To confirm a CSF leak, you should know skull X-rays are almost never of any help in diagnosing basilar skull fractures. So you need to go by clinical signs if you can't get a CT scan done.
The Clinical signs include:
1. Raccoon eyes - this refers to a periorbital (around the eyes) bruising, and is a result of blood tracking down from the skull fracture site to the soft tissue around the eyes.
2. Battle's sign - Named after a guy (unsurprisingly) called Battle, this is bruising around the mastoid process (behind the ears). As with raccoon eyes, this bruising is due to blood tracking there from the skull fracture, not from damage directly to the mastoid process.
3. Cerebrospinal fluid (CSF) otorrhoea -This is leakage of CSF out your ear, via a combination of a ruptured tympanic membrane and nearby basilar skull fracture.
4. CSF rhinorrhoea - This is leakage of CSF out your nose. Usually (but not exclusively) the ethmoid cribriform plate is the part fractured.
5. Cranial nerve palsies - many of the cranial nerves run nearby enough to be injured or compressed by a fractured base of skull. A neurological examination is essential to assess brain injury.
So how do you confirm it is CSF (and not pure blood or a normal nasal discharge) coming out of that nose or ear.
Easy. Look for the halo sign (or ring sign). Dab some of the blood on a tissue or swab. If there is CSF mixed with the blood, it will move by capillary action further away from the centre than the blood will. You'll get something like this:
|Halo sign (on the sheets of a trauma patient)|
The other tests to confirm CSF leaks require either a lumbar puncture or glucose estimation.
So don't forget your HALO! It could save you some trouble.