Blood conditions Flashcards
How do you categorise anaemia
By mean cell volume and by mechanism
What are the different types of anaemia?
Microcytic
Normocytic
Macrocytic
Name causes of microcytic anaemia
IRON DEFICIENCY
Thalassaemia
Anaemia of chronic disease
Sideroblastic anaemia (hypochromic)
Name causes of normocytic anaemia
Acute bleeds Haemolyitic Anaemia of chronic disease Myelophythisic Aplastic
What is myelophthisic anaemia?
Anaemia caused by bone marrow being displaced by due to cancer, osteosclerosis or TB.
What is aplastic anaemia?
Where bone marrow dies.
Causes of macrocytic anaemia.
B12 and folate deficiency leads to megaloblastic anaemia
Sometimes haemolysis can look megaloblastic due to the reticulocytes present.
What is pancytopenia?
Decreased RBCs, WBCs and platelets.
Basic clinical features of anaemia
Tiredness and shortness of breath.
Causes of just splenomegaly with anaemia
Autoimmune haemolytic anaemia, cancer and hereditary spherocytosis.
Causes of hepatosplenomegaly with anaemia
Malaria and thalassaemia (due to extramedullary haematopoeisis.
Causes of jaundice with anaemia
Pre-hepatic: haemolytic anaemia and B12 deficiency.
How is B12 absorbed?
It binds intrinsic factor in the stomach and is absorbed in the terminal ileum.
Causes of B12 deficiency
Coeliac disease, IBD and resection.
Gastrectomy.
Autoimmune
Which anaemias give you haemoglobinuria?
The ones involving intravascular haemolysis.
Which anaemia will give a high unconjugated LFT and a low haptoglobin?
Hemolytic anaemia.
What investigations would you do for anaemia?
RBC, LFTs and blood film,
Iron, folate, B12, and ferritin.
Direct Coombs test.
Bone marrow biopsy or endoscopy.
What are the blood results from an acute bleed?
Increased urea, but less increased creatinine so the urea:creatinine ratio increases.
Also from eating meat and pre-renal failure.
What is a FAST scan?
A US scan of the following regions: perisplenic, perihepatic, pelvis and pericardiac.
List causes of haemolytic anaemias.
Malaria, autoimmune haemolytic anaemias, mechanical heart valve, spherocytosis, paroxysmal nocturnal haemoglobinuria, glucose-6-phosphate dehydrogenase
Causes of intravascular haemolysis
Paroxysmal nocturnal haemoglobinuria
Mech. heart valve
DIC, TTP, HUS, microangiopathic haemolysis.
Types of autoimmune haemolytic anaemias
Warm and cold.
What is the aetiology of warm haemolytic anaemia?
IgG and IgA bind RBCs at 37 degress leading to complement and phagocytosis
What is the aetiology of cold haemolytic anaemia?
IgM binds in the peripheries at 30 degrees, but doesn’t bind well centrally. When it binds in the peripheries, complement binds, but doesn’t form MAC, leading to opsonisation and uptake in the spleen.
What is hereditary spherocytosis
An inherited disorder in which mutation in the cytoskeleton leads to spherical RBCs and splenic haemolysis.
Types of haemoglobinopathy
Sickle cell anaemia
Thalassaemia
What happens in sickle cell anaemia?
RBCs sickle reversibly at low O2 due to polymerisation of Hb.
Complications of sickling in sickle cell anaemia.
Anaemia
Occlusion esp acute chest syndrome when pulmonary vessels occlude.
Increased osteomyelitis as a result of salmonella infections.
Increased gram +ive infections due to autosplenectomy.
Causes of anaemia due to decreased erythropoeisis
Myelophthisic, aplastic, megaloblastic.
Chronic disease
Iron def.
Kidney disease.
Chronic diseases leading to anaemia
Ca, TB, autoimmune
Signs of B12 def neuropathy
UMN, LM, sensory and dementia symptoms.
Ways in which people lose fluid
Diarrhoea and vomiting, fevers, bleeding, drains, fistulas, stomata, 3rd space losses.
Reasons for hypervolaemia.
Kidney failure, iatrogenic, due to abnormal distribution as a result of change in oncotic pressure, polydipsia e.g. schizophrenics.
Causes of hypokalaemia
GI disease e.g. vomiting.
What should you do before prescribing fluids?
Check fluid balance chart, notes (risk of heart/kidney failure), U&Es
Assess pt - cap refill, pulse, BP, JVP, heart sounds.
Which fluid is equivalent to giving water but without the haemolysis?
5% glucose
What are colloid fluids?
Fluids such as blood, gelafusion and dextrans that are meant to stay intravascular.
But careful - some people have a reaction.
List 3 crystalloid fluids.
5% glucose
0.9% NaCl
Hartmann’s
In anemia of chronic disease, which blood test is usually elevated?
ESR
What is the likely cause of a microcytic anemia with increased RDW?
Iron def
What is likely to be the cause of microcytosis with a moderate anemia in a North African?
Thalassaemia
How is HBA2 affected in thalassaemia?
It is raised to above 3.4%
What is the likely cause of a patient presenting with a severe macrocytic anemia with moderate neutropenia and some thrombocytopenia?
Pernicious anemia. Differentials can be myelodysplasia, leukaemia and aplastic anaemia.
What anaemia can methotrexate cause?
Folate deficiency anaemia - can’t be corrected with folate. Use folinic acid.
Causes of folate deficiency.
Malabsorption Diet Excess EtOH Methotrexate Myelofibrosis Haemolysis
In B12 and folate deficiency, which should you always give first?
B12 - never give folate alone.
Causes of spherocytes on a blood film.
AI haemolytic anaemia, hereditary spherocytosis.
Causes of red cell fragments on a blood film
Mechanical, or disseminated malignancy
Causes of bitten out red cells on a blood film.
Glucose-6-phosphate dehydrogenase deficiency, unstable Hb or oxidative drug therapy.
What is the DAT test?
Direct anti-globulin test for autoimmune haemolytic anaemia.
What is the treatment for autoimmune haemolytic anaemia?
Corticosteroids.
What is the cause of urinary haemosiderin?
Chronic intravascular haemolysis.
Which major haemolytic diseases cause hyposplenism
Sickle cell disease and thalassaemia.
What do you give for a sickle crisis?
O2, analgesia.
For acute chest syndrome, give exchange blood transfusion and Abx as well.
What are the causes of polycythaemia?
It can be primary, secondary to hypoxia or to increased EPO (cerebellar, uterine, renal causes).
What is the cause of dark urine in G6PD def?
Haemoglobinuria and increased urobilinogen. Not bilirubin as the jaundice is pre-hepatic.
Major causes of coagulopathy
Liver disease
Kidney disease
Inherited coagulopathy
DIC
Common causes of splenomegaly in the UK
Leukaemia, lymphomas, glandular fever, haemolytic disorders and portal hypertension.
Classes of causes of splenomegaly
Haematological
Infections
Portal hypertension
Immunological (Rh, SLE)
What electrolyte can be deranged in blood tranfusions?
Potassium - causes hyperkalaemia.
How long do you have to give iron to someone to renew their iron stores after iron deficiency?
4-6 months
What is noticeable about the bone marrow in sideroblastic anaemia?
There are ringed sideroblasts there.
How do you treat sideroblastic anaemia?
With Vit B6
How does B12 and folate deficiency cause megaloblastic anaemia?
By impairing DNA synthesis. This leads to formation of megaloblasts (hence macrocytic) which are mostly removed by macrophages (hence anaemic).
Formation of haemoglobin - and how microcytic anaemias disrupt it.
Iron and protophyrin rings combine to form haem. This is disrupted by iron def., by lead poisoning, and by chronic disease.
Amino acids combine to form globin chains, which are disrupted in thalassaemias and lead poisoning.
Haem and globins combine to form haemoglobin.
How long does B12 deficiency anaemia take to develop?
About 2 years.
How long does folate deficiency take to develop?
A few months.
Which haemolytic anaemias are due to hereditary defects in RBCs?
Spherocytosis (cytoskeleton defects) G6PD def (enzyme defect) Sickle cell anaemia.
Which haemolytic anaemias are due to acquired defects in RBCs?
Paroxysmal nocturnal dyspnoea (a lack of GPI anchored proteins leads to increased complement action).
Which haemolytic anaemias are due to autoimmune mediated RBC destruction?
Warm AI anaemia
Cold
Paroxysmal cold
How does thalassaemia lead to anaemia
Increased production of the healthy chain leads to agglutination in the cell, and the cell is phagocytosed.
What are the signs of hypercalcaemia?
Stones (renal)
Bones (bone pain)
Groans (abdominal pain, nausea and vomiting)
Thrones (polyuria)
Psychiatric overtones (confusion and cognitive dysfunction, depression, anxiety, insomnia, coma)
Which vitamin def causes anaemia, irritability, seizures
B6
What is the most common inherited bleeding disorder?
Von-Willebrand’s disease (autosomal dominant)
Features of primary sclerosing cholangitis
cholestasis: jaundice and pruritus
right upper quadrant pain
fatigue
Hereditary haemochromatosis - basics
Autosomal recessive disorder of iron absorption and metabolism resulting in iron accumulation. It is caused by inheritance of mutations in the HFE gene on both copies of chromosome 6*. It is often asymptomatic in early disease and initial symptoms often non-specific e.g. lethargy and arthralgia
Types of crisis in sickle cell anaemia
thrombotic, ‘painful crises’
sequestration
aplastic
haemolytic
What is a thrombotic crisis in sickle cell anaemia?
Also known as painful crises or vaso-occlusive crises
precipitated by infection, dehydration, deoxygenation
infarcts occur in various organs including the bones (e.g. avascular necrosis of hip, hand-foot syndrome in children, lungs, spleen and brain
What is a sequestration crisis in sickle cell anaemia?
Sickling within organs such as the spleen or lungs causes pooling of blood with worsening of the anaemia.
Acute chest syndrome: dyspnoea, chest pain, pulmonary infiltrates, low pO2 - the most common cause of death after childhood
What is an aplastic crisis in sickle cell anaemia?
caused by infection with parvovirus
sudden fall in haemoglobin (without concomitant rise in reticulocytes)
What is a haemolytic crisis in sickle cell anaemia
rare
fall in haemoglobin due an increased rate of haemolysis
