Haematology Flashcards
Ix for anaemia
- Hb
- MCV = mean cell volume
- B12
- Folate
- Ferritin
- Blood film
- OGD and colonoscopy for unexplained iron deficiency anaemia – urgent cancer referral for suspected gastrointestinal ca
- Bone marrow biopsy – if cause remains unclear
Causes of microcytic anaemias
MICROCYTIC ANAEMIA = TAILS • T = Thalassaemia • A = Anaemia of chronic disease • I = Iron deficiency anaemia • L = Lead poisoning • S = Sideroblastic anaemia
Causes of normocytic anaemia
NORMOCYTIC ANAEMIA = 3 As and 2 Hs • A = Acute blood loss • A = Anaemia of chronic disease • A = Aplastic anaemia • H = Haemolytic anaemia • H = Hypothyroidism
Causes of macrocytic anaemia
MACROCYTIC ANAEMIA = megaloblastic or normoblastic
• Megaloblastic – impaired DNA synthesis preventing the cell from dividing normally so it keeps growing into a larger abnormal cell
o B12 deficiency
o Folate deficiency
• Normoblastic anaemia o Alcohol o Reticulocytosis – from haemolytic anaemia or blood loss o Hypothyroidism o Liver disease o Azathioprine
Anaemia symptoms
- Tiredness
- SOB
- Headaches
- Dizziness
- Palpitations
- Worsening of other conditions e.g., angina, HF, PVD
- Pale skin
- Conjunctival pallor
- Tachycardia
- Raised respiratory rate
Causes of iron deficiency anaemia
- Blood loss e.g., menstruation in women
- Insufficient dietary iron
- Iron requirements increase e.g., in pregnancy
- Loss of iron e.g., from slow bleeding colon cancer, oesophagitis, gastritis, IBD
- Inadequate iron absorption e.g., PPIs, coeliac disease, Crohn’s disease
- Hookworm
Ix for iron deficiency anaemia
FBC Blood film Total iron binding capacity - High Transferrin saturation - Low Serum iron - Low Ferritin- Low (Unless infection/malignancy, then high) Coeliac serology Gastroscopy/colonoscopy Stool microscopy - hookworm
Specific signs of chronic iron deficiency anaemia
- Koilonychia
- Atrophic glossitis
- Angular cheilosis
- Plummer-Vinson syndromes: post-cricoid webs
Define pernicious anaemia
an autoimmune condition where antibodies form against parietal cells or intrinsic factor therefore is a cause of B12 deficiency anaemia. B12 deficiency can be caused by insufficient dietary intake OR pernicious anaemia.
Neurological symptoms of B12 deficiency
a. Peripheral neuropathy
b. Loss of vibration sensation or proprioception
c. Visual changes
d. Mood/cognitive changes
Diagnosis of pernicious anaemia
o 1st line - Intrinsic factor antibody
o 2nd line - Gastric parietal cell antibody
Tx for pernicious anaemia
- Cyanocobalamin – oral replacement for dietary deficiency of B12
- IM hydroxycobalamin – for pernicious anaemia as absorption is the problem
In which order should you treat folate and B12 deficiency?
If there’s folate deficiency, treat the B12 deficiency first. Treating patients with folic acid when they have B12 deficiency can lead to subacute combined degeneration of the cord.
Define haemolytic anaemia
Definition = destruction of RBCs (haemolysis) leading to anaemia. There’s inherited and acquired conditions that lead to haemolysis of RBCs.
Causes of inherited haemolytic anaemia
- Hereditary spherocytosis
- Hereditary elliptocytosis
- Thalassaemia
- Sick cell anaemia
- G6PD deficiency
Causes of acquired haemolytic anaemia
- Autoimmune haemolytic anaemia
- Alloimmune haemolytic anaemia – transfusion reactions & haemolytic disease of the newborn
- Paroxysmal nocturnal haemoglobinuria
- Prosthetic valve related haemolysis
Symptoms of haemolytic anaemias
- Anaemia
- Splenomegaly – spleen becomes filled with destroyed RBCs
- Jaundice – bilirubin released during the destruction of RBCs
Ix for haemolytic anaemia
- FBC – normochromic anaemia
- Blood film – schistocytes (fragments of RBCs)
- Direct Coomb’s test - +ve in autoimmune haemolytic anaemia
What is hereditary spherocytosis? (inheritance, pathology, presentation, diagnosis, tx)
- Inherited haemolytic anaemia
- Autosomal dominant
- Sphere shaped RBCs that get broken down easily in the spleen
- Presentation: gallstones, jaundice, splenomegaly, aplastic crisis (in the presence of pavovirus)
- Diagnosis: family hx and blood film
- Tx: folate, splenectomy, cholecystectomy if gallstones
What is hereditary elliptocytosis?
- Inherited haemolytic anaemia
- Autosomal dominant
- RBCs ellipse shaped
- Presentation: gallstones, jaundice, splenomegaly, aplastic crisis
- Tx: folate, splenectomy
What is G6PD deficiency and how is it diagnosed?
- X linked recessive condition
- More common in Mediterranean and African patients
- Defect in RBC enzyme G6PD
- Causes crises triggered by infections, medications (primaquine, ciprofloxacin, sulfonylureas, sulfasalazine & other sulphonamide drugs) and fava beans (broad beans)
- Presentation: jaundice, gallstones, anaemia, splenomegaly
- Diagnosis: Heinz bodies on blood film, G6PD enzyme assay
What is autoimmune haemolytic anaemia?
• Antibodies are created against the patients RBCs = destruction of RBCs
• 2 types:
o Warm type autoimmune haemolytic anaemia – more common. Idiopathic.
o Cold type autoimmune haemolytic anaemia – AKA cold agglutinin disease. Antibodies cause RBCs to clump together (agglutination). Secondary to lymphoma, leukaemia, SLE, mycoplasma/EBV/CMV/HIV infection
• Ix: Coombs test
• Mx: blood transfusions, prednisolone, rituximab, splenectomy
What is Allo-immune haemolytic anaemia?
- In transfusion reaction and haemolytic disease of the newborn
- Haemolytic transfusion reactions = antibodies produced against antigens on foreign RBCs that have been transfused into the patient = destruction of those RBCs
- Haemolytic disease of the newborn = antibodies cross the placenta from mother to fetus that target RBCs of the fetus
What is paroxysmal nocturnal haemoglobinuria?
- Rare
- Gene mutation in haemopoietic stem cells in bone marrow
- Loss of proteins on surface of RBCs that inhibit the complement cascade = activation of complement cascade on the surface of RBCs
- Red urine in the morning (contains Hb and haemosiderin)
- Predisposed to VTE & smooth muscle dystonia (oesophageal spasm & erectile dysfunction)
- Mx: eculizumab, bone marrow transplant
What is microangiopathic haemolytic anaemia?
• Small blood vessels gave structural abnormalities that cause haemolysis of RBCs
• Secondary to:
o Haemolytic uraemic syndrome (HUS)
o DIC
o Thrombotic thrombocytopenia purpura (TTP)
o SLE
o Ca
What is prosthetic valve Haemolysis?
- Haemolytic anaemia is a complication of prosthetic heart valves
- Mx: monitoring, oral iron, blood transfusion, revision surgery
What is thalassaemia?
genetic diseases of unbalanced Hb synthesis, with under production (or no production) of one globin chain. Autosomal recessive conditions.
- Defects in alpha-globin chain = alpha thalassemia
- Defects in beta globin chain = beta thalassemia
Pathology of thalassaemia
- RBCs more fragile as they’re laking a global chain, the spleen destroys damaged RBCs therefore swells = splenomegaly
- Bone marrow expands to produce extra RBCs to compensate for the chronic anaemia, therefore:
a. More susceptible to fractures
b. Pronounced forehead
c. Malar eminences – cheekbones
Diagnosing thalassaemia
- FBC – microcytic anaemia
- Hb electrophoresis – used to diagnose globin abnormalities
- DNA testing – for genetic abnormalities
- Screening in pregnant women
what is alpha thalassaemia, the chromosome involved and mx?
Defects in alpha-globin chains
Chromosome 16
Mx:
- Monitor FBC
- Monitor for complications
- Blood transfusions
- Splenectomy
- Bone marrow transplant (can be curative)
what is beta thalassaemia, the chromosome involved and the 3 types (+their mx)?
Defects in beta-globin chain
Chromosome 11
3 types:
- Thalassaemia major – homozygous for deletion genes, no functioning beta-globin chains. Severe anaemia and failure to thrive in early childhood.
a. Mx – regular transfusions, iron chelation, splenectomy, bone marrow transplant - Thalassaemia intermedia – two abnormal copies of gene, significant microcytic anaemia
a. Occasional blood transfusions - Thalassaemia minor – carries of gene, mild microcytic anaemia
a. Monitoring
Risk factors for DVT
- Immobility
- Recent surgery
- Long haul travel
- Pregnancy
- Hormone therapy with oestrogen – HRT/COCP
- Malignancy
- Polycythaemia
- SLE
- Thrombophilia :
o Antiphospholipid syndrome
o Factor V leiden
o Antithrombin deficiency
o Protein C or S deficiency
o Hyperhomocysteinaemia
o Prothrombin gene variant
o Activated protein C resistance
Presentation of DVT
- Unilateral
- Calf or leg swelling: measure the circumference of the calf 10cm below the tibial tuberosity, >3cm difference between calves is significant
- Dilated superficial veins
- Tenderness to calf – over the site of the deep veins
- Oedema
- Colour changes to the leg
- Ask PE symptoms
What is the Well’s Score?
- Predicts the risk of a patient presenting with symptoms having a DVT or PE
- To calculate score:
o Clinical signs and symptoms of DVT (leg swelling with pain on palpation of deep veins)
o Alternative diagnosis is less likely
o Heart rate >100
o Recent surgery or immobilisation
o Previous PE/DVT
o Haemoptysis
o Malignancy
Diagnosis of DVT
- D-dimer (sensitive but not specific) – good for excluding DVT where there is low suspicion
a. Other causes of raised d-dimer: pneumonia, malignancy, HF, surgery, pregnancy - Doppler US.
a. Repeat after 6-8 days if negative but positive D dimer and Well’s score is suggestive of a DVT - CTPA for PE or ventilation perfusion (VQ) scan
Ix for unprovoked DVT
- Ix for cancer – medical hx, baseline bloods and examination (?CT TAP)
- Antiphospholipid syndrome
- Hereditary thrombophilias
Mx for DVT
- Treatment dose apixaban/rivaroxaban
- Catheter directed thrombolysis in patients with symptomatic iliofemoral DVT & <14 days of symptoms
- Long term
o DOAC / warfarin / LMWH if pregnant
o Continue anticoagulation for
3 months if reversible cause
Beyond 3 months is cause unclear
3-6 months in active cancer
o IVC filters – device inserted into IVC to filter out blood clots in patients not suitable for anticoagulation
What is Budd-Chiari syndrome
: thrombosis in the hepatic vein, blocking outflow of blood from the liver. Causes acute hepatitis with the following triad of symptoms: abdominal pain, hepatomegaly and ascites.
What is thalassaemia?
A genetic defect in the protein chains that make up haemoglobin
Normal hb = 2 alpha and 2 beta globin chains
What is the genetic inheritance of thalassaemia?
Autosomal recessive
Pathology of thalassaemia
In thalassaemia the RBCs are more fragile and break down more easily.
The spleen collects all the destroyed RBCs and swells = splenomegaly
Bone marrow expands to produce extra RBCs to compensate for the chronic anaemia
= more susceptible to fracture & pronounced forehead/malar eminences
Two types of thalassaemia
Alpha thalassaemia - defects in alpha globin chains
Beta thalassaemia - effects in beta globin chains
Signs and symptoms of thalassaemia
Microcytic anaemia Fatigue Pallor Jaundice Gallstones Splenomegaly Poor growth/development Pronounced forehead Pronounced malaria eminences - cheek bones
Diagnosis of thalassaemia
FBC - microcytic anaemia
HB electrophoresis - to diagnose globin abnormalities
DNA testing - for genetic abnormality
Pregnant women screened at booking
What is a complication of thalassaemia?
Iron overload
Why do patients with thalassaemia suffer with iron overload?
as a result of faulty creation of red blood cells, recurrent transfusions and increased absorption of iron in response to the anaemia.
Monitoring for thalassaemia patients
Serum ferritin - to monitor for iron overload
What are the symptoms of iron overload?
Fatigue Liver cirrhosis Infertility and impotence Heart failure Arthritis Diabetes Osteoporosis and joint pain
What is the genetic abnormality in alpha thalassaemia?
defect on chromosome 16
Mx for alpha thalassaemia
Monitoring the full blood count Monitoring for complications eg iron overload Blood transfusions Splenectomy may be performed Bone marrow transplant can be curative
What is the genetic abnormality in beta thalassaemia?
Defect on chromosome 11
There may be abnormal copies of the gene for the beta globin chain so they retain some function or deletion of the gene
What are the 3 types of beta thalassaemia?
Thalassaemia minor / trait
Thalassaemia intermedia
Thalassaemia major
What happens in thalassaemia minor/trait?
carrier state - one normal and one abnormal gene
usually asymptomatic
there is mild anaemia that can worsen in pregnancy
What happens in thalassaemia intermedia?
Have 2 defective genes or one defective and one deletion gene
Moderate anaemia that doesn’t usually require transfusions
what happens in thalassaemia major?
abnormalities in both b globin chain genes
Prevents in 1st year of life with severe microcytic anaemia
Get skull bossing, hepatosplenomegaly and osteopenia
Need lifelong blood transfusions, iron chelation, splenectomy and bone marrow transplants can be curative
what does a blood film show in thalassaemia major?
hypo chromic microcytic cells, target cells and nucleated RBCs
What is sickle cell anaemia?
a genetic condition that causes sickle (crescent) shaped red blood cells
Makes the RBCs fragile = easily destroyed = haemolytic anaemia
Genetic inheritance of sickle cell anaemia?
Autosomal recessive - abnormal gene for beta-globin on chromosome 11
One copy abnormal gene = carrier = sickle cell trait
Two copies abnormal gene = sickle cell disease
Diagnosis of sickle cell anaemia
Newborn screening heel prick test on day 5
Complications of sickle cell anaemia
Anaemia Increased risk of infection Stroke Avascular necrosis in large joints such as the hip Pulmonary hypertension Painful and persistent penile erection (priapism) Chronic kidney disease Sickle cell crises Acute chest syndrome
Mx of sickle cell anaemia
Avoid dehydration Vaccinations Abc prophylaxis with pen V Hydroxycarbamide - stimulates production of fetal Hb Blood transfusions in severe anaemia Bone marrow transplant
How to manage a sickle cell crisis
Have a low threshold for admission to hospital
Treat any infection
Keep warm
Keep well hydrated (IV fluids may be required)
Simple analgesia such as paracetamol and ibuprofen
Penile aspiration in priapism
What is haemophilia?
Inherited severe bleeding disorder
What are the types of haemophilia?
Haemophilia A Haemophilia B (Christmas disease)