Platelets (Thrombocytes)

Platelets (Thrombocytes)

Background Information of Platelets (Thrombocytes)

Platelets, (thrombocytes), are small, disc shaped clear cell fragments, 2–3 µm in diameter (smallest visible blood components visible under light microscope) which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors. 

Their function is to circulate in the blood and be ready to be activated maintain hemostasis, leading to the formation of blood clots. A signal will be transmitted to the platelets when a damage blood vessel is detected, the platelets will then travel to the affected area and transform into their "active" formation to recruit more platelets to form a blood clot and hence prevent further bleeding. 

Cellular Description

Platelets do not have any nucleus and are the smallest visible blood component in the blood. They resemble fragments and are stained lightly in shades of pink and purple.

Clinical Significance

1. Thrombocytosis (Excess Platelets)

• Primary or essential thrombocytosis – Abnormal cells in the bone marrow cause an increase in platelets, but the reason is unknown
• Secondary thrombocytosis – The same condition as primary thrombocytosis, but may be caused by an ongoing condition or disease such as anemia, cancer, inflammation, or infection
• Recent Spleenectomy: Spleen removal, hence platelets do not get removed promptly after their maximum lifespan is reached

2. Thrombocytopenia (Abnormally low platelet count)

• Cancer chemotherapy
• Certain medications
• Disseminated intravascular coagulation (DIC): Exccessive formation of clots resulting in excessive consumption of platelets.
• Hemolytic anemia
• Hypersplenism: Organ expansion leading to excessive removal of healthy platelets
• Idiopathic thrombocytopenic purpura (ITP)
• Leukemia
• Massive blood transfusion
• Prosthetic heart valve
• Thombotic thrombocytopenic purpura (TTP)
• Celiac disease
• Vitamin K deficiency: Deficiency leads to uncontrolled bleeding and hence constant consumption of platelets to stop bleeding