Abstract
Dear Sir We read with great interest the recent case report by Georgiadis et al. (1) of a young man who developed a cluster-like headache following cerebral venous thrombosis (CVT). We would like to present a new case of extensive CVT associated with ulcerative colitis (UC) that was preceded by 3 months of an episodic headache resembling a cluster headache (CH).
A 51-year-old man, with no prior history of headache, had been diagnosed with UC involving the ileum and colon 15 years before. As the UC had been poorly controlled, an ileo-colectomy had been performed 2 years after the diagnosis. The rectal relapses had consisted of pruritus and scarce diarrhoea. These symptoms had been controlled with topical steroids. He went to the emergency room due to episodes of unilateral severe headache lasting up to 90 min. The headache was localized around the right eye and was accompanied by conjunctival injection, lacrimation, ptosis and miosis. He suffered around 10 episodes a day and the headache improved with ergotamine 2 mg or zolmitriptan 5 mg. Neurological examination was normal without papilloedema in bilateral fundoscopy and a non-contrast brain computed tomography (CT) showed no abnormal signs. A brain magnetic resonance (MR) scan was not performed. The headache period lasted 4 weeks and was self-limited. Three months later he was admitted to the hospital with a rapidly evolving picture of bilateral motor partial seizures and headache for 24 h. The patient's neurological examination disclosed mild left hemiparesis and bilateral extensor plantar responses. A CT scan without contrast demonstrated hyperdense signal in the sagittal and left transverse sinus and a subarachnoid haemorrhage in the left insular sulci. Brain MR imaging scan showed thrombosis of the superior sagittal and bilateral transversal sinus without any brain lesions. MR venography confirmed the pathological changes. Tests to rule out coagulation abnormalities were normal. Dose-adjusted intravenous heparin and dexamethasone were initiated, neurological symptoms began to improve and the patient was asymptomatic in 3 days. After changing to warfarin for maintenance therapy, he was discharged without any neurological sequelae 3 weeks after admission. MR imaging performed 6 weeks after admission showed partial recanalization of the pathological sinuses. The patient remained free from headache for a follow-up of 18 months.
Patients with UC are at increased risk of CVT due to a hypercoagulability state associated with coagulation abnormalities and platelet disorders (2, 3). Post-mortem examinations have suggested that venous thrombosis of all sites may complicate UC in 39% of cases, but only 1% of patients are clinically affected (4). The clinical presentation of CVT is extremely variable and often misleading. In up to 20% of cases the onset is insidious, lasting >30 days. There are extremely benign forms limited to transient ischaemic attack, headache or epilepsy which spontaneously resolve and which are probably still under-recognized. In all series, headache is the most common symptom, present in about 80% of cases. It is also the earliest symptom in two-thirds of cases. The headache has no specific features. It is mostly diffuse, progressive and permanent, but it can be misleading, mimicking migraine or the typical headache of subarachnoid haemorrhage (5, 6). The possibility of isolated headache as the only symptom of CVT and the fact that headache precedes the development of other neurological deficits for days, even weeks or exceptionally months, have recently been emphasized. In these cases, the diagnosis of CVT is difficult, particularly if the results of CT are normal, as occurs in 10–20% of cases in patients with proven CVT and in up to 50% of patients presenting with isolated intracranial hypertension (7). In a recent study, headache was present in the absence of intracranial hypertension, subarachnoid haemorrhage or meningitis, and such cases were essentially associated with lateral sinus thrombosis (8). The exact mechanism of the headache remains unknown: stretching of nerve fibres in the walls of the occluded sinus is a possibility, as well as it being a local inflammatory reaction.
CVT is a disease with a large range of severity. More and more incidental and asymptomatic cases have been recognized with improved, non-invasive imaging techniques. It is conceivable that the presence or absence and the efficiency of intracranial venous collaterals, as well as early spontaneous recanalization, may have an impact on the extent of brain tissue damage and hence the prognosis of acute CVT (9). It may be expected that the opening of the end-to-end anastomosis of the meningeal veins to other venous channels preserves a functioning vascular drainage system, but this process demonstrates great interindividual and interhemispheric variation (10). Furthermore, there are data that imply that the extent and function of venous collaterals at the time of thrombosis are probably more important than recanalization occurring days and months after onset of CVT (11). On the other hand, in contrast to arterial thrombosis, the thrombotic process in CVT continues over days, weeks or even months with the spread of thrombosis on one side and recanalization on the other, as thrombosis and endogenous fibrinolysis occur concurrently in CVT (6).
In the case of cluster-like headache in CVT reported by Georgiadis et al. (1), the patient was suffering from headache when CVT was diagnosed and his symptoms resolved after initiation of anticoagulation. In our case, it is not possible to assess retrospectively whether CVT was already present at the time of the CH episode, although we consider there to be a causal connection between the cluster-like headache and an ongoing process of CVT. Areas of only transiently and reversibly disturbed brain tissue can be found after sinus venous occlusion in cases of preserved collateral pathways without persistent ischaemic damage to brain tissue. However, if venous occlusion is maintained for longer time periods, the described ‘meta-stable’ areas may become necrotic (12). In a case reported, a worsening of extensive CVT was preceded by 3 months of intermittent headache (13). Moreover, the patient has not suffered another CH episode for 2 years, a difference from the 73% of episodic CH patients who suffered from one or two cluster periods a year (14). A secondary reversible irritation of ophthalmic division of the trigeminal nerve produced in the walls of the putative pathological sinus would have activated the trigeminovascular system triggering the CH episodes. A plausible hypothesis is that the CH episodes disappeared because CVT may have improved by development of collateral veins or by endogenous fibrinolysis before the thrombotic process could have extended, with the occurrence of new neurological symptoms.