Does Hypertension (elevated BP) Cause Headache?

This is an age old question that many of us have struggled with in the ED for many years...

Other questions include: Does elevated BP cause headaches? Do we need to scan hypertensive patients with headache just because they have a headache? At what level of BP does the BP actually cause headache? 

A few quick pearls:

• Although incredibly high BPs (diastolics above 130 mm Hg) have been correlated with headache, the general concensus is that hypertension doesn't really cause headaches. 
• At really high blood pressures (again, diastolic BP > 130-140), cerebral autoregulation breaks down and may lead to cerebral edema and headache...hypertensive encephalopathy.
• Elevated systolic BP may actually be protective for developing headaches
• CT scanning the hypertensive patient with a headache is not warranted a lot of the time, unless the patient has a neuro deficit, or if the headache was acute onset or associated with other findings of hypertensive encephalopathy.
• Patients with HTN are as likely to have a headache in the ED as non-hypertensive patients