Anemia — Types, Symptoms, Diagnosis and Treatment

One of the most common reasons patients are tired, breathless, or simply "not themselves" is anemia, and it is often missed because the symptoms creep in slowly. A single blood test can usually tell us what is going on.

What is anemia?

Anemia means your blood carries too little hemoglobin, the iron-rich protein inside red blood cells that delivers oxygen to your tissues. By World Health Organization thresholds, anemia is generally defined as hemoglobin below 13 g/dL in men, below 12 g/dL in non-pregnant women, and below 11 g/dL in pregnancy.

It is a sign, not a diagnosis in itself. The real task is to find out why the hemoglobin is low.

Types and causes of anemia

The easiest way I classify anemia in clinic is by red cell size (MCV) on the blood count:

• Microcytic (small cells): iron deficiency anemia, thalassemia, and anemia of chronic disease.
• Normocytic (normal size): acute blood loss, chronic kidney disease, hemolysis, and chronic inflammation.
• Macrocytic (large cells): vitamin B12 or folate deficiency, liver disease, and heavy alcohol use.

Worldwide, iron deficiency anemia is the most common type. Typical causes include heavy menstrual bleeding, pregnancy, a diet low in iron, malabsorption (for example celiac disease), and slow gastrointestinal blood loss from ulcers, hookworm, or tumors. In men and postmenopausal women, iron deficiency should always make us look for a bleeding source.

Symptoms to look for

The most common complaint is persistent fatigue, followed by pallor of the skin, palm creases, and inner eyelids. Other features include shortness of breath on exertion, palpitations, dizziness, headaches, and cold hands and feet.

Iron deficiency has some clues of its own: brittle nails, hair loss, sore tongue, cracks at the corners of the mouth, restless legs, and pica, a craving for ice, clay, or starch. Chest pain, fainting, or severe breathlessness needs urgent medical attention.

How anemia is diagnosed

Complete blood count (CBC)

The CBC confirms low hemoglobin and gives the MCV and RDW, which point toward the likely type. Platelet and white cell counts help exclude bone marrow problems.

Ferritin and iron studies

Ferritin reflects iron stores and is the single best test for iron deficiency. A low value is diagnostic, but ferritin also rises with infection and inflammation, so a "normal" result can hide true deficiency. Transferrin saturation and TIBC help in these cases.

Peripheral smear

Looking at the blood under the microscope adds real detail. Iron deficiency shows small, pale (hypochromic) cells with pencil shapes. B12 or folate deficiency shows large oval cells and hypersegmented neutrophils. Target cells suggest thalassemia, and fragmented cells point toward hemolysis. A reticulocyte count tells us whether the marrow is responding appropriately.

Treatment

Treatment always has two parts: replace what is missing and fix the cause.

• Iron deficiency: oral iron is first-line. Taking it once daily or on alternate days often improves absorption and reduces stomach upset. Hemoglobin usually begins to rise within a few weeks, and iron is generally continued for about three months after it normalizes to refill stores.
• Intravenous iron: used when tablets are not tolerated, absorption is poor, blood loss is ongoing, or in chronic kidney disease.
• B12 or folate deficiency: replacement by injection or tablets, depending on the cause.
• Severe or symptomatic anemia: blood transfusion may be needed, along with treatment of the underlying condition.

Dietary measures such as red meat, lentils, and leafy greens with vitamin C help, but diet alone rarely corrects established iron deficiency anemia.