Vascular malformations

CNS lesion with high likelihood of hemorrhage s/p chemical thrombol3dic agents (e.g., hrain tumors, abscess, vascular malformation, aneurysm, contusion)... 

Topically administered local anesthetics are useful in dermatology for preparation of the skin prior to minor surgical procedures, such as skin biopsies, laser treatment of vascular malformations, and curettage of mol-luscum contagiosum lesions, particularly in young children and needle-phobic adults. The topical anesthetic may be used alone or may be applied prior to intrader-mal injection of a local anesthetic to reduce the pain caused by the needle. Two recently approved drugs in... 

Human erythrocytes, for blood pool imaging, red blood cell mass determination, detection of vascular malformations and nuclear cardiology. Heat-damaged red blood cells also yield an excellent agent for spleen imaging15,241. 

Alternatively, 3D images of MR angiographies can be calculated using volume rendering techniques (VRT) or shaded surface display (SSD). Both methods, however, depend on threshold values and therefore they carry the risk of unwanted manipulation. They are less suitable for the depiction of stenoses and are commonly used for aneurysms and other vascular malformations. 

Thus, acute, subacute, or chronic impairment of spinal blood supply can result from a deficient arterial supply and from venous circulatory problems (Mull and Thron 2004). Spinal vascular malformations like spinal dural arteriovenous (AV) fistulas and AV malformations (AVM) of the perimedullary fistula type are the typical disorders associated with venous congestion of the spinal cord. On the other hand, AVM of the glomerular type are seldom combined with a venous outflow disorder. 

In the presence of an intraspinal hemorrhage spinal vascular malformation, cavernoma, coagulopathy and tumor have to be differentiated. 

In spinal vascular malformations abnormally thick, often tortuous vessels on the surface of the spinal cord can be identified as well as the angiomalike nidus of the AVM. MRI facilitates the differentiation between SDAVF and intramedullary AVM. 

Spinal angiography remains the gold standard in spinal vascular malformations and can help to elucidate the underlying pathology of acute spinal cord ischemia in selected cases (Di Chiro and Wener 1973 Djindjian et al. 1970 Lasjaunias et al. 2001). 

Ischemic infarction of the spinal cord is difficult to establish in the early phase, only 50% of the patients show early demarcation within 24 h. The role of MRI in the acute phase is to exclude hematomyelia, spinal vascular malformation (which requires spinal angiography in special cases) or a compressive lesion. 

Selective spinal DSA has a better spatial resolution and plays a main role in the exclusion of spinal vascular malformations. In selected cases affection of the radicular artery and occlusion of the anterior spinal artery system can be demonstrated as well as collateral supply even in the later course of the ischemia (Mull et al. 2002). Thus, spinal DSA helps to identify pathologic vascular conditions in spinal cord ischemia. The main indication remains to exclude a spinal vascular malformation. Angiographic information about the acute phase of spinal cord ischemia is not yet available. 

Aminoff MJ, Barnard RO, Logue V (1974) The pathophysiology of spinal vascular malformations. J Neurol Sci 23 255-263 Backes W, Nijenhuis R, Mull M, Thron A, Wilmink J (2004) Contrast-Enhanced MR Angiography of the Spinal Arteries Current Possibilities and Limitations. Rivista di Neuro-radiologia 17 (3) 282-291... 

Thron AK, Caplan L (2003) Vascular Malformations and Interventional Neuroradiology of the Spinal Cord. In Neurological Disorders Course and Treatment, Second Edition, Elsevier Science 517-528... 

Chang S.D., Lopez J.R., and Steinberg G. K. (1999) The usefulness of electrophysi-ological monitoring during resection of central nervous system vascular malformations. J. Stroke Cerebrovasc. Dis. 8,412-422. 

Sometimes arterial occlusion is demonstrated by angiography in migrainous stroke and the cause is hypothesized to be in-situ thrombosis complicating vasospasm. No provoking factors are known. Other possible causes of stroke in the context of headache must be considered carotid dissection, mitochondrial cytopathy, ruptured vascular malformation, antiphospholipid antibody syndrome and CADASIL (cerebral autosomal dominant arterio-pathy with subcortical infarcts and leukoencephalopathy). Migraine auras without headache may be confused with TIA (Ch. 8). 

Primary intracerebral hemorrhage is more common than subarachnoid hemorrhage, and its incidence increases with age (see Fig. 1.1). It is more frequent in Southeast Asian, Japanese and Chinese populations than in whites. The most common causes are intracranial small vessel disease, which is associated with hypertension, cerebral amyloid angiopathy and intracranial vascular malformations (Sutherland and Auer 2006). Rarer causes include saccular aneurysms, hemostatic defects, particularly those induced by anticoagulation or therapeutic thrombolysis, antiplatelet drugs, infective endocarditis, cerebral vasculitis and recreational drug use (Neiman et al. 2000 O Connor et al. 2005). 

The site of primary intracerebral hemorrhage provides information as to the cause hypertensive hemorrhages (Fig. 7.1a) tend to occur in the basal ganglia, thalamus, and pons, while lobar hemorrhages are more often caused by cerebral amyloid angiopathy, vascular malformations and hemostatic failure (Dickinson 2001 Smith and Eichler 2006 Sutherland and Auer 2006) (Table 7.1) (Fig. 7.1b). Multiple hemorrhages suggest certain specific causes ... 

The hematoma continues to expand after stroke onset, frequently causing further deterioration (Brott et al. 1997 Leira et al. 2004). Some brainstem hemorrhages evolve subacutely, particularly those caused by a vascular malformation (O Laoire et al. 1982 Howard 1986). Any large hematoma may cause brain shift, transtentorial herniation, brainstem compression and raised intracranial pressure. Hematomas in the posterior fossa are particularly likely to cause obstructive hydrocephalus. Rupture into the ventricles or on to the surface of the brain is common, causing blood to appear in the subarachnoid space. 

Primary intraventricular hemorrhage is very unusual, except in premature babies. In adults, a cause is not always found. Some may be secondary to a vascular malformation in the ventricular wall (Gates et al. 1986 Darby et al. 1988). The clinical features may be indistinguishable from subarachnoid hemorrhage and it may only be differentiated at autopsy. 

Intracranial vascular malformations are uncommon, probably congenital, and sometimes familial (Byrne 2005). Those in the dura, draining into the sinuses rather than cerebral veins, can also be caused by skull fracture, craniotomy or dural sinus thrombosis. The overall intracranial vascular malformations detection rate is approximately 3 per 100 000 population per annum and the prevalence is about 20 per 100 000 (Brown et al. 1996). 

Bornebroek M, Westemdorp RGJ, Haan J et al. (1997). Mortality from hereditary cerebral haemorrhage with amyloidosis Dutch type. The impact of sex parental transmission and year of birth. Brain 120 2243-2249 Brott T, Broderick J, Kothari R et al. (1997). Early haemorrhage growth in patients with intracerebral haemorrhage. Stroke 28 1-5 Brown RD, Wiebers DO, Torner JC et al. (1996). Incidence and prevalence of intracranial vascular malformations in Olmsted, County Minnesota 1965 to 1992. Neurology 46 949-952... 

Structural intracranial lesions tumor, chronic subdural hematoma, vascular malformation, giant aneurysm Multiple sclerosis... 

The main clinical indications for imaging the cerebral circulation are TIA (e.g. to identify arterial stenosis), acute ischemic stroke (e.g. to identify vessel occlusion), intracerebral hemorrhage (e.g. to identify an underlying vascular malformation) and possible arterial dissection, flbromuscular dysplasia or other arteriopathies, cerebral aneurysm, intracranial venous thrombosis or cerebral vasculitis. 

Spinal subarachnoid hemorrhage is very rare. It is caused by a vascular malformation, hemostatic failure, coarctation of the aorta, inflammatory vascular disease, mycotic aneurysm or a vascular tumor such as ependymoma. Accumulating hematoma may compress the spinal cord. Suspicion is aroused if the cerebral angiogram is negative and the patient develops spinal cord signs. 

Histology Due to vascular malformation, thin-walled spaces, which are titled with blood and lined with endothelium, develop they are separated by septa. The blood is thrombosed or the thrombus becomes organized. The surrounding liver parench)mia is unchanged, (s. tig. 36.5)... 

This benign infantile tumour is of embryonic origin and usually diagnosed within the first months of life, whereby girls are twice as often affected as boys. In most cases, capillary haemangiomas of the skin and mucosa as well as of other organs are also in evidence. Cardiac and vascular malformations are likewise often found. 

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