Journal of Human Hypertension (2004) 18, 287–289 & 2004 Nature Publishing Group All rights reserved 0950-9240/04 $25.00 www.nature.com/jhh CASE REPORT Recurrent posterior reversible syndrome (PRES)

G Hagemann1, T Ugur1, OW Witte1 and C Fitzek2 1Department of , Friedrich-Schiller-University, Jena, Germany; 2Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University, Jena, Germany

Posterior reversible encephalopathy syndrome is a drome is usually fully reversible. We report a case of proposed cliniconeuroradiological entity characterized recurrent PRES of unknown aetiology following inten- by , altered mental status, cortical blindness, sive care unit treatment and only moderately elevated , and other focal neurological signs, and a blood pressure. Clinicians as well as radiologists must diagnostic magnetic resonance imaging picture. A be familiar with this clinically frightening, underdiag- variety of different etiologies have been reported like nosed condition to assure timely diagnosis and treat- hypertension, pre-/eclampsia, cyclosporin A ment to prevent persistent deficits. or tacrolimus neurotoxicity, uraemia and porphyria. Journal of Human Hypertension (2004) 18, 287–289. With early diagnosis and prompt treatment, the syn- doi:10.1038/sj.jhh.1001664

Keywords: PRES; reversible encephalopathy; cortical blindness

Introduction ferred to a normal ward, she showed a fluctuating agitated confusional state that was accounted for as Posterior reversible encephalopathy syndrome a prolonged alcohol withdrawal syndrome. She was (PRES) is a proposed cliniconeuroradiological entity 1,2 given vitamins, haloperidol and benzodiazepines with a vast spectrum of different aetiologies. The and gradually recovered. After 27 days, she was able clinical hallmark of this syndrome are headache, to walk a few steps without assistance, was fully confusion, seizures, cortical visual disturbances or orientated and did not show any focal neurological blindness and, less common, other focal neurologi- abnormality. All laboratory results but serum cal signs. A variety of causes are known, like glucose levels (15 mg/dl) and a decreasing CRP hypertension, pre-eclampsia/eclampsia, cyclosporin (50 mg/l) had returned to normal. At day 32 after A or tacrolimus neurotoxicity, uraemia and porphy- 2–6 admission, she complained of headache and pro- ria. We report a patient with recurrent PRES in gressive visual disturbance. The BP was 140/ whom blood pressure (BP) was only moderately 80 mmHg and the heart rate (HR) 90 minÀ1 and elevated and no other aetiology of PRES could be had been measured manually thrice a day (Figure 1) unfolded. with highest measurements of 170/115 mmHg (HR 80 minÀ1) 5 days before this episode. The Electrocardiogram showed a sinusrhythm and no Case report signs of left ventricular hypertrophy (Sokolow–Lyon criteria). On echocardiography, concentric left ven- A 42-year-old woman with a history of alcohol abuse tricular hypertrophy was found (IVSd+LVPWd: 21; developed an acute necrotizing pancreatitis with a height: 160 cm). Her serum level of sodium was severe sequelae of secondary diabetes, acute renal 131 mmol/l, potassium 4.02 mmol/l and creatinine and respiratory failure, which made intensive care 44 mmol/l. unit (ICU)-treatment with temporary assisted venti- On neurological examination, the patient was lation necessary. She was known to have medically found to have a confusional state, an , a treated arterial hypertension but BP was not mon- short-lasting cortical blindness, a prolonged homon- itored regularly. After 11 days, having been trans- ymous hemianopia to the right and a transient right- sided hemiparesis. Funduscopy was normal and did Correspondence: Dr G Hagemann, Department of Neurology, not reveal any signs of papilledema or hypertensive Friedrich-Schiller-University, Philosophenweg 3, 07740 Jena, retinopathy. A magnetic resonance imaging (MRI) Germany. E-mail: [email protected] scan revealed high signal intensities on T2-weighted Received 1 September 2003; revised and accepted 13 October images, which were most pronounced in the parieto- 2003 occipital cortices in both hemispheres (Figure 2a, b). Recurrent (PRES) G Hagemann et al 288 tendency to lower values during the second week after the episode. A follow-up MRI at day 48 showed a marked reduction of the former signal intensities in the posterior region with only slight hyperintensities around the ventricles but now a marked, clinically asymptomatic, hyperintensity in the pons was noticed (Figure 2c). At follow-up, 2 months later, the MRI was completely normal (Figure 2d). Figure 1 Systolic and diastolic BP (BP: upper part of diagram) and heart rate (HR: lower part of diagram) of patient during the whole stay in hospital (day of admission ¼ 0). BP was measured Discussion automatically intra-arterially during the stay in ICU (days 0–11) and manually by trained nursing staff thereafter. Grey-shaded PRES can be diagnosed with (massive) reversible lines depict time period when patient became neurologically symptomatic and was investigated with MRI and time point of hyperintensities on T2-weighted cranial MR-images. follow-up MRI, respectively. Predominantly, it affects the territory of the posterior circulation and the clinical hallmarks are headache, confusion, seizures, cortical visual disturbances or blindness and, less common, other focal neurologi- cal signs. Modern imaging modalities (diffusion weighted imaging (DWI) with apparent diffusion coefficients (ADC-maps)) could prove that most cases of PRES are caused by vasogenic rather than cytotoxic oedema.3,7 The pathogenesis is attributed to a failure of cerebral autoregulation that probably is facilitated in posterior brain regions due to a sparse sympathetic innervation of the vertebrobasi- lar vascular system.3,8 Isolated brainstem involve- ment is rare but has even been reported as a clinically silent reversible phenomenon.9–11 In any case, the absence of abnormalities on DWI (with increased ADC) can be interpreted as a favorable prognostic finding whereas increased signal on DWI or reduced ADC point towards frank ischaemia with cytotoxicity and cell loss.7 In our case DWI (b-value ¼ 1000 s/mm2) did not show any abnorm- ality, ADC values were increased in the lesions and neurological symptoms as well as T2-hyperintensi- ties were fully reversible. The aetiology of PRES in this patient remains unclear; BP was and has been only moderately high when the patient became symptomatic and had only transiently been higher when the pontine lesion occurred. However, most reports dealing with hypertensive encephalopathy describe systolic BP Figure 2 MRI of the patient (a) TSE-FLAIR image (turbo spin-echo values well above 200 mmHg or increments of BP, fluid-attenuated inversion recovery sequence) while patient was compared to measurements obtained at least 1 week symptomatic. Note the marked parieto-occipital hyperintensities. prior to the onset of symptoms, of at least 35%.3,11 It (b) Diffusion weighted image (trace image) at the same time point has been suggested that in patients with pre- shows no abnormality pointing towards interstitial oedema. (c) FLAIR sequence 2 weeks later reveals an asymptomatic lesion in eclampsia and cyclosporin A neurotoxicity, addi- the pons. (d) At follow-up, 2 months later, no abnormalities were tional factors predispose to leakage of blood vessels detectable with FLAIR (not shown for pons). even without high BP.1,4,9 In fact, in a group of women suffering neurological symptoms with pre- eclampsia/eclampsia occurrence of PRES was not associated with hypertension levels. Instead, in this A posterior reversible encephalopathy syndrome study, most women with PRES showed abnormal was suspected and BP treated more vigorously. red blood cell morphology.4 It can be speculated that The patient completely recovered within the in our patient the severe antecedent condition with following days. Despite antihypertensive medica- ICU-treatment and renal failure had a similar tion, more than 50% of BP measurements were preconditioning effect on the vascular territory, above 170/100 mmHg (HR 50–70/minÀ1) with a facilitating recurrent vasogenic oedema. As this

Journal of Human Hypertension Recurrent (PRES) G Hagemann et al 289 patient has had high BP before, with an echocardio- 3 Schwartz RB et al. Diffusion-weighted MR imaging in graphic evidence of left ventricular hypertrophy, hypertensive encephalopathy: clues to pathogenesis. it is conceivable that the BP increase, when Am J Neuroradiol 1998; 19: 859–862. becoming symptomic, was not really extraordinary 4 Schwartz RB et al. Preeclampsia–eclampsia: clinical for her. Even taken her ‘low’ BP during the and neuroradiographic correlates and insights into the pathogenesis of hypertensive encephalopathy. Radiol- postillness phase as a baseline, the increment ogy 2000; 217: 371–376. of BP during the first event was well below 30%. 5 Truwit CL et al. MR imaging of reversible cyclosporin Thus one feels reluctant to diagnose ‘hypertensive A-induced neurotoxicity. Am J Neuroradiol 1991; 12: encephalopathy’ and should favour ‘PRES’ in this 651–659. patient instead. 6 Utz N et al. MR imaging of acute intermittent The key to diagnosis in PRES naturally is the porphyria mimicking reversible posterior leukoence- image, but suspicion must be raised by the clinician. phalopathy syndrome. Neuroradiology 2001; 43: Both should be familiar with this underdiagnosed, 1059–1062. clinically frightening syndrome to avoid persistent 7AyHet al. Posterior leukoencephalopathy without deficits. It mostly is a benign, reversible condition, severe hypertension: utility of diffusion-weighted MRI. Neurology 1998; 51: 1369–1376. especially once the causative factor (eg hyperten- 8 Edvinsson L, Owman C, Sjoberg NO. Autonomic sion) can be eliminated. nerves, mast cells, and amine receptors in vessels. A histochemical and pharmacological study. Brain Res 1976; 115: 377–393. References 9 Casey SO, Truwit CL. Pontine reversible edema: a newly recognized imaging variant of hypertensive 1 Casey SO et al. Posterior reversible encephalopathy encephalopathy? Am J Neuroradiol 2000; 21: 243–245. syndrome: utility of fluid-attenuated inversion recov- 10 Chang GY, Keane JR. Hypertensive brainstem ence- ery MR imaging in the detection of cortical and phalopathy: three cases presenting with severe brain- subcortical lesions. Am J Neuroradiol 2000; 21: stem edema. Neurology 1999; 53: 652–654. 1199–1206. 11 Morello F et al. Hypertensive brain stem encephalo- 2 Hinchey J et al. A reversible posterior leukoencephalo- pathy: clinically silent massive edema of the pons. pathy syndrome. N Engl J Med 1996; 334: 494–500. Neurol Sci 2001; 22: 317–320.

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