If your child does not get the amount of sleep that his body requires, he will likely feel lethargic throughout the day. A child's immune system is weakened and he may exhibit behavioral changes when he feels lethargic. When you know that your child is getting the appropriate amount of sleep for his age and he has little energy, he needs to be evaluated by a physician, as this may be a sign of illness.
A possible explanation for your child's lack of energy could be Reye syndrome. The syndrome is rare and occurs in children younger than 15 years old. A virus that could cause your child to have a lack of energy is Hepatitis B, which is a liver disease. A common bacterial infection called cat-scratch disease is another cause of children feeling lethargic. Rubella is a rare disease in the United States because of the availability of the vaccine against this infection, but it does occur and decreases energy in children. If your child is abnormally tired, he may have come into contact with Shigella, a bacteria that attacks the lining of the large intestine by producing toxins.
Reye syndrome causes repeated vomiting every one or two hours over two to three days. The child feels lethargic or sleepy and then becomes agitated, dilirious, confused, angry or unresponsive. Children are at risk for seizures and coma if the disease progresses. Hepatitis B can make children experience a loss of appetite, muscle and joint pain, jaundice, diarrhea or vomiting. Cat scratch disease may cause infections in the liver and spleen, prolonged fever, swelling of the retina, bone infection, pneumonia, swollen lymph nodes and encephalitis. If your child experiences a low-grade fever, a rash, swollen glands at the back of his neck or behind his ears, he may have Rubella. When Shigella enters a child's body, swelling, ulcers on the intestinal wall, and bloody diarrhea may occur.
Avoiding the use of aspirin when your child has a viral illness will protect her against Reye Syndrome. Vaccinating your child with three doses of the Hepatitis B vaccine will help your child avoid being infected with Hepatitis B. Teach your child how to avoid being scratched or bitten when she plays with cats in order to avoid cat scratch disease. Rubella can be avoided by vaccinating your child with the Rubella vaccine. The best way for your child to avoid a Shigella infection is frequent and careful hand washing with soap.
Reye Syndrome can affect any part of the body, but frequently affects the brain and the liver. Teenagers that are sexually active carry a greater risk for contracting Hepatitis B. Cat scratch disease may occur if a cat licks an open wound or broken skin on your child. Rubella can be so mild in children that parents may not know there is an infection. Your child can contract Shigella easily because very small amounts of the bacteria can cause an infection in children.
When to Contact a Physician
Call your pediatrician as soon as you suspect that your child could be infected with Reye Syndrome, Hepatitis B, cat scratch disease, Rubella, Shigella or any other illness. Diarrhea and vomiting can lead to dehydration, especially in young children, so contact a physician if your child is not urinating regularly.