ICD-10 Code G47.4 – Narcolepsy and cataplexy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G47.4 – Narcolepsy and cataplexy
What it is
G47.4 identifies narcolepsy with cataplexy, a sleep disorder marked by sudden, uncontrollable sleep episodes and brief muscle weakness triggered by emotion. Use this code when documentation clearly links both narcolepsy and cataplexy.
Clinical signs
Common findings include excessive daytime sleepiness, sudden sleep attacks, and cataplexy such as brief loss of muscle tone with laughter or surprise. Clinical features vary; refer to documentation.
When to use this code
Use G47.4 when the provider diagnoses narcolepsy and specifically documents cataplexy. It may also apply when records describe classic narcolepsy symptoms plus emotion-triggered muscle weakness. If the chart does not confirm cataplexy, check documentation before coding.
Do not use for
Do not use this code for narcolepsy without cataplexy or for other sleep disorders with daytime sleepiness alone. If the diagnosis is unclear or mixed, check documentation.
Coding tip
Confirm that cataplexy is explicitly documented; narcolepsy alone usually requires a different code.