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Paediatrics > Ch 79 Vascular malformations > Flashcards

Ch 79 Vascular malformations Flashcards

1
Q

What are direct fistulas (aka dural AVM / dural AVF)?

A

Arteries connecting to veins without a nidus (tangle of abnormal vessels)

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2
Q

Define an AVM?

A

A collection of dysplastic vessels where an artery feeds into a vein without any capillary bed.

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3
Q

How do you classify AVMs?

A

Parenchymal, dural and mixed. Parenchymal are pial, subcortical, paraventricular or combined.

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4
Q

Which hereditary syndrome is associated with AVMs?

A

HHT

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5
Q

What age are AVMs diagnosed?

A

Most <40years. Present with haemorrhage, seizures, mass effect, ischaemia (steal phenomenon)

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6
Q

What is the rupture rate for an AVM?

A

2-4% unless there are high-risk features such as flow aneurysms where the risk rises to 8%. Rupture risk is higher if purely deep drainage and prior haemorrhage.

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7
Q

How do you calculate the culmulative risk of haemorrhage?

A

= 1 - annual risk bleed ^ expected years left to live or = 105 - age in years (assuming a 3% annual rupture rate)

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8
Q

What is the Spetzler-Martin grade for AVMs?

A

Size (<3 = 1, 3-6 = 2 and >6 cm =3) Deep venous drainage (Yes =1) Eloquent (Yes =1)

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9
Q

What is the Lawton-Young supplementary grade for AVMs? (ABC)

A

Age (<20y=1, 20-40y=2, >40y=3) Bleed (No =1) Compact/Diffuse nidus (Diffuse =1)

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10
Q

What are the findings of the ARUBA (A Randomized trial of Unruptured Brain AVM) trial?

A

By 5 years the risk of any intervention is (surgery, SRS, embolization or a combination) greater than conservative management. Problem with ARUBA is that the follow up is too short.

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11
Q

What is the role for SRS in AVM management?

A

Small <3 cm Deep Down-staging

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12
Q

What is normal perfusion pressure breakthrough?

A

Swelling and haemorrhage after AVM resection due to loss of autoregulation.

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13
Q

What are developmental venous anomalies associated with?

A

Cavernomas (so do a GRE or SWI)

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14
Q

What is the characteristic finding of a cavernoma on MRI?

A

Popcorn lesion

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15
Q

What do cavernomas look like histologically?

A

Sharp demarcation from neuropil. Large blood filled vascular spaces separated by connective tissue. Haemosiderin ring. May calcify.

Stains for vWF. No smooth muscle. Electron microscopy shows abnormal endothelial tight junctions.

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16
Q

What is a risk factor for developing cavernomas?

A

Radiotherapy

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17
Q

What is the inheritance of genetic cavernomas?

A

Dominant.

CCM1 = hispanics KRIT1 mutation

CCM2 = Malcavernin gene

CCM3 = PDCD10. For 3 new cavernomas per year.

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18
Q

How do you define a haemorrhage from a cavernoma?

A

Angioma alliance definition:

Acute or subacute symptoms (headache, seizure, impaired conciousness or worsening neurological deficit) with radiological evidence of haemorrhage. An increase in size is not part of the defintion.

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19
Q

What is the risk of cavernoma rupture?

A

0.1-2% annual rupture rate for incidental cavernomas

Risk of bleeding increased x5 if previous bleed and x4 if brainstem location.

5% annual risk in familial cases.

5% 5 year risk of seizures

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20
Q

When should you operate on a brainstem cavernoma?

A

After a second bleed

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21
Q

What is the evidence for SRS for cavernomas?

A

Can be considered for deep inaccessible lesions but on real evidence. Some suggestion that it reduces haemorrhage risk after 2-3 years.

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22
Q

What are dural AV fistulas?

A

Where the vascular fistula is contained within the dura. Unlike AVMs these are considered to be acquired not congenital. Usually found adjacent to venous sinuses (most commonly the transverse/sigmoid). Thought to be secondary to venous thrombosis.

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23
Q

What is the most common presenting feature of dural AVF?

A

Pulsatile tinnitus > occiptial bruit > headache > visual impairment / papilledema

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24
Q

Why do dAVFs bleed?

A

Cortical venous reflux / hypertension

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25
Q

What type of DSA is needed to evaluate a dAVF?

A

6 vessel

26
Q

What is the Borden classification?

A

1 - dAVF drains into sinus with normal antegrade flow

2 - dAVF drains into sinus but also has retrograde flow into cortical vein

3 - dAVF drains into cortical vein causing venous hypertension

27
Q

What is the Cognard classification?

A

Used more for transverse-sigmoid dAVFs:

1 - dAVF flows into sinus with normal antegrade flow

2a - dAVF flows into sinus with normal antegrade flow but also has retrograde flow within the sinus (20% haem risk)

2b - dAVF flows into sinus with normal antegrade flow but also has retrograde flow into cortical vein (10% haem risk)

2a+b - combination of above (66% haem risk)

3 - direct drainage into cortical vein only without venous ectasia (40% haem risk)

4 - direct drainage into cortical vein only with venous ectasia (65% haem risk)

5- drainage into spinal perimedullary veins (50% risk of venous congestive myelopathy)

28
Q

Which dAVF locations are through to have more aggressive behaviour?

A

Tentorial > Sylvian > Ethmoidal

29
Q

When should you treat a dAVF?

A

Cortical venous drainage

Neurological deficit

Bleed

Orbital venous congestion

Refractory headache / pulsatile tinnitus

30
Q

What are the treatment options for dAVFs?

A

Manual carotid compression (with the hand on the side of the compression). 10 minutes a day and then increase.

Endovascular embolization. Transarterial (onyx) or transvenous (coils).

Surgery by ligation of the fistula point with outflow vein. Surgery best for ethmoidal and tentorial dAVFs.

31
Q

When do vein of galen malformations form?

A

<3 months embyro.

These are fed from medial and lateral post. choroidal, anterior choroidal, pericallosal, mesencephalic and meningeal arteries.

32
Q

How do vein of galen malformations present?

A

Congestive heart failure in the first few weeks of life and a cranial bruit.

Hydrocephalus may be from aqueduct compression or increased venous pressures.

33
Q

How are vein of galen malformations treated?

A

Endovascular embolisation - arterial access is through the umbilical artery or femoral puncture. Cyanoacrylate glue is used to target the shunt in a staged fashion.

34
Q

What are the types of carotico-cavernous fisutal?

A

Type A = Direct (from ICA)

Type B = Indirect (from meningeal branches)

35
Q

What is the classical triad of presentation of a CCF?

A

Chemosis / pulsatle proptosis and ocular bruit

36
Q

What drain becomes engorged with CCFs?

A

Superior opthalmic vein

37
Q

How do you treat CCFs?

A

25-50% of low flow CCFs thrombose so observe if vision is not at risk. Try carotid compression.

High flow CCFs need embolisation - transarterial with coils deployed at the fistulas point through the ICA or transvenous through the superior ophthalmic vein (entered via the supraorbital vein through an eyebrow incision).

38
Q

What demographic are predominantly affected by FMD?

A

Middle-aged women (cervical ICA 75%) and bilateral 60%

Classic ‘string of beads’ appearance

39
Q

What investigation would you perform for a young patient with a spontaneous SDH?

A

CT angiogram to rule out PCom aneurysm

40
Q

What proportion of perimesencephalic haemorrhages are actually due to an aneurysm?

A

4%

41
Q

In which direction do superior hypophyseal arteries point?

A

Medially under the optic nerve toward the sella

42
Q

Where do ACom perforators supply?

A

Fornix, corpus callosum and septal region

43
Q

What can Heubner occlusion cause?

A

Hemiparesis or aphasia

44
Q

What is the management of a rupture during coiling?

A

Stop the bleeding by packing with coils if possible

Check pupillary reflexes and perform CT head

Insertion of external ventricular drain if required

Clinical reassessment regarding need for surgical intervention

45
Q

How does the basilar artery form embryologically?

A

From the union of paired longitudinal neural arteries that fuse at 5th week of gestation. Failed fusion may result in duplicate basilar arteries or a fenestration.

46
Q

What CN palsy is associated with large SCA aneurysms?

A

CN3

47
Q

Why do traumatic dissecting aneurysms form at the P2/3 junction?

A

As this is where the PCA crosses the tentorium resulting in trauma to the vessel and subsequent pseudoaneuryms formation

48
Q

What mutation is responsible for AD polycystic kidney disease?

A

PKD1 on Ch16

49
Q

Which gene is mutated in Marfan’s disease?

A

Fibrillin-1 (Ch15)

50
Q

Which gene is mutated in Ehlers-Danlos syndrome?

A

Multiple mutations including COL5A, COL3A and COL1A

51
Q

What is the NNT for malignant MCA decompressive hemicraniectomy?

A

4 to survive with a mRS of 3 or less

52
Q

What scleral vessels are seen with CCFs?

A

Corkscrew scleral vessels

53
Q

What are the features of Wallenberg’s syndrome?

A

Ipsilateral sensory loss to the face (spinal trigeminal nucleus damage)

Ipsilateral Horner’s (hypothalamo-spinal tract fibres)

Ipsilateral ataxia (Inf cerebellar peduncle / vestibular nuclei)

Contralateral fine touch loss (gracile / cuneate nuclei)

Loss of gag reflex (nuc ambiguus and solitary nucleus)

Contralateral hemibody loss of pain and temperature (spinothalamic tract)

54
Q

What is Dejerine Roussy syndrome?

A

Thalamic stroke resulting in contralateral body pain and hemisensory loss

55
Q

What is Balint syndrome?

A

Optic ataxia resulting in loss of voluntary but not reflex eye movements. Due to bilateral parieto-occipital injury (Bilateral P2 strokes)

56
Q

What is top of the basilar syndrome?

A

Opthalmoplegia

Behavioural abnormalities

Somnolence / hallucinations

No motor defect.

Due to Bilateral rostral midbrain and posterior thalamus damage

57
Q

What did the Japanese moya moya trial show?

A

Compared EC-IC bypass to conservative management for Moya Moya disease. Surgery reduces the risk of rebleed and stroke / haemorrhage at 5 years

58
Q

Label the skull base triangles

A
  1. Oculomotor triangle
  2. Opticocarotid triangle
  3. Supratrochlear triangle
  4. Infratrochlear triange (Parkinson’s triangle for access to the intracavernous ICA)
  5. Anteromedial triangle (Mullan’s triangle) between V1/V2
  6. Anterolateral triangle between V2/3
  7. Posterior lateral triangle (Glassock’s) Lateral to V3 - access to petrous cavernous ICA
  8. Posterior medial triange (Kawase) - access to anterolateral brainstem
  9. Inferior lateral - access to Meckel’s case
  10. Inferior medial - access to Dorello’s canal
59
Q

What are the STICH trials?

A

STICH1 randomized all ICHs >2cm with GCS>5 to surgery or conservative management where there was equipoise. No difference in outcomes but suggestion that superficial haematomas do better.

STICH2 randomised superficial ICHs <1cm from cortex with volume 10-100ml. No difference in outcomes. Suggestions that early surgery may be better if GCS9-12.

60
Q

How was the WFNS SAH grading scale derived?

A

From expert opinion based on the results of the Cooperative Aneurysm study in 1988.

The most important predictor of death of disability was the level of consciousness.

The most important predictor of disability was hemiparesis or aphasia.

WFNS grading is a good predictor of outcome with an unfavourable outcome at 3 months in 13% of Grade 1s and 66% of Grade 5s.

61
Q

What was the intention of the Hunt and Hess grading scale (1968)

A

To guide the timing of aneurysm clipping based on surgical risk. They found meningeal reaction alone (confusion) increases surgical risk.

1 = Minimal headache

2 = Severe headache, nuchal rigidity or cranial palsy

3 = confusion / drowsy

4 = Stupor / hemiparesis / decerebrate

5 = Deep coma / decorticate

*Add one point for severe comorbidity

Paediatrics (13 decks)

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