Anaemia

When examining a patient suspected of having iron-deficiency anaemia (IDA), here are the key clinical features to look for:

1. General and Conjunctival Pallor: Patients with IDA often exhibit paleness of the skin and conjunctiva due to reduced haemoglobin levels.
2. Atrophic Glossitis: This refers to a painful tongue with loss of papillae, which can occur in IDA.
3. Angular Cheilitis: Ulcers at the corners of the mouth may be present.
4. Koilonychia: Some individuals may have spoon-shaped nails.
5. Dry Skin and Hair: Reduced iron affects skin and hair health.
6. Flow murmur/high-output cardiac failure

Remember that these findings are non-specific and can overlap with other conditions.

• Pernicious anaemia is a type of megaloblastic anaemia resulting from vitamin B12 deficiency due to impaired absorption, primarily caused by autoimmune destruction of gastric parietal cells and intrinsic factor.
• Aetiology:
  • Autoimmune destruction of gastric parietal cells and intrinsic factor.
  • Genetic predisposition.
• Pathophysiology:
  • Autoimmune destruction of gastric parietal cells leads to decreased production of intrinsic factor.
  • Intrinsic factor is necessary for the absorption of vitamin B12 in the terminal ileum.
  • Vitamin B12 deficiency impairs DNA synthesis, leading to megaloblastic changes in erythropoiesis.
• Clinical Features:
  • Symptoms of anaemia (fatigue, weakness, pallor).
  • Glossitis, angular stomatitis.
  • Neurological symptoms (e.g., paresthesias, ataxia, dementia) in severe cases.
• Diagnostic Evaluation:
  • CBC: Macrocytic anaemia, increased MCV (>100 fL).
  • Peripheral blood smear: Hypersegmented neutrophils.
  • Serum B12 levels: Decreased (<150 pg/mL).
  • Serum methylmalonic acid (MMA) and homocysteine levels: Elevated.
• Treatment:
  • Vitamin B12 supplementation:
    • Intramuscular cyanocobalamin initially for rapid replenishment.
    • Long-term maintenance with oral cyanocobalamin or intramuscular injections.
  • Identify and treat underlying autoimmune condition.

Macrocytic anaemia is characterized by the presence of abnormally large red blood cells (macrocytes) in the peripheral blood, resulting in a decreased haemoglobin concentration and haematocrit.

Classification of causes:

1. Megaloblastic Anaemia:
   • Characterized by impaired DNA synthesis leading to ineffective erythropoiesis.
   • Common causes include deficiencies in vitamin B12 (cobalamin) or folate (vitamin B9).
2. Non-Megaloblastic Macrocytic Anaemia:
   • Results from factors other than impaired DNA synthesis.
   • Includes conditions such as liver disease, alcoholism, and certain medications.

Aetiology:

1. Megaloblastic Anaemia:
   • Vitamin B12 Deficiency:
     • Dietary insufficiency (rare, primarily seen in strict vegetarians).
     • Malabsorption due to pernicious anaemia (autoimmune destruction of gastric parietal cells leading to intrinsic factor deficiency), gastrointestinal surgery, or diseases affecting the ileum (e.g., Crohn’s disease).
   • Folate Deficiency:
     • Inadequate dietary intake (rare in developed countries due to food fortification).
     • Malabsorption syndromes or increased demand (e.g., pregnancy, haemolytic anaemias).
2. Non-Megaloblastic Macrocytic Anaemia:
   • Alcoholism: Chronic alcohol consumption can lead to impaired folate metabolism and direct bone marrow toxicity.
   • Liver Disease: Conditions such as cirrhosis can result in decreased production of proteins required for erythropoiesis and impaired metabolism of folate and vitamin B12.
   • Hypothyroidism: Thyroid hormone deficiency can result in macrocytosis due to impaired erythropoiesis.
   • Myelodysplastic Syndromes (MDS): Clonal hematopoietic stem cell disorders characterized by ineffective haematopoiesis, which can present with macrocytic anaemia.

Iron deficiency anaemia (IDA) is defined as a haemoglobin concentration below 13.5 g/dL in males or 11.5 g/dL in females, in association with a low mean cell volume (MCV) and evidence of depleted iron stores (i.e. a low ferritin and a raised total iron binding capacity). In the developed world IDA is usually secondary to chronic blood loss from gastrointestinal, uterine and urinary tract sources. (Worldwide, hookworm infection and schistosomiasis are common causes.) In cases where the source of bleeding is obvious, further investigation is usually not necessary and treatment can begin; however, in many instances, bleeding goes unnoticed and is secondary to a more sinister cause such as gastrointestinal malignancy. As such, patients with IDA without an obvious cause must be referred for investigation of the upper and lower gastrointestinal tract in the first instance.

Iron deficiency anaemia is most commonly treated with oral iron supplementation. However, there are several indications for offering an intravenous iron infusion, including when a rapid response is required. In this case the haemoglobin level is very low and the patient is significantly symptomatic, so an intravenous iron infusion should be offered. A blood transfusion is associated with risks of infection and would only normally be considered if the haemoglobin level was below 70g/L (or 80g/L in the presence of cardiovascular or respiratory disease).