Management of Iron Deficiency
1. Rule out an underlying cause
Occult gastrointestinal bleeding (always in men, and post-menopausal females).
For pre-menopausal females, consider if the degree of anaemia is out of proportion to dietary intake and menstrual blood loss.
Menorrhagia in pre-menopausal females.
Take a detailed menstrual history including cycle length, number of bleeding days,
flow and presence of clots.
Menorrhagia may require specialist gynaecological management,
especially if there is an anatomical cause (e.g. fibroids).
Exclude other sources of bleeding
Take a detailed dietary history.
Foods which are rich in iron include red meat, fortified cereals, legumes, spinach and tofu.
2. Iron supplementation
Oral iron supplementation
is usually sufficient for most people.Iron-deficient individuals usually require 200mg of elemental iron per day, in divided doses.
Different iron preparations contain varying quantities of elemental iron;
it is hence important to dose iron replacement
based on the amount of elemental iron in each preparation.
Oral iron supplementation is often poorly-tolerated due to gastrointestinal side-effects
(nausea, vomiting, constipation, abdominal cramping).
These side-effects can be addressed by reducing the dose and frequency of elemental iron prescribed.
A minimum of 60mg elemental iron per day should be prescribed (Camaschella, 2019).
Intravenous iron
can be considered in patients who are intolerant of, or who do not respond to oral iron. Compared to oral iron, there are almost no gastrointestinal side-effects,
and the effect is more rapid.
A randomised, double-blind controlled trial of
intravenous ferumoxytol versus ferric carboxymaltose
in iron-deficient patients who had failed oral iron therapy
found that the ferritin levels peaked at 2 weeks post-infusion,
declining but still remaining at 5 weeks post-infusion.
The least-squares mean change in haemoglobin was 1.4-1.6g/dL at 5 weeks
(Adkinson et al., 2018).
Newer, low-molecular weight iron dextran preparations
have a much lower incidence of hypersensitivity reactions than older, high-molecular weight preparations;
they are much safer for routine use
and premedication is not generally required
(Auerbach and Ballard, 2010).
There is a theoretical risk of infection
as bacteria and other infectious agents require iron as a growth factor.
Meta-analysis data has shown no increased risk of infection with IV iron (Avni et al., 2015).
Hypophosphataemia has been reported with certain preparations of IV iron.
However, clinical sequelae of hypophosphataemia are usually asymptomatic or mild.
