthrie' screening card
- Sickle cells can be seen on the blood film
- Hb electrophoresis can confirm the diagnosis and also distinguish variants - 48How does SCA normally present?- Often presents first few months of life, with anaemia developing as HbF levels fall, with acute haemolytic crises occurring causing bone infarcts and painful dactylitis
- In adulthood, there is normally a chronic haemolytic anaemia but is well tolerated unless there is a crisis - 49What are the complications of SCA?- If untreated there is splenic infarction leading to hyposplenism, renal infarction to CKD, and cerebrovascular accidents
- Bone necrosis
- Chronic leg ulcers
- Iron overload (if multiple transfusions)
- Long term pulmonary damage - 50Outline the long-term management of SCA- Lifelong folate supplementation
- Pneumococcal vaccination and prophylactic penicillin due to hypsplenism
- Hydroxycarbamide (hydroxyurea) can help by increasing HbF production and is advised if there are frequent crises
- Regular life-long transfusions (2-4 weekly), with iron chelators to prevent overload
- Bone marrow transplantation is curative but limited by donor matches - 51What are the different types of crises in SCA?- Vaso-occlusive crises (painful crises)
- Aplastic crises
- Sequestration crises
- Haemolytic crises (rare) - 52What happens in a vaso-occlusive crisis?- Occur due to microvascular occlusion
- Often affect bone marrow leading to severe pain
- Can be precipitated by cold, infection, dehydration or hypoxia
- Other presentations: mesenteric ischaemia, cerebral infarctions or priapism - 53What happens in an aplastic crisis?- Due to parvovirus B19
- Causes a sudden reduction in marrow production, particularly RBCs
- Usually self-limiting (<2 weeks), but transfusion may be required - 54What happens in a sequestration crisis?- Mainly affects children as spleen has not yet undergone atrophy
- Pooling of blood in the spleen +/- liver, with organomegaly, severe anaemia and shock
- Urgent transfusion required - 55Discuss the general management of a sickle cell crisis- A-E resus, high flow O2 and IV fluids
- Strong analgesia within 30 mins
- FBC, reticulocytes, cross-match
- Screen for infection (culture, MSU, CXR) and treat early
- Prophylactic enoxaparin
- Give fully cross-matched blood transfusion if Hb or reticulocytes fall sharply
- Exchange transfusion if rapidly deteriorating - 56Discuss G6PD deficiency: genetics and presentation- X-linked inheritance
- More common in African and Mediterranean males (females have mild symptoms)
- Mostly asymptomatic, but susceptible to oxidative crises
- These attacks cause rapid anaemia and jaundice, may be precipitated by drugs (aspirin, sulphonamides), broad bean consumption or illness - 57Outline the diagnosis and treatment of G6PD- Heinz bodies, 'bite cells' and 'blister cells' seen on blood film
- Proper diagnosis is made with enzyme assay 3 months after initial crisis
- Tx: precipitant avoidance, plus transfusion if severe - 58Discuss pyruvate kinase (PK) deficiency- Autosomal recessive condition
- ↓ ATP production shortens RBC lifespan
- Homozygotes present with neonatal jaundice, and later chronic jaundice with hepatosplenomegaly
- Diagnosis with enzyme assay
- Often well tolerated, so no specific therapy needed - 59What is hereditary spherocytosis?- Autosomal dominant
- Membrane defect leading to spherical RBCs
- Less deformable, thus can become trapped in the spleen leading to haemolysis, splenomegaly and jaundice
- Treated with folate
- Splenectomy is curative, but reserved for severe disease - 60Discuss autoimmune haemolytic anaemia- Extravascular haemolysis and spherocytosis
- Disease most commonly idiopathic but can be 2° to lymphoproliferative diseases or aother autoimmune disease
- Classified according to optimal temperature that antibodies bind to RBCs - 61What is the difference between 'warm' and 'cold' autoimmune haemolytic anaemia?- Warm: IgG mediated, optimal binding at 37 degrees, treated with steroids or immunosuppressants +/- splenectomy
- Cold: IgM mediated, optimal binding below 4 degrees, associated with Raynaud's, treated with cold avoidance +/- chlorambucil - 62Give different causes of microangiopathic anaemia (mechanical haemolysis due to physical trauma in the circulation)- Malignant HTN/ pre-eclampsia
- HUS
- Thrombotic thrombocytopenic purpura
- Vasculitis (e.g. SLE)
- DIC
- Mechanical heart valves - 63Describe anaemia screening before surgery- <60g/L will require transfusion
- <100g/L may require transfusion depending on cardiac risk and anticipated blood loss
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- (Haematology) Medicine Fichas sobre Anaemia, creado por Liam Musselbrook el 24/10/2017.
- Creado por
- Liam Musselbrook
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