• The terms pseudotumor cerebri, benign intracranial hypertension, and idiopathic intracranial hypertension (IIH), are all synonymous terms which describe a condition of elevated intracranial pressure (ICP), but the latter is the preferred term of use.
• IIH almost ubiquitously presents with a generalized headache and papilledema (i.e. fundoscopic examination imperative!).  Visual disturbance and non-specific symptoms such as dizziness may also be present.
• Elevated ICP and papilledema are clinical emergencies until the presence or absence of an intracranial mass is confirmed. 
• The following conditions must be met in order to diagnose IIH:

1. Non-focal neurologic examination (except for 6th nerve palsy in some cases)
2. Elevated opening pressure on lumbar puncture, > 20 to 25 mmH2O (perform only after risk for herniation assessed!)
3. Normal cytologic and chemical cerebrospinal fluid analysis
4. Small, symmetric brain ventricles on neuroimaging
5. Exclusion of other sources of IH such as venous sinus thromboses by obtaining an MRI/venographic study of the head

References

Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology. Nov 26 2002;59(10):1492-5.