Red blood cell pyruvate kinase (PK) deficiency is an autosomal recessive hereditary hemolytic disease. Its incidence is second only to G-6-PD deficiency but is rare in China. Due to PK deficiency, ATP production in red blood cells is significantly reduced, affecting cations within the red blood cell membrane and the intracellular environment, leading to membrane rigidity. This makes the cells more susceptible to destruction by macrophages in the spleen or liver, resulting in hemolysis. Heterozygotes of this condition typically show no clinical symptoms or hematological changes, but their red blood cells exhibit decreased ATP levels and premature aging.

bubble_chart Clinical Manifestations

Approximately one-third of cases manifest in the neonatal period, with mild to grade III hemolysis occurring within a few days after birth. Jaundice is severe and can lead to bilirubin encephalopathy or even fetal edema. Hepatosplenomegaly is common. Cases that develop beyond infancy present with milder symptoms, typically chronic hemolytic anemia (chronic nonspherocytic hemolytic anemia), which may be triggered by acute infections leading to aplastic crisis. Gallstones may also occur as a complication.

bubble_chart Auxiliary Examination

1. Blood picture: The degree of anemia varies, mostly presenting as normochromic macrocytic anemia, with the presence of abnormal and polychromatic red blood cells. Reticulocyte count is increased.
2. Hemolysis examination: Increased fragility of red blood cells, enhanced destruction in the autolysis test, which can only be corrected by the addition of ATP, and a positive incubation test. Serum indirect bilirubin is elevated.
3. PK activity assay: The PK fluorescence spot test shows intermediate to complete deficiency. PK activity measurement indicates reduced activity (<1.2～2.2u)。

bubble_chart Treatment Measures

There is no specific treatment. Mild cases do not require treatment. Severe cases (such as neonatal hemolytic jaundice) often require blood transfusions, and exchange transfusion may be necessary to prevent neonatal bilirubin encephalopathy. Alternatively, intravenous injections of adenine, guanosine, and inosine can be tried daily. Splenectomy may also be considered for severe cases to improve the condition and reduce the need for blood transfusions. Bone marrow transplantation is worth attempting.