Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 24-08: Stroke + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Subarachnoid hemorrhage or focal deficit Abnormal imaging studies +++ General Considerations ++ Most aneurysms are located On the anterior part of the circle of Willis, particularly on the anterior or posterior communicating arteries At the bifurcation of the middle cerebral artery At the bifurcation of the internal carotid artery Saccular aneurysms ("berry" aneurysms) Occur at arterial bifurcations Are frequently multiple (20% of cases) Are usually asymptomatic Are associated with polycystic kidney disease, moyamoya disease, familial aldosteronism type 1, and coarctation of the aorta Mycotic aneurysms resulting from septic embolism occur in more distal vessels and often at the cortical surface +++ Demographics ++ Risk factors for aneurysm formation include cigarette smoking, hypertension, and female sex + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ May cause a focal neurologic deficit by compressing adjacent structures Most are asymptomatic or produce only nonspecific symptoms until they rupture, causing a subarachnoid hemorrhage (see Subarachnoid Hemorrhage) "Warning leaks" of a small amount of blood from the aneurysm sometimes precede the major hemorrhage by a few hours or days, leading to headaches, nausea, and neck stiffness Focal neurologic signs may be absent in subarachnoid hemorrhage and secondary to a focal hematoma or ischemia in the territory of the vessel with the ruptured aneurysm Focal arterial spasm in the area of the ruptured aneurysm may occur after 4–14 days, causing hemiplegia or other focal deficits Cause of vasospasm is unknown and likely multifactorial Vasospasm may lead to significant cerebral ischemia or infarction and increase in intracranial pressure Subacute hydrocephalus due to interference with the flow of cerebrospinal fluid may occur after 2 or more weeks; leads to a delayed clinical deterioration and is relieved by shunting +++ Differential Diagnosis ++ Meningitis or meningoencephalitis Ischemic stroke Space-occupying lesion, eg, brain tumor Subdural hemorrhage Epidural hemorrhage Migraine + Diagnosis Download Section PDF Listen +++ +++ Imaging Studies ++ Digital subtraction angiography (bilateral carotid and vertebral studies) Definitive evaluation Generally indicates the size and site of the lesion Sometimes reveals multiple aneurysms May show arterial spasm if rupture has occurred Visualization by CT or MR angiography Not usually adequate if operative treatment is under consideration because lesions may be multiple and small lesions are sometimes missed Can be used to screen patients who have two or more first-degree relatives with intracranial aneurysms + Treatment Download Section PDF Listen +++ +++ Medications ++ Medical management as outlined for subarachnoid hemorrhage is continued for about 6 weeks and followed by gradual mobilization +++ Surgery ++ Definitive treatment requires surgery and clipping of the aneurysm base, or endovascular treatment by interventional radiology +++ Therapeutic Procedures ++ Major aim is to prevent further hemorrhages Conscious patients are Confined to bed Advised against exertion or straining Treated symptomatically for headache and anxiety Given laxatives or stool softeners If severe hypertension, lower blood pressure gradually but not below a diastolic level of 100 mm Hg + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ After surgical obliteration of aneurysms, symptomatic vasospasm may be treated by Intravascular volume expansion Induced hypertension Transluminal balloon angioplasty of involved intracranial vessels +++ Complication ++ Subarachnoid hemorrhage; factors that confer a higher risk for this complication include Older age Female sex "Non-white" ethnicity Hypertension Tobacco smoking High alcohol consumption (exceeding 150 g per week) Previous symptoms Posterior circulation aneurysms Larger aneurysms +++ Prognosis ++ Unruptured aneurysms that are symptomatic merit prompt treatment However, small asymptomatic aneurysms discovered incidentally are often monitored arteriographically and corrected surgically only if > 10 mm Greatest risk of further hemorrhage is within a few days of initial bleed; thus, early obliteration (within 2 days) is preferred Approximately 20% of patients will have further bleeding within 2 weeks and 40% within 6 months +++ When to Refer ++ All patients should be referred +++ When to Admit ++ All patients with a subarachnoid hemorrhage All patients for detailed imaging All patients undergoing surgical or endovascular treatment + References Download Section PDF Listen +++ + +Ellis JA et al. Intracranial aneurysm: diagnostic monitoring, current interventional practices, and advances. Curr Treat Options Cardiovasc Med. 2018 Oct 24;20(12):94. [PubMed: 30353282] + +Engele T et al. Cost comparison of surgical clipping and endovascular coiling of unruptured intracranial aneurysms – a systematic review. World Neurosurg. 2019 May;125:461–8. [PubMed: 30743038] + +Hackenberg KAM et al. Unruptured intracranial aneurysms. Stroke. 2018 Sep;49(9):2268–75. [PubMed: 30355003] + +Park YK et al. Intraprocedural rupture during endovascular treatment of intracranial aneurysm: clinical results and literature review. World Neurosurg. 2018 Jun;114:e605–e615. [PubMed: 29548958] + +Rinkel GJE. Management of patients with unruptured intracranial aneurysms. Curr Opin Neurol. 2019 Feb;32(1):49–53. [PubMed: 30516639] + +Yokoya S et al. Pros and cons of tentative clipping in intracranial aneurysm surgery: Review of 867 direct clippings in single institution. World Neurosurg. 2018 Oct;118:e185–e187. [PubMed: 29966797]