Consider pregnancy test (for medication selection)
Diagnosis is normally clinical
Make sure you considered other causes of emergent<unk> 
Make sure you considered other causes of emergent<unk>
Migraine headache
Tension headache
Cluster headache
Postpartum headache
Meningitis/encephalitis
Post-lumbar puncture headache
Neoplastic meningitis
Benign paroxysmal positional vertigo