
Cerebrospinal fluid (CSF) is a mixture of water and electrolytes that circulates the brain and spinal cord. A CSF leak through the nose may be caused by a disruption in the lining of the brain, or in the bone that separates the brain from the sinuses. Most often, the CSF drainage will appear as a noticeable clear nasal drip when leaning or bending over, or arising from a laying position.