Anaemia - Iron deficiency (Microcytic)

Question 1

How is iron absorbed by our body?

Answer 1

Fe2+ actively transported into duodenum intestinal epithelial cells by intestinal haem transporter 1 (HCP1) which is highly expressed in the duodenum
Some converted to FERRITIN = acts as intracellular store for iron
Absorbed iron which doesn’t bind to ferritin is released into blood and circulates body bound to plasma protein TRANSFERRIN
Transferrin transports iron into bone marrow to be incorporated into new erythrocytes

Question 2

Where is ferritin stored?

Answer 2

Reticuloendothelial cells
Hepatocytes
Skeletal muscle cells
Either as FERRITIN (majority as most easily mobilised into Hb+ found as small amounts in plasma + most cells esp. liver, spleen, and bone marrow) or HAEMOSIDERIN (found in macrophages in the bone marrow, liver and spleen)

Question 3

Two forms of haem

Answer 3

Heme = Fe2+ = animal meat
Non-heme = Fe3+ = plant-based food

Question 4

How is Fe3+ activated and why

Answer 4

Only Fe2+ can be directly enter into duodenal cells. Fe3+ must be activated by HCl in stomach first (Fe3+ -> Fe2+)

Question 5

Epidemiology

Answer 5

Menstruating women

Question 6

Risk factors

Answer 6

Underdeveloped countries (south Asia, Caribbean)
High veg diet
Premature infants
Introduction of mixed feeding delayed- since breastmilk contains low iron

Question 7

Pathophysiology

Answer 7

Inadequate iron for haemoglobin synthesis = thus smaller RBCs = microcytic, also have less haemoglobin = hypochromic
Microcytic RBCs can’t carry enough O2 to the tissues = hypoxia
- hypoxia signals the bone marrow to increase RBC production
- bone marrow goes into overdrive + pumps out incomplete RBCs = POIKILOCYTOSIS, ANISOCYTOSIS

Question 8

Anaemia levels

Answer 8

Men < 135g/L
Women < 115 g/L

Question 9

Aetiology

Answer 9

Infants = malnutrition, prolonged breastfeeding
Children = malnutrition, malabsorption (coeliacs, IBD)
Adults = malnutrition, malabsorption, menorrhagia, hookworm (MC worldwide cause = GI blood loss)
Elderly (60+) = RARE, RED FLAG, for COLON CANCER BLEEDING
NICE recommend urgent endoscopy for any 60+ with Fe def

Question 10

Signs

Answer 10

KOILONYCHYA (spoon shaped nails)
ANGULAR STOMATITIS (ulceration at mouth corners)
ATROPHIC GLOSSITIS (tongue enlargement + atrophy of papillae)

Question 11

Symptoms

Answer 11

Fatigue
Dyspnoea
Palpitations
(Specific to iron def)
Brittle hair and nails
Pica - craving non-food substances

Question 12

Diagnosis

Answer 12

FIRST LINE = FBC
- microcytic, hypochromic RBC with poikilocytosis + anisocytosis
- low serum ferritin
- low serum iron
- low reticulocytes
- high soluble transferrin receptors
- high serum transferrin

GOLD STANDARD = Bone marrow biopsy

Question 13

Treatment

Answer 13

Oral iron - ferrous sulphate
Alternative = ferrous gluconate
Parenteral iron (IV, IM) in extreme cases only e.g. severe malabsorption
Asorbic acid - if diet is mainly non-heme iron

Question 14

Side effects of ferrous sulphate

Answer 14

Nausea
Abdominal discomfort
Black stools

Question 15

Complications

Answer 15

Polycythaemia
Haemochromatosis
Pre term delivery
Developmental delays