Cerebrospinal Fluid Fistula: The sinuses have close relationship with the brain. The brain is separated from the nose and the sinuses by thin bone which can sometimes be so thin (or there may be a defect in this bone) that the membranes covering the brain (dura and the arachnoids) may prolapse into the nasal cavity or into the sinuses. These membranes may sometimes rupture causing the fluid that surrounds the brain (cerebrospinal fluid) to leak in the nose. This is called a Cerebrospinal Fluid fistula. Thin watery like nasal discharge especially from one side of the nose and on bending forward may be suspicious of a cerebrospinal fistula (Figure 1a) Such defects need to be closed to prevent the risk of ascending infection from the nose to the brain. The risk of meningitis (infection of the membranes covering of the brain) can be as high as 30%. Diagnosis is usually established from the history, examination of the nasal discharge, and imaging studies. A test called the beta-transferrin is test for the CSF is highly specific and will confirm that the “watery fluid” from the nose is CSF. Imaging studies such as CT and MRI scans will assist in localizing the defect.