I67.5: Moyamoya disease

The blood vessels in your brain have narrowed or got blocked.

You have a congenital disorder, which means you were born with it. With this, over a long period of time, the blood vessels in your brain get narrower or get blocked. As a result, the brain no longer receives enough blood and it gets damaged. Collateral circulation may also occur to bypass the bottlenecks. Collateral circulation involves new connections between blood vessels. Bleeds occur more easily from such a collateral circulation.

Various symptoms can appear over a period of time. For example, one’s memory may get worse or one might get confused more often. One sometimes has problems with moving, or in carrying out certain activities.

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.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).