Living with immune thrombocytopenic purpura

Dr Zeenat Moorad helps us understand why the bleeding disorder immune thrombocytopenic purpura occurs and the treatment options available.

What is immune thrombocytopenic purpura (ITP)?

ITP is a rare bleeding disorder that increases with age with a slight female preponderance. It’s characterised by a decrease in the number of platelets in the blood, known as thrombocytopenia. Purpura refers to the purple discolouring of the skin, as with a bruise. Platelets are specialised blood cells that are fundamental in preventing bleeding, by forming a blood clot at sites of blood vessel injury. Platelets are made in the bone marrow in response to a hormone (thrombopoietin) that makes the body produce new platelets.

What happens in ITP?

Antibodies are an important part of the immune system, helping the body to fight infection. ITP may occur as primary ITP which accounts for the majority of cases. In this autoimmune disorder, the immune system is stimulated to attack the body’s own platelets. Most often this is a result of antibody production against platelets. Sometimes the antibody that is destroying the platelets also attack the special cells (megakaryocytes) in the bone marrow that make platelets, which reduces platelet production. Why these antibodies against platelets form is not known.

Without enough platelets, blood may not clot as quickly as it needs to, and bleeding can occur inside the body (internal bleeding) or underneath or from the skin (external bleeding).

Secondary ITP may occur due to underlying conditions, such as infections. These include HIV infection, auto-immune diseases, such as systemic lupus erythematosus, or cancers.

What are the symptoms of ITP?

Symptoms are varied, and are those of excessive bruising or bleeding including:

• Petechiae (tiny red or purple dots that may resemble a rash)
• Purpura (larger spots)
• Bruises and haematomas (blood collections under the skin with minimal or no trauma)
• Epistaxis (nosebleeds that are frequent and long-lasting)
• Gum bleeds, especially during dental work
• Heavy menstrual bleeding
• Blood in the urine or stool
• Fatigue, which is often severe and disabling

How is ITP diagnosed?

A blood test called a full blood count (FBC) indicates the decrease in the platelet count. A peripheral blood smear, which a haematologist looks at under a microscope, confirms that platelets are truly reduced, and there is no clumping of platelets. In some patients, a bone marrow aspirate and trephine (BMAT) biopsy may be required.

How is ITP treated?

There is currently no known cure for ITP. However, there a number of treatments with different mechanisms of action that can be used to:

1. Stop the body’s immune system from destroying platelets.
2. Prompt the body’s own natural processes to make new platelets, thus improving platelet counts and keeping ITP under control.

ITP may resolve spontaneously in some people but is often a chronic disorder lasting more than a year in adults.

The choice of treatment depends on a number of factors

• Age of the patient, overall health, lifestyle and medical history
• Disease extent
• Patient tolerance and preference for certain medicines, procedures and therapies
• Medications

1. Some medications include corticosteroids (prednisone) which is usually the mainstay of initial therapy.
2. Intravenous immunoglobulin (IVIG) works faster than corticosteroids (24 – 48 hours).
3. Immunosuppressive medicines (rituximab, azathioprine, or mycophenolate) stop the immune system from destroying platelets.
4. Thrombopoietin-receptor analogues (romiplostim and eltrombopag) stimulate the bone marrow to produce more platelets.
5. Removal of the spleen (splenectomy) has also been used to remove the main site of platelet destruction.

• Patients with low platelet counts must avoid over-the-counter medicines and herbal medicines and supplements. Acetylsalicylic acid, ibuprofen and fish oils are particular culprits that impair platelet function.
• Dangerous activities and contact sports may result in serious injuries and must be avoided.
• Special circumstances, such as pregnancy and surgery, require close monitoring and interventions (platelet transfusions) may be necessary in bleeding patients.
• Patients with ITP may experience severe anxiety in relation to their low platelet counts.

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