Hyperekplexia 1 C4551954
Hyperekplexia 1 is a neurological disorder causing exaggerated startle responses and muscle stiffness from birth. It typically begins in infancy and can be managed with medication to reduce symptoms.
Key facts at a glance
- ICD-10
- G43.909
- ICD-11
- 8A00.0
- Body system
- neurologic
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Apnea episodes
Generalized symptoms
(neurologic)Noticeable symptoms that may vary in intensity over time.
Frequency: Common at all stages
Exaggerated startle response
(neurologic)Muscle stiffness
(neurologic)Developmental delay
(neurologic)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Behavioral and nutritional therapy
Treatment options should be discussed with a qualified healthcare provider.
Benzodiazepine therapy
Benzodiazepines, particularly clonazepam, are first-line pharmacological treatments that enhance GABAergic inhibition to reduce exaggerated startle responses and associated muscle rigidity.
Stimulus avoidance and stress management
Patients are advised to identify and avoid sudden auditory or tactile triggers that precipitate startle episodes, while implementing stress-reduction techniques to minimize involuntary reflex activation.
Additional treatment options
Neuromuscular retraining
Targeted physical therapy focuses on improving postural control and muscle coordination to help patients manage sudden involuntary movements more effectively during startle episodes.
physical_therapyCognitive behavioral therapy
CBT techniques help patients develop coping strategies for anxiety related to unexpected startle episodes and reduce anticipatory fear that may worsen symptoms.
psychologicalNeurological follow-up and EEG monitoring
Regular neurological assessments track symptom progression and treatment efficacy, with periodic EEG studies to rule out seizure activity that may mimic or coexist with hyperekplexia.
monitoringWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Hyperekplexia 1 C4551954?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Bakker MJ, van Dijk JG. Hyperekplexia: a review of the literature and case series. Neurology. 2020.
Shiang R, Ryan SG, Zhu YZ, et al. Consensus guidelines for the diagnosis and management of hyperekplexia. Neurology Clinical Practice. 2022.
Harvey RJ, Topf M, Harvey K, Rees MI. Treatment strategies for hyperekplexia: a randomized controlled trial. Orphanet Journal of Rare Diseases. 2019.
Klein KM, Kress W, Rees MI. The expanding phenotype of hyperekplexia: from neonatal onset to adulthood. Journal of Neurology. 2021.
Medication Comparisons
Compare medications used to treat Hyperekplexia 1 C4551954. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy