Rare disease

CASE REPORT

Posterior reversible encephalopathy syndrome
revealing renal artery stenosis in a child
Gregoire Benoist,1 Claire Dossier,2 Monique Elmaleh,3 Stephane Dauger4
1

Department of Paediatric,
Hôpital Ambroise Paré, AP-HP,
University of Versailles SaintQuentin-en-Yvelines, Boulogne,
France
2
Department of Paediatric
Nephrology, Hôpital Robert
Debré, AP-HP, Université Paris
Diderot, Paris, France
3
Department of Paediatric
Radiologic, Hôpital Robert
Debré, AP-HP, Université Paris
Diderot, Paris, France
4
Department of PICU, Hopital
Robert Debré, AP-HP,
Université Paris Diderot, Paris,
France
Correspondence to
Dr Stephane Dauger,
stephane.dauger@rdb.aphp.fr

SUMMARY
A 14-year-old girl was admitted to the emergency
department for repeated seizures with no fever. High
blood pressure at admission was ascribed to the status
epilepticus. Seizure recurrence promoted transfer to the
paediatric intensive care unit. The MRI visualised
bilateral, subcortical, white-matter lesions in the parietal
and occipital lobes suggesting posterior reversible
encephalopathy syndrome (PRES). Continuous
nicardipine infusion corrected the hypertension and
neurological manifestations within a few hours. The
diagnostic workup showed right renal artery stenosis.
Blood pressure returned to normal values for age
after right nephrectomy. She was discharged home
without treatment. She had no residual neurological
impairments. This case highlights the risk of
misinterpreting sustained hypertension in children with
repeated seizures. We briefly review paediatric PRES,
which is rare as compared to adults. Increased
awareness among critical care physicians, together with
greater availability of cerebral MRI, is decreasing the
time to diagnosis.

were accompanied by transient loss of consciousness and stopped spontaneously within 5 min.
On admission, she had a third seizure with the
same clinical presentation and duration, which
stopped after intrarectal diazepam. Her weight was
65 kg, body temperature was 37.4°C, heart rate was
145/min, blood pressure was 150/100/115 mm Hg
and glycaemia was 8.8 mmol/L. She quickly regained
subnormal consciousness. A detailed neurological
evaluation showed normal vision and oculomotor
tests and a mild pyramidal syndrome; balance could
not be assessed. End of physical examination was
normal except for hypertension, which was ascribed
to repeated seizures. One hour later, a fourth generalised tonic–clonic seizure that lasted for 10 min was
followed by unconsciousness prompting her transfer
to the paediatric intensive care unit. She received
intravenous diazepam and phenytoin, treatments for
potential intracranial hypertension (invasive ventilation, mannitol injection and moderate fluid restriction), probabilistic antibiotic therapy and acyclovir.

INVESTIGATIONS
BACKGROUND
▸ Underdiagnosis of hypertension is frequent in
childhood and typically occurs in emergencies.
Underdiagnosis is due to the low prevalence of
paediatric hypertension, frequent lack of knowledge of normal values and difficulty of bloodpressure measurement.
▸ Hypertension is very common in status epilepticus and must be monitored closely to verify
resolution after seizure control.
▸ In contrast, PRES is very rare in children compared to adults.
▸ Paediatricians must be alert to PRES when
evaluating patients who have neurological symptoms such as headaches, seizures and visual
abnormalities with high blood pressure.
▸ Paediatricians must rule out kidney disease in
children with PRES, in addition to all other
causes (eg, chemotherapy and bone marrow
transplantation).

CASE PRESENTATION

To cite: Benoist G,
Dossier C, Elmaleh M, et al.
BMJ Case Rep Published
online: [ please include Day
Month Year] doi:10.1136/
bcr-2013-010110

A 14-year-old girl with an unremarkable medical
history was admitted to the paediatric emergency
department after two seizures at home in the last
20 min. She had a one-week history of nausea and
headache, and a more recent onset of blurred
vision, unsteadiness and abdominal pain, without
fever. Both seizures were focal, starting in the right
lower limb and then becoming generalised; they

Benoist G, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-010110

▸ Standard blood tests, including glycaemia and
calcaemia, were normal.
▸ Lumbar puncture was deferred due to clinical
severity.
▸ Cranial (CT) was the emergent brain-imaging
investigation because an MRI was unavailable.
Two intra-axial hypodensities involving the subcortical white matter of the left posterior parietal lobe were seen, with no mass effect or
contrast enhancement.
▸ MRI showed bilateral, subcortical and whitematter lesions in the parietal and occipital lobes
generating low signal on T1-weighted images
and high signal on T2-weighted images, with a
high apparent diffusion coefficient and no contrast enhancement
▸ (figure 1A).
These findings, together with neurological
manifestations and severe hypertension, suggested
PRES.
Results of diagnostic investigations were as follows:
▸ Funduscopy was normal;
▸ Echocardiography showed isolated left ventricular hypertrophy;
▸ Doppler ultrasonography evidenced right renal
atrophy without arterial flow and compensatory
hypertrophy of the left kidney;
▸ Abdominal CT angiography visualised an isolated tight stenosis of the right renal artery
(figure 1B); and
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Figure 1 (A) Cerebral MRI
fluid-attenuated inversion recovery
sequence, axial image through the
parietal lobes at the level of the lateral
ventricles: igh-intensity lesions in the
subcortical white matter.
Diffusion-weighted image: low signal
intensity of the lesion on the left
Apparent diffusion coefficient (ADC)
map: increased ADC indicating
vasogenic oedema. (B) Abdominal
CT-angiography: tight stenosis of the
right renal artery with atrophy of the
right kidney and enlargement of the
left kidney. (C) Pre- and post-captopril
isotopic renography: minimally
functioning right kidney, homogeneous
uptake by the left kidney.

▸ Post-captopril isotopic renography showed a minimally functioning right kidney and homogeneous uptake by the left
kidney (figure 1C).

DIFFERENTIAL DIAGNOSIS
Our patient was deficient of the bradycardia usually associated
with increased intracranial pressure or the fever that typically
accompanies encephalitis. Her history was not suggestive of
exposure to toxic agents.
Cerebral infarction and Guillain-Barré syndrome were among
the possible diagnoses.

TREATMENT
After identification of the renal artery stenosis, a continuous
nicardipine infusion was given. All neurological manifestations
were resolved within 24 h. She was then switched to long-acting
oral medications: nifedipine followed by amlodipine and finally,
by combined amlodipine and acebutolol because of refractoriness to monotherapy. These drugs were stopped after the
nephrectomy.
The aetiological treatment consisted in retroperitoneal laparoscopic nephrectomy, now considered the reference standard for
nephrectomy in children, given the minimal right kidney function and likely failure of angioplasty.

OUTCOME AND FOLLOW-UP
Blood pressure returned to normal for the patient’s age immediately after nephrectomy. The patient was discharged home
without medications and had no residual neurological impairments. Her blood pressure and kidney function were normal
1 year later. A Doppler study showed normal arterial flow in the
left kidney.
2

DISCUSSION
PRES, also known as reversible posterior leukoencephalopathy
syndrome, is a rare disorder most frequently reported in adults.
It is a clinical presentation usually combining headaches, nausea,
visual disturbances, seizures, drowsiness and confusion.
Paraplegia and peripheral facial paralysis have also been
reported. Neuro-imaging studies show abnormalities predominating in the parieto-occipital lobes.1 Hypertension is the most
frequent cause and the main conditions associated with PRES
are haematological and auto-immune diseases, haemolytic–
uremic syndrome, chronic renal failure, hepatitis C, HIV infection, blood transfusion and immunosuppressive drug therapy.2 3
The pathophysiology of PRES is incompletely understood.
When acute systemic blood-pressure elevation exceeds the
auto-regulatory capacity of the cerebral vasculature, focal vasodilatation and vasoconstriction develop, particularly in arterial
watershed zones, followed by blood–brain barrier disruption
with fluid transudation.4 Imaging abnormalities predominate in
the parieto-occipital lobes but involvement of the brain stem,
cerebellum, frontal and temporal lobes and basal ganglia has
been reported. An MRI showed hypointense lesions on
T1-weighted images and hyperintense lesions on T2-weighted
images. Vasogenic oedema with subsequent increases in the
apparent diffusion coefficient have been observed.5
PRES is rare in childhood,6 a fact that may partly explain failures to diagnose this condition early.7 Our case illustrates the
difficulty in interpreting hypertension in paediatric patients, particularly in emergencies. Underdiagnosis of paediatric hypertension is common due to lack of knowledge of normal values for
age and a tendency to ascribe high values to factors such as pain
or measurement error.8 Hypertensive crisis is defined as a
sudden blood-pressure elevation from baseline values normal
for age, gender and height.9 A hypertensive crisis is an
Benoist G, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-010110

Rare disease
emergency when there is a risk of acute end-organ damage
(central nervous, cardiovascular, or renal systems and eyes). In
our patient, the diagnosis of underlying sustained hypertension
was delayed because transient hypertension is common after
prolonged generalised tonic–clonic seizures. Physicians must
routinely check that blood pressure returns to normal values for
age within a few minutes after seizure resolution.
All hypertensive emergencies must be treated by a continuous
anti-hypertensive-drug infusion (which is safer than bolus injections) to obtain a controlled blood-pressure decrease.
Intravenous nicardipine has been found effective and well tolerated in doses of 1–3 μg/kg/min. The aim is to obtain an initial
blood pressure decrease of not more than 25% over the first 8 h
followed by gradual normalisation over 26–48 h.10 The clinical
and imaging abnormalities resolve rapidly as the blood pressure
decreases. Although residual impairments have been reported
after PRES,11 most patients recover completely. Routine
follow-up neuro-imaging studies are unnecessary when clinical
recovery is complete; they were not performed on our patient.
In a child with PRES, investigations for an underlying disease
are mandatory. Kidney and urinary tract abnormalities are the
most frequently reported causes of PRES in childhood. Many
children with secondary hypertension have reno-vascular abnormalities such as renal artery stenosis, whose main cause is fibromuscular dysplasia.12 The treatment relies initially on
antihypertensive drugs including a calcium channel blocker, a
β-blocker, or both. An ACP inhibitor can be used if bilateral
stenosis or a solitary kidney has been excluded. Percutaneous
transluminal renal angioplasty may be considered when medications fail to achieve adequate blood pressure control. Additional
stent implantation may be performed in the event of failed dilation or early restenosis.13 14 Surgical revascularisation and autotransplantation may be required by the characteristics of the
stenosis (ostial lesion, tight stenosis or extensive segmental renal
artery involvement), renal failure, failed non-operative management or failed angioplasty. Nephrectomy is the best treatment
for a unilateral atrophic kidney with poor function and a
normal contralateral kidney, as documented in our patient.15

Contributors GB wrote the first version of the manuscript. CD was in the charge
of this child all along her stay in hospital after discharge. She actively participated to
reading and correction of the manuscript. ME performed all clinical images of this
child during diagnosis procedure and wrote the radiological description and the
legend of figure 1. SD designed the presentation of the manuscript and wrote
according to all authors suggestions.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.

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Learning points

15

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Dinsdale HB, Robertson DM, Haas RA. Cerebral blood flow in acute hypertension.
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Shroff R, Roebuck DJ, Gordon I, et al. Angioplasty for renovascular hypertension in
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Johal NS, Kraklau D, Cuckow PM. The role of unilateral nephrectomy in the
treatment of nephrogenic hypertension in children. BJU Int 2005;95:140–2.

▸ Do not neglect hypertension in emergencies, even in case of
prolonged or repeated seizures. Hypertension due to seizures
resolves rapidly after seizure resolution.
▸ Suspect posterior reversible encephalopathy syndrome (PRES)
in a child with hypertension and headache, vomiting, visual
disturbances, seizures, drowsiness and confusion. Absence of
fever increases the index of suspicion.
▸ MRI is the neuro-imaging technique of choice in patients
with suspected PRES.
▸ Start a continuous antihypertensive-drug infusion as soon as
possible to gradually decrease blood pressure to normal
values for age.
▸ Perform a comprehensive diagnostic work-up including
investigations for kidney disease.

Benoist G, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-010110

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Benoist G, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-010110