Symptoms:

The main symptom is a severe headache that starts suddenly and is often worse near the back of the head. Patients often describe it as the "worst headache ever" and unlike any other type of headache pain. The headache may start after a popping or snapping feeling in the head.

Other symptoms:

• Decreased consciousness and alertness
• Eye discomfort in bright light (photophobia)
• Mood and personality changes, including confusion and irritability
• Muscle aches (especially neck pain and shoulder pain)
• Nausea and vomiting
• Numbness in part of the body
• Seizure
• Stiff neck
• Vision problems, including double vision, blind spots, or temporary vision loss in one eye

Other symptoms that may occur with this disease:

• Eyelid drooping
• Pupil size difference
• Sudden stiffening of back and neck, with arching of the back (opisthotonos; not very common)

Signs and tests:

Signs include:

• A physical exam may show a stiff neck
• A brain and nervous system exam may show signs of decreased nerve and brain function (focal neurologic deficit)
• An eye exam may show decreased eye movements -- a sign of damage to the cranial nerves (in milder cases, no problems may be seen on an eye exam)

If your doctor thinks you may have a subarachnoid hemorrhage, a head CT scan (without contrast dye) should be done right away. In 5 - 10% of cases, the scan may be normal, especially if there has only been a small bleed. If the CT scan is normal, a lumbar puncture (spinal tap) must be performed.

Other tests that may be done include:

• Cerebral angiography of blood vessels of the brain
• CT scan angiography (using contrast dye)
• Transcranial Doppler ultrasound -- to look at blood flow in the arteries of the brain
• Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) (occasionally)