Injury-related subarachnoid hemorrhage is often seen in the elderly who have fallen and hit their head. Among the young, the most common injury leading to subarachnoid hemorrhage is motor vehicle crashes.
Subarachnoid hemorrhage caused by a cerebral aneurysm that breaks open (ruptures) occurs in about 40 - 50 out of 100,000 people over age 30. Subarachnoid hemorrhage due to rupture of a cerebral aneurysm is most common in persons ages 20 to 60. It is slightly more common in women than men.
A strong family history of aneurysms may also increase your risk.
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.
Sudden stiffening of back and neck, with arching of the back (opisthotonos; not very common)
Signs and tests
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.
Reinhardt MR. Subarachnoid hemorrhoid. J Emerg Nurs. 2010;36(4):327-329.
Rabinstein AA, Lanzino G, Wijdicks EF. Multidisciplinary management and emerging therapeutic strategies in aneurysmal subarachnoid hemorrhage. Lancet Neurol. 2010;9(4):504-519.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by Joseph V. Campellone, MD, Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.