Diff: Anaemia

'''Anaemia''' is a condition in which the blood has too little haemoglobin, too few red blood cells, or red blood cells that do not work properly. Haemoglobin is the iron-containing protein in red blood cells that carries oxygen from the lungs to the rest of the body.

== Overview ==

Anaemia is not a single disease. It is a finding with many possible causes. Some forms are mild and temporary. Others are long-term, inherited, linked to chronic disease, or caused by blood loss.

Anaemia reduces the blood's oxygen-carrying capacity. The body may compensate by increasing heart rate or breathing effort, but symptoms can still appear when tissues receive less oxygen than they need.

== Main Types ==

Common types and causes include:

* '''Iron deficiency anaemia''': caused by low iron stores, often from blood loss, pregnancy, poor absorption, or increased need.

* '''Vitamin B12 deficiency anaemia''': caused by low vitamin B12 intake, poor absorption, pernicious anaemia, or digestive conditions.

* '''Folate deficiency anaemia''': caused by low folate intake, poor absorption, pregnancy, some medicines, or increased need.

* '''Anaemia of chronic disease''': associated with long-term inflammation, infection, kidney disease, cancer, or autoimmune disease.

* '''Haemolytic anaemia''': caused by red blood cells being destroyed too quickly.

* '''Aplastic anaemia and bone marrow disorders''': caused by reduced production of blood cells.

* '''Inherited anaemias''': including sickle cell disease and thalassaemia.

== Symptoms ==

Symptoms depend on the severity, the speed of onset, and the cause. Slowly developing anaemia may cause few symptoms at first.

Common symptoms include:

* Tiredness and low energy.

* Shortness of breath.

* Pale skin or pale inner eyelids.

* Palpitations.

* Dizziness, light-headedness, or faintness.

* Headache.

* Cold hands and feet.

* Chest discomfort in some people, especially if heart disease is present.

* Reduced exercise tolerance.

Some causes produce extra clues. Iron deficiency may cause brittle nails, hair loss, a sore tongue, pica, or difficulty swallowing. Vitamin B12 deficiency may cause numbness, tingling, memory problems, balance changes, or other nerve symptoms.

== Causes ==

Anaemia can develop through blood loss, reduced red-cell production, increased red-cell destruction, or a mixture of these.

Important causes include:

* Heavy menstrual bleeding.

* Pregnancy.

* Gastrointestinal bleeding, including ulcers, bowel disease, cancer, or medicine-related bleeding.

* Low iron intake or poor absorption, including malabsorption from [[Coeliac Disease|coeliac disease]].

* Vitamin B12 or folate deficiency.

* Chronic kidney disease.

* Inflammatory and autoimmune disorders.

* Bone marrow disease.

* Inherited haemoglobin disorders.

In men and post-menopausal women, iron deficiency anaemia often needs investigation for gastrointestinal blood loss. NHS inform notes that bleeding in the stomach or intestines is the most common cause in those groups.

A full blood count is the usual starting test. It measures haemoglobin, red blood cells, white blood cells, and platelets. Red-cell size and appearance help narrow the cause.

Further tests may include:

* Ferritin and iron studies.

* Vitamin B12 and folate levels.

* Reticulocyte count, which shows whether the bone marrow is making new red blood cells.

* Kidney, liver, thyroid, or inflammatory marker tests.

* Blood film examination.

* Tests for hidden blood loss from the bowel.

* Coeliac disease testing where malabsorption is suspected.

* Bone marrow tests in selected cases.

Diagnosis should identify the cause, not only the low haemoglobin. Treating the cause reduces the risk of recurrence.

== Treatment ==

Treatment depends on the type of anaemia and the underlying cause.

Iron deficiency anaemia is commonly treated with iron replacement and investigation or treatment of the reason iron was lost. Vitamin B12 deficiency may need hydroxocobalamin injections, especially where absorption is poor. Folate deficiency is usually treated with folic acid tablets and dietary advice.

Other treatments may include:

* Treating heavy menstrual bleeding or gastrointestinal bleeding.

* Treating coeliac disease, inflammatory bowel disease, kidney disease, or another underlying condition.

* Changing medicines that contribute to bleeding, where clinically appropriate.

* Erythropoietin-stimulating treatment in selected kidney disease or specialist settings.

* Blood transfusion for severe anaemia or urgent clinical need.

== Complications ==

Untreated anaemia can affect daily function, work, exercise, pregnancy, and recovery from illness. Severe anaemia can strain the heart and lungs. In pregnancy, severe or untreated anaemia can increase risks for both mother and baby.

Vitamin B12 deficiency is especially important because nerve symptoms may become long-lasting if the deficiency is not recognised and treated.

* [[Haemoglobin]]

* [[Coeliac Disease]]

* [[Thalassemia]]

* [[Red Blood Cells]]

* [https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/treatment/ NHS: Vitamin B12 or folate deficiency anaemia treatment]

* [https://www.nice.org.uk/guidance/ng239 NICE: Vitamin B12 deficiency in over 16s]

* [https://www.healthdirect.gov.au/anaemia Healthdirect Australia: Anaemia]