International Headache Society (IHS) code and diagnosis: 6.6 Cerebral venous thrombosis

World Health Organization (WHO) code and diagnosis: G 44.810 Headache associated with other vascular disorders

Short description: Headache is the most frequent symptom (present in up to 90%), and often with unilateral location. The temporal course is most often progressive, but it has also been reported to have a thunderclap presentation. The pain may be severe, and in the vast majority of cases there are associated focal symptoms (neurologic deficits or partial seizures) and/or signs of increased intracranial pressure (papilledema, diplopia, encephalopathy). After diagnosis, best achieved with magnetic resonance imaging (MRI) and MR angiography (MRA) or venography (MRV), standard evaluation should include routine laboratory studies and a hypercoagulable profile to evaluate for a prothrombotic state. Women on oral contraceptive pills and during pregnancy and the puerperium are at particular risk. Heparin is the treatment of choice, as headache responds most definitively to resumption of venous flow. The prognosis is favorable in most cases and headaches rarely (10%) become chronic.

In the absence of population-based epidemiologic studies, the incidence of cerebral venous thrombosis (CVT) is unknown. Decidedly less common than arterial stroke (32), autopsy studies have suggested that CVT accounts for up to 10% of deaths due to cerebrovascular disease (2). It is suspected that the true incidence of CVT may be higher than generally reported because of missed diagnosis given its varied presentation and a usually favorable prognosis.

All age groups may be affected by CVT—from the neonate (43) to the very old (78), although data from the International Study on Cerebral Vein Thrombosis found a mean age of 39 years, with women affected up to three times more frequently than men (18).

The venous vascular bed contains 70 to 80% of cerebral blood volume. Superficial veins drain the cortex and subcortical regions and empty into the dural sinuses (sagittal, transverse, petrosal, and cavernous), and then into the internal jugular vein. Deep veins drain the periventricular regions, deep white matter, the thalami, the basal ganglia, and choroids plexus, emptying into the internal cerebral and great cerebral veins. The deep and superficial veins are connected through anastomotic channels. Pathologic findings in CVT vary depending on the site of thrombosis. The superior sagittal sinus (62%) and left (43%) or right (40%) transverse sinuses are involved most frequently (18). In about half of all cases, multiple sinuses are involved. Deep draining veins, which are involved in one tenth of reported CVT cases, are paired, and thrombosis may, on occasion, involve the thalami or basal ganglia, bilaterally. Hemorrhage, related to vessel rupture following thrombosis, occurs in 15 to 49% of patients (18,27,33) and, although usually in the territory of infarcted parenchyma, may also involve the subdural and subarachnoid regions (22,75). Increased intracranial pressure from dural sinus thromboses accounts for many of the associated signs and symptoms of this condition (6). Cerebellar vein thrombosis may lead to compression of the fourth ventricle and obstructive hydrocephalus.

Women of childbearing age are most commonly affected by CVT related to pregnancy, the puerperium, and due to use of oral contraceptive, and rarely, to hormone
replacement therapy (13,17,19,46,57,65,71,74) (Table 112-1). Comparing different regions of the world, there is considerable variability among the incidence of these different reproductive-related CVT cases (17,71). Genetically determined thrombophilias predisposing to CVT include activated protein C resistance (subset: Factor V Leiden mutation); protein S, protein C, and antithrombin III deficiencies; the prothrombin gene mutation; and hyperhomocysteinemia (8,9,16,28,30,55,63,79,81,82). Acquired thrombocytosis, polycythemia, and antiphospholipid antibodies are also important CVT risk factors. Any of the prothrombotic risk factors may play a role, either in isolation or coupled to another predisposing risk factor. Therefore, a history of prior CVT or other venous thrombosis (deep venous thrombosis, pulmonary embolus) in a person with persistent headache should increase the level of suspicion for cerebral venous thrombosis (4,21,29,38,48). Cancer, especially adenocarcinomas, leukemias, and lymphomas, increase the risk of CVT through altered coagulation status (42,44). Lowered intravascular volume with dehydration, sepsis, or malnutrition plays a particularly important role in CVT, especially at the extremes of age (20,34,40,47). Injuries to the dural sinus wall related to trauma, surgery, and conditions that compress or invade the sinus (e.g., solid tumors) set the stage for CVT (52,61). Inflammatory conditions (e.g., ulcerative colitis, Crohn, Behçet) and infections, both intracranial and in structures adjacent to the dural sinuses (e.g., otitis media, mastoiditis, sinusitis), also increase the risk of CVT (5,20,51,55,59,67,72, 77,82).

The IHS diagnostic criteria for cerebral venous thrombosis (Revised International Classification of Headache Disorders [ICHD-II]) are as follows:

A. Any new headache, with or without neurologic signs fulfilling criteria C and D.

B. Neuroimaging evidence of cerebral venous thrombosis.

C. Headache (and neurologic signs if present) develops in close temporal relationship to cerebral venous thrombosis.

D. Headache resolves within 1 month after appropriate treatment.

Although CVT manifests as a wide spectrum of presentations (Table 112-2), headache is the most frequent symptom (occurring in over 80% of cases), often the inaugural one, and it may even occur in isolation (1,3,19,29). Headache may result from distension of pain-sensitive structures (veins and sinuses) or from increased intracranial pressure.