Pyruvate kinase deficiency is a rare hereditary disease. It's also a hemolytic anemia, because the red blood cells break apart and cause anemia in those with this disorder. The broken red blood cells release high amounts of hemoglobin into the bloodstream. The hemoglobin is then converted to bilirubin and causes jaundice.
What is Jaundice?
Red blood cells normally last 120 days, then some parts of the cells are recycled. As explained in the "Handbook of Pathophysiology" by Elizabeth Corwin, Ph.D., part of the hemoglobin from the red blood cell is changed to bilirubin, sent to the liver and changed again so it can be excreted in the urine or in a bowel movement. In jaundice, there is a high amount of bilirubin in the bloodstream. People with jaundice have yellowish skin and are yellow in the normally white part of the eye.
What is Pyruvate Kinase?
Mature red blood cells do not have a structure called a mitochondria, in which they would use oxygen to make energy. They have to make energy anaerobically, or without using oxygen. They do this in a process called glycolysis, in which they break down glucose to a substance called lactate, as explained by Lucio Luzzatto, M.D., Ph.D. and professor of hematology at the University of Florence in "Harrison's Principles of Internal Medicine." While they are breaking down glucose, they make energy. Pyruvate kinase is a type of protein called an enzyme, which the red blood cells use in glycolysis.
Pyruvate Kinase Deficiency and Jaundice
Dr. Luzzatto writes in "Harrison's Principles of Internal Medicine" that pyruvate kinase deficiency is a rare hereditary disease, affecting one in 10,000 people. Without pyruvate kinase, the red blood cells cannot make enough energy. If they had enough energy, they would use most of it to move substances across their cell membranes, but without enough energy, the red blood cells break. This releases pieces of the cell into the bloodstream, including the hemoglobin. The high amount of hemoglobin results in high levels of bilirubin in the bloodstream, which causes jaundice.
Symptoms
Approximately 33 percent of the children with pyruvate kinase deficiency have symptoms when they are newborns, according to Daniel Ambruso, M.D., and professor in the Department of Pediatrics at the University of Colorado School of Medicine in "Current Diagnosis & Treatment: Pediatrics." The disease is a type of hemolytic anemia, because the children become anemic from having so many of their red blood cells break. The anemia and jaundice can be so severe that they need treatment. The symptoms may be mild in older children, but some of them may also need treatment.
Treatment
The treatment depends upon the severity of the disease. Newborns may need transfusions or phototherapy. In phototherapy, babies receive light at a certain wavelength. The bilirubin in the skin absorbs the light and is changed to a form that can be excreted. Older children may need a transfusion. Children with a severe case have a large spleen, and removing it results in less transfusions. Waiting until they are at least 4 years old lowers the risk of getting an infection after surgery, writes Adrian Park. M.D., vice chair for the Division of General Surgery at the University of Maryland Medical Center in "Schwartz's Principles of Surgery."
References
- "Current Diagnosis & Treatment: Pediatrics"; William Hay, Jr., M.D., Myron Levin, M.D., Judith Sondheimer, M.D., Robin Deterding, M.D.; 2009
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, Ph.D., FNP; 2000
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- "Schwartz's Principles of Surgery"; F. Charles Brunicardi, M.D.; 2010
