Anaemia - Presentation, Diagnosis and Treatment Flashcards

1
Q

What factors may be considered when diagnosing anaemia?

A
  • All biological measurements will have a range of normality
  • Range will be age/gender related
  • Expressed as reference range- often a “normal distribution”
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2
Q

What Hb range is used to diagnose anaemia?

A

For Hb typically in adult male 135-175, female 120-155 g/ (previously g/dl)

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3
Q

What are the symptoms of anaemia?

A

“Tired all the time”- need to unpack this
Symptoms relating to reduced O2 delivery
- short of breath
-muscle pain on exertion
-dizzy
-angina
Symptoms relating to the cause of the anaemia

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4
Q

What are the clinical signs of anaemia?

A
  • Palor in skin and conjunctiva
  • Tachycardia
  • Rapid breathing
  • Peripheral oedema if severe anaemia
  • Signs relating to cause of anaemia
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5
Q

What are the symptoms of mild anaemia?

A

Mild anaemia likely to cause no symptoms unless extreme exertion

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6
Q

What is the effect of anaemia on cardiac output?

A

Cardiac output increases- rate and stroke volume

• Changes in distribution of blood flow

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7
Q

What factors are used to classify the type of anaemia?

A
  • Under-production or increased loss of RBC
  • Congenital or acquired
  • Acute or chronic
  • By mean cell volume (MCV) – microcytic/normocytic/macrocytic
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8
Q

How do you calculate the classification of anaemia by mean cell volume?

A

Haematocrit (Hct) (%) X10
RBC count (number as 1012/l)
• MCH- mean cell Hb - Hb RBC
• MCHC- mean cell Hb concentration- Hb Hct
•RDW red cell distribution width is a measure of spread of RBC size eg retics/transfusion

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9
Q

What is a mean cell volume of 60-80fl indicative of?

A

Microcytic anaemia- iron def, thalassaemia

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10
Q

What does microcytic anaemia refer to?

A

Abnormally small erythrocyte, linked to certain types of anaemia

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11
Q

What is a mean cell volume of 80-100fl indicative of?

A

Normocytic anaemia - blood loss, anaemia of chronic disease,

renal impairment

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12
Q

What does normocytic anaemia refer to?

A

An anaemia caused by chronic disease, v prevalent in over 85 y/o

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13
Q

What is a mean cell volume of 100 -120fl indicative of?

A

Macrocytic anaemia - megaloblastic anaemia- B12/folate deficiency, myelodysplasia

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14
Q

What does macrocytic anaemia refer to?

A

Abnormally large erythrocytes linked to certain types of anaemia

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15
Q

What is hypochromic anaemia?

A

Any type of anaemia where the erythrocyte is paler than normal, iron def, thalassaemia

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16
Q

What is the most common cause of anaemia worldwide?

A

Iron deficiency anaemia

17
Q

What is the pathology of iron deficiency anaemia?

A

Typically reduction in MCV (microcytic) to 65-80, then in Hb, low ferritin, low transferrin saturation with iron. Rest of blood count normal- ?raised platelets if bleeding.

18
Q

What may cause iron deficiency anaemia?

A

-Poor intake of iron

  • Blood loss- menstrual
  • —GI tract ?haematemesis or melaena eg peptic ulcer/cancer/angiodysplasia/hookworm
  • Malabsorption- coeliac disease
  • Increased need eg growth spurt/pregnancy
19
Q

What are the clinical features of iron deficiency anaemia?

A
  • Pale
  • Tachycardia
  • Koilonychia
  • Hair loss
  • Pica
  • Glossitis/angular stomatitis
  • Features relating to the cause eg wt loss/abdo pain/bowel change/heavy periods
20
Q

How should one investigate iron deficiency anaemia?

A
  • Be guided by history- recent and past and clinical findings
  • Confirm iron def by low ferritin and typical FBC •Screen for coeliac disease (IgA tissue transglutaminase or tGA)
  • Upper and lower endoscopy for all except pre-menopausal women
  • Consider other imaging/capsule endoscopy
21
Q

How should one orally treat iron deficiency anaemia?

A
  • Oral- replacement with sufficient iron for long enough period eg ferrous sulfate 200mg 2 or 3 per day- 65mg elemental iron per dose
  • Side effects- nausea/abdo pain/constipation- dose related- may improve if changed to ferrous gluconate or fumarate
  • Typically patients need 3 months of iron AFTER correction of anaemia to build up iron stores
  • Treat the underlying cause
  • Rise in Hb generally 10g/l per week if not bleeding
22
Q

How should one treat iron deficiency anaemia parenterally?

A

• Intramuscular- not used now- painful, multiple doses, stains skin
• Intravenous-
Ferric carboxymaltose- ferinject- over 15-30mins. Often needs 2 doses Iron dextran- cosmofer- over 4-6 hours after a test dose.

All IV iron preparations can cause ‘flu like symptoms and a small risk of hypersensitivity reaction or anaphylaxis

23
Q

Describe B12 deficiency

A

Think KT
• Typically a macrocytic anaemia- MCV 100-120 and later a pancytopenia. Often bilirubin and LDH raised
• Can also cause peripheral neuropathy- demyelination and posterior column damage
• B12 result can be falsely low in pregnancy/oral contraceptive/on metformin
• Pernicious anaemia- gastric atrophy and auto antibodies to parietal cells and intrinsic factor preventing absorption
• Strict vegan or terminal ileal disease also possible

24
Q

What treatments are available for B12 deficiency?

A
  • Hydroxocobalamin 1mg IM alternate days for 5 doses then 3 monthly if confirmed ongoing need eg pernicnious anaemia
  • Cyanocobalamin available orally but not available on prescription
25
Q

Describe Folate deficiency

A
  • Blood count and film appearance same as B12 def.
  • Limited stores of folate so deficiency can develop in weeks
  • Poor intake, increased use eg pregnancy/haemolysis, malabsorption, drugs eg anti-epileptics or trimethoprim
  • Replacement with oral folic acid 5mg per day
  • Pre-conception folic acid reduces neural tube defects. Likely plan to add folic acid to flour
26
Q

Describe anaemia due to blood loss

A

• Hb immediately after blood loss will be normal
• Drop after fluid replacement
• Each 500ml loss gives approx
drop of Hb by 10-15 g/l
• Retic response within hours/days
• May need blood transfusion to replace loss eg trauma/GI bleed/around delivery

27
Q

Describe anaemia of chronic disease

A
  • Typically a normocytic anaemia associated with chronic inflammatory disease
  • Plentiful iron stores but poor transfer to RBC due to hepcidin and cytokines
  • History of chronic disease, inflammatory markers increased eg CRP/ESR/plasma viscosity, exclusion of other causes
  • Will respond to treatment of underlying disease
28
Q

Describe anaemia of renal failure

A
  • Drop in Hb once creatinine clearance drops below 20-30 ml/min chronically
  • Mainly due to lack of erythropoietin
  • Contribution from blood loss at dialysis, inflammatory disease
  • Responds well to erythropoietin eg weekly or alternate weeks s/c
29
Q

Describe effects and causes of haemolysis

A

• Increased RBC destruction, marrow can increase production 5 -10 fold
• Can be acute or chronic, congenital or acquired
• Issues to do with- RBC membrane
- RBC enzymes -Globin chains in Hb

30
Q

What are the causes of haemolysis of the RBC membrane due to disease?

A
  • Congenital spherocytosis- autosomal dominant defect in spectrin causing spherical cells – less able to deform so shortened survival
  • Auto-immune haemolysis- auto antibodies against RBC surface antigens- Fc portion recognised by macrophages in spleen. Treated with steroids/splenectomy/rituximab
31
Q

What are the mechanical and enzyme based causes of haemolysis of the RBC membrane?

A

Prosthetic heart valve- mechanical

Disseminated intravascular coagulation (DIC)- eg in sepsis, prostate cancer causing RBC fragmentation by fibrin

RBC enzyme def eg G6PD or pyruvate kinase can cause shortened RBC survival

32
Q

What is the cause of anaemia due to abnormal haemoglobin?

A

Haemoglobinopathy eg Sickle cell disease- single point mutation causing Hb polymerisation in hypoxic cells in homozygotes

33
Q

Describe anaemia due to abnormal haemoglobin

A

• Haemoglobinopathy eg Sickle cell disease- single point mutation causing Hb polymerisation in hypoxic cells in homozygotes
• Shortened RBC survival, reduced production
• Chronic anaemia and bone/liver/lung/brain
“crisis” ie acute infarction
• Treated by supportive care, hydroxycarbamide to increase HbF production, ??stem cell transplant

34
Q

Describe anaemia due to thlassaemia

A
  • Inbalance of globin chain production
  • Beta thalassaemia- as Hb F (2 alpha, 2 gamma chains) declines after birth- progressive anaemia. Supportive care, transfusion, ?stem cell transplant
  • Progressive iron overload
  • Antenatal screen for Hb-opathy and thalassaemia
35
Q

What is the physiological cause and treatment of anaemia due to marrow infiltration?

A

• Myeloma-
B cell malignancy of mature plasma cells- produce monoclonal immunoglobulin or light chains
Presents as chance finding, anaemia, renal failure, hypercalcaemia, bone pain or fracture
Treatment- supportive care, chemotherapy, radiotherapy

36
Q

How does one discover anaemia due to marrow infiltration?

A

Presents as chance finding, look in anaemia, renal failure, hypercalcaemia, bone pain or fracture

37
Q

Give a brief overview of anaemia due o marrow infiltration

A
  • Haematological malignancy eg lymphoma, acute leukaemia
  • Diagnosed by sampling marrow- pelvis or sternum
  • Treated by chemotherapy/immunotherapy
  • Other “solid” tumours can spread to marrow eg prostate, breast, small cell lung
38
Q

What anaemias are caused by marrow failures?

A
  • Myelodysplastic disorders- progressive decline in Hb, neutrophils, platelets, macrocytosis. Tendency to progress to acute leukaemia. Treated by supportive care, chemotherapy or stem cell transplant in some.
  • Aplastic anaemia- pancytopenia. Expected result post chemotherapy but can be drug induced eg NSAIDs, chloramphenicol or idiopathic. Treated by supportive care, anti- thymocyte globulin, stem cell transplant
39
Q

In summary, what be anaemia?

A
  • Anaemia is a blood count finding with associated symptoms and signs
  • Multiple causes relating to underproduction or increased loss
  • Use other blood count indices to identify a likely cause
  • Treatment relates to cause and underlying disease