Blood Disorders: An Overview of Common Types

Main groups of blood disorders

Anemias

Anemia means a low level of hemoglobin, the oxygen-carrying protein in red cells. It causes tiredness, weakness, pale skin, shortness of breath on exertion, dizziness and a fast heartbeat.

• Iron deficiency anemia: the most common blood disorder worldwide; from heavy periods, pregnancy, gut bleeding or low iron intake.
• Vitamin B12 and folate deficiency: large red cells; B12 deficiency can also damage nerves.
• Anemia of chronic disease: with kidney disease, inflammation or cancer.
• Inherited anemias: sickle cell disease, thalassemia, G6PD deficiency, hereditary spherocytosis.
• Hemolytic anemia: red cells destroyed early by autoimmune disease, medicines or infections.
• Aplastic anemia: the bone marrow fails to make enough cells.

Bleeding disorders

Signs include easy bruising, nosebleeds, bleeding gums, heavy periods and prolonged bleeding after cuts, dental work or surgery.

• Von Willebrand disease: the most common inherited bleeding disorder, often undiagnosed in women with heavy periods.
• Hemophilia A and B: missing clotting factor VIII or IX, mainly in males; bleeding into joints and muscles.
• Platelet disorders: low platelets from immune thrombocytopenia, medicines, infections or marrow disease.
• Acquired causes: liver disease, vitamin K deficiency, blood thinners.

See easy bruising for how these present.

Clotting disorders

Abnormal clots block veins or arteries:

• Deep vein thrombosis: a clot in a leg vein causing pain and swelling.
• Pulmonary embolism: a clot that travels to the lungs; causes sudden breathlessness and chest pain.
• Inherited thrombophilias: factor V Leiden, prothrombin gene mutation, protein C or S deficiency.
• Antiphospholipid syndrome: an autoimmune condition causing clots and pregnancy loss.

Risk rises with surgery, immobility, cancer, pregnancy, estrogen-containing contraceptives and long-distance travel.

White blood cell disorders

• Neutropenia: low neutrophils, causing frequent or severe infections; often from chemotherapy, medicines or viral infections.
• High white counts: usually from infection or inflammation, but sometimes leukemia.

Myeloproliferative neoplasms

The marrow makes too many cells: polycythemia vera (too many red cells), essential thrombocythemia (too many platelets) and myelofibrosis. They raise the risk of clots and bleeding.

Blood cancers

• Leukemia: cancer of white blood cell precursors; fatigue, infections, bruising, bone pain.
• Lymphoma: cancer of lymphocytes in lymph nodes; painless swollen glands, fevers, night sweats, weight loss.
• Multiple myeloma: cancer of plasma cells; bone pain, fractures, kidney problems, high calcium, anemia.
• Myelodysplastic syndromes: faulty marrow production, mainly in older adults.

Tests for blood disorders

• Complete blood count (CBC): red cells, hemoglobin, white cells and platelets.
• Blood smear: a look at cell shape and immature cells under the microscope.
• Iron studies, B12 and folate levels.
• Reticulocyte count: shows whether the marrow is responding to anemia.
• Clotting tests: PT/INR, aPTT, fibrinogen, specific factor levels, von Willebrand tests.
• Hemoglobin electrophoresis for sickle cell disease and thalassemia.
• D-dimer and ultrasound or CT for clots.
• Bone marrow biopsy for leukemia, myeloma and marrow failure.
• Genetic tests such as JAK2 for myeloproliferative neoplasms.

Treatment approaches

Treatment depends entirely on the condition:

• supplements: iron, B12, folate
• transfusions of red cells, platelets or plasma
• clotting factor replacement or non-factor therapies for hemophilia
• anticoagulants (blood thinners) for clots
• medicines that modify disease, such as hydroxyurea for sickle cell disease and polycythemia
• chemotherapy, immunotherapy and targeted drugs for blood cancers
• stem cell (bone marrow) transplant for some cancers, marrow failure and severe inherited conditions
• gene therapies, now approved for some patients with sickle cell disease, thalassemia and hemophilia

Frequently asked questions

What are the most common blood disorders?

Iron deficiency anemia is the most common worldwide. Other common ones include anemia from chronic disease, deep vein thrombosis, von Willebrand disease and low platelet counts. Sickle cell disease and thalassemia are common in people with African, Mediterranean, Middle Eastern and Asian ancestry.

What are the symptoms of a blood disorder?

Symptoms depend on the type. Common ones include tiredness, pale skin, breathlessness, easy bruising, nosebleeds, heavy periods, frequent infections, swollen glands, night sweats, weight loss and, with clots, a swollen painful leg or sudden breathlessness.

How are blood disorders diagnosed?

Most start with a complete blood count and a blood smear. Depending on the results, doctors add iron studies, vitamin levels, clotting tests, genetic tests, imaging or a bone marrow biopsy. A hematologist specializes in diagnosing and treating them.

Are blood disorders inherited?

Some are. Sickle cell disease, thalassemia, hemophilia, von Willebrand disease and some clotting disorders are inherited. Many others, including iron deficiency, most clots and blood cancers, are acquired during life. Genetic counseling helps families with inherited conditions.

Can blood disorders be cured?

Some can. Nutritional anemias are cured by replacing what is missing. Many leukemias and lymphomas can be cured. Stem cell transplant and gene therapy can cure some inherited disorders. Others are lifelong but well controlled with treatment.