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Megalencephaly secondary to occlusion and stenosis of sigmoid sinuses
Megalencephaly Secondary to Occlusion and Stenosis of Sigmoid Sinuses Dinesh Talwar, MD*t, Michael J. Schwartzman, DOt, and Robert E. McGeachie, MD~
Bilateral, idiopathic, essentially asymptomatic but hemodynamically significant stenosis or occlusion of the sigmoid sinuses is extremely rare. We report a child with the angiographic features of occlusion of the right sigmoid sinus and severe stenosis on the contralateral side, presenting with megalencephaly and a cranial bruit. Cranial computed tomographic scans demonstrated increased subarachnoid spaces and borderline ventricular enlargement. Talwar D, Schwartzman MJ, McGeachie RE. Megalencephaly secondary to occlusion and stenosis of sigmoid sinuses. Pediatr Neurol 1990;6:51-3.
Introduction With antibiotic therapy and prompt management of precipitating factors, the incidence of dural sinus and venous thromboses has declined. Nevertheless, in patients at risk, these thromboses may be accompanied by prominent neurologic symptoms and signs, sequelae, and death. Asymptomatic or mildly symptomatic bilateral thrombosis, occlusion, or absence of sigmoid sinuses rarely has been reported [ 1,2] and clinical presentation has been inadequately explained. We report a child with severe, hemodynamically significant stenosis of the left sigmoid sinus and occlusion of the contralateral homologous dural sinus on angiography, who manifested insignificant symptoms. Clinical evaluation demonstrated megalencephaly, cranial bruit, and radiologically increased subarachnoid spaces and borderline ventricular enlargement. Clini-
From the *Division of Pediatric Neurology, tDepartment of Neurology; *Department of Diagnostic Radiology; University of Minnesota Medical School; Minneapolis, Minnesota.
cal and radiologic features were similar to "external hydrocephalus" [3].
Case Report This 3-year-old male presented with an unusual feeling of vibration behind the left ear which had been palpated by the mother for approximately 1 year; the patient had experienced discomfort in that area for 2 weeks and left-sided neck pain. A large head was noted soon after birth, although precise onset and progression of abnormal enlargement could not be ascertained due to lack of objective measurements. Pregnancy and delivery were uncomplicated; developmental milestones were normal. There were no recurrent ear infections or mastoiditis. On physical examination, weight was 14.4 kg (25th percentile), length 93 cm (25th percentile), and occipitofruntal circumference (OFC) 54.5 cm (> 98th percentile). At 24 months of age, OFC was 53.4 cm (> 98th percentile). His head was dolichocephalic and disproportionately large; prominent, tortuous scalp veins were observed in the left temporal region and eyelid. A thrill was palpated and a loud cranial bruit heard behind the left ear. A grade 2/6 ejection systolic murmur was auscultated at the lower left sternal border. Denver Developmental Screening Test demonstrated appropriate achievement of milestones for a 3-year-old. Routine laboratory urine and blood studies, coagulation parameters, M-Mode, and 2-D echocardiograms of the heart, and 12-lead electrocardiography were normal. Enhanced and unenhanced cranial computed tomographic (CT) scans demonstrated a borderline increase in the size of the ventricles and moderately increased subarachnoid spaces, predominantly in the frontal and superior parietal areas (Fig 1). Focal left occipital bone erosion adjacent to the sigmoid sinus and a large left sigmoid sinus were visualized. The right sigmoid sinus could not be identified. Temporal bone aeration was normal. No arteriovenous malformation was observed on the enhanced study. Skull radiography revealed widening of the coronal sutures. A neuro-ophthalmologic consultant found dilated tortuous intraocular and lid veins greater in the left eye, but no papilledema. Four-vessel cerebral angiography demonstrated normal arterial structures and poor filling of the jugular veins with collateral circulation to the veins on the spinal cord and in the cervical epidural space. There was minimal filling of the right internal jugular vein. The right proximal sigmoid sinus was occluded just below the level of the tentorium (Fig 2). The left sigmoid sinus was extremely stenotic just before entry into the jugular foramen (Fig 2). Large transcranial collateral emissary veins arose from the left sigmoid sinus and caused focal bony erosion. Subsequent examination at 38 months of age revealed an OFC of 54.5 cm; at 40 months, 55 cm; and at 49 months, 55.2 cm. At age 38 months, cranial magnetic resonance imaging confirmed CT findings and did not demonstrate transependymal cerebrospinal fluid (CSF) migration.
Discussion Prior to the antibiotic era, sigmoid sinus thrombosis was very common, particularly in children with otitis media, and contributed to many deaths. In early series, sinus thrombosis mortality rates were as high as 34% [4]; with current therapy, the incidence, mortality, and morbidity have declined [1]. Dural sinus and venous thromboses are related to alterations in blood constituents, vessel wall, or blood flow.
Communications should be addressed to: Dr. Talwar; Box 486; Division of Pediatric Neurology; University of Minnesota Hospitals; 420 Delaware Street SE; Minneapolis, MN 55455. Received September 6, 1989; accepted November 13, 1989.
Talwar et al: Sigmoid Sinus Occlusion
51
A
B
Figure 1. Contrast-enhanced cranial CT demonstrating (A) borderline ventrieular size, prominent venous struetures, and increased .f~'ontoparietal subaraehnoid spaces and (B ) diffusely prominent subaraehnoid spaces.
Although it may not be identified, a causative or precipitating factor may occur in children secondary to cyanotic congenital heart disease, infections, hematologic disorders, dehydration and hyperpyrexia, neoplasms, and trauma [1,4]; however, unexplained bilateral occlusion or absence of the sigmoid sinuses is very rare. One patient was reported in an extensive review [1]. In a later report, a child with idiopathic bilateral occlusion of the sigmoid sinuses, with clinical features similar to our patient (i.e., macrocephaly, dilated scalp veins, and mild ventriculomegaly) was described [2]. Unilateral absence or occlusion of the sigmoid sinus has been reported more frequently [1,4] and may result in significant manifestations when the preponderant transverse or sigmoid sinus is occluded. In our patient, there were no identifiable predisposing factors; the onset of sigmoid sinus pathology could not be discerned. The presenting symptoms were related to turbulent blood flow through the stenotic sigmoid sinus and collateral veins. Clinical and radiologic evaluation demonstrated megalencephaly, prominent subarachnoid spaces, and only borderline ventriculomegaly. There was no evidence of developmental delay, significant neurologic symptoms or signs, frank communicating hydrocephalus despite the large head size, or increased intracranial pressure (ICP). Clinical and radiologic features of our patient are similar to those observed in "external hydrocephalus," an entity characterized by macrocephaly, increased subarachnoid spaces in the frontoparietal region, widened frontal interhemispheric fissure, and occasionally mild ventriculo-
52 PEDIATRICNEUROLOGY Vol.6 No. 1
megaly. It occurs in children born prematurely, after diffuse CNS insults, in certain syndromes associated usually with macrocephaly, but is usually idiopathic [3]. Our patient's cranial CT exhibited some diffuse increase in subarachnoid spaces, in addition to the localized frontoparietal increase in subarachnoid spaces reported in "external hydrocephalus." Because of the large head and brain size, the diffuse increase in subarachnoid spaces cannot be characterized as "atrophy." There have been no prior reports of CT findings of bilateral sigmoid sinus occlusion. The pathophysiology of the clinical signs and radiologic features of our patient are not known. Hydrocephalus, with enlarged ventricles, can be produced by ligation of the jugular veins in experimental animals [5] and is described with increased intracranial venous pressure in children [6,7]. Pseudotumor cerebri may also occur following venous outflow obstruction [8,9]. Although it is not completely understood, the pathogenesis of pseudotumor probably occurs secondary to CSF outflow disturbance [9,10]; however, despite significant venous outflow obstruction, our patient did not develop frank communicating hydrocephalus or pseudotumor. On the contrary, the presentation was megalencephaly. We postulate that the radiologic features and megalencephaly were partly caused by venous engorgement and increased blood volume in the brain, impaired CSF absorption, and elevated venous pressure secondary to an almost complete obstruction of the venous outflow which occurred congenitally or soon after birth. The compliance of the skull due to open cranial sutures during infancy may prevent the development of increased
pressure may cause cerebral, ventricular, or subarachnoid space enlargement, or only an increase in intracranial pressure, depending on the compliance of the brain and skull and the time course of venous occlusion. We believe that such cases probably are very rare. Dural sinus occlusion and stenosis, however, should be considered in children with asymmetric cranial bruits. Significant venous outflow obstruction should be considered in children presenting with megalencephaly with or without classic EH in the absence of another etiology.
References
Figure 2. Angiogram, oblique view, right common carotid injection, digital subtraction technique. Arterial structures are shown in white as a result of the subtraction process. Solid curved arrow: occluded proximal right sigmoid sinus; open curved arrow: stenotic left sigmoid sinus just before entry into jugular fossa; straight arrow: extracranial collateral veins.
intracranial pressure or communicating hydrocephalus and allow the skull size to increase. In some young children, this compliance may support the development of"extemal hydrocephalus" [11]. Mechanisms leading to megalencephaly with or without classic "external hydrocephalus" versus a communicating hydrocephalus are not known and may be related to multiple factors, such as the degree of direct arachnoid granulation involvement or rate of collateral circulation development. Despite poor understanding of the underlying mechanisms, increased venous
[1] Kalbag RM, Woolf AL. Cerebral venous thrombosis: With special reference to primary asceptic thrombosis. London: Oxford University Press, 1967;1-280. [2] Smith KR Jr. Idiopathic bilateral sigmoid sinus occlusion. Neurosurgery 1968;29:427-30. [3] Maytal J, Alvarez LA, Elkin CM, Shinnar S. External hydrocephalus: Radiologic spectrum and differentiation from cerebral atrophy. AJNR 1987;8:271-8. [4] Krayanbuhl HA. Cerebral venous and sinus thrombosis. Clin Neurosurg 1966; 14:1-24. [5] Bering EZ Jr, Salibi B. Production of hydrocephalus by increased cephalic-venous pressure. Arch Neurol Psychiatry 1959;81: 693-8. [6] Rosman NP, Shands KN. Hydrocephalus caused by increased intracranial venous pressure: A clinicopathologic study. Ann Neurol 1978;3:445-50. [7] Stewart DR, Johnson DG, Myers GG. Hydrocephalus as a complication of jugular catheterization during total parenteral nutrition. J Pediatr Surg 1975;10:771-7. [8] Greer M. Management of benign intracranial hypertension. Clin Neurosurg 1967;15:161-74. [9] Gjerris E Soelberg S0rensen P, Vorstrup S, Paulson BB. Intracranial pressure, conductance to cerebrospinal outflow, and cerebral blood flow in patients with benign intracranial hypertension (pseudotumor cerebri). Ann Neurol 1985; 17:158-62. ll0] Fishman RA. The pathophysiology of pseudotumor cerebri: An unsolved puzzle. Arch Neurol 1984;41:257-8. [11] Chapman PH. External hydrocephalus. Concepts. Pediatr Neurosurg 1983;4:102-18.
Talwar et al: Sigmoid Sinus Occlusion
53
Bilateral, idiopathic, essentially asymptomatic but hemodynamically significant stenosis or occlusion of the sigmoid sinuses is extremely rare. We report a child with the angiographic features of occlusion of the right sigmoid sinus and severe stenosis on the contralateral side, presenting with megalencephaly and a cranial bruit. Cranial computed tomographic scans demonstrated increased subarachnoid spaces and borderline ventricular enlargement. Talwar D, Schwartzman MJ, McGeachie RE. Megalencephaly secondary to occlusion and stenosis of sigmoid sinuses. Pediatr Neurol 1990;6:51-3.
Introduction With antibiotic therapy and prompt management of precipitating factors, the incidence of dural sinus and venous thromboses has declined. Nevertheless, in patients at risk, these thromboses may be accompanied by prominent neurologic symptoms and signs, sequelae, and death. Asymptomatic or mildly symptomatic bilateral thrombosis, occlusion, or absence of sigmoid sinuses rarely has been reported [ 1,2] and clinical presentation has been inadequately explained. We report a child with severe, hemodynamically significant stenosis of the left sigmoid sinus and occlusion of the contralateral homologous dural sinus on angiography, who manifested insignificant symptoms. Clinical evaluation demonstrated megalencephaly, cranial bruit, and radiologically increased subarachnoid spaces and borderline ventricular enlargement. Clini-
From the *Division of Pediatric Neurology, tDepartment of Neurology; *Department of Diagnostic Radiology; University of Minnesota Medical School; Minneapolis, Minnesota.
cal and radiologic features were similar to "external hydrocephalus" [3].
Case Report This 3-year-old male presented with an unusual feeling of vibration behind the left ear which had been palpated by the mother for approximately 1 year; the patient had experienced discomfort in that area for 2 weeks and left-sided neck pain. A large head was noted soon after birth, although precise onset and progression of abnormal enlargement could not be ascertained due to lack of objective measurements. Pregnancy and delivery were uncomplicated; developmental milestones were normal. There were no recurrent ear infections or mastoiditis. On physical examination, weight was 14.4 kg (25th percentile), length 93 cm (25th percentile), and occipitofruntal circumference (OFC) 54.5 cm (> 98th percentile). At 24 months of age, OFC was 53.4 cm (> 98th percentile). His head was dolichocephalic and disproportionately large; prominent, tortuous scalp veins were observed in the left temporal region and eyelid. A thrill was palpated and a loud cranial bruit heard behind the left ear. A grade 2/6 ejection systolic murmur was auscultated at the lower left sternal border. Denver Developmental Screening Test demonstrated appropriate achievement of milestones for a 3-year-old. Routine laboratory urine and blood studies, coagulation parameters, M-Mode, and 2-D echocardiograms of the heart, and 12-lead electrocardiography were normal. Enhanced and unenhanced cranial computed tomographic (CT) scans demonstrated a borderline increase in the size of the ventricles and moderately increased subarachnoid spaces, predominantly in the frontal and superior parietal areas (Fig 1). Focal left occipital bone erosion adjacent to the sigmoid sinus and a large left sigmoid sinus were visualized. The right sigmoid sinus could not be identified. Temporal bone aeration was normal. No arteriovenous malformation was observed on the enhanced study. Skull radiography revealed widening of the coronal sutures. A neuro-ophthalmologic consultant found dilated tortuous intraocular and lid veins greater in the left eye, but no papilledema. Four-vessel cerebral angiography demonstrated normal arterial structures and poor filling of the jugular veins with collateral circulation to the veins on the spinal cord and in the cervical epidural space. There was minimal filling of the right internal jugular vein. The right proximal sigmoid sinus was occluded just below the level of the tentorium (Fig 2). The left sigmoid sinus was extremely stenotic just before entry into the jugular foramen (Fig 2). Large transcranial collateral emissary veins arose from the left sigmoid sinus and caused focal bony erosion. Subsequent examination at 38 months of age revealed an OFC of 54.5 cm; at 40 months, 55 cm; and at 49 months, 55.2 cm. At age 38 months, cranial magnetic resonance imaging confirmed CT findings and did not demonstrate transependymal cerebrospinal fluid (CSF) migration.
Discussion Prior to the antibiotic era, sigmoid sinus thrombosis was very common, particularly in children with otitis media, and contributed to many deaths. In early series, sinus thrombosis mortality rates were as high as 34% [4]; with current therapy, the incidence, mortality, and morbidity have declined [1]. Dural sinus and venous thromboses are related to alterations in blood constituents, vessel wall, or blood flow.
Communications should be addressed to: Dr. Talwar; Box 486; Division of Pediatric Neurology; University of Minnesota Hospitals; 420 Delaware Street SE; Minneapolis, MN 55455. Received September 6, 1989; accepted November 13, 1989.
Talwar et al: Sigmoid Sinus Occlusion
51
A
B
Figure 1. Contrast-enhanced cranial CT demonstrating (A) borderline ventrieular size, prominent venous struetures, and increased .f~'ontoparietal subaraehnoid spaces and (B ) diffusely prominent subaraehnoid spaces.
Although it may not be identified, a causative or precipitating factor may occur in children secondary to cyanotic congenital heart disease, infections, hematologic disorders, dehydration and hyperpyrexia, neoplasms, and trauma [1,4]; however, unexplained bilateral occlusion or absence of the sigmoid sinuses is very rare. One patient was reported in an extensive review [1]. In a later report, a child with idiopathic bilateral occlusion of the sigmoid sinuses, with clinical features similar to our patient (i.e., macrocephaly, dilated scalp veins, and mild ventriculomegaly) was described [2]. Unilateral absence or occlusion of the sigmoid sinus has been reported more frequently [1,4] and may result in significant manifestations when the preponderant transverse or sigmoid sinus is occluded. In our patient, there were no identifiable predisposing factors; the onset of sigmoid sinus pathology could not be discerned. The presenting symptoms were related to turbulent blood flow through the stenotic sigmoid sinus and collateral veins. Clinical and radiologic evaluation demonstrated megalencephaly, prominent subarachnoid spaces, and only borderline ventriculomegaly. There was no evidence of developmental delay, significant neurologic symptoms or signs, frank communicating hydrocephalus despite the large head size, or increased intracranial pressure (ICP). Clinical and radiologic features of our patient are similar to those observed in "external hydrocephalus," an entity characterized by macrocephaly, increased subarachnoid spaces in the frontoparietal region, widened frontal interhemispheric fissure, and occasionally mild ventriculo-
52 PEDIATRICNEUROLOGY Vol.6 No. 1
megaly. It occurs in children born prematurely, after diffuse CNS insults, in certain syndromes associated usually with macrocephaly, but is usually idiopathic [3]. Our patient's cranial CT exhibited some diffuse increase in subarachnoid spaces, in addition to the localized frontoparietal increase in subarachnoid spaces reported in "external hydrocephalus." Because of the large head and brain size, the diffuse increase in subarachnoid spaces cannot be characterized as "atrophy." There have been no prior reports of CT findings of bilateral sigmoid sinus occlusion. The pathophysiology of the clinical signs and radiologic features of our patient are not known. Hydrocephalus, with enlarged ventricles, can be produced by ligation of the jugular veins in experimental animals [5] and is described with increased intracranial venous pressure in children [6,7]. Pseudotumor cerebri may also occur following venous outflow obstruction [8,9]. Although it is not completely understood, the pathogenesis of pseudotumor probably occurs secondary to CSF outflow disturbance [9,10]; however, despite significant venous outflow obstruction, our patient did not develop frank communicating hydrocephalus or pseudotumor. On the contrary, the presentation was megalencephaly. We postulate that the radiologic features and megalencephaly were partly caused by venous engorgement and increased blood volume in the brain, impaired CSF absorption, and elevated venous pressure secondary to an almost complete obstruction of the venous outflow which occurred congenitally or soon after birth. The compliance of the skull due to open cranial sutures during infancy may prevent the development of increased
pressure may cause cerebral, ventricular, or subarachnoid space enlargement, or only an increase in intracranial pressure, depending on the compliance of the brain and skull and the time course of venous occlusion. We believe that such cases probably are very rare. Dural sinus occlusion and stenosis, however, should be considered in children with asymmetric cranial bruits. Significant venous outflow obstruction should be considered in children presenting with megalencephaly with or without classic EH in the absence of another etiology.
References
Figure 2. Angiogram, oblique view, right common carotid injection, digital subtraction technique. Arterial structures are shown in white as a result of the subtraction process. Solid curved arrow: occluded proximal right sigmoid sinus; open curved arrow: stenotic left sigmoid sinus just before entry into jugular fossa; straight arrow: extracranial collateral veins.
intracranial pressure or communicating hydrocephalus and allow the skull size to increase. In some young children, this compliance may support the development of"extemal hydrocephalus" [11]. Mechanisms leading to megalencephaly with or without classic "external hydrocephalus" versus a communicating hydrocephalus are not known and may be related to multiple factors, such as the degree of direct arachnoid granulation involvement or rate of collateral circulation development. Despite poor understanding of the underlying mechanisms, increased venous
[1] Kalbag RM, Woolf AL. Cerebral venous thrombosis: With special reference to primary asceptic thrombosis. London: Oxford University Press, 1967;1-280. [2] Smith KR Jr. Idiopathic bilateral sigmoid sinus occlusion. Neurosurgery 1968;29:427-30. [3] Maytal J, Alvarez LA, Elkin CM, Shinnar S. External hydrocephalus: Radiologic spectrum and differentiation from cerebral atrophy. AJNR 1987;8:271-8. [4] Krayanbuhl HA. Cerebral venous and sinus thrombosis. Clin Neurosurg 1966; 14:1-24. [5] Bering EZ Jr, Salibi B. Production of hydrocephalus by increased cephalic-venous pressure. Arch Neurol Psychiatry 1959;81: 693-8. [6] Rosman NP, Shands KN. Hydrocephalus caused by increased intracranial venous pressure: A clinicopathologic study. Ann Neurol 1978;3:445-50. [7] Stewart DR, Johnson DG, Myers GG. Hydrocephalus as a complication of jugular catheterization during total parenteral nutrition. J Pediatr Surg 1975;10:771-7. [8] Greer M. Management of benign intracranial hypertension. Clin Neurosurg 1967;15:161-74. [9] Gjerris E Soelberg S0rensen P, Vorstrup S, Paulson BB. Intracranial pressure, conductance to cerebrospinal outflow, and cerebral blood flow in patients with benign intracranial hypertension (pseudotumor cerebri). Ann Neurol 1985; 17:158-62. ll0] Fishman RA. The pathophysiology of pseudotumor cerebri: An unsolved puzzle. Arch Neurol 1984;41:257-8. [11] Chapman PH. External hydrocephalus. Concepts. Pediatr Neurosurg 1983;4:102-18.
Talwar et al: Sigmoid Sinus Occlusion
53