Cerebrospinal fluid nasal leakage is sometimes an unpredictable, seemingly non-existent “problem” that can sometimes have serious consequences. It can be intermittent, just a drip from the nose, but when it leads to intracranial infection, it can be very aggressive and even life-threatening. The diagnosis and treatment of the disease are also uncertain and difficult due to this characteristic. Close communication and full understanding between the patient and the doctor are needed to change the uncertainty of the diagnosis from the beginning to the success of the skull base repair. The disease can be completely cured. 1. What are the symptoms of cerebrospinal fluid nasal leakage? Nasal drip, a clear liquid, increases when the head is lowered, lying down, turning over, constipation, and bending over. Headache and high fever often occur intermittently, and some patients are admitted to hospital and diagnosed with intracranial infection. 2. Why does cerebrospinal fluid nasal leakage occur? (1) Most of them are caused by trauma, surgery or even some firing treatments that damage the skull base and cause weak areas, and the pulsation of intracranial blood vessels conducts the pressure of cerebrospinal fluid in the weak areas, and with the accumulation of time, causes the dura mater of the skull base, which is already damaged, to perforate and cause intracranial communication with the nasal cavity. This results in cerebrospinal fluid leakage (nasal leakage of cerebrospinal fluid), intracranial infection (entry of bacteria and viruses from the nose into the skull), or pneumocranial (entry of air into the skull). (2) There are also spontaneous cerebrospinal fluid nasal leaks, which tend to occur in women, who have chronic diseases such as diabetes or hypertension, or who have had huge setbacks in their lives. These may be the causes of spontaneous cerebrospinal fluid rhinorrhea. (3) Of course, it can also occur in patients with cerebrospinal fluid circulation disorders. 3. What are the difficulties in the diagnosis of cerebrospinal fluid rhinorrhea? There are two points: (1) Qualitative diagnosis, i.e., is this cerebrospinal fluid rhinorrhea: usually the doctor has to make a judgment based on past history, such as history of cranial trauma, history of runny nose, history of intracranial infection, and high-resolution CT or MRI of the skull base of the sinuses. The clear water left in the nose for routine and biochemical determination of cerebrospinal fluid is of great guidance. If the lumbar puncture is performed during the period of intracranial infection with high fever, and the extracted cerebrospinal fluid has septic and inflammatory changes, the diagnosis will be more significant. (2) Localization diagnosis: It mainly relies on high-resolution CT or MRI of the skull base of the sinuses. For some leaks, there are typical features and the doctor can make a conclusion at that time. However, some leaks are abnormally small and hidden, so it is difficult to make a conclusion on the image. In this case, a careful nasal endoscopy is needed. If the leak is still undetectable, a transnasal endoscopic surgical exploration of the skull base is required. This requires the patient to understand the complexity and insidious nature of the disease. This is what is referred to in the opening paragraph as “erratic, seemingly absent”. We once treated a female patient 4 years after craniocerebral trauma, and it took 6 hours to find and repair her cerebrospinal fluid nasal leak, which was successfully repaired after finding the left nasal cavity from the right nasal cavity. 4.What is the difficulty in the treatment of cerebrospinal fluid nasal leak? I think the key is to qualify and locate the most important diagnosis. In our hands, cerebrospinal fluid nasal leaks can be repaired in the nasal cavity by transnasal endoscopy. For all kinds of cerebrospinal fluid nasal leaks, even high-flow leaks, large leaks, leaks caused by surgery or even leaks directly through the brain pool or ventricles, we are able to repair them through the nasal cavity by endoscopic, minimally invasive methods and avoid craniotomy. The overall success rate is higher than 95%. 5.What is the key to success in the treatment of cerebrospinal fluid nasal leakage? I believe that a true understanding of the disease by the patient and family, authorization (informed consent), accurate diagnosis by the physician, and repair techniques are the keys to success. For cases that are really “indefinite and seemingly absent”, we can wait and see. There is no rush to surgery.