Headache (from increased<unk>  on heavily innervated meninges)
Characteristically worse in the morning
Nausea/vomiting
Vomiting due to increased ICP typically occurs in the morning, often effortless
Seizure
Lethargy
Cranial nerve palsies
CN 6 palsy (false localizing sign)
Papilledema (bilaterally blurred optic disc margins)
ECG with QT prolongation and T-wave inversions
Dilated optic nerve on ocular ultrasound
Measure optic nerve 3mm posterior to the globe, from inner wall to inner wall
Normal is <5mm
Characteristically worse in the morning
Vomiting due to increased ICP typically occurs in the morning, often effortless
CN 6 palsy (false localizing sign)
Measure optic nerve 3mm posterior to the globe, from inner wall to inner wall
Normal is <5mm
Elevated intracranial pressure
Intracranial hemorrhage
Ventriculoperitoneal shunt obstruction
Intra-axial
Post-lumbar puncture headache
Hemorrhagic stroke 
Ventriculoperitoneal shunt overdrainage
Traumatic intracerebral hemorrhage