**6. Conclusion**

Our experience points towards the possibility of CVT onset in young women using hormonal contraceptives. This condition needs to be taken into account in cases of intracranial difficulties. CVT is most commonly manifested with headaches, vertigo and visual disorders. That is why the diagnosis should be considered when a sudden onset of such manifestations occurs in otherwise healthy young woman. The CT or MRI examinations should be directed towards the possibility of affection of the venous intracranial system. MRI and MR-venography or 3DX-RA venography significantly decrease the diagnostic process in patients with disorders of the deep venous cerebral system and a rapid development of symptoms. Direct endovascular thrombolysis, with the possibility of mechanical revascularization may dramatically improve the clinical course of patients with thrombosis of cerebral veins in patients with insufficient effect of anticoagulation therapy, associated with rapidly progreding disorders of consciousness. Thrombolytic therapy also decreases the occurrence of secondary complications following thrombolyses of cerebral veins, such as chronic intracranial hypertension with visual disorders or onset of arteriovenous shunts. (24,25) Taking into account the incidence of these serious complications, we consider as essential, in compliance with recommendations of the Czech Society of Gynaecology and Obstetrics JEP, prior to administration of HAK, to perform a detailed analysis of personal and family history, and in indicated cases also a detailed examination of the presence of thrombophilic states. The significance of individual thrombophile mutations is inconsistent. Absolute contraindications for HAK usage include deficit of the antithrombin III, protein C deficit, homozygous form of V Leiden factor and combination of other thrombophile mutations. Other thrombophile mutations present a relative contraindication only. Screening examination of women prior to administration of HAK is not indicated. (26) However, in our study group, although we performed a detailed retrospective analysis, the personal and family history were negative in all patients. Considering this fact there arises the question of a facultative possibility of thrombophile examination covered by the patient, based on the patient's request, prior to administration of HAK.

As a certain surprise we may mention the high incidence of homozygous form of C677T in out study group (37,5%), which may be in consistence with the findings of Martinelli et al., who proved the risk of CVT onset in users of hormonal contraceptives with hyperhomocysteinemia OR 19,5 95% CI (5,7 – 67,3). The levels of homocystein were not monitored in our patients. Other frequently observed findings included mutations of the plasminogen activator inhibitor gene (PAI-1) and deficit of protein S, which may be also present in combinations strengthening the prothrombogenic effect. On the other hand, we did not observe an incidence of V Leiden factor in patients with CVT, however this factor is frequently mentioned in literature as a significant thrombophilic risk factor.
