Berry (saccular) aneurysms are the most common type of intracranial aneurysm, representing 90% of cerebral aneurysms. Generally speaking, there is a ballooning arising from a weakened area in the wall of a blood vessel in the brain. Depending on the size of the aneurysm, their symptomatology ranges from asymptomatic to intracerebral hemorrhage (subarachnoid) in the most extreme cases. Berry aneurysm is an older terminology that has mostly been replaced by saccular aneurysm. The new nomenclature goes against the old tradition of likening a pathologic process to a variety of fruit products. Aneurysm is from the Greek word, aneurysma, meaning dilation.
Risk Factors for Aneurysm Rupture
Those with previous ruptures or intracranial bleeds are at the highest risk of cerebral artery aneurysm rupture.
Common Sites in the Anterior Circulation
Common Sites in the Posterior Circulation
Berry aneurysms are due to outpouchings in the blood vessel wall, which be due to either hereditary factors or acquired disease. Repetitive trauma and shearing forces against the weak point in the blood vessel’s wall cause aneurysms to enlarge.
Older dogma considers berry aneurysms to be passively enlarging vascular structures. More recent evidence suggests that berry aneurysms, along with other forms of aneurysms, are created and enlarged through a continuous process of inflammation and tissue degradation.
Some traditional classifications pose this as a model for organizing the types of intracranial aneurysms:
The clinical picture of berry aneurysms includes the most severe manifestation of a major aneurysmal rupture, such as a subarachnoid hemorrhage to minor hemorrhage, also known as a sentinel bleed, nonhemorrhagic scenarios, or asymptomatic situations in which the aneurysm is found incidentally.
Many of these patients may be brought in in extremis, and as such, ABCs take priority. Assess the patient's airway, breathing, and establish good IV access. In the setting of trauma, give priority to your primary survey, and do not forget to do a thorough secondary survey. Do not be distracted by dramatic extremity injuries. Give priority to emergent neuroimaging once the patient has been stabilized hemodynamically.
Other patients may present less extreme and warrant a thorough history and physical, even outside the setting of trauma.
Your History should include some key elements as described below:
The physical exam should include and not be limited to the following elements:
Medical management of these patients should begin in the emergency department. In the first 24 hours, there is a very high risk of rebleeding, and this risk can be reduced markedly by controlling blood pressure. Systolic should be kept less than 140 mmHg.
Remember to control the patient's pain. It is not only the right thing to do; adequate pain control will make it easier to control the blood pressure.
Use antiemetics as needed.
Nimodipine may be added in the first 96 hours to help decrease the degree of vasospasm.
Antiseizure medications should also be initiated.
On the differential for saccular aneurysms exist many of the disease processes that cause headaches:
Many aneurysms will never cause a patient any discomfort or sequelae.
If an aneurysm does rupture, the prognosis depends on several factors including:
Twenty-five percent of patients with ruptured aneurysms will not survive the first 24 hours.
Of those who survive initially, 25 percent will die from other complications in the next six months.
Patients should know to utilize the emergency medical services (EMS) available to them such as emergency rooms, via EMS when available, to seek the expert advice of an emergency physician if headache develops which is severe or different from baseline headaches.
Currently, research is being done in a variety of fields including targeting specific genes and improving the diagnostic accuracy of our neuroimaging such that this diagnosis can be made swiftly and accurately, thereby improving patient outcomes and decreasing the morbidity and mortality associated with saccular aneurysms, especially ones that have burst. Outcomes can be enhanced by an interprofessional team including EMS personnel, emergency department nurses and physicians, radiologists, neurologists, physiatrists, and therapists. [Level 5]
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