Dural Sinuses Thrombosis

Thrombosis of the dural sinuses

ICD-10: Q04.9

Rare. Few cases have been described in prenatal life.^{1, 2}

With only 12 known cases diagnosed prenatally, it is difficult to interpret the etiology this condition during fetal life. Most of the data are based on pediatric series. Dural sinus thrombosis in infancy was first described by Baily and Hass in 1931.³ Before 1980, there were no reports of neonatal dural sinus thrombosis, other than in postmortem examination studies of asphyxiated newborns.⁴ Early reports emphasized an association with trauma and underlying systemic conditions such as sepsis, meningitis and dehydration. Prematurity and perinatal asphyxia are considered predisposing factors.⁵ Wu et al. reported that four of 30 newborns with dural sinus thrombosis had thrombophilias.⁶ A possible role of maternal pre-eclampsia has also been suggested.⁷ However; in up to 40% of cases the condition is idiopathic.⁸

The blood clot is found most frequently at the level of the torcular Herophilii or sinus confluence. In the most severe cases, the thrombus may extend into the straight sinus and the great cerebral vein as well. The thrombus may obstruct blood flow, leading to enlargement of the tributary sinuses and/or vein. Cerebral circulation may be impaired, resulting in infarct of the cortex.

Usually the condition is isolated. Abnormalities of cerebral architecture may result from impaired cerebral circulation.

Real time and color Doppler ultrasound allow to visualize the dural sinuses and the blood flowing within them during antenatal life.9 In the cases thus far diagnosed in utero, the transabdominal scans revealed the dilated superior sagittal sinus as a triangular sonolucent area in the occipital region. In the most posterior aspect of the fluid collection the thrombus was seen as a round echogenic mass.1, 2Transvaginal sonography was helpful to identify the dilated sinuses and to demonstrate the interruption of blood flow in the dilated sinuses with Color Doppler. Antenatal MRI has been used to confirm the sonographic diagnosis and to evaluate the presence of additional cerebral malformations.1

The dilatation of the venous collecting system must be differentiated from intracranial cysts including Dandy-Walker malformation and the thrombus must be distinguished from other echogenic masses, such as tumors.

Thrombosis of the dural sinuses is a rare condition that furthermore spans along a wide spectrum of severity. Although the anomaly has been recognized in the second trimester, the pathophysiology is unknown and is certainly compatible with late appearance. Probably a standard scan will only reveal the most severe cases.

Once a fluid filled intracranial structure is identified, a specific diagnosis of torcular thrombosis is usually possible by using a combination of views. Median and coronal views are most helpful in assessing abnormal anatomy, as well as vaginal sonography and Color Doppler of cerebral circulation. The most important prognostic factor in these cases, apart from the possible presence of associated anomalies, is the integrity of brain architecture and the normal vascularization of the deep cerebral veins. MR is an important adjunct to ultrasound.

Dural sinus thrombosis may result in perinatal death and brain damage. However, complete resolution with recanalization of the sinuses and a normal outcome is also possible. In pediatric patients, neurologic disability is usually the consequence of the extension of the thrombosis to the deep cerebral vein resulting in infarct of the hemispheres. Isolated thrombosis of the dural sinuses with normal cerebral circulation usually has a good prognosis.¹⁰ Predicting in utero those cases that will undergo resolution is difficult. The presence of associated anomalies, brain damage, progressive enlargement of the dural sinuses and thrombosis of the deep cerebral veins are considered poor prognostic factiors.¹ Conversely, normal cerebral architecture and Doppler evidence of normal flow in the deep cerebral view are good prognostic factors. MR is an important adjunct to neurosonography to rule out damage to the placenta and to assess vascularization. In a review of antenatal cases, of 8 infants that had good prognostic factors on prenatal imaging and were delivered, 2 died one at age of two weeks, due to uncontrollable bleeding during the surgery and the other at age of 4, 5 months due enlarging thrombus) and 6 recovered without neurologic complications.¹

The optimal obstetric management of continuing pregnancies remains uncertain. Serial ultrasound examination and MR are clearly indicated to assess the lesion and identify prognostic factors. In continuing pregnancies, delivery may occur at term and there is no clear contraindication to the vaginal route.1 Postnatally, a conservative general medical and neurologic supportive care is the mainstay of treatment. The experience indicates that surgery is associated with significant risk and should be considered with extreme caution.

1. Laurichesse Delmas H, Winer N, Gallot D, Lopes K, Perrotin F, Fluncker S, Geissler F, Beaufrere AM, Vendittelli F, Couture C, Lemery D. Prenatal diagnosis of thrombosis of the dural sinuses: report of six cases, review of the literature and suggested management. Ultrasound in Obstetrics and Gynecology. 2008;32(2):188-98. Epub 2008/06/03.

2. Visentin A, Falco P, Pilu G, Perolo A, Valeri B, Santini D, Bovicelli L. Prenatal diagnosis of thrombosis of the dural sinuses with real-time and color Doppler ultrasound. Ultrasound in Obstetrics and Gynecology. 2001;17(4):322-5. Epub 2001/05/08.

3. Baily OT, Hass GM. Dural sinus Thrombosis in early life: The clinical manifestations and extent of brain injury in acute sinus thrombosis. J Pediatr. 1931;11:755-71.

4. Towbin A. Central nervous system damage in the human fetus and newborn infant. Mechanical and hypoxic injury incurred in the fetal-neonatal period. Am J Dis Child. 1970;119(6):529-42. Epub 1970/06/01.

5. Wong VK, LeMesurier J, Franceschini R, Heikali M, Hanson R. Cerebral venous thrombosis as a cause of neonatal seizures. Pediatric neurology. 1987;3(4):235-7. Epub 1987/07/01.

6. Wu YW, Miller SP, Chin K, Collins AE, Lomeli SC, Chuang NA, Barkovich AJ, Ferriero DM. Multiple risk factors in neonatal sinovenous thrombosis. Neurology. 2002;59(3):438-40. Epub 2002/08/15.

7. Medlock MD, Olivero WC, Hanigan WC, Wright RM, Winek SJ. Children with cerebral venous thrombosis diagnosed with magnetic resonance imaging and magnetic resonance angiography. Neurosurgery. 1992;31(5):870-6; discussion 6. Epub 1992/11/01.

8. Hanigan WC, Tracy PT, Tadros WS, Wright RM. Neonatal cerebral venous thrombosis. Pediatric neuroscience. 1988;14(4):177-83. Epub 1988/01/01.

9. Laurichesse-Delmas H, Grimaud O, Moscoso G, Ville Y. Color Doppler study of the venous circulation in the fetal brain and hemodynamic study of the cerebral transverse sinus. Ultrasound in Obstetrics and Gynecology. 1999;13(1):34-42. Epub 1999/04/14.

10. Barron TF, Gusnard DA, Zimmerman RA, Clancy RR. Cerebral venous thrombosis in neonates and children. Pediatric neurology. 1992;8(2):112-6. Epub 1992/03/01.

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