CASE REPORT A case of cerebral venous thrombosis following the use of contraceptive medication G Bunea* FCRad(SA) IB Copley+ FRCS (Ireland) o Ajarrl" FRCS (Edinburgh) Abstract Cerebral venous thrombosis is an uncommon and serious complication of contraceptive medication, which often masquerades as a simple headache. The clinical picture is often confusi ng and imaging is critical to the diagnosis of this disorder. This case report iIIustrates a case of dural venous thrombosis and a review of the radiological features of cerebral venous thrombosis. 'Department of Diagnostic Radiology, 1Department of Neurosurgery, Medical University of Southern Africa (MEDUNSA) 33 SA JOURNAL OF RADIOLOGY. January 2000 Introduction Venous sinus thrombosis is a rare event and may have an insidious on- set and late sequelae in contradistinc- tion to cavernous sinus thrombosis as- sociated with infection and florid signs. Thrombosis involving the du- ral sinuses is due to three causes: those from changes in blood flow, changes in the vessel wall, or blood abnormali- ties. Blood flow changes are most commonly seen in dehydration. Changes in flow and vessel wall are seen in depressed fractures about the midline of the vault. Operative interhemispheric (e.g. transcallosal) procedures near the superior sagittal sinus may produce local trauma and stasis. Another entity is the vasculitis of Behcet's disease. Common, non-in- fectious causes of cerebral venous thrombosis include oral contracep- tives, pregnancy and the puerperium. Abnormal changes in blood constitu- ents are seen in malnutrition, and blood deficiencies antithrombin III, protein S & C, disseminated intravas- cular coagulation, iron deficiency anaemia.' Occlusion of the anterior third of the superior sagittal sinus does not produce symptoms or signs whereas thrombosis of the middle third pro- duces upper motor neurone signs, hemi- or quadriparesis. Visual field disturbances or blindness may occur with occlusion of the posterior third of the sinus rapidly followed by de- creasing level of consciousness. Thrombosis of a transverse sinus is less significant than if the opposite sinus is also occluded. Any involve- ment of the posterior two-thirds is as- sociated with cerebral oedema indi- cated by engorgement of retinal veins, topage34 A case of cerebral venous thrombosis follo\Ni ng the use of contraceptive medication frompage33 meningism and decreased level of consciousness. In subdural parafalx empyema, venous thrombosis fol- lowed by infarction may be seen in neglected cases. As the empyema may be restricted to one side or another of the falx, so the neurological deficit may be unilateral before rapid dete- rioration as the whole superior sagit- tal sinus becomes involved. Case report The patient P.M., a healthy 23 year- old woman, had no previous medical history. She had a child of 5 years of age. A year after delivery, she began with three-monthly injections of norethisterone enantate 200 mg. Soon after starting on this treatment, she developed headaches and amenorrhea. Three months prior to admission, ow- ing to the headaches, she was changed to levonorgestrelI50 ug, ethinyl oestra- diol 30 ug oral contraceptive. The change relieved the headaches and there were scanty periods. Approxi- mately two days prior to admission, the patient presented at a peripheral hos- pital with severe headache, nausea and vomiting, decreased vision and confu- sion (GCS nilS) followed by deep- ening coma. On recovering conscious- ness, she had a right hemiparesis. Her mental recovery was such as to provide the foregoing history. Computerized to- mography (CT) done at the peripheral hospital (Figure 1 and 2) was reported as "a large subdural haematoma (possi- ble venous sinus) occipitally; blood in the quadrigeminal cisterns, possible subarachnoid haemorrhage (SAH), blood in the region of the straight si- nus. Post contrast filling defect in the sagittal sinus - possible dural sinus thrombosis". Because of the reported SAH, the patient was treated with nimodipine. Four-vessel angiography, Figure 2: CT scan post-contrast shows the empty delta sign in the superior sagittal sinus Figure 1a, band c: CT scan pre-contrast on admission demonstrated high-density thrombus in straight sinus, superior sagittal sinus, and in left transverse sinus. A thrombosed vein (cord sign) is seen on the medial aspect of the left temporal lobe Figure 3a and b: Digital cerebral angiogram in the venous phase demonstrated poor and irregular fil/ing of the superior sagittal sinus, straight sinus, vein of Galen, and transverse sinuses. Note prominent cortical tributary veins draining into the rostral aspect of the superior sagittal sinus performed Il days later (Figure 3), confirmed the diagnosis of venous si- nus thrombosis. 34 SA JOURNAL OF RADIOLOGY· January 2000 topage35 A case of cerebral venous thrombosis foliovvi ng the use of contraceptive rrieclicatiori frompage34 Figure 4a and b: Repeat CT scan with contrast injection, 12 days later showed strong enhance- ment of the straight sinus with a central filling defect, and the empty delta sign in the superior sagittal sinus A second CT with contrast (Fig- ure 4) was done 12 days later which showed a clear delta sign and clot within straight sinus. Magnetic reso- nance (MR) imaging was requested at 18 days and showed typical high sig- nal thrombus (Figure 5) in the dural sinuses. It also showed a left cortical venous infarct. hypertension, and cerebral venous thrombosis (CVT). The evaluation of a patient on contraceptive medica- tion, who complains of worsening headaches, requires exclusion of CVT2 by computed tomography or magnetic resonance imaging. Discussion The cerebral side effects of the contraceptive medication include non- specific headaches or migraine, with- drawal headaches, benign intracranial 35 SA JOURNAL OF RADIOLOGY. January 2000 Figure Sa, b, c and d: Sagittal, coronal, and axial T1 and T2-weighted MR images showed high intensity signal within the superior sagittal sinus The manufacturers state that the occurrence for the first time of a mi- graine type of headache, the more fre- quent occurrence of an unusually se- vere headache, or sudden perception disorders is sufficient reason for im- mediate discontinuation.! A mere change of the drug is probably haz- ardous. This case shows that CVT can masquerade for many months as a simple headache or even a benign in- tracranial hypertension. Extensions to the deep cerebral veins are associated with a sudden neurological deterioration and poor outcome. Imaging is critical to the di- agnosis of this disorder, which can be made by non-invasive modalities such as CT or MR. Non-enhanced CT scans may show hyperdense thrombus in the dural sinus (dense sinus sign), deep cerebral veins, or cortical veins (cord sign), cortical and subcortical haemorrhagic infarctions, and diffuse cerebral swelling. After contrast the thrombosed sinus remains unopacified with enhancement of the topage36 A case of cerebral venous thrombosis fof lovvi ng the use of contraceptive medication from page35 collaterals in the dura leaves (empty delta sign), the falx appears thickened, there is tentorial (shaggy tentorium) and gyral enhancement, and the transcortical medullary veins may en- hance strongly. Deep cerebral vein thrombosis appears as a high density thrombus in the deep veins, vein of Galen, or straight sinus, with or with- out basal ganglia infarctions and pe- techial haemorrhages. The differential diagnosis of dural sinus thrombosis on CT scans includes normal neonates with unmyelinated brain and dense sinus, high-splitting tentorium and pseudodelta sign seen in subarachnoid haemorrhages. MR findings vary with clot age.An acute thrombus is iso-intense with the cortex on Tl -weighted images, older haematomas are hyper-intense on TI- weighted scans and hypo-intense on T2-weighted images, while sub-acute thrombi are typically hyper-intense on all pulse sequences. In the chronic phase, prominent collateral venous channels can be seen around and within the thrombosed sinus (i.e. recanalisation), and intense enhance- ment of the thrombus after gadolin- ium injection (i.e. conversion to vas- cularized connective tissue). Other causes of increased signal within a si- nus on spin-echo images must be ex- cluded, such as: turbulent or slow flow, flow entry phenomenon, even echo rephasing, and flow compensa- tion techniques. Flow enhancing gra- dient-echo sequences along with spin- echo sequence should allow the dif- ferentiation. In acute thrombosis, high field strengths can give a low signal which can be confused with a patent dural sinus. MR Angiography or Venography provides conclusive evi- dence of flow in the sinus rather than relying on flow-related enhancement effects in standard imaging. Angiographic signs of a throm- bosed sinus include non-filling of the dural sinus, filling defects, enlarged medullary veins and other collaterals. Thrombosed cortical veins are seen as contrast collections which appear to hang in space with contrast persisting well into the very late venous phase. Deep cerebral vein thrombosis is seen as the non-filling of the vein of Galen and internal cerebral veins, with or without collaterals." Cerebral CTVenography, possible with spiral CT and three-dimensional reconstructions, allows an accurate evaluation of the flow in the cerebral 36 SA JOURNAL OF RADIOLOGY. January 2000 venous system.' Venous transcranial Doppler ultrasonography can be used as a monitoring tool in the evaluation of the collateral venous flow in supe- rior sagittal sinus thrombosis, however it needs further evaluation." Apart from anticoagulation and control of raised intracranial pressure, selective venous administrations of fibrinolytic agents by an interventional neuroradiologist is possible.' It is con- jectural as to whether or not the use of nimodipine contributed to the pa- tient's eventual excellent recovery. References 1. Hoffman MW, Bill PLA, Bhigjee AI, Modi G, Haribhai HC, Keble C. The clinicoradiological profile of cerebral venous thrombosis. S Afr Med. J, 1992: 82: 341-348. 2. Naim-Ur-Rahman, Abdul Tahman AI Tahan. Computed tomographic evidence of an extensive thrombosis and infarction of the deep venous system. Stro/le, 1993: 24,5: 744-746. 3. M/MS Medical Specialties, 1998: 38,4: 184. 4. Osborn AG. Diagnostic neuroradiology. St Louis: Mosby. 1994 : 385-395. 5. Casey SO, Alberico RA, Patel M, Jiminez JM, et al. Cerebral CT venography. nadiology, 1996: 198,1: 163-170. 6. Valdueza JM, Schultz M, Harms L, Einhaepel KM. Venous transeramal Doppler, ultrasound monitoring in acute dural sinus thrombosis. Stroke, 1995: 26,7: 1196-9. 7. Scott JA, Pascuzzi RM, Hall PV, Becker GJ. Treatment of dural sinus throm bosis with local urokinase infusion. J Neurosurg, 1988: 68: 284- 287.