(1)
Neurosurgery Teaching Hospital, Baghdad, Iraq
This book contains some difficult questions marked with “ * “ sign.
- 1.
The most common intracerebral vascular malformations
The TRUE answer is:
- A.
AVMs
- B.
Cavernous malformation
- C.
Venous angioma
- D.
Capillary telangiectasia
- E.
Aneurysm
- A.
The answer is C.
DVA or venous angiomas are the most common intracerebral vascular malformation in general and also in autopsy.
- 2.
AVMs
Definition, the FALSE answer is:
- A.
True AVMs are abnormalities of the intracranial vessels in which the arterial and venous systems are connected without an intervening capillary bed.
- B.
Mainly congenital lesions which develop during the late somite stage, between the fourth week and the eighth week of embryonic life.
- C.
The AVMs are the most common clinically (or surgically) significant vascular malformation.
- D.
They are high-flow, high-pressure lesions.
- E.
Never contains parenchymal tissue within the nidus.
- A.
The answer is E.
There may be parenchymal element within the nidus but if present tend to be gliotic, hemosiderin stained, and nonfunctional.
AVMs are mainly congenital in origin but the presentation is usually at adult life.
AVMs are high flow and high pressure especially in adult.
- 3.
AVMs
Location, the FALSE answer is:
- A.
Supratentorial in 85 % and infratentorial in 15 %.
- B.
Parietal area is the most common region involved in supratentorial lesions.
- C.
Hemispheric AVMs are located in the MCA, PCA, and ACA territories in declining frequencies.
- D.
The location of the base in most AVMs is periventricular.
- E.
There is no significant hemispheric preference.
- A.
The answer is D.
The location of the apex in most AVMs is periventricular because small arteries from the ependymal surface feed the AVM. The AVM base usually faces the cortex.
Also the parietal area is the most common location of AVM to give rise to seizures followed by insula, frontal, and temporal lobes.
Superficial is slightly more than deep AVMs.
The eloquent location is slightly more than non-eloquent.
- 4.
AVMs
Pathology, the FALSE answer is:
- A.
Classic morphologic features are feeding arteries, draining veins, and a dysplastic vascular nidus composed of a tangle of abnormal vessels.
- B.
The AVMs fed predominantly by the trans-cerebral vessels.
- C.
AVMs classically assume the shape of a cone (wedge), based on the cortical surface with its apex often reaching the ventricular wall.
- D.
Most AVMs demonstrate a gliotic core associated with the nidus.
- E.
Most AVMs demonstrate a gliotic wall around the malformation forming a “true capsule” which helps in surgical dissection.
- A.
The answer is E.
Most AVMs demonstrate a gliotic core associated with the nidus and a gliotic wall around the malformation forming a “false capsule” which helps in surgical dissection.
A type of proliferative or diffuse AVM without a focal nidus is often seen in pediatric patients.
- 5.
AVMs
Pathology, the FALSE answer is:
- A.
Dilation and tortuosity of feeding arteries.
- B.
Smooth muscle hyperplasia associated with fibroblasts and connective tissue elements known as fibromuscular cushions.
- C.
Vascular or interstitial calcification of the vessel in an AVM is never occurring.
- D.
Thickening of the vein due to collagenous tissue is usually noted and thrombosis may be found.
- E.
Arteries and arterialized veins may be difficult to distinguish from one another.
- A.
The answer is C.
Vascular or interstitial calcification of vessel in an AVM is common to occur.
- 6.
AVMs
Natural history, the FALSE answer is:
- A.
The average age of patients diagnosed with AVMs is around 30 years.
- B.
Large AVMs tend to present more often as hemorrhages than do small ones.
- C.
The annual rebleed rate is 2–4 %.
- D.
The annual mortality rate is 1 %.
- E.
Spontaneous closure may occur.
- A.
The answer is B.
Small AVMs tend to present more often as hemorrhages than do large ones.
The incidence of first bleed for unruptured AVM or the annual rebleed rate or lifelong risk of bleeding per year is 2–4 %, while the risk of rebleed from an AVM in the first year is as high as 5–15 %.
Because of the higher pressures in the feeding artery, it was postulated that larger AVMs presented as seizure more often simply because their size made them more likely to involve the cortex.
The combined annual morbidity plus mortality from AVMs is approximately 2 %, the annual mortality rate is 1 %, the mortality at each bleed is 10 %, and the morbidity for each bleed is 30 to 50 %.
About statement E, the exact mechanisms involved in spontaneous AVM regression are uncertain but the most common is compression of the lesion (leading to acute intravascular thrombosis) from intracranial hemorrhage.
Several factors appear to be associated with spontaneous occlusion of cerebral AVM: single draining vein (84 % of cases of spontaneous occlusion), solitary arterial feeder (30 %), and small size of the nidus (<3 cm in 50 %).
- 7.
AVMs
Clinical features, the FALSE answer is:
- A.
15 % of AVMs have no symptoms.
- B.
The most common presentation of AVM is ICH then seizures and less likely headache, stroke, or neurological deficit.
- C.
Common cause of SAH.
- D.
The older the patient at diagnosis, the higher the risk of developing convulsions.
- E.
The factor that is significantly different in pediatric age group is the initial mode of presentation, withbleeding outnumbering other symptoms in children.
- A.
The answer is D.
The younger the patient at diagnosis, the higher the risk of developing convulsions.
The factor that is significantly different between the pediatric and adult age groups is the initial mode of presentation, with bleed (90 %) outnumbering other symptoms in children.
- 8.
AVMs
Factors that increase the risk of bleeding of AVMs, the FALSE answer is:
- A.
High feeding artery pressure
- B.
Aneurysm or deep venous drainage
- C.
Increasing age or pediatric patients or pregnancy or history of hypertension
- D.
Arterial border zone location of brain AVMs
- E.
Residual nidus after surgery or Spetzler-Martin grade IV or V AVMs.
- A.
The answer is D.
Arterial border zone location of brain AVMs is an independent determinant of lower risk of incident AVMs hemorrhage.
- 9.
AVMs
Anatomic factors that increase the risk of bleeding of AVMs, the FALSE answer is:
- A.
Aneurysm (feeding artery and intranidal aneurysms)
- B.
Nidus (diffuse morphology and small-size AVM)
- C.
Venous recruitment
- D.
Location (deep locations, periventricular, intraventricular space, and infratentorial)
- E.
Impaired venous drainage
- A.
The answer is C.
Factors that increase the risk of bleeding of AVMs:
Anatomic factors:
- 1.
Aneurysm (feeding artery and intranidal aneurysms)
- 2.
Nidus (diffuse morphology)
- 3.
Location (deep locations, periventricular, intraventricular space, and infratentorial)
- 4.
Impaired venous drainage: deep venous drainage, venous stenosis, single draining vein, and venous reflux into a sinus or a deep vein
- 5.
Small-size AVM
- 1.
Hemodynamic factors: high feeding artery pressure
Patient factors: increasing age, pediatric patients, pregnancy, history of hypertension
Others: residual nidus after surgery, Hispanic race/ethnicity, Spetzler-Martin grade IV or V AVMs
Factors that decrease the risk of bleeding of AVMs:
- 1.
Arterial stenosis
- 2.
Arterial angioectasia
- 3.
Arterial border zone location of brain AVMs
- 4.
Venous recruitment
- 1.
The risk of AVM bleeding (at least once) over one’s lifetime:
Lifetime risk (%) = 105 – the patient’s age in years
(Assuming approximately a 2 to 4 %/year bleed rate)
- 10.
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AVMs AND PREGNANCY
The FALSE answer is:
- A.
Hemorrhage secondary to AVM rupture remains a major cause of non-obstetric morbidity and mortality in pregnant women.
- B.
Up to 50 % of pregnant women presenting with intracranial hemorrhage have ruptured AVMs.Related posts:
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- A.
