Anaemia

Anaemia is a condition where there is a reduced number of red blood cells or haemoglobin in the blood, leading to decreased oxygen delivery to the body’s tissues. It is a common health problem in both primary and secondary care and can be a standalone condition or a symptom of an underlying disease. Anaemia can range from mild to life-threatening, depending on the cause and severity.

Causes

Anaemia has various causes, often classified into three main categories:

• Blood loss: Due to gastrointestinal bleeding (e.g., peptic ulcer, colorectal cancer), heavy menstruation, trauma, or surgery.
• Reduced red blood cell production: Seen in nutritional deficiencies (iron, vitamin B12, folate), chronic kidney disease, bone marrow disorders, and chronic inflammation.
• Increased red blood cell destruction (haemolysis): Caused by autoimmune diseases, haemoglobinopathies (e.g., sickle cell disease), infections, or certain medications.

Pathophysiology

The primary role of red blood cells is to transport oxygen via haemoglobin. When the number or function of red blood cells is compromised, tissues receive less oxygen. The body may respond by increasing cardiac output, redistributing blood flow, and enhancing erythropoietin production from the kidneys to stimulate red blood cell production. In chronic anaemia, compensatory mechanisms may prevent symptoms until the anaemia is severe.

Signs and Symptoms

Symptoms depend on the severity and speed of onset. Common symptoms include:

• Fatigue and weakness
• Pale skin
• Shortness of breath
• Dizziness or light-headedness
• Headache
• Palpitations
• Cold hands and feet
• Chest pain in severe cases
• Signs on examination may include pallor (especially conjunctiva), tachycardia, systolic flow murmur, and in severe cases, signs of heart failure.

Risk Factors

Risk factors vary by anaemia type but may include:

• Poor dietary intake (e.g., low iron, B12, folate)
• Chronic diseases (CKD, cancer, autoimmune conditions)
• Menstruation and pregnancy
• Gastrointestinal disorders (e.g., coeliac disease, inflammatory bowel disease)
• Older age
• Alcohol dependence
• Medications (e.g., NSAIDs, chemotherapy)

Investigations

Initial assessment includes:

• Full blood count (FBC): Confirms anaemia and categorises by mean corpuscular volume (MCV) into microcytic, normocytic, or macrocytic.
• Serum ferritin: Low in iron deficiency anaemia; raised in inflammation.
• Serum iron, transferrin saturation: Helpful in iron studies.
• Vitamin B12 and folate levels: For macrocytic anaemia.
• Reticulocyte count: Indicates bone marrow activity.
• Peripheral blood film: Assesses red cell morphology.
• Renal function tests: To check for CKD.
• Liver function tests
• CRP/ESR: To assess for chronic inflammation.
• Further investigations may include endoscopy or colonoscopy for GI bleeding, or imaging (e.g., abdominal ultrasound) to assess organ pathology.

Management

1. Non-Pharmacological Management

• Dietary advice: Encourage iron-rich foods (e.g., red meat, leafy greens), B12 sources (meat, dairy), and folate (vegetables, legumes).
• Lifestyle modification: Reducing alcohol, smoking cessation, managing chronic disease.
• Treating underlying cause: E.g., coeliac disease, bleeding source, malignancy.

2. Pharmacological Management

• Iron supplementation: Oral ferrous sulphate or fumarate is standard for iron deficiency. Intravenous iron is used when oral is not tolerated or ineffective.
• Vitamin B12 and folate: Replaced depending on cause. B12 is given IM in pernicious anaemia.
• Erythropoiesis-stimulating agents: Used in chronic kidney disease-related anaemia under specialist guidance.
• Transfusions: Reserved for severe or symptomatic anaemia, particularly when Hb is less than 70g/L or with cardiovascular symptoms.

3. Surgical Management

Surgery is not a primary treatment for anaemia but may be necessary for the underlying cause, such as removal of bleeding lesions (e.g., polypectomy, tumour resection) or treating fibroids.

Complications

Untreated or severe anaemia may lead to:

• Cardiovascular stress or failure
• Impaired cognitive function
• Decreased immunity
• Poor pregnancy outcomes (preterm birth, low birth weight)
• Death in cases of severe or unrecognised blood loss
• Chronic anaemia can also affect quality of life and physical function, particularly in older adults.

References

• NICE Clinical Knowledge Summary: Anaemia – Iron Deficiency (2022)
• NICE NG8: Anaemia management in chronic kidney disease (2015)
• British Society for Haematology Guidelines on Investigation and Management of Anaemia
• Royal College of Pathologists – Guide to Diagnosis and Investigation
• General Medical Council (GMC): Good Medical Practice