Tuesday, May 17, 2011

Cerebral vascular malformations

Cerebral vascular malformations are congenital lesions resulting from an abnormal embryo that have the potential to become symptomatic or break them up, typically at ages younger than aneurysms. About 5% of the hemorrhages are caused by the rupture intraparenchimatoase a vascular malformation.
  
Vascular malformations are classified according to histological features: arteriovenous malformation, cavernous angioma, venous angioma, spider.
  
Arteriovenous malformations (AVM) are congenital malformations consisting of clusters of blood vessels are abnormal structure or vein and the other without a well defined structure, appearing just like dilated channels. Through these channels it establishes an abnormally increased blood flow, which did not pass through the capillary bed, but directly from the arteries in the veins. This increased blood flow and increased elongation favors progressive vascular channels and their tendency to break suddenly causing injury bleeding.
  
MAV are the most common birth defects and slight prevalence in males. MAV large local and systemic effects. Local thefts occur through the blood of normal arteries malformation. Bleeding occurs in about 50% of cases and occurs especially in their 20s and 30s.More frequent breaks segment of venous malformation, the bleeding that may be less intense than damaging the arterial segment. There may be a correlation of bleeding tendency factors as sex, age, location, size. Sometimes, surgery or necropsy can be found hemosiderin deposits, which are evidence of previous asymptomatic bleeding. MAV infratentoriale constitute approximately 10% of the total. And tend to bleed more frequently than supratentorial resangera and have a worse prognosis.
  
Cryptic vascular malformations are birth defects that escape the angiographic examination, but were identified at necropsy in the cause of cerebral hemorrhage unspecified young people aged from 20 to 40 years. Lesions are small and generally correspond to certain MAV or cavernous angioma. May remain asymptomatic and are discovered incidentally at necropsy, but suggests that they are present in the cause of unexplained bleeding, bleeding but destroyed in the outbreak. The expression and angiographically occult vascular malformations because rid of this investigation is due to the small size or because of compression exerted on them by bleeding. The diagnosis of these defects has been facilitated by the introduction computertomografiei (CT), which sometimes can be seen adjacent to calcified deposits hemorrhagic outbreak.
  
Cavernous hemangioma is a vascular malformation (congenital) that consists of a cluster of newly formed capillaries, whose frequency has been underestimated before the introduction of CT and MRI.
  
Localization is predominantly supratentorial, most commonly in the temporal lobe. In subtentoriala location found in the cerebellum, deck and ponto-cerebellar angle. Appears in young adults in the Third Decade and the Fourth of life, with a slight preponderance in females. Are generally small, between 1 mm and 3-4 cm.
  
The lesion is usually single, but multiple lesions have been reported. At cerebellum is most commonly manifested by bleeding.Bleeding in this type of malformation has no other distinguishing marks to trigger bleeding. Small hemorrhages may have recurrent nature of periods of weeks or months, and progressive neurological signs may suggest a brain tumor.
  
Venous angioma, a benign tumor formed by widening blood vessels, is rare in clinical examinations were found at autopsy. It is located predominantly in the supratentorial subtentorial in the cerebellum and frontal lobe. The potential for bleeding in the cerebellum is much increased when associated with cavernous angioma.
  
Telangiectasia, which are dilated capillaries, has the lowest potential for bleeding. It is found in the cerebellum, bulb, and deck and can coexist with cavernous angioma. Spider veins are a symptom of a congenital hereditary complex: Rendu-Osler syndrome.
  
Clinical
  
Signs and symptoms most common in the vascular malformations are mild headache, seizures and signs associated with failure. In half the cases, arteriovenous malformations manifested by intracerebral hemorrhage, especially intraparenchimatoasa, can be small or massive (leading to exitus).
  
In general, the hematoma is reabsorbed in 6-8 weeks. If MAV-carotid artery system can detect cerebral artery mean systolic and diastolic murmur with an outbreak of listening to the forehead, eyes and neck.
  
Treatment of vascular malformations
  
If surgery is saving large hematoma patient's life threatening. It takes into consideration the medical treatment of hypertension that can produce new bleeding. Good results are obtained with anticomitial treatment.
  
Surgical treatment of unruptured malformations is aimed at total excision of the lesion when possible. Interventions are most common practice is surgical excision, obliteration of interventional radiology, radiotherapy.

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