Cerebrospinal fluid (CSF ... The doctor may recommend keeping the head elevated to encourage CSF drainage, as well as precautions against nose-blowing or straining on the toilet.

A CSF leak is when CSF drains from a tear or hole in the membrane that surrounds the brain and spinal cord. In rare cases, the drainage can escape from a person's nose—appearing like a runny nose.

Important clues suggesting that a runny nose could represent cerebral fluid include: Clear, watery drainage: CSF is usually ...