Brief Answer:
Several conditions can cause this symptom.

Detailed Answer:
Hello and thanks for using HCM.

I have read your query about your sister's problem and understand your concerns.

Hearing blood rushing or swooshing in head is a symptom that may be related to several conditions such conductive hearing loss or impairment ( in this case there are hearing problems too) that results in amplified hearing of inner sounds, it could be related to high blood pressure, but also is a symptom of neurovascular disorders such brain arteriovenous malformations and brain arteriovenous fistula.

So, there is need for a clinical evaluation by your sister's primary care Doctor and, if in doubt after this evaluation, brain imaging such MRI, in order to have a correct diagnosis.

Hope you found the answer helpful.

Let me know if I can assist you further.

Greetings.

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