Makindo Medical Notes

Related Subjects: |Iron deficiency Anaemia |Haemolytic anaemia |Macrocytic anaemia |Megaloblastic anaemia |Microcytic anaemia |Myelodysplasia |Myelofibrosis

An iron deficiency anaemia in an older patient is a gastrointestinal malignancy until proved otherwise. The patient will require an upper GI endoscopy as well as colonoscopy.

About

• Always consider Gastrointestinal malignancy

Aetiology

• Poor intake or excess loss or utilisation. Most Iron is reused
• There is period of iron loss before becomes evident

Causes

• Gastrointestinal blood loss
• Menstrual loss
• Pregnancy
• Dietary
• Hookworm: commonest cause worldwide
• Schistosomiasis
• Paterson Brown Kelly syndrome

Clinical

• Fatigue, Anaemia, Koilonychia - spoon-shaped nails
• Pallor of the conjunctiva and palmar creases
• Brittle nails and hair, Cheilosis, Glossitis, Flow murmurs
• Pica - desire to eat strange things e.g. ice (pagophagia) and clay (geophagia

Investigations

• Microcytic anaemia with a low MCV but sometimes MCV is normal. RBCs are hypochromic and microcytic and there are low reticulocytes due to reduced production
• Low ferritin is considered to be the most specific for identifying iron deficiency anaemia unless infection or inflammation are present
• Plasma Iron low and Increased total Iron binding capacity (TIBC)
• Increased soluble plasma transferrin receptors: the number of transferrin receptors on red cells rises in iron deficiency but remains normal in secondary anaemia. This test is replacing bone marrow aspirate in the diagnosis of iron deficiency in patients such as this.
• Transferrin saturation index < 15% may indicate iron deficiency. Once the transferrin saturation falls to 15 to 20%, haemoglobin synthesis is impaired.

Key Components of Iron Studies

• Serum Iron: Measures the amount of iron in the blood. Normal ranges are typically 10-30 µmol/L (55-160 µg/dL).
• Total Iron-Binding Capacity (TIBC): Reflects the maximum amount of iron that can be bound by proteins in the blood, primarily transferrin. Normal range is 45-70 µmol/L (250-450 µg/dL).
• Transferrin Saturation (%): The percentage of transferrin that is saturated with iron. It is calculated as (Serum Iron / TIBC) × 100. Normal range is 20-50%.
• Serum Ferritin: Indicates the amount of stored iron in the body. Normal range is 15-300 µg/L in men and 15-200 µg/L in women.

Interpreting Iron Study Results

The interpretation of iron studies involves assessing each component in conjunction with the others to diagnose and monitor various conditions. Below is a table summarizing common patterns and their clinical implications:

Additional Investigations

• Rectal exam to exclude rectal tumour
• Proctoscopy for piles
• Upper GI endoscopy + jejunal biopsies for peptic ulcer disease and coeliac
• Colonoscopy for polyps, tumour and colitis
• Anti-endomysial and Anti tissue Transglutaminase for coeliac
• Urine and stool for parasites
• Gynae/Urology for those with menorrhagia or haematuria
• Small Bowel MRI
• Capsule endoscopy
• Meckel's scan
• Angiography if heavy occult bleeding

Once daily FeSO4, or one every other day, is enough. Please stop prescribing 3x/day oral iron as this only causes more side effects

Management

• Identify cause. Consider FeSO4 200 mg once or alternate days usually for 6 months. More frequent doses can lead to severe constipation which can worsen piles.
• There is usually a rise in the reticulocyte count and Hb should increase by 1 g/dl per week
• Parenteral iron is used when the patient is intolerant to oral iron or with severe anaemia and wanting to build up Iron levels quickly
• Blood transfusion if the patient is severely anaemic and symptomatic