The Clinical and Radiological Spectrum of Posterior Reversible
Encephalopathy Syndrome: A Retrospective Series of 24 Patients
Jun Ni, MD, Li-Xin Zhou, MD, Hong-lin Hao, MD, Qing Liu, MD, Ming Yao, MD, Ming-li Li, MD, Bin Peng, MD,
Li-ying Cui, MD
Department of Neurology (JN, L-XZ, H-lH, QL, MY, BP, L-yC) and Department of Radiology (M-lL), Peking Union Medical College Hospital, Beijing, China.
Acceptance: Received November 8,
2009, and in revised form February 24,
2010. Accepted for publication March 15,
The first two authors contributed equally
to the paper.
Correspondence: Address correspon-
dence Li-ying Cui, MD, Department of
Neurology, Peking Union Medical College
Hospital and Chinese Academy of Med-
ical Science, Shuai Fu Yuan 1#, Dong
Cheng District, Beijing 100730, China.
J Neuroimaging 2011;21:219-224.
A B S T R A C T
BACKGROUND AND PURPOSE
Some patients with posterior reversible encephalopathy syndrome (PRES) present with
atypical clinical and neuroimaging findings. The purpose of this study is to review the
clinical and neuroimaging findings in patients diagnosed with PRES.
We retrospectively included all patients diagnosed with PRES between January 2005
and March 2009. We reviewed demographic, clinical and laboratory data, neuroimaging
findings, and prognosis.
Twenty-four patients were included with a median age of 19 years. The clinical pre-
sentations included seizures (91.7%), headache (83.3%), visual disturbance (62.5%),
encephalophathy (29.2%), and paralysis (8.3%). Co-morbidities included systemic lupus
erythematous (29.2%), kidney disease (20.8%), eclampsia (20.8%), renal artery steno-
sis (12.5%), Takayasu arteritis (4.2%), Sheehan’s syndrome (4.2%), allergic purpura
(4.2%), and acute intermittent porphyria (4.2%). Acute elevation of blood pressure was
found in 22 patients (91.7%). Ten patients (41.7%) used steroids or immunosuppres-
sants, three (12.5%) had acute renal failure before the symptoms. Atypical neuroimaging
features included involvement of the frontal lobe (54.2%), basal ganglia (4.2%) or cortex
(8.3%), and irreversible lesions (3/18, 16.7%).
A large proportion of patients with PRES may present with atypical neuroimaging findings.
Apart from the known risk factors, such as hypertension, immunosuppressants, and renal
failure of various etiologies may be the precipitants of PRES.
Posterior reversible encephalopathy syndrome (PRES), also
called reversible posterior leukoencephalopathy syndrome
(RPLS), is a recent clinico-imaging syndrome characterized by
headache, encephalopathy, visual disturbances, and seizures.1,2
PRES is not a disease entity in itself; rather it is a syndrome. The
typical neuroimaging finding is reversible vasogenic edema in
the subcortical white matter of the parietal-occipital lobes.1-4
Some atypical clinical and imaging presentations, such as
the involvement of regions other than the parieto-occipital
lobes, hemorrhage, and irreversible presentations have been
described previously.5-9Still, many patients are not diagnosed
during the initial stage. Previous reports showed that the pre-
cipitants of PRES include hypertension, acute renal failure,
eclampsia, blood transfusion, radio-contrast, and certain drug
classes, including immunosuppressive agents, corticosteroids,
and certain cytotoxic medications.1,4,5,10-15Co-morbid condi-
tions include connective tissue diseases, renal disease, eclamp-
sia, thrombotic thrombocytopenic, and acute intermittent por-
China. The purpose of this study is to identify the clinical and
neuroimaging findings of all patients admitted to our institution
with a diagnosis of PRES.
Patients and Methods
We retrospectively identified 24 patients with PRES diagnosed
in Peking Union Medical College Hospital between January
2005 and March 2009. Included patients had a clinical presen-
tations and neuroimaging abnormalities consistent with PRES.
Ten patients, including all patients with atypical presentations,
traction angiography (DSA) and cerebral spinal fluid exami-
nations at the initial stage to exclude artery stenosis, venous
sinus thrombosis or lupus encephalopathy. We gathered demo-
laboratory data including cerebral spinal fluid results and the
initial and follow-up neuroimaging findings. All neuroimaging
C2010 by the American Society of Neuroimaging219
eclampsia who presented with headache. Blood pressure was 160/110 mmHg. A1, Fluid-attenuated inversion-recovery imaging (Flair-MRI)
showed lesions with hyperintensity in bilateral posterior partial white matter. A2, Diffusion weighted imaging showed the lesions with hyper and
hypointensity. A3, The lesions were hyperintensity in cranial apparent diffusion coefficient (ADC) map, which was consistent with vasogenic
edema. A4, Repeated Flair-MRI showed these lesions were completely resolved. B1-B4 are cranial Flair-MRI of a 20-year-old-woman with
renal artery stenosis who presented headache and seizures. Blood pressure was 200/110 mmHg. B1 and B2 were the initial imaging showing
bilateral occipital, parietal and frontal lobe hyperintensity signal which predominantly involved subcortical white matter. C3 and C4 were
follow-up images revealing all the lesions as almost resolved with only a small residual lesion in left frontal white matter.
Typical imaging findings of PRES involving the posterior cerebral white matter. A1-A4 are cranial MRIs of a 23-year-old woman with
findings were reviewed by a neurologist and a radiolo-
gist.The radiologist was blinded to the clinical aspects of the
We identified 24 patients (19 females and 5 males). The median
age (range) was 19 years (15-71 years). Comorbid conditions in-
cluded systemic lupus erythematosus (SLE) with lupus nephritis
(n = 7;29.2%), primary kidney disease (n = 5;20.8%), eclamp-
sia (n = 5;20.8%), renal artery stenosis (n = 3;12.5%), Takayasu
arteritis (n = 1;4.2%), Sheehan’s syndrome (n = 1;4.2%), al-
lergic purpura (n = 1;4.2%), and acute intermittent porphyria
(n = 1;4.2%). Acute elevation of blood pressure was found
in 22 patients (91.7%). Before symptom onset, 10 patients
(41.7%) used steroids or immunodepressants, 3 patients (12.5%)
had acute renal function failure and 2 patients (8.3%) had
Clinical Presentations and Prognosis
Seizures and headache were the most common symptoms and
occurred in 22 (91.7%) and 20 (83.3%) patients, respectively.
Visual disturbance occurred in 15 patients (62.5%), mental sta-
tus change was found in 7 patients (29.2%), and paralysis was
present in 2 patients (8.3%). The median peak systolic and di-
astolic blood pressure readings during the acute stage were
170 mmHg (range, 98-230 mmHg) and 110 mmHg (range, 71-
Of the 24 patients, 1 patient was misdiagnosed with a de-
myelinating disorder and was given intravenous prednisolone.
This patient developed permanent cortical blindness. The pa-
tient with acute intermittent porphyria worsened and died.
Two patients were misdiagnosed with lupus encephalopathy
and were given large doses of steroids and immunosupres-
sant medications; these patients had residual visual distur-
bances and seizures, respectively. The other 20 patients were
treated timely, with aggressive control of blood pressure and
seizures. All of those patients achieved complete neurological
recovery, which occurred within a mean of 6.2 days (range,
Twelve patients received lumber puncture examinations and
and mild-moderate elevation of protein in 8/12 patients (range,
was previously diagnosed with SLE. The fundoscopic ex-
amination of that patient did not reveal papilledema. Other
220 Journal of Neuroimaging Vol 21 No 3 July 2011
pressure was 210/130 mmHg. The top cranial imagings were obtained on the day of symptom onset. CT angiogram showed bilateral occipital
lobe hypointensity (A1). The MRI on the day of onset revealed bilateral brain stem and partial-temporal-occipital lobe hypointensity in T1-MRI
(A2), hyperintensity in T2-MRI (A3), and multiple punctiform enhanced lesions in MRI-enhancement (A4). MRA (B1) and MRV(B2) obtained
on the day of symptoms onset showed normal. The repeated MRI including T2(C1) and Flair-MRI (C2) showed the lesions completely
A 57-year-old man with focal segmental glomerulosclerosis presented with headache, hemiplesia, and visual disturbances. Blood
patients with elevated intracranial pressure underwent MRV
and a fundus examination to rule out venous sinus thrombosis
or chronic ICP elevation. All 12 patients had normal white cell
counts (range, 0-2/mL).
Neuroimaging Findings and Prognosis
(n = 2) or MRI (n = 22). Cerebral subcortical white matter in-
volvement was found in all patients. Parietal lobe involvement
was found in 21 patients (87.5%), occipital lobe involvement
in 20 patients (83.3%), frontal lobe involvement in 13 patients
(54.2%), temporal lobe involvement in 4 patients (16.7%), and
anterior or posterior cingulate gyrus involvement in 6 patients
(25%) (Fig 1 shows the typical imaging presentation of 2 pa-
tients). The cerebellum was involved in 3 patients (12.5%), and
the brain stem in 1 patient (4.2%) (Fig 2).
Atypical neuroimaging features included frontal involve-
ment in 13 patients (54.2%), cortical or basal ganglia gray
matter lesions in 3 patients (12.5%) (Fig 3), and irreversible
lesions in three of 18 patients who had repeat MRIs (16.7%)
Twelve patients underwent diffusion-weighed imaging
(DWI) and cranial apparent diffusion coefficient (ADC) map-
ping. DWI showed either hypo, iso or slight hyperintensity
within the lesions, which were hyperintense on ADC map. This
suggested that the most lesions represented vasogenic edema
Follow-up MRI in 18 patients (including all atypical clin-
ical and imaging presentations) showed complete or almost
complete resolution of the abnormalities in 15 patients, partial
resolution in 1 patient and extension of the lesions in the other
Since it was first described by Hinchey in 1996,1PRES has
been increasingly diagnosed with the extensive use of modern
neuroimaging techniques. Our study showed that PRES was
associated with a variety of disorders, including SLE with lu-
pus nephritis, primary kidney disease, eclampsia, renal artery
tent porphyria. Interestingly, we also found that Sheehans syn-
drome combined with baseline hypotension could cause PRES.
This is the first reported case of PRES in Sheehans syndrome.
The probable mechanism of PRES syndrome in this case was
an acute elevation of blood pressure with water-sodium reten-
tion caused by supplying sodium too quickly. PRES should be
suspected when in the course of treatment for hypotension, a
patient with Sheehans syndrome develops neurological symp-
toms. It is essential to supply electrolytes slowly to a patient
Ni et al: Clinical and Radiological Spectrum221
and seizures. Blood pressure was 170/120 mmHg. A1-A4 are from the initial Flair-MRI performed on the next day of symptoms and show
hyperintensity in bilateral frontal-parietal-occipital lobes, anterior and posterior cingulate gyrus, bilateral caudate nucleus, putamen, and
cerebellum. B1 and B2 were repeated. Flair-MRI showed near-complete resolution of the lesions except for residual hyperintensity in the right
parietal subcortical white matter. C1 and C2 are MRV, which was normal at the initial stage.
Atypical imaging findings involving basal ganglia and cerebellum: A 17-year-old woman with Takayasu arteritis developed headache
with Sheehans syndrome to avoid acute blood pressure eleva-
tion that can cause PRES.
Acute elevation of blood pressure was found in the major-
ity of our patients. The co-morbidities in those patients with
high blood pressure included eclampsia, primary renal disease
and lupus. Before the onset of neurological symptoms, 10 pa-
tients used steroids or immunosuppressants. Most of these pa-
tients had hypertension. Perhaps these triggers contributed to
endothelial injury and disruption of the blood–brain barrier in
some patients. One of the patients was given cyclosporine A for
5 days before the onset of neurologic symptoms. Cyclosporine
A can affect the vascular endothelium and can also disrupt the
blood–brain barrier; however, it can also elevate arterial blood
pressure.19,20Therefore, PRES should be suspected whenever
patients develope headache or seizure after being given cy-
closporine A. Prompt withdrawal of the offending drug is very
important in such cases.
Here, it is essential to discuss PRES in combination with
SLE. In the current study, all 7 patients with SLE had lupus
nephritis, 6 patients had acute elevation of blood pressure and
six were given steroid and/or immunosuppresant treatment be-
fore neurological symptom onset. In general, the patient with
SLE often had underlying endothelial injury caused by vas-
culitis and/or its associated complications such as vessel spasm
and angiopathy.21Moreover, two cases in our study were diag-
nosed with lupus encephalopathy and were given steroid and
immunosupressant treatments that could increase blood pres-
sure and aggravate endothelial injury.22The patients had resid-
ual clinical symptoms and irreversible imaging lesions. Thus,
PRES should be suspected when patients with SLE have acute
headache and seizures, especially in those patients who have
high blood pressure and are on immunosupressive treatments.
To distinguish from lupus encephalopathy and guide further
treatment, prompt CSF analysis and MRI examination are
The typical neuroimaging presentation of PRES is vaso-
genic edema predominantly involving the posterior white mat-
ter of the cerebral hemispheres, especially the bilateral parieto-
occipital lobes; the calcarine and paramedian occipital-lobe
are usually spared.1Of course, diffusion-weighted (DW) MRI
can distinguish vasogenic edema in PRES from the cytotoxic
edema presents iso or hypointensity in DWI and hyperinten-
sity in ADC map, whereas cytotoxic edema presents hyperin-
tensity in DWI and hypointensity in ADC map.18-20DWI of
our patients showed that the lesions with either hyper, iso or
hypointensity were all hyperintense on the ADC map. This
pattern is consistent with vasogenic edema. However, some
atypital presentations have been described in the last decade.
There have been reports of involvement of the frontal lobe,
cortical gray matter, brain stem, or basal ganglia.4,26-28Irre-
versible and hemorrhagic imaging findings have also been re-
ported.4,8,9,27In our patients, these atypical imaging presenta-
tions were found frequently (14/24), especially with frontal lobe
involvement, which was present in 54.2% of patients. In addi-
tion, we found involvement of cortical and basal ganglia gray
222 Journal of Neuroimaging Vol 21 No 3 July 2011
visual disturbance. Blood pressure was 160/120 mmHg. A1-A3 are the initial Flair-MRI images showing bilateral frontal-parietal subcortical
white matter hyperintensities. B1-B3 are the repeated Flair-MRI, revealing the lesion extension to the bilateral temporal-occipital lobe in addition
to the initial frontal-parietal lobe.
Atypical imaging of the lesions extension: A 17-year-old woman with acute intermittent porphyria presented with seizures, coma, and
matter and irreversible lesions. One patients was misdiagnosed
steroid and immunosupressant treatments. None of these 3 pa-
tients received treatment for blood pressure control or with-
drawal of the offending drug, resulting in irreversible clinical
and imaging findings. MRI, including DWI and MRV, should
be performed to exclude vascular lesions such as central venous
thrombosis and stroke. Analysis of the CSF is necessary to rule
tal for the prompt management of hypertension, the correction
of renal dysfunction and the withdrawal of the offending agents.
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224 Journal of Neuroimaging Vol 21 No 3 July 2011