Ruptured saccular aneurysm

Changed by Frank Gaillard, 30 Jul 2018

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Rupture of a berry aneurysm, also known as a saccular aneurysm, can cause either usually results in a subarachnoid haemorrhage (SAH) but can, depending on the location of the rupture and presence of adhesions to the aneurysm, also result in cerebral haematoma, subdural haematoma and/or intraventricular haemorrhage.

Epidemiology

Berry aneurysms form 97% of all aneurysms of the central nervous system. Up to 80% of patients with a spontaneous subarachnoid haemorrhage have ruptured an aneurysm. and 90% of these aneurysms are located in the anterior circulation (carotid system) and, with 10% are found in the posterior circulation (vertebrobasilar system).

Clinical presentation

Rupture of a saccular aneurysm with associated subarachnoid haemorrhage most frequently presents with a sudden, excruciating headache often described as 'the worst I've ever had' or 'thunderclap', resulting from blood being forced into the subarachnoid space under arterial pressure. Other features include:

  • visual changes
  • facial pain
  • seizures
  • autonomic disturbances (nausea/vomiting, chills and palpitations)
  • focal neurology (sensory loss, weakness, memory loss, language difficulties) 

Examination findings include meningisms (nuchal ridigityrigidity, fever, photophobia), altered consciousness, and other focal neurological signs such as ophthalmoplegia and pupillary abnormalities

Mortality from the first rupture is between 25-50% with repeat bleeding a common complication in survivors. With each recurrent bleed, the prognosis is worsened. In the first few days following a subarachnoid haemorrhage, there is an increased risk of additional ischaemic injury from the reactive vasospasm from surrounding vasculature. 5

Pathology

The pathologyAlthough some of the details of the pathophysiology of the formation of a berry aneurysm remain unknown, the vast majority of aneurysms arise at arterial branching points along the circle of Willis 5. It is large unknown but rupture usually manifests aslikely that the difference in composition of intracranial arteries compared to similarly sized arteries in the rest of the body (e.g. reduced thickness of adventitia) plays a devastating subarachnoid haemorrhagesignificant role in aneurysm formation and rupture. 5Additional deficiencies in arterial wall strength (e.g. connective tissue disease or infection) further increase the incidence of aneurysm formation - see below.

Rupture of a berry aneurysm is in most cases spontaneous with no clear precipitant. In approximately one-third of cases associated defined increased intracranial arterial pressure can be surmised by history or examination at the time of presentation (e.g. coital rupture, recreational drugs, childbirth etc..) 6.

Aetiology
  • rupture of berryinfection (mycotic aneurysm:
    • two-thirds are sporadic
    • one-third of cases associated with increased intracranial pressure 6
    )
  • Location
    • most commonly at arterial branching points along the circle of Willis 5
    Macroscopic appearance
    • an unruptured aneurysm appears as a thin-walled, shiny red outpouching usually measuring a few milimeters to 3 cm in diameter 
    • rupture usually occurs at the apex of the sac 5
    Microscopic appearance
    • the arterial wall adjacent to the neck of the sac usually shows thickening of the intima and thinning out of the media as the neck is approached
    • the sac itself is usually made up of thickened intima with the adventitia of the parent artery surrounding the sac 5

    Radiographic features

    Determining the site of rupture

    After rupture, the location of the blood or haematoma can help determine the site of the ruptured aneurysm in the majority of cases:

    Aneurysmal characteristics suggestive of rupture

    In cases of subarachnoid haemorrhage with multiple aneurysms, it is often important to identify which aneurysm has bled, as not all aneurysms present can be treated simultaneously. The location of blood, particularly if there is a parenchymal haematoma, is very helpful in identifying the responsible aneurysm. If this is not present or if blood is diffusely within the subarachnoid space, then aneurysm morphology can be helpful:

    • largest aneurysm
    • length-to-neck ratio >1.6 4
    • increased volume to surface area 4
    • aneurysm angulation 4
    • presence of an apical bleb 4

    Treatment and prognosis

    The rupture of an intracranial aneurysm is a medical emergency with a high mortality index 3 Treatment focuses on managing both the aneurysm and complications of haemorrhage. 

    See also

    and vasospasm
    • -<p><strong>Rupture of a berry aneurysm</strong>, also known as a <a href="/articles/saccular-cerebral-aneurysm">saccular aneurysm</a>, can cause either a <a href="/articles/subarachnoid-haemorrhage">subarachnoid haemorrhage (SAH)</a>, <a href="/articles/intracerebral-haemorrhage">cerebral haematoma</a> and/or <a href="/articles/intraventricular-haemorrhage">intraventricular haemorrhage</a>.</p><h4>Epidemiology</h4><p><a href="/articles/saccular-cerebral-aneurysm">Berry aneurysms</a> form 97% of aneurysms of the central nervous system. Up to 80% of patients with a spontaneous subarachnoid haemorrhage have ruptured an aneurysm. 90% of these aneurysms are located in the anterior circulation (carotid system) and 10% are found in the posterior circulation (vertebrobasilar system).</p><h4>Clinical presentation</h4><p>Rupture of a saccular aneurysm with associated subarachnoid haemorrhage most frequently presents with a sudden, excruciating headache often described as 'the worst I've ever had' or 'thunderclap', resulting from blood being forced into the subarachnoid space under arterial pressure. Other features include:</p><ul>
    • +<p><strong>Rupture of a berry aneurysm</strong>, also known as a <a href="/articles/saccular-cerebral-aneurysm">saccular aneurysm</a>, usually results in a <a href="/articles/subarachnoid-haemorrhage">subarachnoid haemorrhage (SAH)</a> but can, depending on the location of the rupture and presence of adhesions to the aneurysm, also result in <a href="/articles/intracerebral-haemorrhage">cerebral haematoma</a>, <a title="Subdural haematoma" href="/articles/subdural-haemorrhage">subdural </a><a title="Subdural haematoma" href="/articles/subdural-haemorrhage">haematoma</a> and/or <a href="/articles/intraventricular-haemorrhage">intraventricular haemorrhage</a>.</p><h4>Epidemiology</h4><p><a title="Berry aneurysms" href="/articles/saccular-cerebral-aneurysm">Berry aneurysms</a> form 97% of all aneurysms of the central nervous system. Up to 80% of patients with a spontaneous subarachnoid haemorrhage have ruptured an aneurysm and 90% of these aneurysms are located in the anterior circulation (carotid system), with 10% are found in the posterior circulation (vertebrobasilar system).</p><h4>Clinical presentation</h4><p>Rupture of a saccular aneurysm with associated subarachnoid haemorrhage most frequently presents with a sudden, excruciating headache often described as 'the worst I've ever had' or 'thunderclap', resulting from blood being forced into the subarachnoid space under arterial pressure. Other features include:</p><ul>
    • -</ul><p>Examination findings include <a title="Meningism" href="/articles/meningism">meningisms</a> (nuchal ridigity, fever, photophobia), altered consciousness, and other focal neurological signs such as ophthalmoplegia and pupillary abnormalities</p><p>Mortality from first rupture is between 25-50% with repeat bleeding a common complication in survivors. With each recurrent bleed, prognosis is worsened. In the first few days following a subarachnoid haemorrhage, there is an increased risk of additional ischaemic injury from the reactive vasospasm from surrounding vasculature. <sup>5</sup></p><h4>Pathology</h4><p>The pathology of the formation of a berry aneurysm is large unknown but rupture usually manifests as a devastating subarachnoid haemorrhage. 5</p><h5>Aetiology</h5><ul>
    • -<li>formation of berry aneurysm:<ul>
    • -<li>largely unknown</li>
    • -<li>sporadic</li>
    • -<li>likely genetic component due to increased incidence in first-degree relatives of affected patients<ul><li>increased incidence in <a href="/articles/vascular-ehlers-danlos-syndrome-1">Ehlers-Danlos syndrome type IV</a>, <a href="/articles/neurofibromatosis-type-1">neurofibromatosis type 1</a>, <a href="/articles/marfan-syndrome">Marfan syndrome</a>, <a href="/articles/autosomal-dominant-polycystic-kidney-disease-1">autosomal dominant polycystic kidney disease</a>
    • -</li></ul>
    • -</li>
    • -</ul>
    • +</ul><p>Examination findings include <a href="/articles/meningism">meningisms</a> (nuchal rigidity, fever, photophobia), altered consciousness, and other focal neurological signs such as ophthalmoplegia and pupillary abnormalities</p><p>Mortality from the first rupture is between 25-50% with repeat bleeding a common complication in survivors. With each recurrent bleed, the prognosis is worsened. In the first few days following a subarachnoid haemorrhage, there is an increased risk of additional ischaemic injury from the reactive vasospasm from surrounding vasculature. <sup>5</sup></p><h4>Pathology</h4><p>Although some of the details of the pathophysiology of the formation of a berry aneurysm remain unknown, the vast majority of aneurysms arise at arterial branching points along the circle of Willis <sup>5</sup>. It is likely that the difference in composition of <a title="Intracranial arteries" href="/articles/intracranial-arteries">intracranial arteries</a> compared to similarly sized arteries in the rest of the body (e.g. reduced thickness of adventitia) plays a significant role in aneurysm formation and rupture. Additional deficiencies in arterial wall strength (e.g. connective tissue disease or infection) further increase the incidence of aneurysm formation - see below.</p><p>Rupture of a berry aneurysm is in most cases spontaneous with no clear precipitant. In approximately one-third of cases associated defined increased intracranial arterial pressure can be surmised by history or examination at the time of presentation (e.g. coital rupture, recreational drugs, childbirth etc..) <sup>6</sup>.</p><h5>Aetiology</h5><ul><li>formation of berry aneurysm:<ul>
    • +<li>sporadic (most)<ul><li>although a genetic component is likely as incidence in first-degree relatives of affected patients is increased</li></ul>
    • -<li>rupture of berry aneurysm:<ul>
    • -<li>two-thirds are sporadic</li>
    • -<li>one-third of cases associated with increased intracranial pressure <sup>6</sup>
    • +<li>genetic<ul><li>
    • +<a href="/articles/vascular-ehlers-danlos-syndrome-1">Ehlers-Danlos syndrome type IV</a>, <a href="/articles/neurofibromatosis-type-1">neurofibromatosis type 1</a>, <a href="/articles/marfan-syndrome">Marfan syndrome</a>, <a href="/articles/autosomal-dominant-polycystic-kidney-disease-1">autosomal dominant polycystic kidney disease</a>
    • +</li></ul>
    • +<li>infection (<a title="Mycotic aneurysm" href="/articles/mycotic-aneurysm">mycotic aneurysm</a>)</li>
    • -</li>
    • -</ul><h5>Location</h5><ul><li>most commonly at arterial branching points along the circle of Willis <sup>5</sup>
    • -<strong>ACOM:</strong> ~35%, <a href="/articles/septum-pellucidum">septum pellucidum</a>, <a href="/articles/interhemispheric-fissure">interhemispheric fissure</a> and intraventricular​</li>
    • +<strong>ACOM:</strong> ~35%, <a href="/articles/septum-pellucidum">septum pellucidum</a>, <a href="/articles/interhemispheric-fissure">interhemispheric fissure</a> and intraventricular</li>
    • -</ul><h5>Aneurysmal characteristics suggestive of rupture</h5><ul>
    • +</ul><h5>Aneurysmal characteristics suggestive of rupture</h5><p>In cases of subarachnoid haemorrhage with multiple aneurysms, it is often important to identify which aneurysm has bled, as not all aneurysms present can be treated simultaneously. The location of blood, particularly if there is a parenchymal haematoma, is very helpful in identifying the responsible aneurysm. If this is not present or if blood is diffusely within the subarachnoid space, then aneurysm morphology can be helpful:</p><ul>
    • +<li>largest aneurysm</li>
    • -</ul><h4>Treatment and prognosis</h4><p>The rupture of an intracranial aneurysm is a medical emergency with a high mortality index <sup>3</sup>.  </p><h4>See also</h4><ul><li><a href="/articles/saccular-cerebral-aneurysm">berry aneurysm</a></li></ul>
    • +</ul><h4>Treatment and prognosis</h4><p>The rupture of an intracranial aneurysm is a medical emergency with a high mortality <sup>3</sup>.  Treatment focuses on managing both the aneurysm and complications of haemorrhage. </p><p>The aneurysm needs to be secured, either endovascularly by introduction of coils and/or stents or by surgery with clipping of the aneurysm neck. </p><p>Complications that require management include <a title="Hydrocephalus" href="/articles/hydrocephalus">hydrocephalus</a> and <a title="Cerebral vasospasm following subarachnoid haemorrhage" href="/articles/cerebral-vasospasm-following-subarachnoid-haemorrhage">vasospasm</a>. </p>

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