Reversible Cerebral Vasoconstriction Syndrome

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Learning objectives

  • Appropriate settings to look for RCVS
  • Supporting evidence to ensure firm diagnosis
  • Treatment options

Introduction

RCVS is underdiagnosed and probably misdiagnosed syndrome [Ducros A et al. 2007] with thunderclap headache and angiographic changes. It may be misdiagnosed as both SAH and Cerebral vasculitis. The outcome is usually benign and the risks are in misdiagnosis and over treatment with cytotoxic drugs.

Aetiology

The basic aetiology is not understood. The use of vasoactive drugs may play a role. Some disturbance in cerebral flow and vascular tone with segmental and multiple focal areas of constriction and dilation may occur. Some have no precipitants and are spontaneous and others are secondary to extrinsic factors. It is commoner in females and migraineurs . The incidence of migraine matches the background population level. There appears to be some possible overlap with posterior reversible encephalopathy syndrome. There may be resultant localised subarachnoid bleeding which may be over the convexities of the cerebral hemispheres which is seen in a quarter of cases, parenchymal ischaemic stroke or haemorrhagic stroke seen in 5-10% [Ducros A et al. 2009].

Epidemiology

It is between 2 and 10 times commoner in females. Mean age of onset is 45. So patients tend to be middle-aged women [Chen S 2010]. Most cases are seen post-partum or with exposure to vasoactive substances.

Clinical

The headache which is the dominant feature is often thunderclap and may wane after 1-3 hours leaving behind a 'background' headache. Seizures recorded in 20%. The headaches can persist almost daily for several weeks. Triggers are varied including sex, sneezing, urinating, defaecation, head movements and bathing. There may be associated nausea and sickness but not to the degree of migraine. Focal neurology may suggest convexity SAH which supports diagnosis.

Precipitants

  • Precipitant range from post-partum to cannabis, cocaine, amphetamines, LSD, binge drinking, ergotamine
  • Nasal decongestants, SSRIs, Triptans, Nicotine patches, phaeochromocytoma and cervical dissection.
  • This list is constantly expanding and changing as the diagnosis is increasingly recognised and diagnosed.

Criteria for Diagnosis

Criteria for RCVS [Calabrese et al. 2007]
Acute and severe headache (often thunderclap headache) with or without focal neurological deficits or seizures
Monophasic course without new symptoms more than 1 month after clinical onset
Segmental vasoconstriction of cerebral arteries demonstrated by angiography (MRA, CTA or catheter)
Exclusion of subarachnoid haemorrhage due to a ruptured aneurysm
Normal or near normal CSF (protein <1g/l, white cells < 15/mm3, normal glucose)
Complete or marked normalisation of arteries demonstrated by a repeat angiogram (MRA, CTA or catheter) after 12 weeks, although they may be normal earlier

Differentials

  • Aneurysmal and non-aneurysmal SAH
  • Cervical artery dissection
  • Cerebral venous sinus thrombosis
  • Primary Angiitis of the Central Nervous System
  • Migraine

Investigations

  • CT head: initially may show subarachnoid blood which may be on the convexity of the brain and sulci rather than in the traditional surfaces associated with saccular aneurysmal bleeds.
  • LP result: see table on previous page. LP is not needed if there is blood on the CT scan and is usually done as part of a SAH exclusion for those who present late with a normal CT and history of thunderclap headache.
  • MRI/MRA/MRV and Cervical T1 with fat saturation and contrast: MRI will show infarction or bleed. It may show changes of posterior reversible encephalopathy (symmetrical high signal on FLAIR) or Subarachnoid or subdural bleeding. Changes with RCVS are dynamic and one negative imaging test does not exclude the diagnosis.
  • MRA or DSA: Angiography is diagnostic (DSA is superior to MRA/CTA) and shows various segmental narrowing 'string of beads' of the intracranial vessels which disappear on angiograms within 12 weeks. Vasoconstriction may be missed if angiography done too early. Vasoconstriction may not peak for several weeks after presentation. The CSF which should be done to exclude SAH is usually normal but of there is even small rise in lymphocytes it is prudent to repeat a few weeks later to demonstrate normality and exclude chronic meningitis.
  • Transcranial Doppler: may be used to monitoring the cerebral vasoconstriction producing increased flow velocities. RCVS may be mistaken for Primary Angiitis of the Central Nervous System (PACNS) due to the presence of similar angiographic features of segmental narrowing of cerebral arteries.

Management

  • IV fluids and hydration and Calcium channel blockers such as Nimodipine 60 mg PO every 4 hrs have been used in the acute and subacute setting though there is no real evidence base. Other agents are under investigation. Avoid use of triptans which may make any vascular issues worse. Vasospasm is possible for all within the first 2 weeks.
  • However despite substantial risks of subarachnoid haemorrhage, ischaemic or haemorrhagic stroke approximately 95% of patients have no long term neurological deficits in two large prospective series [Chen et al. 2009; Ducros et al. 2007]. The prognosis appears to be excellent.

References and further reading

  • 1. Ducros A et al. The clinical and radiological spectrum of reversible cerebral vasoconstriction syndrome. A prospective series of 67 patients. Brain (2007), 130, 3091-3101
  • 2. Ducros A et al. Reversible cerebral vasoconstriction syndrome Anne Ducros, Marie-Germaine Bousser. Practical Neurology 2009; 9 253-253
  • 3.<A href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3002654/pdf/10.1177_1756285610361795.pdf">Reversible cerebral vasoconstriction syndrome: an under-recognized clinical emergency. Ther Adv Neurol Disord (2010) 3(3) 161171 </a>