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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3644_Библиотеки_им_академика_М_И_Перельмана
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to enlarge often allows giant pouches to be diagnosed with almost no
mass-related symptoms (Fig. 4.2). These huge pouches are therefore
rarely directly responsible for symptoms in children as the adjacent brain
is apparently capable of adapting to them. Neurological deficits and
seizure activity may occur in relationship to these pouches in some patients,and in our experience,this is nearly always associated with a spontaneous partial thrombosis of the pouch. MRI at this point demonstrates
an area of increased signal in the brain surrounding the pouch (Berenstein 1992a; Lee and terBrugge 2003). It is of interest to note that the
thrombosis of similar pouches induced by embolization does not produce the same perilesional changes, nor does it produce deficit or
seizures, as it also closes or reduces the flow through the AVF. These
pouches can increase in size over time subsequent to the development of
restriction of the downstream outlets.
4.2.2 Multiple CAVFs
AVFs can be single or multifocal if each fistulous communication harbors
a distinctly separate vein draining each fistulous point (Fig. 4.3). Multiplicity is a common feature of CAVFs in the pediatric age group and
should raise the suspicion of associated or systemic conditions (see
Sect. 4.3.1) (Fig.4.4).
231Multiple CAVFs
Fig. 4.2A–F. A 9-month-old boy presented with increasing head circumference and
mild developmental delay. MRI in coronal (A) and sagittal (B) views demonstrates
large area of flow void along medial aspect of left temporal occipital lobe.Vertebral
angiogram at 12 months of age in AP (C,D) and lateral (E,F) views demonstrates AVF
fed by several branches of the left posterior cerebral artery all converging in to a single draining vein,which was dramatically enlarged, causing mass effect
▲
4Cerebral Arteriovenous Fistulas232
Fig. 4.3A–D. Legend see p.233
233Multiple CAVFs
Fig. 4.3A–H. A 23-month-old boy initially presented with a generalized seizure at the
age of 1 year and subsequently developed headaches and left-sided weakness. T2W
MRI axial views (A, B) demonstrated multiple tortuous signal voids along the lateral
aspect of the right temporal lobe, which was atrophic and showed increased signal of
white matter.Angiography of right internal carotid artery on lateral views (C, D) and
left vertebral artery in AP (E) and lateral (F) views demonstrated seven arteriovenous
fistulas, each draining into separate dilated veins.G, H At 15 months of follow-up,the
morphological result was satisfactory but the child was severely handicapped
▲
Series and case reports of multifocal lesions and unusual associations
have been published (Reddy 1987; Rodesch et al. 1988; Schlater 1980;
Smith et al. 1981; Willinsky et al. 1990a; Tamaki et al. 1971; Tada et al.
1986; Zellem and Buchheit 1985; Hoffman et al. 1976). Among 52 pediatric patients with AVFs, 23 (45%) had multiple AVFs ranging from one to
seven per patient; three patients had both supra- and infratentorial locations of the AVFs and one patient also had a spinal cord location in Yoshida’s series (Yoshida et al.2004; Weon et al. 2005).
The number of multifocal lesions in children, in our experience, is
twice that of adults (17.2% vs 9%).Any variation of AV shunt can occur in
the same patient, but we often find the same type of architecture in all
sites in the same individual,i.e., multiple fistulas or multiple niduses.
Ta bles 4.1–4.3 summarize the characteristics of pediatric CAVFs in
We on and Yoshida’s experiments.
4Cerebral Arteriovenous Fistulas234
Fig. 4.4A,B. CAVF in a young adult.Note the flow-related aneurysm at the basilar tip
Ta ble 4.1. Incidence of CAVFs in children in comparison to overall intradural AVM
cases from Weon et al. 2005 and Yoshida et al. 2004): 52 CAVF children for 80 AVFs
Number %
To tal AV shunts referred (all ages) 52/1565 0.33%
To tal AV shunts in children (<16) 52/620 0.84%
Non-Galenic AVSs in children 52/303 17.2%
Posterior fossa AVMs in children 47/303 15.5%
Posterior fossa AVFs/posterior fossa AVMs in children 11/47 23.4%
Posterior fossa AVFs/AVFs in children 11/52 21.1%
Supratentorial AVMs in children 256/303 84.5%
Supratentorial AVFs/supratentorial AVMs in children 38/256 14.8%
Supratentorial AVFs/AVFs in children 38/52 73.1%
Posterior fossa + supratentorial AVFs/AVFs in children 3/52 0.06%
CAVF, cerebral arteriovenous fistula; AVS, arteriovenous shunt; AVM, arteriovenous
malformation.
235Multiple CAVFs
Ta ble 4.2a. Angioarchitectural features (supratentorial CAVFs) (Weon et al. 2005)
Angioarchitecture No.of cases (%)
Ve nous ectasia 36 (87.8%)
Pial venous stenosis or thrombosis 17 (41.5%)
Dural sinus stenosis or thrombosis 9 (21.9%)
Pial venous reflux 5 (12.2%)
Angiogenesis 5 (12.2%)
Tr ansdural supply 5 (12.2%)
Arterial stenosis 3 (7.3%)
False venous aneurysm 2 (4.9%)
Flow-related arterial aneurysm 2 (4.9%)
Ta ble 4.2b. Angiographic features (infratentorial CAVFs) (Yoshida et al. 2004)
Angioarchitecture No.of cases (%)
Ve nous ectasia 13 (93%)
Pial venous congestion 6
a
(46%)
Dural sinus thrombosis 6
a
(46%)
Pial venous stenosis 4 (31%)
Dural sinus stenosis 3 (23%)
False venous aneurysms 2 (15%)
Arterial stenosis 1 ( 8%)
Angiogenesis 1 ( 8%)
Arterial aneurysms 0
Tr ansdural supply 0
Tr ansependymal supply 0
Pial venous thrombosis 0
Multiple fistulae 5 (38%)
a
Two presented with hemorrhage.
Ta ble 4.3. To pography of the supratentorial AVFs
a
(Weon et al. 2005)
Frontal lobe Temporal lobe Occipital lobe Parietal lobe
Single (24/24 cases) 16 (25.4%) 7 (11.1%) 1 (1.6%)
Multiple (39/17 cases) 7
a
(11.1%) 15a(23.8%) 9 (14.3%) 8a(12.7%)
To t al (63
b, c
/41 cases) 23 (36.5%) 22 (35.4%) 10 (15.9%) 8 (12.7%)
a
Three cases had an additional associated infratentorial AVF not included in this total number.
b
One had two additional parietal AVFs; one had an additional temporal AVF, and one had additional frontal AVF.
c
There were two multiple lesions associating large AVFs with separate or closely related micro-AVMs.
These micro-AVMs are not included in this total number.
4.3 Associated Conditions
4.3.1 Hereditary Hemorrhagic Telangiectasia
Hereditary hemorrhagic telangiectasia (HHT) (previously called RenduOsler-Weber Disease) is a rare autosomal disorder,characterized by multiple mucocutaneous and visceral telangiectasias (Fig. 4.5),giving rise to
hemorrhagic complications in adulthood (MacAllister et al.1994).
Although autosomal dominant (chromosome 9q33-q34, long arm, the
locus is named HHT1, a second genotype is located on chromosome
12q), HHT exhibits a cellular recessive pathology and requires inactivation of the normal allele as the initiating event in the formation of a vascular lesion.Alternatively,the initiating event in the formation of a vascular lesion might be damage to the vessel wall with associated failure to remodel normally.
4Cerebral Arteriovenous Fistulas236
Fig. 4.5A–C. Usual appearance of skin lesions in hereditary hemorrhagic telangiectasia (HHT)
237Hereditary Hemorrhagic Telangiectasia
Fig. 4.6. A Diagrammatic representation of the progression of HHT in a given patient, which shows the acute changes observed following hormonal events. B Similar
approach for a patient with slowly progressive worsening of symptoms not obviously
related to hormonal events. Note the repeated embolization sessions needed in this
particular case.M, packing; R, radiation;C, electrocoagulation;T, transfusion;D, dermoplasty; E, embolization. Stage 1: episodic but spontaneously resolved bleeding
requiring no specific treatment and often neglected by the patient. Stage 2: periodic
bleeding sometimes following mechanical trauma (sneezing, blowing nose) requiring
no more than one hospitalization per year and/or one blood transfusion, permitting
normal professional life. Stage 3: frequent spontaneous bleeding requiring multiple
hospitalizations and transfusions per year with incapacitation
Recent careful epidemiological studies in France,Denmark, andJapan,
however, have revealed an incidence of 1 in 5,000–10,000 (Bideau et al.
1989; Kjeldsen et al. 1999; Dakeishi et al. 2002).The incidence was previously reported at 1 or 2 in 100,000 (Guttmacher et al.1995). Three mutations altering the synthesis of endoglin have been found in affected individuals, one substitution (CÆG: TAG code) and two deletions (nucleotide 882 and nucleotide 1553). Endoglin is a homodimeric integral
membrane glycoprotein expressed on human endothelial cells of capillaries, arterioles, and venules. The earliest event in the formation of
telangiectasias appears to be dilatation of postcapillary venules. Endothelial cells lacking endoglin respond poorly to transforming growth
factor-b1 (TGF-b1) and form abnormal vessels, particularly in response
to injury. Endoglin is the most abundant TGF-b-binding protein. TGF-b
in vivo is a potent angiogenic factor and a mediator of vascular remodeling, as it controls extracellular matrix production by endothelial cells,
smooth muscle cells, and pericytes. TGF-b is the prototype of a family of
at least 25 growth factors that regulate growth, differentiation, motility,
tissue remodeling, normal repair, and programmed cell death in many
cell types. The locus heterogeneity in this disorder may be due to mutations within other members of the TGF-b receptor complex or other en-
dothelial cell components of the TGF-b signal transduction pathway.
One could question whether the deficiency or immaturity of a similar
protein fraction in non-HHT patients could cause the same type of AVM.
We have never observed a new CNS AVF in follow-up of HHT patients
and have rarely seen high-flow AVFs in adult HHT patients. This suggests
that the inherited protein deficiency expresses itself only in AVF at an
early age and differently later due to the various maturation processes involved and compensatory mechanisms.
Recurrent epistaxis, hemoptysis, melena, and genital bleeding are not
uncommon manifestations in adults with HHT, but are rare in children
(Aasar 1991; Boynton and Morgan 1973; Lasjaunias 1987; Willinsky et al.
1990a; Mahadevan et al. 2004b). Mucocutaneous telangiectasias and visceral hemorrhagic complications are unusual in children; cerebral or
spinal AVM may be the sole manifestation of HHT at this age.Our observations correlate well with the literature, in which telangiectasias and
mucosal hemorrhagic complications increase in frequency with age in
patients with HHT (Fig. 4.6) (Table 4.4). In HHT patients, CNS AV mal-
4Cerebral Arteriovenous Fistulas238
Ta ble 4.4. HHT criteria (Mahadevan et al. 2004b)
Adult Children Total
Epistaxis 10 (90.9%) 13 (56.5%) 23 (67.6%)
FH of epistaxis 8 (72.7%) 17 (73.9%) 25 (73.5%)
Cutaneous lesions 8 (72.7%) 6 (26.1%) 14 (41.2%)
F/H of cutaneous angioma 2 (18.2%) 5 (21.7%) 6 (17.7%)
Hepatic lesion 1 (9.1%) 1 (4.3%) 2 (5.9%)
Gastric lesion 5 (45.5%) 0 (0%) 5 (14.7%)
Pulmonary lesion 5 (45.5%) 3 (13.0%) 8 (23.5%)
Family history of HHT (F/H) 11 (100%) 18 (78.3%) 29 (85.3%)
FH, family history.
239Hereditary Hemorrhagic Telangiectasia
Fig. 4.7A–D. A 3-year-old child presented with a generalized seizure.A family history of epistaxis suggested the diagnosis of HHT. Internal carotid (A, B) and selective
anterior cerebral angiogram (C) on lateral views demonstrated single-hole AVF with
drainage toward the inferior sagittal sinus.Vertebral angiogram on AP view (D) disclosed a second AVF at the posterior fossa level
formations conform to the usual AVF and AVM types (Boynton and Morgan 1973; Reddy 1987; Roman et al. 1978) and should be distinguished
from telangiectasias. This suggests that AVMs represent either an associated lesion or the early expression of the capillary-remodeling disorder
in HHT. AVMs of the CNS are present in approximately 8% of patients
with HHT (Reddy 1987). Multiplicity increases this likelihood significantly and Willinsky et al. (1990a) reported that 28% of patients with
multiple CNS AV malformations had HHT (Fig. 4.7). Identification of
multiple CAVMs should therefore lead one to suspect the possibility of
HHT disorder. Garcia Monaco et al. (1995) reported five cases in which a
CAVF was the initial manifestation of HHT disorder among 120 children
with CAVMs. None of the children had mucocutaneous telangiectasias at
clinical examination, but all of them had a strong family history of HHT.
None of the children complained of a subjective bruit (pulsatile tinnitus),
although an objective cranial bruit was perceived by auscultation in three
of them, suggesting that the AVF was present at birth or shortly thereafter. In two patients, the main symptoms were related to AVF rupture,
but in three patients venous ischemic and congestive manifestations were
found. All patients seen with HHT had one or several single-hole
AVFs with a large venous ectasia; two of them also had a small nidus type
of lesion demonstrated during the four-vessel work-up. No patients
showed focal melting-brain syndrome,indicating the rapid subarachnoid
drainage of the AVF and suggesting an explanation for the consistency of
the venous pouches reported.
More recently,Mahadevan et al. (2004b) reviewed the Bicêtre experience and noted that among 620 children with CAVM there were 23 (3.7%)
patients with HHT disorder (Table 4.5). Significant differences in the
4Cerebral Arteriovenous Fistulas240
Ta ble 4.5. CAVM population reviewed (Mahadevan et al. 2004b)
Number No. and % of HHT
To tal CAVM 1,566 34 (2.2%)
To tal CAVM in adults 946 11 (1.2%)
Non-Galenic CAVM in children 303 23 (7.6%)
To tal SCAVM 194 5 (2.6%)
SCAVM Spinal cord arteries venous malformation.
Ta ble 4.6. Presenting symptom that led to diagnosis (Mahadevan et al.2004b)
Adult Pediatric Total
Epilepsy 2 (18.2%) 4 (17.4%) 6 (17.6%)
Headache 2 (18.2%) 3 (13.0%) 5 (14.7%)
Deficit without ICH 0 (0%) 4 (17.4%) 4 (11.8%)
Cardiac Insufficiency 0 (0%) 4 (17.4%) 4 (11.8%)
Deficit with ICH 0 (0%) 3 (13.0%) 3 (8.8%)
Macrocrania 0 (0%) 3 (13.0%) 3 (8.8%)
Incidental/prenatal 7 (63.6%) 2 (8.7%) 9 (26.5%)
To tal number of cases 11 (32.4%) 23 (67.6%) 34 (100%)
ICH, intracerebral hemorrhage.
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