From the Guidelines
The answer is (b) hereditary spherocytosis, as it is a defect that responds to splenectomy, although the provided evidence does not directly support this condition, it is known that hereditary spherocytosis is a genetic disorder characterized by defects in the red blood cell membrane proteins. The provided evidence discusses pyruvate kinase deficiency, a different condition, but it does mention that splenectomy may be required in severely affected patients and results in a hemoglobin increase of 1–3 g/dL, and may reduce or even eliminate transfusion requirements 1. However, hereditary spherocytosis is a condition that is known to respond to splenectomy, as it removes the primary site of red blood cell destruction, thereby prolonging the lifespan of the affected cells and improving anemia. Some key points to consider are:
- Hereditary spherocytosis is a genetic disorder characterized by defects in the red blood cell membrane proteins, particularly spectrin and ankyrin, which connect the membrane to the underlying hemoglobin.
- The defect leads to abnormally shaped spherical red blood cells that are less flexible and more fragile than normal biconcave disc-shaped cells.
- These spherocytes are prematurely destroyed in the spleen, resulting in hemolytic anemia.
- Splenectomy is an effective treatment for hereditary spherocytosis because it removes the primary site of red blood cell destruction, thereby prolonging the lifespan of the affected cells and improving anemia. In contrast, the other options do not respond to splenectomy in the same way:
- Idiopathic thrombocytopenic purpura also responds to splenectomy, but it is not a hemoglobin chain defect.
- Thalassemia involves defective hemoglobin synthesis but typically doesn't respond well to splenectomy.
- Glucose-6-phosphate dehydrogenase deficiency is an enzymatic defect that causes episodic hemolysis but doesn't generally warrant splenectomy as a treatment.
From the Research
Defect in the Hemoglobin Chain that Responds to Splenectomy
- The defect in the hemoglobin chain that responds to splenectomy is hereditary spherocytosis, a benign hematologic disease that requires surgical treatment when medical therapy fails 2, 3, 4, 5, 6.
Characteristics of Hereditary Spherocytosis
- Hereditary spherocytosis is a disease affecting the red blood cells membrane and belongs to the congenital hemolytic anemias 4.
- The clinical spectrum ranges from asymptomatic patients to severe forms requiring transfusions in early childhood 4.
- The diagnosis can be based on the physical examination, complete red blood cell count, reticulocytes count, medical history, and specific tests, preferentially the EMA test and AGLT 4.
Treatment of Hereditary Spherocytosis
- Splenectomy is considered the standard surgical treatment in moderate and severe forms of hereditary spherocytosis 2, 4, 6.
- Total splenectomy exposes the patient to a life-long risk of potentially lethal infections, and thus, its usage was reconsidered 4.
- Partial splenectomy is a feasible alternative that aims to retain splenic immunologic function while decreasing the rate of hemolysis 3, 4.
Outcome of Splenectomy
- The long-term outcomes of patients with total or subtotal splenectomy for congenital hemolytic anemia still remain unclear, but the majority of the studies showed a qualitative resolution of anemia and reduction of transfusion rate 4.
- Splenectomy increases the lifespan of red cells, significantly reducing the severity of anemia and improving many physiological signs of hereditary spherocytosis 6.