Consider DravetDiagnostic Criteria
Dravet syndrome is diagnosed based on medical history, neurologic examination, EEG pattern and observation. While a diagnosis of Dravet syndrome is made clinically, approximately 70%-80% of patients who have clinical features of Dravet syndrome will also test positive for a mutation of the SCN1A (sodium channel alpha subunit) gene.
A Dravet syndrome diagnosis should be considered when a patient’s medical history includes multiple hallmarks of the syndrome:
- Onset of seizures in the first year of life in an otherwise healthy infant
- Initial seizures are either generalized or unilateral and are typically prolonged.
- Other seizure type, including myoclonic, absence and complex partial typically develop after the first year of life.
- In virtually all patients, prolonged exposure to warm temperatures induces seizures.
- Seizures are also associated with fevers due to illness or vaccines, hot baths, high levels of activity and sudden temperature changes.
- In some DS patients, seizures may be induced by strong natural and fluorescent lighting, as well as certain visual patterns.
- Initial EEGs are often normal, with later EEGs showing background slowing and severe generalized polyspikes.
- In most patients, initial development is normal but development slow or stagnates during the first few years of life.
- Virtually all patients have some degree of hypotonia.
- Many, but not all, patients have unstable gait and balance issues.
- Younger patients often have ankle pronation and flat feet, and some patients develop a crouched gait as they age.