Phase 2 - Haem Flashcards
3 catagories of anaemia
Microcytic (MCV <80)Normocytic (MCV 80-95)Macrocytic (MCV >95)
Causes of microcytic anaemia
TAILS- Thalassaemias- Anaemia of chronic disease- IRON DEFICIENCY(lead poisoning)- Sideroblastic - unable to put iron into haemoglobin - linked to alcohol excess, heavy metal poisoning, VIt B deficiency (Als deficiency - iron trapped in mitochondria - autosomal recessive)
Causes of normocytic anaemia
- BLOOD LOSS (acute - too rapid to adjust)
- HAEMOLYTIC (high cell turnover)
- SICKLE CELL
(- Malaria) - Hereditary spherocytosis
- spherocytes are more fragile (a membranopathy) - G6PDH (glucose 6 phosphate dehydrogensase) deficiency
- haemolysis occurs when exposed to certain triggers
- Autoimmune Haemolytic anaemia
- SICKLE CELL
- Non-haemolytic (low reticulocytes)
- aplastic anaemia
- CKD
- normal cells, just fewer present)
- Myelophthisic
- bone marrow failure due tp malignant invasion
- HAEM MALIGNANCY
Causes of macrocytic anaemia
- Megaloblastic causes (related to impaired DNA synthesis) - B12 DEFICIENCY - Folate deficiency* Non-megaloblastic (nothing wrong with DNA synthesis) - HYPOTHYROID - ALCOHOL - LIVER disease (increase membrane cholesterol of RBCs - increased surface area) - esp NAFLD - CKD - Bone marrow failure (esp MDS - increased immature RBCs) - drugs (Methotrexate, hydroxyurea)(Haemolytic anaemia - more rbcs destroyed so more young, large reticulocytes present)
Iron metabolism process
~15-20mg average daily intake but only ~1mg (or 10%) absorbed in DUODENUM- actively transported into DUODENAL EPITHELIAL CELLS by intestinal HAEM TRANSPORTER (HCP1) - highly expressed in duodenumSome stored intracellularly bound to FERRITIN (usually - more easy to mobilise) in:- reticuloendothelial cells (e.g. monocyte derived - esp in liver)- hepatocytes- skeletal muscleor in HAEMOSIDERIN:- in macrophages (esp liver, spleen, bone marrow)Circulating iron bound to TRANSFERRIN - transports to bone marrow to make erythrocytes
Iron deficiency anaemia - causes
most common cause of anaemiaBlood loss:- menorrhaegia- Hookworm (leading cause of deficiency worldwide)- GI bleedingPoor diet: - esp in children (uncommon in adults) - esp in poverty- PROLONGED BREAST FEEDING in infants (poor Fe source)Malabsorption - Coeliac disease, IBDIncreased demands (growth, pregnancy)RARE in ELDERLY - RED FLAG SIGN for COLON CANCER BLEEDING (recomen urgent endoscopy for any >60y/o w/ Fe def)
Risk factors for iron deficiency
- Less developed countries/poverty- High veg diet (iron best absorbed from animal products) - VEGAN- premature infants- Delayed introduction of mixed feeding (breastmilk contains less iron)
Signs and symptoms of anaemia
Symptoms (non-specific):- FATIGUE, headaches and faintness* Dyspnoea * Intermittent claudication (ischaemic pain in peripheries)* COLD* PALPITATIONS* Angina (if there is pre-existing coronary disease)* AnorexiaSigns (may be absent even in severe anaemia):* Pallor (esp conjunctival)* Brittle hair* Leukonychia (white patches on nails)* Tachycardia* Systolic flow murmur* Cardiac failure
presentation of iron deficiency
- anaemic symptoms- Brittle nails/hair- spoon nails (koilonychia - dip in nails)- tongue papillae atrophy (atrophic glossitis)- ulceration of corners of mouth (angular cheilitis/stomatitis)
Diagnosis of iron deficiency anaemia
- Blood film * low blood count * MICROCYTIC and HYPOCHROMATIC * pokilocytosis (variation in shape); anisocytosis (variation in size) - TARGET CELLS (bulls eye pattern - non specific) - HOWELL JOLLY BODIES (nucleated RBCs - non-specific)- LOW FERRITIN (diagnostic) * tho it is an acute phase protein so will be normal/high in inflammation even if anaemic- IRON STUDY: * low serum iron (not very useful) * LOW TRANSFERRIN SATURATION <19% (more transferrin made to bind as much iron as possible so higher quantity of transferrin which is not saturated) * HIGH TOTAL IRON BINDING CAPACITY (lots of transferrin so highly bound)(high serum soluble transferrin receptors)- LOW RETICULOCYTE countFurther examinations if blood loss (e.g. GI tract exam)
Management of iron deficiency
Treat underlying causeORAL IRON - FERROUS SULPHATE- Side effects: * nausea, abdo discomfort, diarrhoea/constipation, black stools (from increased free iron)- Vit C improves absorption- Alt: FERROUS GLUCONATEIf severe:- IV/IM iron * rare anaphylaxis; potential sub epidermal stainingHb should increase by 20 every month - continue for 3 months after Hb/MCV normal to replenish stores
Define thalassaemia
reduced production of a specific Hb chain type - IMBALANCE OF Hb SYNTHESIS- causes INEFFECTIVE ERYTHROPOIESIS (death of precursors in bone marrow from precipitation of globin chain imbalance)- precipitation in mature RBCs -> HAEMOLYSISBeta Thalassaemia - reduced B chainAlpha thalassaemia - reduced A chain
Beta thalassaemia - pathophysiology
low B chain synthesis = EXCESS A CHAINS- combine with delta + gamma chains- increased HbA2/HbFUsually caused by point mutations (>200 varieties)-> defects in transcription, RNA splicing/modification, translation -> UNSTABLE B-GLOBIN - can’t be utilisedIf heterozygous - ASYMPTOMATIC microcytosis; maybe MILD anaemia
3 variations in b-thalassaemia presentation
B-THALASSAEMIA MINOR (aka carrier/trait)B-THALASSAEMIA INTERMEDIA (symptomatic but not requiring regular transfusions)B-THALASSAEMIA MAJOR (severe homozygous - requires lifelong transfusions)
How do you differentiate between B-thalassaemia minor and iron deficiency
Both have hypochromic, microcytic RBCsBUT serum ferritin/iron stores normalHb electrophoresis -> raised HbA2 and often raised HbF
Presentation of B-thalassemia intermedia
- SPLENOMEGALY (from haemolysis)- Bone deformaties- Recurrent leg ulcers- Gallstones- Infection
Presentation of B-thalassaemia major
Presents in children in 1ST YEAR OF LIFE- failure to thrive - recurrent bacterial INFECTION- severe ANAEMIA from 3-6 months (when switch to HbA)- EXTRAMEDULLARY HAEMATOPOIESIS - ineffective RBC OUTSIDE MARROW -> HEPATOSPLENOMEGALY (from haemolysis) - bone marrow expansion (distictive appearance)Clinically:- hair on end skull x-ray- bone abnormalities- Low MCV - MICROCYTIC- Blood film: large and small irregular hypochromic RBCs- NORMAL SERUM FERRITIN
Diagnosis of homozygous b-thalassaemia
BLOOD COUNT and FILM- HYPOCHROMIC, MICROCYTIC anaemia- RAISED RETICULOCYTES- NUCLEATED RBC in PERIPHERALSHaemoglobin electrophoresis - increased HbF; absent/less HbA
Treatment of beta-thalassaemia
In more severe:- regular (2-4 weeks) LIFE-LONG transfusions to keep Hb above 90g/L AND SUPPRESS ineffective EXTRAMEDULLARY HAEMATOPOIESIS -> to allow normal growth- Splenectomy if hypersplenism persists -> INCREASING TRANSFUSION DEMANDS - do after childhood -> reduce infection risk- Bone marrow transplant- Long term FOLIC ACID
Complications of blood transfusion
INCREASED IRON LOADING -> overload- Mainly deposit in liver/spleen -> liver fibrosis/cirrhosis- also in endocrine glands + HEART -> * Diabetes * Hypothyroidism * Hypocalcaemia * Premature death
Treatments for the complications of blood transfusions
IRON-CHELATING agents - STOP iron OVERLOAD- oral DEFERIPRONE - sub-cutan DESFERRIOXAMINE - side effects: cataracts, deafnessASCORBIC ACID (large dose) -> increases urinary exc of iron
Pathophysiology of Aplha-thalassaemia
- 2 copies of gene for a-goblin on both chromosomes 16 normally - in a-thalassaemia: 1 (most common) or both of the genes are deleted on one or both chromosomes
Clinical presentation of 4 alpha-globin gene deletion
INCOMPATIBLE WITH LIFE - stillborn/die shortly after birth- HYDROPS FETALIS * Pale * Oedematous * hepatosplenomegaly(Only Hb Barts present - 4 gamma chains - can’t carry O2)
Presentation of 3 gene alpha-globin deletion
HbH disease (common in parts of asia) - severe alpha reductionHbH = 4 beta chainsModerate ANAEMIA and SPLENOMEGALYUsually not transfusion dependant
Presentation of 2 gene a-globin deletion
trait/ CARRIERMICROCYTOSIS - potential MILD ANAEMIA
Presentation of 1 gene a-globin deletion
Usually normal blood picture
Treatments for a-thalassaemia
DAILY FOLIC ACIDBlood transfusions as needed (-> chelation therapy)May need splenectomy or venesectomy
Pathophysiology of sickle cell anaemia
SINGLE BASE MUTATION: ADENINE -> THYMINE- VALINE substituted for GLUTAMIC ACID (6th CODON) in BETA-GLOBIN chain-> HbS -> INSOLUBLE + POLYMERISES when DEOXYGENATED -> sickling (RIGID)Initially reversible but repeated sickling -> lose membrane flexibility -> IRREVERSIBLY SICKLED- DEHYDRATED + DENSE- shortened RBC survival -> HAEMOLYSIS- impaired passage through microcirculation -> OBSTRUCTION, INFARCTION, PAINAlso get cytopenias of other cell types (esp NEUTROPENIAS) as bone marrow focusses on producing more ineffective RBCs
What precipitates sickling
- Infection- Dehydration- Cold- Acidosis- Hypoxia
Why do sickle cell patients often feel well despite being anaemic (when not in crises)
HbS release oxygen more readily (lower oxygen binding affinity)
Clinical presentation of sickle cell trait
Symptom free but can sickle under increased hypoxia/stress e.g. anaesthesia, upressurised aircarft- vaso-occlusion may occurPROTECTIVE against FALCIPARUM MALARIASlight increased risk of renal disease/cancer
Conditions caused by homozygous sickle cell anaemia
Vaso-occlusive crisesACUTE CHEST SYNDROMEPulmonary hypertensionAnaemia- can complicate to BONE MARROW APLASIA (usually after PARVOVIRUS B19 infection)
S&S of vaso-occlusive crisis + complications
- ACUTE PAIN - HANDS and FEET (dactylitis) in KIDS - LONG BONES such as the femur, spine, ribs and pelvis - ADULTS * vaso-occlusion of small vessels and AVASCULAR NECROSIS of BONE MARROW- Possible CNS infarction in children -> stroke, seizures and cognitive defects- Attacks vary in frequency - can occur as much as every day to once a year depending on patient
What occurs in Acute chest syndrome + S&S + causes
PULMONARY VASO-OCCLUSIVE CRISIS(occurs in 30%)Caused by INFECTION (CHLMYDIA, MYCOPLASMA, STREP PNEUMONIAE)-> FAT EMBOLISM from NECROTIC BONE MARROWOR-> PULMON INFARCT - SEQUESTRATION of sickle cellsSOB, CHEST PAIN, HYPOXIA (vicious cycle)
Define pulmonary hypertension
Mean pulmonary artery pressure greater than 25mmHg (checked by right heart CATHETERISATION - inserted into right heart)
Pulmonary hypertension in sickle cell
Occurs in 10% of patients- Most probably caused by damage from repeated chest crises and repeated thromboembolism and intravascular haemolysis- Increases the risk of hypoxaemia and worsening sickle cell crisesCommon cause of death in adults with SCD
Anaemia in SCD
Stable low haemoglobin in CHRONIC HAEMOLYSISACUTE FALL:- SPLENIC SEQUESTRATION -> splenomegaly + acute fall in Hb -> Fibrotic, non-functioning spleen (potentially) - BONE MARROW APLASIA - PARVOVIRUS B19 (slapped cheek appearance) INVADES PROLIFERATING ERYTHROID PROGENITORS -> NO RETICULOCYTES IN PERIPHERAL - FAILURE OF ERYTHROPOESIS in marrow * Aplastic crisis
Long term complications of SCD
Growth + development delayedAvascular necrosis of hips, shoulder; compression of vertebrae; shortening of peripheral small bones- Osteomylelitis from S. aureus, S. pneumoniae, SalmonellaCardiomegaly, arrhythmias (+ iron overload cardiomyopathy)- MI25% -> TIA, fits, cerebral infarcts, comaChronic hepatomegaly + dysfunctionChronic tubulointersitial nephritisRetinopathy/detachment, vitreous haemorrhageImpaired placental flow in pregnancy -> spontaneous abortion
Diagnosis of SCD
Blood count:- Hb 60-80 g/L- RAISED RETICULOCYTESBlood film - SICKLED ERYTHROCYTESSICKLE SOLUBILITY TEST - positiveHb ELECTROPHORESIS [- DIAGNOSTIC]- 80-95% HbS (NO HbA)Best to diagnose with CORD BLOOD at BIRTH -> PROMPT PNEUMOCOCCAL PROPHYLAXIS
General reatment of SCD
Avoid/rapidly treat precipitating factors e.g. prophylaxis vaccineFOLIC ACID for all HAEMOLYTIC ppl
Treatment for acute painful attacks in SCD
IV fluidsANALGESIA (morphine, codeine, paracetamol, NSAIDs)O2 + antibiotics if needed
Treatment for SCD anaemia
BLOOD TRANSFUSION (iron overload risk)- Acute chest syndrome- Acute anaemia due to acute splenic sequestration- Aplastic crisis- Stroke- Heart failureORAL HYDROXYCARBAMIDE/HYDROXYUREA- Increases HbF concStem cell transplant
How long can body store folate
Low stores for ~ 4 months
Where is folate absorbed
Duodenum/proximal jejunum
Folate deficiency pathophys
Folate - essential for DNA synthesisIn deficiency:-> impaired DNA synthesis-> DELAYED NUCLEAR MATURATION-> large RBCs + decreased RBC productionAffects all cells in body but BONE MARROW most affected due to HIGH ACTIVITYAlso needed for fetal development so -> neural tube defects
Causes of folate deficiency
POOR INTAKE (main cause)Increased demand (pregnancy, increased cell turnover - haemolysis, malignancy, inflam disease, renal dialysis)MALABSORPTION (coeliac/crohn’s)ANTIFOLATE DRUGS (METJOTREXATE, TRIMETHOPRIM)
Risk factors for folate deficiency
- Elderly- Poverty- Alcoholic- Pregnant- Crohn’s/coeliac
Presentation of Folate deficiency
May be asympSymptoms of anaemiaGLOSSITIS can occur (sore tongue)NO NEUROPATHY (unlike B12)
Diagnosis of folate deficiency
Blood count/film:- MEGALOBLASTIC- MACROCYTIC RBCs- OVAL MACROCYTES and HYPERSEGMENTED NEUTROPHILS (>=6 lobes) in peripheral filmSERUM + RBC folate - LOWGI investigation to excludeSerum bilirubin may be high - from ineffective erythropoiesis -> increased haemolysis
Treatment of folate deficiency
FOLIC ACID TABLETS daily for 4 months - BUT ONLY WITH NORMAL B12/B12 SUPPLEMENTS! (may worsen B12 def -> spinal cord degeneration)Treat underlying cause
What food is folate found in
Green veg (spinach, broccoli)NutsYeastLiver
What food is B12 found in
MeatFishDairy(NOT PLANTS)
How long do B12 body stores last
4 years
How is B12 absorbed
Binds to INTRINSIC FACTOR from PARIETAL CELLS (in stomach)Absorbed in TERMINAL ILEUM
Pathophys of B12 deficiency
ESSENTIAL for THYMIDINE -> DNA synthesisIMPAIRED DNA synth -> DELAYED NUCLEAR MATURATION-> Megaloblasts + reduced RBC productionBone marrow most affected (high activity)
Causes of B12 deficiency
Dietary (vegans)Malabsorption (lacking intrinsic factor, ileal resection)PERNICIOUS ANAEMIA (most common)
Risk factors for Pernicious anaemia
Elderly (>60)FEMALEFair-haired, blue-eyedBlood group AOTHER AUTOIMMUNE (Thyroid, Addison’s)
Pathophys of pernicious anaemia
- Parietal cell antibodies (present in 90% - but NON-SPECIFIC)- INTRINSIC FACTOR ANTIBODIES (only present in 50%)-> Autoimmune gastritis of FUNDUS - plasma cell/lymphoid INFILTRATIONParietal/CHIEF cells REPLACED BY MUCIN-SECRETING cells-> ACHLORHYDRIA (reduced HCl)-> ABSENT INTRINSIC FACTOR secretion
Presentation of B12/Pernicious anaemia
INSIDIOUS ONSET - increasing symp of anaemiaPotential LEMON-YELLOW skin - pallor + mild jaundice (from haemolysis)GLOSSITIS + ANGULAR CHEILOSIS/STOMATITIS (potentially)NEURO FEATURES if V. LOW B12:- Symmetrical parasthesia - fingers + toes- LOSS OF VIBRATION + PROPROCEPTION (1ST thing lost)- Progressive weakness/ataxia -> potential PARAPLEGIADementia, psychiatric problems, hallucinations, delusions and optic atrophy may occur (from vitamin B12 deficiency)
Diff diagnosis for pernicious anaemia (megaloblastic + B12 def)
Folate def (also megaloblastic) - no neuropathyOther causes of B12 deficiency- Terminal ileum disease/bacterial overgrowthGastrectomy
Diagnosis of pernicious anaemia
Blood count/film:- MEGALOBLASTIC- MACROCYTIC- Peripheral: OVAL MACROCYTES + HYPERSEGMENTED NEUTROPHILSPotential raised biliirubinLOW SERUM B12 LOW Hb + RETICULOCYTE COUNTINTRINSIC FACTOR ANTIBODIES (DIAGNOSTIC) (- low sensitivity, not present in all patients)
Treatment of B12 deficiency
If malabsorption - INJECTIONS -> IM HYDROXOCOBALAMINOral B12 if dietaryTreat other underlying causes
Prophylactic folate in pregnancy (dose)
400mg for first 12 weeks
Types of leukaemias
Acute Lymphoblastic leukaemia (lymphoblast)Acute Myeloid lukaemia (myeloblast)Chronic myeloid leukaemia (myeloid progenitor???)Chronic Lymphocytic leukaemia (B lymphocyte)
Markers of high cell turnover in haemolytic anaemia
INCREASED LDH (lactate dehydrogenase - enzyme of cell turnover), and UNCONJ BILIRUBIN (from haemolysis)LOW HAPTOGLOBIN (protein that binds to free haem - lots of free haem in haemolysis so haptoglobin being used up)
How do you differentiate between Normocytic anaemias
Non haemolytic (CKD, malig, Endocrine, mixed) have low reticulocytesCan differentiate between Blood loss/haemolysis by presence of cell turnover markers in haemolysis
How to differentiate between microcytic anaemias
IRON PANEL:- Ferritin low, TIBC high (iron def)- Feritin normal, TIBC low, low serum iron (chronic disease)- HIGH serum iron + low TIBC (Thal/Sideroblastic)
Risk factors for AML
- AGE > 65- Down’s, Patau’s (trisomy 13) and Klinefelter’s (XXY) syndrome- Chemo (METHOTREXATE) - previous treatment- Previous heamatological disorders e.g. MDS- Irradiation- Benzene exposure- inherited genetic conditions (e.g. Fanconi’s anaemia, ataxia telangiectasia, germilne TP53 mutation (tumour suppressor gene))
Pathophys of AML
Rapid proliferation of immature myeloid blasts in bone marrow, peripheral blood or extramedullary tissues (Granulocytes are not being made)Rapid progression if not treated quickly (3y survival)Defined by >= 20% blast cells in BM OR PERIPHERAL bloodAcute promyelocytic leukaemia subtype is particularly characterised by hypergranular promyelocytes + Auer rods and is linked to t(15:17)
Presentation of AML
BONE MARROW FAILURE:- functional pancytopaenia * Anaemia = pallor, fatigue, dizzy, palpitations * Neutropenia = infections * Thrombocytopaenia = bruising (ecchymosis or petechiae), bleeding (esp muscosal)- bone painTISSUE INFILTRATION:- swollen gums- skin/testicular mass- Hepatoplenomegaly- lymphadenopathy
What is Plummer-Vinson syndrome
Web-like growth of membrane in throat from iron deficiencyDysphagia, Upper oesophageal webs, IRON DEFICIENCY ANAEMIA
Diagnosis of AML
FBC/Blood film:- AUER RODS (dark rods in cytoplasm of neutrophils)- neutropenia (can have normal/high WCC)- Anaemia- Thrombocytopenia - coag panel typically normal tho - abnormal suggests DIC- serum LDH may be raised+ U+E, LFTs, RFTs, etcBone marrow BIOPSY (aspirate or trephine) or Peripheral BLOOD SMEAR >= 20% MYELOBLASTS (definitive, gold standard)- typicaly paler nuclei + lack of cell varietyHistory of pre-esisting malignancy (esp MYELODYSPLASTIC SYNDROME or Myeloproliferative neoplasm e.g. polycythaemia vera)Acute promyelocytic leukaemia = t(15:17)Immunophenotyping = -ve for TdT (terminal deoxynucleotidyl transferase) + +ve for myeloperoxidase
Differential diagnosis of AML
- Haematinic deficiency (B12/folate/iron)- Infection (e.g. retroviral, herpervirus)- Meds- Autoimmune- Liver disease
Management of AML in fit individual
CHEMO - ~4-6 weeks (~4 cycles)(ATRA for acute promyelocytic leukemia - subtype)- HICKMAN/PICC LINE or portacathSupportive measures:- transfusions- treat infections(- fertility cryopreservation)Check basline cardiac, liver + renal function (blood tests, ECHO etc.) - damage can occur from chemo