Complications of Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency

Introduction

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited condition in which the enzyme glucose-6-phosphate dehydrogenase is not produced enough by the body. This enzyme is needed to help the red blood cells (RBCs) of the body to function normally.

If there is a lack of this enzyme, hemolytic anemia can occur. Hemolytic anemia is a condition wherein RBCs are rapidly destroyed than they are produced. Excessive RBC destruction can be triggered by drugs, certain infections, or fava bean consumption. 

Complications of G6PD

1. Hydrops Fetalis

Hydrops fetalis is a life-threatening problem characterized by an abnormal fluid accumulation in the tissues and organs of an unborn baby or newborn. This excessive accumulation of fluid can cause extreme swelling. This fetal condition is also called hydrops, which has two types:

• Immune hydrops (erythroblastosis fetalis): It is the most dangerous complication of blood group incompatibility between a mother and her baby. This complication occurs when the mother's immune system attacks the baby's blood cells, which leaves the baby anemic or with a low blood count. To replace the destroyed blood cells, the baby's organs work hard and become enlarged. These organs eventually fail. They include the heart, adrenal gland, kidneys, and liver. Another term for this complication is erythroblastosis fetalis since the blood cells produced in these organs are immature, which are called erythroblasts. 
• Nonimmune hydrops: This type is more common and can result when complications or diseases inhibit the infant's ability to manage fluid. Today, nonimmune hydrops accounts for 75-90 percent of hydrops cases. It can also be a symptom of other congenital conditions. 

2. Heinz Bodies

Heinz bodies are hemoglobin precipitates or deposits that are microscopically seen inside red blood cells (RBCs). They are named after the German physician named Robert Heinz, who described these precipitates in related cases of hemolytic anemia in 1890. 

Heinz bodies are formed when there is damage to the component molecules of hemoglobin from genetic mutations or through the administration of oxidant drugs. In this way, an electron from hemoglobin is transferred to an oxygen molecule and produces a reactive oxygen species, which can cause extreme damage to cells leading to premature cell lysis. These damaged cells are then removed by macrophages in the spleen, wherein damaged membranes and precipitates are cleared, leading to the appearance of bite cells. The regular elimination of these damaged cells leads to Heinz body anemia. 

When it comes to a G6PD deficiency, the administration of oxidant drugs, such as dapsone, primaquine, and quinidine, can also result in Heinz bodies. Heinz bodies are also found in patients with chronic liver disease. 

3. Hemolytic Anemia

A number of things can cause hemolytic anemia. Some of its causes are inherited, while others may be acquired. However, in people with G6PD deficiency, oxidative stress can occur due to a lack of reduced glutathione, which is an enzyme that G6PD helps create.

Hemolysis can be extreme or subtle. It can also be fatal in rare cases. If a significant number of red blood cells die, the body will be unable to get oxygen all throughout the body, which can result in death if there is no immediate medical treatment, which is usually the transfusion of whole blood. However, blood transfusions can also have severe health risks that can be life-threatening. For these reasons, the triggers of hemolytic anemia must be avoided.

The signs and symptoms of hemolytic anemia include:

• Pale skin
• Chronic fatigue
• Yellowing of the skin and eyes
• Shortness of breath
• Back pain
• Dark urine

There is no cure for a G6PD deficiency, so the best treatment for hemolytic anemia that is caused by a G6PD deficiency is to avoid certain foods and drugs at all costs.

4. Neonatal Jaundice

One of the most common conditions in newborns that require medical attention or hospital readmission is jaundice, and oNewborns who have a yellow discoloration of the skin and sclera often have an accumulation of unconjugated bilirubin. Increased hemolysis and elevation in the level of bilirubin may occur due to inherited genetic enzyme disorders such as the G6PD deficiency.

Various symptoms can also be associated with this condition. The symptoms usually depend on the level of bilirubin and the exact cause. The yellow discoloration is initially seen on the newborn's face or forehead. As the level of bilirubin increases, the discoloration also spreads toward the feet. Healthcare providers are able to estimate bilirubin levels based on the location and extent of jaundice, although these assessments are not always accurate.

Aside from the yellow discoloration of the skin and mucous membranes, neonatal jaundice also causes light-colored stool, poor feeding, lethargy, seizures, muscle tone changes, and high-pitched crying. Elevated levels of bilirubin can also cause kernicterus. This condition should be promptly identified and treated since it affects the central nervous system. Kernicterus is an irreversible and chronic condition. It causes hearing loss, cerebral palsy, and intellectual impairment. If an infant exhibits changes in muscle tone, high-pitched crying, and extreme lethargy, then the infant is most probably starting to develop kernicterus.

The condition can be diagnosed through blood tests. To determine if there is a development of jaundice, healthcare providers will closely monitor the newborn and routinely check the levels of bilirubin before hospital discharge. The most accurate test to determine bilirubin levels is through blood tests. However, sometimes, bilirubin levels can also be obtained through a transcutaneous bilirubin reading using a handheld sensor. To confirm the total bilirubin level, a blood test is usually ordered. Usually, the level of bilirubin peaks when newborns are 3-5 days old. 

Additional blood tests are often required for newborns who require close monitoring and treatment. Treatment is necessary if the level of bilirubin has gone too high or if the level is rising too quickly. Sometimes, the only thing needed is close monitoring of the bilirubin level. Further medical intervention may not be necessary. In some cases, treatment can be done at home, while some newborns need be to treated in the hospital.