Hypoxic-Ischemic Encephalopathy (HIE) is a type of brain injury that occurs when a newborn’s brain doesn’t receive enough oxygen and blood flow at or around the time of birth. This lack of oxygen can lead to long-term impacts, especially in how the brain develops and functions.
Among the most challenging complications for children with HIE are certain types of epilepsy and developmental disorders that arise over time, including infantile spasms, Lennox-Gastaut syndrome, and other developmental and epileptic encephalopathies (DEEs).
Infantile Spasms (IS)
What They Are: Infantile spasms are a rare but severe form of epilepsy that typically occurs in infants under 1 year old, with typical onset betwee 4-8 months old. They involve sudden, jerking movements or muscle contractions that can look like a brief “jerking” or bending of the body, often in clusters.
Why It Happens in HIE: Due to the early brain injury caused by HIE, infants may be at higher risk for abnormal brain electrical activity, which can manifest as spasms. Infantile spasms are particularly concerning as they can interfere with normal brain development and lead to intellectual disabilities if not treated promptly.
Risk Factors: Certain risk factors have identified the most at-risk babies with HIE who may go on to develop Infantile Spasms. Knowing the risks and what to look for can lead to early diagnosis and effective treatment.
Treatment Options: Treatment often includes effective frontline medications like ACTH (adrenocorticotropic hormone), corticosteroids, or anti-seizure medications.
Early diagnosis, intervention and use of frontline medications is key to improving outcomes.
What It Is: Lennox-Gastaut syndrome is a complex, difficult-to-control epilepsy syndrome that typically starts in early childhood, often between 2 and 6 years of age. It’s characterized by multiple types of seizures, cognitive delays, and abnormal EEG patterns.
Why It Happens in HIE: Children with early brain injury, including HIE, are at higher risk for developing LGS due to structural changes in the brain. Over time, the brain’s electrical patterns may become more chaotic, leading to diverse seizure types and developmental delays.
Treatment Options: LGS can be challenging to treat, often requiring a combination of medications, ketogenic diets, or, in some cases, surgical interventions to manage seizures. Regular monitoring and a comprehensive care team are essential for managing this condition.
Developmental and Epileptic Encephalopathies (DEEs)
What They Are: DEEs are a group of severe epilepsy disorders that not only cause frequent seizures but also impair cognitive development, often leading to a wide range of developmental disabilities. DEEs are unique because both seizures and abnormal brain activity disrupt normal development, causing lasting developmental delays.
Why It Happens in HIE: The early brain damage from HIE can lead to a long-term risk of developing DEEs. Structural changes or disrupted connections within the brain can make children more vulnerable to these kinds of severe epilepsy disorders.
Treatment Options: DEEs require a highly individualized approach, often including anti-seizure medications, specialized diets, therapies, and sometimes devices like vagus nerve stimulators to help manage seizures and support development.
Developmental and Epileptic Encephalopathy with Spike-Wave Activation in Sleep (DEE-SWAS) – formerly known as ESES, CSWS, ECSWS
What It Is: DEE-SWAS, or Epileptic Encephalopathy with Spike-Wave Activation in Sleep, is a rare epilepsy syndrome characterized by abnormal electrical brain activity that significantly increases during non-REM sleep. This “spike-wave” pattern disrupts normal sleep, which is essential for learning and memory development, and can lead to progressive cognitive and behavioral difficulties over time.
Why It Happens in HIE: Due to the early brain injury caused by HIE, children are at an increased risk for developing abnormal electrical activity in the brain. In DEE-SWAS, the damage from HIE can trigger these specific patterns of abnormal brain activity during sleep, which disrupts the critical neurodevelopmental processes that happen during restful, deep sleep. This disruption in sleep-based brain activity often causes a worsening in cognitive and developmental milestones, particularly language, memory, and motor skills.
Symptoms to Watch For: Children with DEE-SWAS may show a range of symptoms, including:
Language regression or delays
Behavioral changes, such as irritability or hyperactivity
Loss of motor skills or coordination
Sleep disturbances and waking up frequently
Seizures, particularly during sleep or upon waking
Treatment Options: Management of DEE-SWAS requires a targeted approach due to the unique nature of sleep-related electrical abnormalities. Treatment often includes anti-seizure medications that specifically target spike-wave patterns, as well as therapies that support language, motor, and cognitive development. Other treatments like corticosteroids or immunomodulatory therapy may also be considered. Close monitoring of sleep patterns and regular EEG assessments are essential to tailor the treatment plan effectively.
DEE-SWAS (Developmental and Epileptic Encephalopathy with Spike-Wave Activation in Sleep) was previously known by several different names, as understanding of the condition evolved. Some of these former names include:
Electrical Status Epilepticus in Sleep (ESES): ESES describes the continuous spike-wave activity occurring during non-REM sleep, which is a hallmark of the condition. It is still commonly used to describe the EEG pattern associated with DEE-SWAS.
Continuous Spike and Waves during Slow-Wave Sleep (CSWS): This term emphasizes the characteristic EEG pattern of continuous spike-wave discharges seen during slow-wave (non-REM) sleep, which disrupts normal sleep and impacts cognitive function.
Epilepsy with Continuous Spike-Waves during Sleep (ECSWS): This name highlights the epileptic and developmental nature of the condition, particularly focusing on the continuous spike-wave pattern during sleep.
These older terms primarily focus on the EEG patterns and specific sleep characteristics of the disorder, but recent terminology like DEE-SWAS is more inclusive of both the developmental and epileptic impacts of the condition. This shift reflects a broader understanding of how the condition affects children’s cognitive and developmental progress as well as their epilepsy management.
