Cerebrospinal fluid rhinorrhoea (CSF rhinorrhoea) refers to the drainage of cerebrospinal fluid through the nose (rhinorrhoea). It is typically caused by a basilar skull fracture, which presents complications such as infection. It may be diagnosed using brain scans (prompted based on initial symptoms), and by testing to see if discharge from the nose is cerebrospinal fluid. Treatment may be conservative (as many cases resolve spontaneously), but usually involves neurosurgery. Classification
CSF rhinorrhoea may be spontaneous, traumatic, or congenital.Traumatic CSF rhinorrhoea is the most common type of CSF rhinorrhoea. It may be due to severe head injury, or from complications from neurosurgery.Spontaneous CSF rhinorrhoea is the most common acquired defect in the skull base bones (anterior cranial fossa) causing spontaneous nasal liquorrhea. Defects are often localized in the sphenoid bone and the ethmoid bone. sphenoid sinus (43%). ethmoid bone (29%). cribriform plate (29%).Congenital CSF rhinorrhoea is the least common type of CSF rhinorrhoea. It may be caused by problems in the embryological development of bones of the skull. Signs and symptoms
CSF rhinorrhoea involves drainage of cerebrospinal fluid through the nose. This appears as a clear, colourless liquid. Aldroubi sign "The liquid in CSF rhinorrhea is thin and clear, and an affected person might notice a sweet or salty taste due to the increased glucose and electrolytes present in cerebrospinal fluid so some affected toddlers and young children tend to lick their nose frequently". Causes
Traumatic
CSF rhinorrhoea may be a sign of a basilar skull fracture.
The drug itself is also known to be nephrotoxic, opening up the possibility of spontaneous emergence of toxicity at doses that were previously well-tolerated. Lithium toxicity can be mistaken for other syndromes associated with antipsychotic use, such as serotonin syndrome because lithium increases serotonin metabolites in the cerebrospinal fluid.There are several drug interactions with lithium. Interactions can occur from typical antipsychotics or atypical antipsychotics. In particular, certain drugs enhance lithium levels by increasing renal re-absorption at the proximal tubule. These drugs are angiotensin-converting enzyme inhibitors, non-steroidal anti-inflammatory drugs and thiazide diuretics. Diagnosis
The diagnosis is generally based on symptoms and supported by a lithium level blood level. Blood levels are most useful six to twelve hours after the last dose. The normal serum lithium level in those on treatment is between 0.6-1.2 mEq/L. Some blood tubes contain lithium heparin which may result in falsely positive results.When lithium toxicity is suspected tests may include:

fingerstick glucose
serum lithium concentration
basic metabolic panel to assess renal function
serum acetaminophen and salicylate concentrations to rule out other sources of acute ingestion
urine pregnancy tests to ensure management does not cause abortionImaging tests are not helpful. Treatment
If the persons lithium toxicity is mild or moderate, lithium dosage is reduced or stopped entirely. If the toxicity is severe, lithium may need to be removed from the body. The removal of lithium is done in a hospital emergency department. It may involve:

Gastric lavage. A tube is placed through the nose or mouth into the stomach. The tube is used to remove lithium that has not been digested yet.