NOTE: Some of the items are predisposing factors, while others are findings that would indicate that a headache might be associated with a subarachnoid hemorrhage.
Predisposing conditions:
(1) cigarette smoking
(2) hypertension
(3) alcohol abuse (especially after a recent binge)
(4) personal history of subarachnoid hemorrhage
(5) family history of subarachnoid hemorrhage
(6) polycystic renal disease
(7) hereditary disorder of connective tissue (Ehlers-Danlos Syndrome Type IV, pseudoxanthoma elasticum, fibromuscular dysplasia)
(8) sickle cell disease
(9) alpha-1 antitrypsin deficiency
Features of the headache:
(1) onset of a headache described as abrupt, maximal at onset, like a "thunderclap"
(2) headache that is very severe, described as "worst in life"
(3) a headache different from prior headaches; the first ever of this type or intensity
Findings accompanying the headache:
(1) loss of consciousness
(2) diplopia
(3) seizures
(4) focal neurologic findings
(5) retinal or subhyaloid (vitreous) hemorrhage
(6) nuchal rigidity
