PRES

RCVS

CVT

Eclampsia

Mode of onset

Rapid, postpartum

Abrupt, postpartum

Third trimester or later, gradual

Antepartum, intrapartum or postpartum

Key findings

Seizures. May be accompanied by stupor, visual loss or hallucinations. Headache dull and throbbing

Thunderclap headache. Seizures are less common. Transient focal deficits

Headache is universal, progressive and diffuse. Seizures in 40 %

Seizures, frequent visual symptoms, abdominal pain, hyperreflexia, hypertension and proteinuria

Evolution over time

If BP is controlled, resolves within short period

Changes over time. ICH, second week; ischaemic complications, third week

Evolves over several days, non-arterial territorial infarcts and haemorrhages might develop

Can evolve (from pre-eclampsia) gradually or abruptly

CSF findings

Usually normal

Often normal. Fifty per cent of cases have pleocytosis and raised proteins

Pressure raised in 80 %; 30–50 % have raised proteins and cell counts

Usually normal unless complicated by haemorrhage

Imaging

CT positive in about 50 % of patients; MRI shows prominent T2-weighted and FLAIR abnormalities nearly always in parieto-occipital lobes, but can involve other brain regions; intracerebral haemorrhage in about 15 % of patients