1569210
| Questão | Responda |
| what is anaemia? | low Hb conc <13.5 men <11 women |
| types of anaemia by cell size? | microcytic normocytic macrocytic haemolytic |
| what are the microcytic anaemias? | low MCV: IDA thalassaemia sideroblastic anaemia - rare |
| normocytic anaemias? | acute blood loss anaemia of chronic disease (or microcytic) BM failure renal failure hypothyroid - or macro haemolysis - or macro pregnancy |
| when to suspect marrow failure? | normocytic anaemia low WCC low plt |
| macrocytic anaemias? | B12/folate deficiency alcohol excess/ liver dz reticulocytosis cytotoxics eg hydroxycarbamide myelodysplastic syndromes marrow infiltration hypothyroidism antifolate drugs eg phenytoin |
| what are haemolytic anaemias? | can be normo or macro suspect if: reticulocytosis >2% RBCs mild macro low haptoglobin high bilirubin high urobilogen haemolysis causes prehepatic jaundice so you get mild jaundice but no bilirubin in urine |
| when to transfuse in anaemia? | Hb <7 if acute cause eg haemorrhage w/ peptic ulcer may need to transfuse up to 8 if severe anaemia w/ HF - give packed cells SLOWLY w/ furosemide + check for rising JVP/crackles, if CCF worse stop. can try unit exchange transfusion |
| what are the causes of IDA? | blood loss poor diet - babies + children/poverty malabsorption - coeliac - cause of refractory tropics - hookworm (GI blood loss) |
| signs of IDA? | koilonychia atrophic glossitis angular cheilosis post cricoid webs - plummer vinson |
| tests for IDA? | micro hypo anisocytosis + poikilocytosis confirm w/ low ferritin + low serum iron w/ high TIBC investigate for: GI blood loss gastroscopy sigmoidoscopy barium enema colonoscopy stool micro if hookworm possible all above esp if no obvious cause |
| what to think about with ferritin? | is an acute phase reactant increases w/ infection, inflamm, malignancy etc |
| tx IDA? | tx cause oral iron eg ferrous sulphate 200mg/8h PO continued til Hb normal and for at least 3 months to replenish stores if oral not a go then IV |
| s/e ferrous sulphate? | nausea abdo discomfort diarrhoea constipation black stools |
| why might oral ferrous sulphate not be a go? | compliance functional ID in CRF misdiagnosis |
| what is anaemia of chronic disease? | 2y anaemia commonest in hosp pt, 2nd commonest worldwide after IDA 3 probs where hepcidin plays a role: 1. poor iron use in erythropoiesis 2. cytokine induced short RBC survival 3. low production of/response to EPO |
| causes of 2y anaemia? | chronic infection vasculitis rheumatoid malignancy renal failure |
| tests ACD? | normo normo mild anaemia normal ferritin/ high blood film B12 folate TSH haemolysis tests as may be mulitfactorial |
| tx of anaemia of chronic disease? | underlying cause EPO parenteral iron |
| s/e EPO? | flu like sx HTN mild elevated plt thromboembolism |
| sideroblastic anaemia? | microcytic hypochromic anaemia not responding to iron! marrow - disease defining sideroblasts tx - remove cause / pyridoxine + repeated transfusion |
| causes of sideroblastic anaemia? | xlinked AR myelodysplasia excessive alcohol, pyridoxine deficiency, lead poisoning, copper deficiency excess zinc isoniazid, chloramphenicol, linezolid |
| what is poikilocytosis? | abnormally shaped RBCs |
| what is anisocytosis? | blood cells unequal size |
| what is a ring sideroblast? | perinuclear ring iron granules sideroblastic anaemia - poor erythropoiesis leading to increased iron absorption with iron loading in marrow + haemosiderosis (endocrine, liver,heart damage from iron deposition) |
| where do we see anisocytosis? | megaloblastic anaemia, thalassaemia IDA |
| what are acanthocytes? | spicules on RBCs causes - splenomegaly, ALD, abetalipoproteinaemia, spherocytosis |
| what is basophilic RBC stippling? | denatured RNA in RBCs lead poisoning megaloblastic myelodysplasia liver dz haemoglobinopathy eg thalassaemia |
| what are blasts? | nucleated precursor cells -not normally on periph blood film myelofibrosis, leukaemia, malignancy |
| burr cells? | echinocytes - RBC projections |
| cabot rings? | pernicious anaemia, lead poisoning, bad infections |
| dimorphic picture on PBF? | to pops of RBCs seen in mixed deficiency post transfusion 1y sideroblastic anaemia |
| what are howell jolly bodies? | DNA nuclear remnants in RBCs -usually removed by spleen post splenectomy hyposplenism eg SCD, coeliac, congenital, UC/CD, myeloproliferative dz, amyloid megaloblastic anaemia |
| when is hypochromia seen? | IDA thalassaemia sideroblastic |
| what are pappenheimer bodies? | siderocyte granules containing iron lead poisoning carcinomatosis post splenectomy |
| when is poikilocytosis seen? | IDA myelofibrosis thalassaemia |
| when are reticulocytes seen? | haemolyiss haemorrhage |
| left shift? | immature white cells - eg infection |
| right shift? | hypermature white cells- hypersegmented polymorphs megaloblastic uraemia liver dz |
| what is rouleau formation? | red cells stack together - worm like causes raised ESR chronic inflammation paraproteinaemia myeloma |
| spherocytes? | hereditary spherocytosis + AIHA |
| schistocytes? | fragmented RBCs sliced by fibrin bands in IV haemolysis microangiopathic anaemia eg DIC HUS TTP pre-eclampsia |
| what are target cells? | mexican hat cells RBCs w/ central staining, ring of pallor + outer rim of staining liver dz hyposplenism thalassaemia IDA sometimes |
| what are the causes of neutrophilia? | bacterial infection inflamm - MI, PAN myeloproliferative disorders drugs - steroids disseminated malignancy stress eg trauma, burn, haemorrhage, seizure |
| what is a normal neutrophil count? | 2-7.5 |
| causes of neutropenia? | viral infection drugs -chemo, cytotoxic, carbimazole, sulfonamides severe sepsis nuetrophil abs (SLE, haemolytic anaemia) hypersplenism eg felty's BM failure |
| what is the normal leukocyte count? | 1.5-4.5 |
| causes lymphocytosis? | acute viral infxn chronic infection eg brucella, hep, syph leukaemia/ lymphoma esp CLL |
| what kinds of lymphocytes are seen in EBV infection? | atypical large clear cytoplasm w/ blue rim that flows around neighbouring rbcs |
| causes lymphopaenia? | steroid tx SLE uraemia legionnaire's HIV marrow infiltrate post chemo/ radio |
| what is a normal CD4 count? | 537 - 1571 |
| normal eosinophil levels? | 0.04-0.4 |
| eosinophila causes? | drug rxns eg erythema multiforme allergies asthma parasitic infection skin dz exp pemhigus, eczema, psoriasis, dermatitis herpetiformis malignancy incl lymphoma/leukaemia PAN adrenal insufficiency irradiation convalescence post infection |
| what is HES? | hypereosinophilc syndrome no cause high for > 6wks end organ damage tx - steroid PO + anti IL-5 mab imantinib if genetic predisposition |
| causes of monocytosis? | post chemo/radio chronic infxn eg malaria, TB, brucellosis malignancy - AML, hodgkin's myelodysplasia |
| basophilia causes? | myeloproliferative dz viral infxn IgE HS - urticaria inflamm eg UC, RA |
| macrocytic anaemia causes? | often due to alcohol w/o anaemia megaloblastic - B12 def, folate def, cytotoxic drugs non megloblastic - alcohol, reticulocytosis eg haemolysis, liver dz, hypothyroid, pregnant other blood dz - myelodysplasia, myeloma, myeloproliferation, aplastic anaemia |
| what are megaloblasts? | delayed nuclear maturation compared to cytoplasm |
| tests in macrocytic anaemia? | B12 + folate look same blood film - hypersegmented polymorphs in B+F (target cells if liver dz) other - LFTs, TFTs, serum B12, serum folate (or red cell folate- more reliable) bone marrow bx - indicated if cause not found with other tests |
| what might a bone marrow bx show in macrocytic anaemia? | megaloblasts normoblasts - liver dz, hypothyroid abnormal erythropoeisis - sideroblastic, leukaemia, aplasia increased erthropoeisis - haemolysis |
| where do we get folate? | greens nuts yeast liver stores last 4 months maternal def - neural tube defects |
| causes of folate def? | poor diet - poverty, alcoholic, elderly increased demand eg pregnancy/ haemolysis/ malignancy/ inflamm/renal dialysis malabsorption - coeliac, sprue drugs, alcohol, anti-epileptics, MTX, trimethroprim |
| where is folate absorbed? | duodenum jejunum |
| tx of folate deficiency? | underlying cause folic acid 5mg/day PO 4 months, never w/o B12 unless pt has normal B12 as in low B12 states it can precipitate/worsen SACDC prophylaxis in pregnancy |
| folate + HD | may be a link (unproven) between high homocysteine + IHD, folate reduces homocysteine. |
| folate + cognition? | if borderline deficiency - 88micrograms/day for 3 yrs can benefit - FACIT trial |
| where is B12 found? | meat fish dairy products body stores good for 4 years binds IF in stomach and is then absorbed in terminal ileum |
| what happens in B12 deficiency? | thymidine synthesis + thus dna synthesis is slow so RBC production is slow in turn |
| causes of B12 deficiency? | dietary eg vegans malabsorption - stomach (lack of IF): pernicious anaemia, post gastrectomy -terminal ileum - ileal resection, CD, bacterial overgrowth, tropical sprue, tapeworm congenital metabolic error |
| general features of B12 deficiency? | anaemia sx lemon tinge to skin from combo of pallor (anaemia) + mild jaundice (haemolysis) glossitis - beefy red sore tongue angular cheilosis (stomatitis) |
| neuro features of B12 def? | irritable depression psychosis dementia |
| what are the general features of anaemia? | fatigue SOB faintness palps headache tinnitus anorexia pallor, tachyC, flow murmur, cardiomegaly, retinal haemorrhage HF |
| what is subacute combined degeneration of the spinal cord? | insidious w/ peripheral neuropathy due to low B12: combo of symmetrical dorsal column loss (sensory + LMN signs) and symmetrical CST loss (motor + UMN signs) joint position and vibration sense can be affected 1st - ataxia, stiffness, wkness |
| what is the classical presentation of subacute combined degeneration of the spinal cord? | triad - extensor plantars (UMN) + absent knee jerks (LMN) + absent ankle jerks (LMN) falls at night - ataxia + reduced vision pain and temp can be intact in even severe cases as STT preserved |
| what is pernicious anaemia? | caused by AI atrophic gastritis w/ achlorhydria and lack of IF secretion more in women, >40 more blood group A |
| associations of PA? | other AI dz thryoid vitiligo addison's hypoparathyroid carcinoma of stomach - 3x more common |
| general tests in PA? | low Hb macrocytic low WCC/plt if severe low serum B12 low reticulocytes or normal hyeprsegmented polymorphs megaloblasts in marrow |
| specific PA test? | parietal cell abs in 90% IF ab - specific but low sens |
| tx of PA? | cause if poss if due to malabsorption - injections - hydroxocobalamin (B12) 1mg IM - maintenance is img Im every 3 months for life dietary cause - oral B12 |
| how to know if PA is improving? | transient reticulocytosis and macrocytosis after 4-5 days |
| px B12 deficiency? | supplements help peripheral neuropathy but little help for cord signs tx asap |
| name some non-dietary, non AI causes of B12 deficiency? | CD coeliac post gastric surgery acid suppressors eg ranitidine metformin panc insufficiency |
| haemolytic anaemia basics? | premature breakdown of RBCs before 120d either intravascular or extravascular can be asymptomatic if bone marrow compensates |
| where are the extravascular sites of haemolytic anaemia? | liver, spleen, bone marrow macrophages |
| what questions to ask in an approach to haemolysis? | 1. is there increased RBC breakdown? 2. is there increased RBC production 3. is the haemolysis intravascular or extravascular? 4. why? |
| how to tell if increased RBC breakdown? | normo or macrocytic anaemia high bilirubin - unconjugated from haem breakdown ie prehepatic jaundice high urobilogen - no urinary conj bilirubin high serum LDH as released from RBCs |
| how to tell if increased RBC production? | reticulocytosis causing macrocytosis + polychromasia |
| what are the features of extravascular haemolysis? | splenic hypertrophy + splenomegaly |
| features of intravascular haemolysis? | increased free plasma Hb - from RBCs methaemalbuminaemia decreased plasma haptoglobin - as mopping up free plasma Hb then removed by liver haemoglobinuria - red brown urine w/o RBCs haemosiderinuria - prussian blue staining a week after onset - chronic haemolysis |
| what are the causes of haemolytic anaemia? | acquired - immune + non immune hereditary - enzyme/membrane defects or haemoglobinopathy |
| what are the acquired immune causes of haemolytic anaemia? | coombs test +ve = drug induced/ AIHA/ paroxysmal cold haemoglobinuria coombs test -ve |
| acquired non immune causes of haemolyitic anaemia? | microangiopathic haemolytic anaemia (MAHA) infection paroxysmal noctural haemoglobinuria |
| drug induced immune mediated cooms +ve causes of haemolytic anaemia? | RBC autoab formation - penicillin immune complex formation - quinine |
| what is AIHA (coombs +ve)? | autoab causing mostly extravascular haemolysis + spherocytosis classified by optimal binding temperature to RBCs: warm AIHA cold AIHA |
| warm AIHA? | IgG mediated bind at 37*C tx - steroids/IS +/- splenectomy |
| cold AIHA? | IgM mediated, bind @ <4*C chronic anaemia worse in cold, often w/ raynaud's/ acrocyanosis tx = keep warm/ chlorambucil |
| causes of AIHA? | most idiopathic 2y WAIHA - lymphoproliferative dz eg CLL, lymphoma, drugs, AI eg SLE 2y CAIHA - may follow infxn eg mycoplas/EBV |
| what is paroxysmal cold haemoglobinuria? | viruses/syph cause - donath landsteiner ab sticking to RBCs in cold - complement mediated haemolysis on rewarming. |
| what are the causes of AHIA w/ -ve coomb's? | AIH hep B / C post flu/ other vax drugs - piperacillin, rituximab |
| what infections cause haemolytic anaemia? | malaria- RBC lysis |
| what is paroxysmal nocturnal haemoglobinuria? | rare acquired stem cell disorder haemolysis, marrow failure, thrombophilia visceral thrombosis/ pulm emboli- poor px dx - urinary haemosidern tx - anticoagulation, eculizumab has a role so less SCT needed. |
| what enzyme defect hereditary dz can cause haemolytic anaemia? | G6PD deficiency (glucose 6 phosphate dehydrogenase) pyruvate kinase deficiency |
| what is G6PD deficiency? | X linked RBC enzyme defect men - mediterranean, africa, middle east most no sx BUT can have oxidative crisis precipitated by drugs (primaquine, sulfonamides, aspirin)/illness attack - rapid anaemia + jaundice film - bite + blister cells tx - avoid precipitants eg henna, transfuse if severe |
| what is pyruvate kinase deficiency? | AR low ATP production causes less RBC survival homozyg - neonate jaundice, later haemolysis w/ splenomegaly + jaundice dx enzyme assay tx - often none. splenectomy |
| membrane defects that cause hereditary haemolytic anaemia? | hereditary spherocytosis - AD, spherical RBCs trapped in spleen - extravasc haemolysis (splenomegaly, jaundice) - dx film/ high bilirubin hereditary elliptocytosis - AD - film - mostly no sx - may protect from malaria 10% severe phenotype death in utero. hereditary ovalocytosis/ stomatocytosis - rare - refer all coombs -ve, all need folate, splenectomy may help. |
| what haemoglobinopathies might cause haemolytic anaemia? | SCD thalassaemia |
| what is a coombs test? | antiglobulin test direct - blood sample - washed RBCs are incubated w/ antihuman ab (coombs reagent) - RBCs agglutinate and coombs reagent forms links between RBCs indirect - used in prenatal testing and pre blood transfusion - detects ab against RBCs that are free in serum (incubated w/ RBCs of known antigenicity) - if agglutination - +ve |
| how might the blood film help in haemolytic anaemia? | hypo micro - thalassaemia sickle cells schistocytes - MAHA abnormal cells - haematological malgnancy spherocytes - AIHA/ hereditary spherocytosis elliptocytes heinz bodies/ bite cells - G6PD def |
| what does a +ve coombs test mean? | immune cause of HA |
| what is MAHA? | mechanical disruption of RBCs in circulation intravascular haemolysis + schistocytes |
| causes of MAHA? | HUS TTP DIC pre-eclampsia eclampsia |
| tx MAHA? | cause transfusion plasma exchanage |
| what is sickle cell anaemia? | AR abnormal beta globin chains Glu-val substitution at position 6 produces HbS instead of HbA africans homozygotes have SCD, and hetrozygotes have sickle cell trait |
| SCD vs trait | trait cause no sx and protects against malaria but in hypoxia eg unpressurised aircraft/anaesthesia - vaso-occlusive events can occur SCD has sx |
| pathogenesis of SCD? | HbS polymerises when deoxygenated - sickle cells which are fragile and haemolyse, and block small blood vessels |
| tests for SCD? | haemolysis variable Hb 6-9 increased reticulocytes increased bilirubin film - sickle cells + target cells sickle solubility test +ve but doesn't distinguish HbSS and AS (hetero) Hb electrophoresis - confirms and distinguishes zygosity |
| ideally SCD should be diagnosed... | at birth from cord blood so can have pneumococcal prophylaxis - vaccine |
| signs/sx of SCD? | vaso-occlusive crisis aplastic crisis sequestration crisis |
| what is a vaso-occlusive crisis? | microvascular occlusion pain triggered by cold, dehydration, infection or hypoxia <3yrs hands and feet affected - dactylitis occlusion can cause mesenteric ischaemia mimicking an acute abdomen CNS infarct in 10% children - stroke, seizure, cognitive defect - transcranial doppler US can assess risk and BT can reduce risk avascular necrosis of the femoral head leg ulcers low flow priaprism |
| aplastic crisis? | due to parvovirus B19 sudden reduction in marrow production esp RBCs self limiting may need transfusion |
| sequestration crisis? | children as spleen has not yet undergone atrophy blood pooling in spleen/ liver + organomegaly, severe anaemia, shock need urgent transfusion |
| complications of SCD? | splenic infarct before 2yrs from microvascular occlusion - leads to increased susceptibility to infection - 40% childhood SCD deaths caused this way- zinc supplements poor growth CRF gallstones retinal disease iron overload/ blood borne infection after repeated transfusion lung damage - hypoxia-> fibrosis->pulm HTN |
| mangt chronic dz SCD? | hydroxycarbamide if frequent crises prophylaxis - abx/vax febrile kids risk septicaemia - OP ceftriaxone can avoid admission BMT can cure but controversial |
| prevention SCD? | genetic counselling prenatal testing parent education can prevent deaths |
| how to manage an SCD crisis? | prompt generous analgesia IV opiates crossmatch blood, FBC, blood cultures, MSU/CXR if high temp/chest signs IVI rehydrate keep warm O2 by mask if paO2 low/sats low blind abx if fever/unwell/chest signs - cephalosporin transfuse plasma exchange - if rapidly worsening |
| what is acute chest syndrome in SCD? | pulm infiltrates involving complete lung segments pain, fever, tachyp, wheeze, cough serious main infiltrate cause is fat embolism from bone marrow/ or chlamydia infxn |
| tx acute chest syndrome in SCD? | O2 analgesia blind abx (ceph + macrolide) until culture results bronchodilators if wheeze transfusion exchange if severe ventilate if can't keep paO2 above 9.2kPa on RA |
| what are the thalassaemias? | genetic unbalanced Hb synthesis under/no production of one globin chain RBC membrane damage - haemolysis in marrow mediterranean, far east |
| what types of thalasssaemia are there? | beta: minor/trait, intermedia, major (cooley's anaemia) alpha |
| what causes the beta thalassaemias? | point mutation in b globin genes on ch 11 |
| what tests to do in thalassaemia? | FBC MCV film iron HbA2 HbF Hb electrophoresis MRI can monitor myocardial siderosis |
| beta thalassaemia minor/trait? | carrier no sx mild anaemia >9 can worsen in pregnancy often confused w/ IDA |
| beta thalassaemia intermedia? | moderate anaemia but doesn't need transfusion poss splenomegaly causes: mild homozygous b thal mutations/ co inheritance of b thal trait + other Hbpathy sickle cell b thalassaemia- similar picture to SCD |
| cooley's anaemia? | b thal major both b-globin genes abnormal presents in 1st yr - severe anaemia + failure to thrive head shape - skull bossing (from extramedullary erythropoeisis) hepatosplenomegaly - haemolysis osteopenia skull XR - hair on end sign from increased marrow activity |
| tx osteopenia in b thal major? | zolendronic acid |
| tx of beta thal major? | lifelong BT needed iron overload at 10yrs w/ endocrine failure (pituitary, thyroid, DM), liver dz, cardiotoxicity |
| film in beta thal major? | hypo micro target cells nucleated RBCs HbF is high, Hb A absent on electrophoresis. |
| tx of the beta thals? | fitness, healthy diet + folate supplements reg lifelong transfusion iron chelators to prevent overload - deferipone +desferrioxamine large dose ascorbic acid to increase iron in UOP splenectomy if persistent hypersplenism - after 5yrs hormone replacement for endo conditions BMT can cure |
| s/e of iron chelators? | pain deaf cataract retinal damage higher risk yersinia |
| what are the alpha thalassaemias? | mainly caused by gene deletions ch 16 - 4 genes. if all deleted - death in utero (bart's hydrops) HbH dz if 3 genes deleted - moderate anaemia + haemolysis (hepatosplenomegaly, leg ulcers, jaundice) 2 genes deleted - asymptomatic carrier one gene gone - normal. |
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