Anemia is defined as a decrease in the total amount of red blood cells (RBCs) or
hemoglobin in the blood and is present when it falls below certain
thresholds depending on the age, gender, and race of the patient.
Based on WHO criteria, the lower limit of normal in adults is 13 g/dL in
men and 12 g/dL in women. The blood hemoglobin concentration may more
accurately indicate the total red cell mass compared with the
hematocrit. The various types of anemia are due to blood loss
(usually gastrointestinal bleeding, trauma, others), decreased red
blood cell production (iron deficiency, a lack of vitamin B12, folic
acid, thalassemia, and a number of neoplasms), or increased red blood
cell breakdown ( genetic conditions such as sickle cell anemia,
infections e.g. malaria, and certain autoimmune diseases). The
type of anemia can also be classified based on the size of the red blood
cells (microcytic - smaller, macrocytic - larger, or normocytic - normal
size) and the amount of hemoglobin present in each cell - hypochromic
(paler than normal - less red) or normochromic (normal color).
Symptoms vary greatly and depend on the onset and the
individual's ability to compensate for a loss in oxygen-carrying
capacity. Anemia with a slow onset may go undetected or present with
vague symptoms including tiredness, weakness, shortness of breath, poor
concentration or reduced exercise tolerance. Anemia that occurs rapidly
often has more obvious symptoms such as confusion, mental status
changes, lightheadedness, loss of consciousness, palpitations,
respiratory distress, or hypotension. Symptoms are often more severe if
there is underlying coronary artery disease, congestive heart failure,
or intrinsic pulmonary or cerebrovascular disease. Typical signs
exhibited may include pallor (pale skin, lining mucosa, conjunctiva and
nail beds), however, further testing is required to confirm the
Iron-deficiency anemia is defined as a decrease
in the number of red blood cells or the amount of hemoglobin in the
blood due to a decrease in iron and is estimated to cause approximately
half of all anemia cases globally. Iron is a critical component of
hemoglobin and about 70% of the iron found in the body is bound to
hemoglobin. Iron is primarily absorbed in the small intestine This type
of anemia may be related to blood loss ( uterine fibroids, stomach
ulcers, colon cancer, urinary tract bleeding, other sources),
insufficient dietary intake, or poor absorption of iron from food (may
occur as a result of an intestinal disorder such as inflammatory bowel
disease or celiac disease, or surgery such as a gastric bypass).
Sources of iron:
Iron deficiency anemia can be prevented by eating a diet containing
sufficient amounts of iron or by iron supplementation. Foods high in
iron include meat, nuts, spinach, and foods made with iron-fortified
Other possible symptoms and signs include:
- Angina (chest pain)
- Tingling, numbness, or burning sensations
- Glossitis (inflammation or infection of the tongue)
- Angular cheilitis (inflammatory lesions at the mouth's corners)
- Koilonychia (spoon-shaped nails) or nails that are brittle
- Poor appetite
- Dysphagia (difficulty swallowing)
Anemia of chronic disease - 'Anemia of chronic
inflammation' is a form of anemia seen in chronic infection,
chronic immune activation, and neoplastic disease. The diagnosis can be difficult, especially if it coexists with
iron deficiency. Other contributing causes of anemia should be ruled
out. Anemia of chronic disease is usually mild but can be
severe. It is usually normocytic, but can be microcytic.
In anemia of chronic inflammation without iron deficiency, ferritin is
normal or high, reflecting the fact that iron is sequestered within
cells, and ferritin is being produced as an acute phase reactant. In
iron deficiency anemia ferritin is low.
Total iron-binding capacity (TIBC) is high in iron deficiency,
reflecting production of more transferrin to increase iron binding; TIBC
is low or normal in anemia of chronic inflammation.
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