Reversible Cerebral Vasoconstriction Syndromes

Introduction

Reversible cerebral vasoconstriction syndromes (RCVS) are a range of conditions characterised by reversible narrowing of the cerebral arteries. The underlying pathologies are varied and previously have been categorised as a range of different diagnoses, including ‘drug-induced cerebral arteritis’, ‘migraine angiitis’, ‘postpartum cerebral angiopathy’ and Call-Fleming syndrome (to name but a few). However, recent literature recognises that these patients have nearly identical clinical, laboratory, imaging and prognostic features[i], hence they should be more appropriately categorised as members of the same spectrum of disease.

Clinical presentation

Clinical features have overlap with other conditions, most specifically SAH, presenting typically with thunderclap headache, often accompanied by nausea and photosensitivity. SAH will always be the most important differential diagnosis to exclude. The headache for RCVS is commonly occipital, rapidly reaches maximal intensity, and may last up to several weeks with several exacerbations or more severe recurrences during that period. Headache is the only symptom in one third to three quarters of patients. The rest go on to develop other neurological symptoms or deficits from underlying ischaemia, haemorrhage or cerebral oedema.

Differential diagnoses to consider (not an exhaustive list)

• SAH 
• Cerebral venous thrombosis
• Cervical artery dissection
• Hypertensive crisis (with resulting PRES, Posterior Reversible Encephalopathy Syndrome)
• Pituitary apoplexy
• 3^rd ventricular colloid cyst
• Migraine
• Primary thunderclap headache (arguably a spectrum of RCVS)

Investigations

Initial work up is as for any primary thunderclap headache with non-contrast CTB +/- lumbar puncture as indicated.

The gold standard test is cerebral angiography, and a positive result will show abnormalities, which may be dynamic, most commonly described as a ‘sausage on a string’ appearance of the circle of Willis and its branches. The condition typically starts distally and becomes more proximal over time.

Other investigations will be determined by clinical presentation and resources, but may include CTA, MRI/MRA, MRV, and vertebral or carotid artery imaging.

Up to 70% of patients with RCVS have no abnormality detected on initial brain imaging[ii], however up to 75% of those admitted with symptoms will go on to have ischaemic stroke, subarachnoid haemorrhage (non-aneurysmal), parenchymal haemorrahge and reversible vasogenic brain oedema, as a direct result of the vasoconstriction.

Risk factors

Risk factors include association with pregnancy, migraine, stimulants or vaso-constrictive medications (over 50% of cases)[iii] and other neurosurgical procedures.

Treatment

There is no specific intervention for RCVS. Many therapies have been proposed and trialled, but there is no good evidence base for any specific interventions. The mainstay of management is analgesia (may have high analgesia requirements), and good supportive care.

There is no role for stroke preventative medications unless there are concurrent cardiovascular risk factors, which should be separately addressed.

Prognosis

Over 95% of patients will have a benign clinical course and favourable prognosis; recurrence is rare. Of those with more permanent neurological sequalae (secondary to the aforementioned complications), care is supportive.