Anaemia

Exam Cram

• Anaemia is a sign (not a diagnosis), defined by low haemoglobin

• Presentation: lethargy, pale skin, palpitations/ short of breath

• Classification (MCV): macrocytic, normocytic and microcytic

• GI malignancy should be considered in microcytic anaemias

Outline

Assessment

History

• Insidious reduction in exercise tolerance

• Worsening shortness of breath, palpitations or chest pain

Examination

• Pale conjunctiva

Investigations

• Low haemoglobin

Work up

• MCV

• B12, folate, iron studies

• Consider: reticulocytes, haptoglobin, LDH, Co-ombs test

• Blood film

• Endoscopy, colonoscopy

Classification

The causes of anaemia are usually classified by the mean corpuscle volume:

Low MCV (microcytic)

• Iron deficiency anaemia

• Thalassemia

• Rarer: lead toxicity

Normal MCV (normocytic)

• Anaemia of chronic disease

• Haemolytic anaemia

  • Auto Immune Haemolytic Anaemia AIHA

• Combined iron and B12 anaemia deficiencies

Large MCV (macrocytic)

• B12/ folate deficiencies

• Alcohol abuse

• Aplastic anaemia

Iron Deficiency Anaemia

Still not a diagnosis, a cause should be found:

Background

Iron is absorbed in the iron, hence 100% gastrectomy patients have iron deficiency anaemia

Causes

• Poor diet

  • Vegan/ vegetarian: Fe found in red meats and leafy vegetables (spinach)

• Poor absorption

  • Coeliac Disease

  • IBD: Crohn's Disease or Ulcerative Colitis 

  • Gastrectomy

• Loss of blood

  • GI Cancer

  • Diverticular Disease 

  • Heyde Syndrome 

Diagnosis

1. Fe deficiency: low Ferritin < 100

2. Microcytic anaemia 

Management

1. Assess underlying cause

   1. Ask about heavy menstural bleeding, consider transvaginal USS ?endometrial cancer

   2. Colonoscopy +- endoscopy, if both negative capsule enteroscopy

   3. Basic work up: Fe studies, B12, folate; FBC, EUC, LFTs +- blood film

2. Replace Fe

   1. Don't replace whilst on antibiotics as Fe will feed infection

   2. Oral supplementation

   3. IV Fe

Anaemia of Chronic Disease

Management

• Check for deficiencies: iron, B12, folate

• RBC aim > 70, > 80 if ischaemic heart disease

Macrocytic Anaemia

Core:

• B12/ folate deficiencies

• Alcohol abuse

Aplastic Anaemia

Causes

• MMF

• Parvovirus B19

Resources and References

Written in 2025.