Brain Aneurism and
Subarachnoid Hemorrhage

A brain aneurism (=cerebral aneurysm) is a sac-like malformation of a blood vessel of one of the main arteries underneath the brain. It is a rare condition. However, as it usually ruptures in a younger age group of 40 to 65 years, it has an enormous social impact. The natural course of a ruptured aneurism has recently been described in a large study from Australia and New Zealand (Ref. 4).

After 1 year from the subarachnoid hemorrhage the following was found: Only 56% of patients were alive after one year and 46% of these had a neurologically incomplete recovery. The deficits ranged from memory loss (50%) to mood disturbances (39%), speech problems ( 14%) and problems with self-care(10%). Some of these findings overlap and that's why it adds up to more than 100%.

These authors followed 62 asymptomatic aneurism patients for 6 months to 17 years and they calculated the cumulative risk for bleeding at the 5 year and 10 year follow-up points. For large aneurisms( more than 10 mm in diameter) they found the risks for bleeding to be 7.5% and 22%. For small aneurisms( less than 10 mm) that bleeding risk was 4.5% and 13.9% at the 5 and 10 year point in the study. The authors concluded that with a 3-fold increase of the risk of bleeding in just 5 years regardless of the size of the aneurism and a higher risk for larger aneurisms, the neurosurgeon is justified to intervene by treating the asymptomatic aneurism on a preventative basis.

Another interesting study from Turkey showed that one important, but neglected factor in the development of aneurisms of brain arteries is when high blood pressure is not controlled (Ref. 6). These authors found that the incidence of uncontrolled high blood pressure prior to an subarachnoid hemorrhage was almost double compared to normal controls. They suggested the following sequence of events that lead to the development of aneurisms: The uncontrolled high blood pressure leads to a closing off of the nutritional small blood vessels that supply the arterial wall with nutrients. This leads to a loss of the normal collagen and elastic material in the arterial wall in a focal area. Subsequently the continued pressure inside the artery leads to the pouch of the aneurism, which in time grows larger until it ruptures. This new insight makes it very important for patients to measure their own blood pressure to help reduce the incidence of the complications of intracerebral and subarachnoid hemorrhages.

Aneurism brain symptoms: 

Up to the point of rupture of the aneurysm the patient may be entirely asymptomatic. However, sometimes small warning leaks occur weeks and months before. These usually are associated with a new headache or, if the person is a headache sufferer, perhaps a different type of headache. Because of what was said above, it is important to take this serious and do a CT scan or MRI scan to rule out an aneurism. Sometimes it is very confusing for the physician as well as the patient as tension type headaches and migraine headaches, which are much more common than a new cerebral aneurism, can interfere with the recognition of an aneurism. If the pouch of an aneurism puts pressure on one of the cranial nerves, there might be symptoms such as double vision, visual field loss or cross-eyedness.

Diagnosis:

The initial test usually is a CT scan. However, as the blood vessels are affected with the development of a structural change, angiography is used not infrequently. This test involves the injection of a substance, which shows up on X rays ( radio-opaque). This way all of the blood vessels of the brain can be detected as aneurisms occasionally happen simultaneously in several cerebral arteries.

Treatment:

Without intervention about 35% of patients with a ruptured aneurism die with the first bleed. Another 15% die within a few weeks from another rupture. Because of these unfavorable statistics it is important to be much more aggressive in terms of preventative therapeutic intervention than was done in the past.

A study, which comes from Paris/France, ( Ref. 7) demonstrated on 395 consecutive patients that with either endovascular coiling(75% of patients) or conventional surgical clipping (25% of patients) a total success rate of 98.8% can be achieved. The authors followed these patients for 3 years in intervals and only 6% of the patients had to be retreated. The mortality rate from the procedures was only 4.8%. Considering the overall poor prognosis without intervention, these figures are encouraging and support the authors conclusion that either a neurosurgical clipping or an angiographic coiling procedure can improve the poor survival statistics.

Here is a link for more info on brain aneurism.

Disclaimer:

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.

References:

1. KH Lee et al. Arch Neurol 2000 Jul 57(7): 1000-1008.

2. S Schmulling et al. Stroke 2000 Jul 31(7): 1552-1554.

3. D Jackson et al. Clin Rehabil 2000 Oct 14(5): 538-547.

4. ML Hackett et al. Neurology 2000 Sep 12; 55 (5): 658-662.

5. K Tsutsumi et al. J Neurosurg 2000 Oct 93( 4): 550-553.

6. IS Spetzler Surg Neurol 2000 Jun 53(6): 530-540.

7. G Lot et al. Acta Neurochir (Wien) 1999; 141(6): 557-562.

8. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 174.

9. Noble: Textbook of Primary Care Medicine, 3rd ed.,2001, Mosby Inc.

10. Ferri: Ferri's Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.

11. Rakel: Conn's Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier

Last Modified: Nov.12, 2006