Arteriovenous malformations hemorrhage

Hemorrhagic strokes account for 12% of strokes and include subarachnoid hemorrhage, intracerebral hemorrhage, and subdural hematomas. Subarachnoid hemorrhage may result from trauma or rupture of an intracranial aneurysm or arteriovenous malformation. Intracerebral hemorrhage occurs when a ruptured blood vessel within the brain parenchyma causes formation of a hematoma. Subdural hematomas are most often caused by trauma. 

In subarachnoid hemorrhage due to a ruptured intracranial aneurysm or arteriovenous malformation, surgical intervention to clip or ablate the vascular abnormality substantially reduces mortality from rebleeding. The benefits of surgery are less well documented in cases of primary intracerebral hemorrhage. In patients with intracerebral hematomas, insertion of an intraventricular drain with monitoring of intracranial pressure is... 

History of intracranial hemorrhage, arteriovenous malformation, or aneurysm... 

Contraindications Active internal bleeding or a history of bleeding diathesis within previous 30 days, arteriovenous malformation or aneurysm, history of intracranial hemorrhage, history of thrombocytopenia after prior exposure to tirofiban, intracranial neoplasm, major surgical procedure within previous 30 days, severe hypertension, stroke... 

Moyamoya seems to be mainly confined to the Japanese and other Asians, and in most cases the cause is unknown (Bruno et al. 1988 Chiu et al. 1998). Some cases are familial (Kitahara et al. 1979) others appear to be caused by a generalized fibrous disorder of arteries (Aoyagi et al. 1996), and a few may result from a congenital hypoplastic anomaly affecting arteries at the base of the brain, or associated with Down s syndrome (Cramer et al. 1996). The syndrome may present in infancy with recurrent episodes of cerebral ischemia and infarction, mental retardation, headache, epileptic seizures and, occasionally, involuntary movements. In adults, subarachnoid or primary intracerebral hemorrhage are also common owing to rupture of collateral vessels. There have also been a few reports of associated intracranial aneurysms (Iwama et al. 1997) and also of cerebral arteriovenous malformations. 

Fig. 7.1. Intracerebral hemorrhage, (a) A CT brain scan showing a typical deep "hypertensive" primary intracerebral hemorrhage, (b) These CT brain scans showing a right frontal arteriovenous malformation causing hemorrhage.

Headache, although common, is not by itself diagnostically helpful and may well be a coincidence. Rarely, a bruit can be heard over the skull or orbits. A brainstem arteriovenous malformation can present similarly to multiple sclerosis, with fluctuating symptoms and signs of brainstem dysfunction, perhaps caused by recurrent hemorrhage. 

Telangiectasias are collections of dilated capillaries that are usually of no clinical significance (Milandre et al. 1987). They may be associated with hereditary hemorrhagic telangiectasia (the Osler-Weber-Rendu syndrome), but this is more likely to be associated with neurological complications from a pulmonary arteriovenous malformation with right-to-left shunting, such as cerebral hypoxia, brain abscess, paradoxical and septic embolism, or from an associated intracranial arteriovenous malformation or aneurysm (McDonald et al. 1998). 

Pontine hemorrhages are fatal in around 50% of patients (Wijdicks and St. Louis 1997). Those caused by cavernomas or arteriovenous malformations have a better outcome (Rabinstein et at 2004). The management of patients with hypertensive pontine hemorrhage is usually conservative, but some case reports have documented successful stereotactic aspiration. However, there is likely publication bias and the natural history of the condition is difficult to predict since patients with small hemorrhages do well with conservative management. 

Ruptured arteriovenous malformations have a lower mortality than aneurysmal SAH and are less likely to rebleed, certainly in the early period after the initial hemorrhage (Mast et al. 1997). It is unclear how to identify lesions at particularly high risk of bleeding or epilepsy (Duong et al. 1998). 

For subarachnoid hemorrhage surgical clipping of the causative aneurysm or resection of the arteriovenous malformation is the mainstay of treatment. Endovascular coiling of the aneurysm can also be performed. Post-operative infection (either brain or respiratory) is an uncommon complication and not believed to be any more common than after other invasive surgical procedures. Hypervolemic-hemodilution and hypertensive (HHH) therapy is used to prevent spasm. There may be a role for anti-inflammatory measures for the prevention of vasospasm and delayed cerebral ischemia, as shown in a recent pilot study of patients treated with statins (Lynch et al., 2005). 

A 29-year-old man had a subarachnoid hemorrhage due to an arteriovenous malformation, which was embo-hzed (101). During the procedure he suddenly lost consciousness, regained it 15 minutes later, but complained of total blindness. Cerebral angiography showed no arteriovenous malformation and no abnormality in the vertebrobasilar system. A CT scan of the head showed considerable contrast enhancement of the occipital lobes and 2 hours later the contrast had cleared. An MRI scan 12 hours later showed no evidence of infarction in the occipital lobes. Two days later his sight gradually returned and 7 days later he had completely recovered. 

Arteriovenous malformations—A tangle of blood vessels, both arterial and venous, that can rupture and cause hemorrhage in the brain. 

AVM arteriovenous malformations BP blood pressure CTA CT angiography D50 50% dextrose EKG electrocardiogram i.a. intra-arterial 7C//intracranial hemorrhage i.v. intravenous M7myocardial infarction PCP primary care physician 7Tprothrombin time PTT partial thromboplastin time rt-PA recombinant tissue plasminogen activator SAH subarachnoid hemorrhage... 

White Rl, Jr. (1996) Pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia embolotherapy using balloons and coils [comment]. Arch Intern Med 156 2627-2628... 

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder of blood vessels [21, 63]. Also known as Rendu-Osier-Weber syndrome, HHT is a condition which is transmitted in an autosomal dominant pattern, and characterized by arteriovenous malformations (AVM) in the skin, mucous membranes and visceral organs [4]. There are two... 

Ference BA, Shannon TM, White Rl Jr, Zavin M, Burdge CM (1994) Life-threatening pulmonary hemorrhage with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia. Chest 106 1387-1390... 

Hewes RC, Auster M, White Rl (1985) Cerebral embolism first manifestation of pulmonary arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia. CardioVasc Intervent Radiol 8 151-155... 

Kjeldsen AD, Oxhoj H, Andersen PE, EUe B, Jacobsen JP, Vase P (1999) Pulmonary arteriovenous malformations screening procedures and pulmonary angiography in patients with hereditary hemorrhagic telangiectasia. Chest 116 432-439... 

Vascular malformations of the brain are usually divided into arteriovenous malformations, capillary telangiectasias, venous malformations, and cavernous malformations. However, for a long time, the term angiographically occult vascular malformation or cryptic (Cohen et al. 1982 Dillon 1997 Wilson 1992) has been used to describe those vascular malformations that could not be visualized angiographically, but obviously were able to cause intracerebral hemorrhage. 

Hereditary hemorrhagic telangiectasia (Rendu-Osler disease) is not associated with cerebral capillary telangiectasia, but with other forms of cerebral vascular malformations (Maher et al. 2001), mainly true pial arteriovenous malformations, dural arteriovenous malformations, and, rarely, cavernomas. 

Autopsy data showed that only 12% of AVMs become symptomatic during life (The Arteriovenous Malformation Study Group 1999), and intracranial hemorrhage is the most common clinical presentation (Al-Shahi and Warlow 2001 Hofmeister et al. 2000 The Arteriovenous Malformation Study Group 1999). 

On the basis of retrospective analysis, the rupture of brain AVMs is estimated to be less severe than that of intracranial aneurysms, with mortality between 10% and 15% and an overall morbidity of less than 50% (The Arteriovenous Malformation Study Group 1999). Hemorrhages of brain AVMs are subarachnoidal (30%), parenchymal (23%), intraventricular (16%), and in combined locations in 31% of cases (Hartmann et al. 1998). Parenchymal hemorrhages were most likely to result in a neurological deficit (52%). Overall, in the series of Hartmann et al. (1998), 47% of patients... 

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