G47.4: Narcolepsy and cataplexy

You keep having a very sudden and very intense need to sleep, or you suddenly fall asleep.

There are different reasons why we sleep. The reasons have not been fully understood. So far we know, for example, that sleep helps the body to recover. Sleep also develops the memory, and it brings feelings into equilibrium. Sleep has a particular sequence. There are deep sleep phases and lighter sleep phases. These phases alternate during sleep. The sleep-wake cycle is controlled by different influences such as messenger substances in the body. These messenger substances can be influenced by activity and light.

You keep falling asleep very suddenly, or you have a very sudden and very intense need to sleep. The muscles then feel very weak or they go to sleep for a short time. The person can then quickly fall asleep and afterwards not remember doing so. Sometimes hallucinations also occur, or the person is unable to move their body properly. They may then be very tired during the day.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


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