Schistocytes

Schistocytes

Schistocytes are fragmented red blood cells that are typically seen in peripheral blood smears. They are an important diagnostic feature in various hematological disorders, particularly those involving microangiopathic hemolytic anemia. Schistocytes are irregularly shaped, often appearing as helmet-shaped, triangular, or crescent-shaped cells.

Characteristics

Schistocytes are characterized by their irregular shapes and sizes. They are smaller than normal red blood cells and lack the central pallor that is typical of healthy erythrocytes. The presence of schistocytes in a blood smear is indicative of mechanical damage to red blood cells, often due to passage through fibrin strands or other obstructions in the microvasculature.

Causes

Schistocytes are commonly associated with conditions that cause mechanical destruction of red blood cells. These conditions include:

• Thrombotic Thrombocytopenic Purpura (TTP): A disorder characterized by small blood clots forming throughout the body, leading to hemolytic anemia and schistocyte formation.
• Hemolytic Uremic Syndrome (HUS): Often associated with E. coli infections, this condition also leads to the formation of schistocytes due to microvascular damage.
• Disseminated Intravascular Coagulation (DIC): A condition where widespread clotting occurs, leading to the fragmentation of red blood cells.
• Mechanical Heart Valves: Artificial heart valves can cause mechanical damage to red blood cells, resulting in schistocyte formation.

Diagnostic Importance

The presence of schistocytes is a critical diagnostic marker for microangiopathic hemolytic anemia. A blood smear showing more than 1% schistocytes is considered significant and warrants further investigation. The detection of schistocytes can guide clinicians in diagnosing and managing conditions like TTP, HUS, and DIC.

Laboratory Identification

Schistocytes are identified through microscopic examination of a peripheral blood smear. The smear is stained using a Romanowsky-type stain, such as Wright's stain, to highlight the morphology of the red blood cells. A trained hematologist or laboratory technician examines the smear under a microscope to identify and quantify schistocytes.

Treatment Implications

The treatment of conditions associated with schistocytes depends on the underlying cause. For example:

• In TTP, plasma exchange is the primary treatment.
• In HUS, supportive care and management of renal failure are crucial.
• In DIC, addressing the underlying cause and supportive care are essential.

Also see

• Red Blood Cell Morphology
• Hemolytic Anemia
• Peripheral Blood Smear
• Microangiopathy