According to the National Institutes of Health, seizures that occur between age 6 months and age 5 are, in the majority of cases, benign. In contrast, seizures that occur in the neonatal period and in the first months of life are often the first sign of a severe neurological condition. They are associated with mental retardation, developmental difficulties and a much shortened life expectancy. Neonatal seizures can be very mild and hard to identify. It's important to identify them as early as possible in order to diagnose potentially treatable causes.
Febrile Seizures
According to "Pediatrics," febrile seizures are the most common type of seizures in early childhood, occurring in about 2 to 5 percent of children. Febrile seizures occur in infants and small children, usually appearing between 6 months and 3 years, though they can occur until age 5. The precipitant is an abrupt rise in temperature during a febrile illness. These seizures typically last less than 15 minutes and usually involve both sides of the body. Febrile seizures are usually benign, and the prognosis is excellent.
Anoxic Brain Damage
Lack of oxygen before or during birth is the most common cause for seizures in the first 24 to 48 hours of life. Usually these seizures are preceded by a difficult birth. If the baby survives, he's likely to have severe developmental difficulties, including paralysis, mental retardation and blindness.
Metabolic Causes
Inborn errors of metabolism are a large group of disorders in which the body is incapable of producing energy in the normal way. Seizures are a common symptom. In developed countries, every baby undergoes a screening test to detect inborn metabolic errors. Some are fatal. Some can be treated by modification of the diet. Maple Syrup Urine Disease and Phenylketonuria, or PKU, are some of the better known of these conditions. Children with PKU can develop normally if their diet is free from phenylketonuria. Diet sodas, which often contain phenylketonuria, should not be consumed by people with PKU and carry a warning label to this effect. Despite the overall bleak prognosis, neonatal seizures can be benign and the baby can develop normally.
Infantile Seizure
Seizures that occur from several months of age until 2 years often take the form of infantile spasms, in which the entire body jerks in a folding pattern. The most severe form is known as West syndrome and is associated with often fatal conditions caused by abnormal development of the brain. Phakomatoses are identified as a group of congenital diseases in which there is an abnormality of the skin combined with tumors in the brain. Tuberous sclerosis is one disease in this group. Signs and symptoms include marks on the skin, tumors, epilepsy and mental retardation. Abnormal development of the brain often has no known cause. Ultimately, whether the abnormality is part of a known hereditary syndrome or not, abnormal cortical development is often associated with mental retardation and seizures.
Other Causes
Infections, both infections of the brain itself and general infectious diseases of the body, are one cause of seizures. Poisoning is another. Infants who can crawl, reach and grasp are at risk of accidental poisoning. Many adult medications at normal adult doses are toxic to a small child, and some can cause seizures. Electrolyte disturbances, such as low blood sugar, can cause seizures at any age.
References
- "Adams and Victor's Principles of Neurology"; Maurice Victor and Allan Ropper; 2001
- Journal of Child Neurology; Classification of infantile seizures: implications for identification and treatment of inborn errors of metabolism.; Nordli DR and De Vivo DC; Dec 2002
- National Institutes of Health: Febrile Seizure Fact Sheet
- Pediatrics; Febrile Seizures: Clinical Practice Guideline for the Long-term Management of the Child With Simple Febrile Seizures; Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures; June 2008
