Help Patients Meet the Challenges of Thrombocytopenia

Platelets, also known as thrombocytes, are small blood cells that play an essential role in the process of blood clotting.

The normal platelet count in an adult is 150,000 to 450,000 platelets per microliter of blood.¹ Patients with a count below this range are considered to have thrombocytopenia, a condition that William Duke, MD, first described in 1910.² There may be many causes of this disease, but most are the result of immune thrombocytopenia (ITP).

Individuals with mild thrombocytopenia might not present any obvious symptoms and are often diagnosed with the disease during routine blood tests. Concerns about mild bleeding risk occurs when a patient’s platelet count drops below 50,000 platelets per microliter. If the patient’s platelet count drops below 20,000, they are considered at a serious risk for bleeding.¹

Patients with thrombocytopenia can bleed from anywhere in the body, externally or internally. External signs of bleeding include bruising with little provocation, leading to brown-, purple, and red-colored bruises. Patients may also experience increased duration and frequency of bleeding presenting as abnormally heavy menstrual flow and excessive bleeding after dental work or surgery. Internal bleeding can push blood into organs, such as the brain and intestine. Blood in the urine or red or tarry stools are signs of internal bleeding. Bleeding into the brain is a rare but serious complication that can present with neurological symptoms such as headaches.¹

There are 3 main causes of low platelet count: decreased production; increased breakdown; and increased sequestration. Certain conditions can enlarge the spleen, which increases its storage capacity for platelets. As a result, a lower concentration of platelets is left circulating in the bloodstream. Platelet production in the bone marrow can be affected by a variety of factors, such as anemia, cancer, heavy alcohol consumption, and viral infections.

Increased breakdown can be caused by certain autoimmune diseases where antibodies mediate the destruction of the platelets. Additionally, bacterial infection, pregnancy, and certain medications, such as anticonvulsants, heparin, quinine, and sulfa-containing antibiotics can increase platelet breakdown in the body.³

There are few ways to diagnose patients with thrombocytopenia. A blood test can determine the number of blood cells, such as the number of platelets. Another way to diagnose this disease is through a physical exam and taking a medical history. Most of these patients will show signs of bleeding under the skin and possible spleen enlargement.³

ITP is a rare but serious condition. About 3.3 out of 100,000 adults are diagnosed with ITP each year in the United States. Older adults (<60) are more likely to have the disease, and women are 2.6 times more likely than men to have it.⁴

Treatment options for thrombocytopenia vary based on the cause and severity of the condition. The first step in addressing thrombocytopenia caused by a medication or underlying condition is to treat the condition and discontinue the causative agent. Additional treatment may not be necessary for mild levels of thrombocytopenia. However, patients with greater severity may require blood or platelet transfusions, splenectomy, or medications to suppress the immune system.³ Some medications used for thrombocytopenia include steroids, such as immune globulins and prednisone. Other drugs include medications that can boost platelet production, such as romiplostim (Nplate) and eltrombopag (Promacta), which help the bone marrow in the body to produce more platelets. Rilzabrutinib, a first-in-class BTK inhibitor, is another option, and it received FDA fast-track designation for treatment of ITP.⁵ Tavalisse (Fostamatinib), a kinase inhibitor, is another prescription medication used to treat adults with a low platelet count. Doptelet (avatrombopag) is also used to treat adults with chronic ITP. Meanwhile, Rituximab (Rituxan) acts as an antibody that attaches to B-lymphocytes, causing them to be destroyed. With fewer anti-platelet antibodies, there is less destruction of platelets in the body. Finally, Anti-D immunoglobulin could be another option for treatment of thrombocytopenia and increasing the platelet count. When there is an emergency, a transfusion with platelet concentrate is yet another option.

The acute and short-term type of thrombocytopenia is more common in children and typically resolves after 6 months. When it comes to adults, thrombocytopenia may be chronic and last a lifetime. With more and newer treatment options in the market and in near future, patients with thrombocytopenia will benefit from various treatment regimens and strategies.

Saro Arakelians, PharmD, is vice president of pharmacy operations at a pharmacy in the Los Angeles, California, area. Ngoctran Tran is a PharmD candidate at the University of Southern California School of Pharmacy in Los Angeles.

REFERENCES

• US Department of Health & Human Services. Thrombocytopenia. Accessed December 10, 2020. https://www.nhlbi.nih.gov/health-topics/thrombocytopenia
• Duke WW. The relation of blood platelets to hemorrhagic disease description of a method for determining the bleeding time and coagulation time and report of three cases of hemorrhagic disease relieved by transfusion. JAMA. 1910;55(14):1185-119 doi:10.1001/jama.1910.04330140029009
• Mayo Clinic. Thrombocytopenia (low platelet count). Accessed December 11, 2020. https://www.mayoclinic.org/diseases-conditions/thrombocytopenia/diagnosis-treatment/drc-20378298
• Immune thrombocytopenia. National Organization for Rare Disorders. Accessed December 11, 2020. https://rarediseases.org/rare-diseases/immune-thrombocytopenia/
• Rilzabrutinib granted FDA fast track designation for treatment of immune thrombocytopenia [news release]. Paris, France; November 18, 2020: Sanofi. Accessed December 11, 2020. https://www.sanofi.com/en/media-room/press-releases/2020/2020-11-18-07-15-00