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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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2.3.2.1 PHACE or PHACES
These are acronyms for a syndrome of variable phenotypic expression
comprising posterior fossa malformations, facial hemangiomas, arterial
anomalies, coarctation and other cardiac disorders, eye abnormalities,
and stenotic arterial disease; many of the elements of this disorder could
reflect an underlying abnormality of cell proliferation and apoptosis (see
Chap. 12, this volume) (Bhattacharya et al. 2001).
2.3.2.2 Diffuse Angiodysplasia
Diffuse angiodysplasia was reported in neonates by Hasper (1983) and
Flower (1972): it is characterized by glomeruloid hypertrophy of perithelial and endothelial cells and can be associated with hydranencephaly
and hydrocephalus. Schmitt (1984) reported possible cytomegalovirus
transplacental transmission in one infant, while Flament-Durand (1981)
identified an associated adenovirus type 4 infection.
In children and young adults, proliferative and angioectatic diseases
are frequently triggered by spontaneous or traumatic dissections, viral
infections, immune phenomena, and other causes. Moyamoya disease,
moyamoya-like syndromes, and proliferative angiopathy in children are
the most typical disorders in this group (Figs. 2.18, 2.19). They combine
neoangiogenesis (production of lumen) and angiectasia (production of
vessel wall), which may be difficult to differentiate; however, in such instances there is a discrepancy between the apparent size of the nidus-like
network of vessels and the draining veins that are often normal or slightly enlarged. In angiectasia, the architecture of the nidus is homogeneous
and appears normal, while it is unpredictable in angiogenesis. The rapid
venous filling is usually due to a faster capillary transit time and seldom
caused by true AV shunts in capillarectasia (in some DVAs for example).
The evolution of these proliferative diseases is unpredictable (see
Chap. 18,this volume).Hemorrhagic angiopathy is another entity that we
encounter in some rare cases of intracerebral hematomas in children.
Most often after the age of 5 they correspond to a network of intracerebral subcortical arterioles with normal morphological and sequential
venous drainage. They may rehemorrhage and can therefore be partially
embolized when the area of weakness in the angioarchitecture can be
identified; if it is not possible to identify such a target, one may consider
radiosurgery. The response to radiation therapy is amazingly rapid and
effective (Fig. 2.4).
Even this approach to vascular lesions is too static,since not all malformations are seen at the same age and are invariably not seen at the beginning of their development.The age of a given lesion is therefore unknown
(Scheme 2.4). They often represent significant anatomic differences and
yet are usually discussed as a group, thereby creating confusing statistical
population projections.They are thought to be congenital,which has never been proven,and are believed to be essentially stable in size.Our experience contradicts both statements. Over time, certain CAVMs may appear to increase in size, while others spontaneously thrombose without
51Diffuse Angiodysplasia
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts52
Fig. 2.18A–D. Legend see p. 53
symptoms. However, one never sees a micro-AVM becoming a large one
or a nidus arranged AVM becoming a fistulous lesion.Whenever it is possible to compare high-quality angiographic studies 10 years apart, amazing changes in the vasculature can be observed. These changes are less
spectacular in adults, where the vascular plasticity does not cover the
same range of possibilities as in children and therefore does not show the
same degree of variability. This introduces two new approaches to the
problem of CAVMs in children: the aspect of age and symptoms vs the
impact of vascular remodeling in the congenital concept of CAVM. The
fact that the remodeling is the same during the perinatal period as in infants and children is probably only a gross approximation and not completely correct.
53Diffuse Angiodysplasia
Fig. 2.18A–F. A 12-year-old boy presented at the age of 1 month with a generalized
seizure. A–C MRI was performed. D–F A few months after additional seizures and
transient right-sided deficit,angiography shows a stenotic disease of the ICA anterior
division involving the A1 and M1 segments. There is intracerebral lenticulostriate
angiectasia and angiogenesis corresponding to the first stage of moyamoya disease.
The vertebral artery injection demonstrates the sparing of the posterior fossa arteries
▲
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts54
Fig. 2.19A–D. Legend see pp. 56
55Diffuse Angiodysplasia
Fig. 2.19E,F. Legend see p. 56
2.4 Classification of CAVMs by Age Group
In caring for children over time, one must consider the different phases of
their development. Depending on individual interests and experience,
one may wish to emphasize age,symptoms,or various diseases.However,
clinical practice forces us to constantly switch from one to the other to
establish the most accurate prognosis. To illustrate these various methods and their contributions to decision making, we will consider them
sequentially based on age group.
2.4.1 Fetal Age
Intrauterine antenatal ultrasound or MRI diagnosis of a large fetal intracranial mass as a pseudocystic, nonechogenic or poorly echogenic
spherical image, depending on its topography, illustrates either a VGAM
or a dural sinus malformation (DSM) (Fig. 2.20).In a few cases we made
a prenatal diagnosis of CAVM (Scheme 2.7). Despite all the possible features associated with each type of lesion involved (see the corresponding
chapters),we will concentrate on two abnormalities: macrocrania with or
without encephalomalacia and cardiac tolerance (Scheme2.8). With regard to the mother, there has not been any effect observed during pregnancy of a prenatal diagnosed intracranial AV shunt.We have not found
any trigger responsible for the occurrence of such a shunt at that time.
With regard to the fetal brain, macrocrania can be seen in both VGAM
and DSM, but it has opposing prognostic values. In VGAM, macrocrania
(in the absence of ventricular enlargement) is usually a benign obser-
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts56
Fig. 2.19A–G. A 15-year-old
girl presenting with generalized
seizures was diagnosed a proliferative angiopathy. A,B Note on
the MRI section the amount of
dilated vessel running at the
surface of the cortex. C–F Angiographically, there are several
cortical artery interruptions
with local „explosive“ angiectasia. Diffuse supra- and infratentorial transdural supply at the
base and the convexity testify to
the active angiogenic activity of
this disorder. G Despite medical
treatment,the patient died
4years after the diagnosis from
major ischemic stroke
Intracranial AV Shunt
in Children
Age Groups
Fetus es
Neonates (30 days)
Infants (<2 years)
Children (£15 years)
57Fetal Age
Fig. 2.20. Prenatal diagnosis
of vein of Galen. The baby
presented at birth with mild
cardiac overload and was
treated within the therapeutic
window at 5months of age
Scheme 2.7. Frequency of the
various types of intracranial
arteriovenous (AV) shunts in
children in relation to age
(M months,Y years) at diagnosis. VGAM, vein of Galen
aneurysmal malformation;
AVM, arteriovenous malformation
vation without a negative impact on the prognostic neonatal score
(Table 2.2). In contrast, macrocrania in DSM indicates an already active
sinus dysfunction with water and venous effect; if present, the prognosis,
which is already not good, would become even worse (see Chap. 7, this
volume). The only finding that has the same importance at that age of
diagnosis, regardless of the type of AV shunt, is the presence of encephalomalacia. In fact, even with MRI, it is often difficult to be certain
about the presence of brain damage in fetuses. This diagnosis is certainly
of major importance, since in our management strategy this discovery
may lead to therapeutic abortion. The presence of isolated cardiomegaly
has no impact on prognosis. Experience with DSM is limited because of
the rarity of the disease, but neonates with this malformation seldom present with major systemic symptoms in utero.On the other hand, cardiac
failure in fetuses with VGAM is known to have a poor prognosis. This
finding proved to be the only constant early predictive unfavorable factor
in our series, resulting in a low neonatal score and consequently in treatment being withheld.
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts58
Scheme 2.8. Physiopathological
mechanisms involved in the
clinical presentation of intracranial vascular malformations and arteriovenous
shunts in relation to age
groups.VGAM, vein of Galen
aneurysmal malformation
Ta ble 2.2. Frequency of symptoms revealing vascular malformations or arteriovenous shunts in neonates
VGAM Dural malformation Pial AVM
Systemic +++ + ++
Hydrodynamic +++ +++ +
Convulsive – ++ +++
Haemorrhagic – +++ ++
Neurological – + ++
VGAM,vein of Galen aneurysmal malformation; AVM, arteriovenous malformation;
+++, very frequent; ++,frequent; +,possible; –,not seen (or severe brain damage).
Frequency of Vascular Lesions
Per Age Group
In utero
1. Aneurysmal malformations
of the vein of Galen
2. Dural sinus malformation
3. Pial arteriovenous shunt
2.4.2 Neonatal Age
Not all lesions diagnosed (visible) in utero will become clinically eloquent at birth.When symptomatic, the clinical manifestations are usually the systemic effects of the high-flow lesion. Lack of treatment may
rapidly lead to multiorgan failure and a cerebral melting process within
days or weeks (see Sect. 2.5.3; Fig. 2.21). At that age, there is a fundamental difference between VGAM and non-Galenic AV malformations (pial).
Early neurological symptoms in VGAM are of major negative prognostic
value, to the extent that treatment may be withheld (Fig. 2.22). On the
other hand, similar symptoms are an indication for emergency management in non-Galenic AVSs. In VGAM in neonates, neurological manifestations such as convulsions indicate the anoxic insult to the brain.
VGAM drainage has no venodural resistance and immediately overloads the cardiac venous return, while it protects the cerebral hemodynamic circulation from retrograde pial vein congestion. VGAM venous
outflow is craniofugal without direct interference with the pial veins,and
such anoxic failure, when present, indicates rather diffuse and indirect
brain damage. This effect has usually already started in utero. These
symptoms are never isolated, but indicate the presence of a severe systemic syndrome, which, in turn, should lead to the decision not to treat.
Conversely, a non-Galenic AV malformation in a patient presenting with
a convulsive episode indicates focal, yet early damage in relation to subpial damage of the shunt.Ischemia of venous origin or focal hemorrhage
(hemorrhagic infarct) is the most frequent cause suggested to explain the
convulsion. It requires urgent treatment to avoid the melting-brain syndrome, which otherwise rapidly occurs in the following few weeks. In
non-Galenic lesions,these neurological signs are not consistently associated with cardiac manifestations. The systemic symptoms in neonatally
diagnosed CAVM are usually better tolerated than in VGAM, probably
because the venodural junction is relatively preserved and protects the
cardiac function. Hemorrhage in VGAM in this age group does not occur.
A hemorrhagic episode or convulsion in a neonate should steer one away
from the diagnosis of VGAM.
2.4.3 Infancy
Infancy is dominated by hydrovenous disorders. The water homeostatic
system of neonates is still immature, which results in the venous system
being responsible for the venous drainage and the intrinsic and extrinsic
cerebral water dynamics. The granulations are not functional yet, and
their maturation is likely to be delayed if increased pressure is present in
the dural sinuses. Separation of the circuits between cerebrospinal fluid
(CSF) from choroidal secretion and intrinsic water secreted by capillaries
in the Virchow Robin spaces does not take place.A specific and complex
gradient and equilibrium between the subpial and subependymal space
develops; in addition to the physiological link existing between the ventricle and subarachnoid spaces, a rich venous network is present in the
dura, adjacent to the future dural sinuses (see Chap. 7, this volume).
59Infancy
Frequency of Vascular Lesions
Per Age Group
Neonates
1. Aneurysmal malformation
of the vein of Galen
2. Dural sinus malformation
3. Pial arteriovenous shunt
4. Cavernoma
5. Arterial aneurysm
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts60
Fig. 2.21. A A female neonate presented a generalized convulsive episode leading to
MRI. The diagnosis made at that time was vein of Galen aneurysmal malformation
(double arrows) although a lateralized pouch was seen (single arrow); because of the
absence of systemic manifestations, the child was not treated. Two months later, the
child developed progressive macrocrania and had repeated seizures. B CT demonstrated bilateral venous infarction with focal deep-seated frontal hemorrhages. The
child was then treated successfully at another institution.One year later, the child became severely disabled.C MRI confirms complete exclusion of the malformation and
irreversible brain damage
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