Nosebleeds while sleeping are generally caused by the rupture of the nasal mucosa. Clinically, the causes of rupture of the nasal mucosa are as follows: 1. related diseases, such as hypertension, vitamin K deficiency and leukemia, aplastic anemia, etc. can also lead to bleeding. Usually, it is necessary to go to the hospital for examination, such as nasal endoscopy or nasopharyngoscopy, blood routine, etc. If necessary, CT or MRI examination is needed, most of them can confirm the diagnosis.