Posterior reversible encephalopathy syndrome: incidence of atypical regions of involvement and imaging findings

Hemorrhage in posterior reversible encephalopathy syndrome: imaging and clinical features

BACKGROUND AND PURPOSE

Hemorrhage is known to occur in posterior reversible encephalopathy syndrome (PRES), but the characteristics have not been analyzed in detail. The purpose of this study was to evaluate the imaging and clinical features of hemorrhage in PRES.

MATERIALS AND METHODS

Retrospective assessment of 151 patients with PRES was performed, and 23 patients were identified who had intracranial hemorrhage at toxicity. Hemorrhage types were identified and tabulated, including minute focal hemorrhages (<5 mm), sulcal subarachnoid hemorrhage, and focal hematoma. Clinical features of hemorrhage and nonhemorrhage PRES groups were evaluated, including toxicity blood pressure, coagulation profile/platelet counts, coagulation-altering medication, and clinical conditions associated with PRES. Toxicity mean arterial pressure (MAP) groups were defined as normal (<106 mm Hg), mildly hypertensive (106-116 mm Hg), or severely hypertensive (>116 mm Hg).

RESULTS

The overall incidence of hemorrhage was 15.2%, with borderline statistical significance noted between the observed clinical associations (P = .07). Hemorrhage was significantly more common (P = .02) after allogeneic bone marrow transplantation (allo-BMT) than after solid-organ transplantation. The 3 hemorrhage types were noted with equal frequency. A single hemorrhage type was found in 16 patients, with multiple types noted in 7. Patients undergoing therapeutic anticoagulation were statistically more likely to develop hemorrhage (P = .04). No difference in hemorrhage incidence was found among the 3 blood pressure subgroups (range, 14.9%-15.9%).

CONCLUSIONS

Three distinct types of hemorrhage (minute hemorrhage, sulcal subarachnoid hemorrhage, hematoma) were identified in PRES with equal frequency. The greatest hemorrhage frequency was seen after allo-BMT and in patients undergoing therapeutic anticoagulation. Hemorrhage rate was independent of the toxicity blood pressure.

Acute toxic leukoencephalopathy: potential for reversibility clinically and on MRI with diffusion-weighted and FLAIR imaging

OBJECTIVE

Toxic leukoencephalopathy may present acutely or subacutely with symmetrically reduced diffusion in the periventricular and supraventricular white matter, hereafter referred to as periventricular white matter. This entity may reverse both on imaging and clinically. However, a gathering together of the heterogeneous causes of this disorder as seen on MRI with diffusion-weighted imaging (DWI) and an analysis of their likelihood to reverse has not yet been performed. Our goals were to gather causes of acute or subacute toxic leukoencephalopathy that can present with reduced diffusion of periventricular white matter in order to promote recognition of this entity, to evaluate whether DWI with apparent diffusion coefficient (ADC) values can predict the extent of chronic FLAIR abnormality (imaging reversibility), and to evaluate whether DWI can predict the clinical outcome (clinical reversibility).

MATERIALS AND METHODS

Two neuroradiologists retrospectively reviewed the MRI examinations of 39 patients with acute symptoms and reduced diffusion of periventricular white matter. The reviewers then scored the extent of abnormality on DWI and FLAIR. ADC ratios of affected white matter versus the unaffected periventricular white matter were obtained. Each patient's clinical records were reviewed to determine the cause and clinical outcome. Histology findings were available in three patients. Correlations were calculated between the initial MRI markers and both the clinical course and the follow-up extent on FLAIR using Spearman's correlation coefficient.

RESULTS

Of the initial 39 patients, seven were excluded because of a nontoxic cause (hypoxic-ischemic encephalopathy [HIE] or congenital genetic disorders) or because of technical errors. In the remaining 32 patients, no correlation was noted between any of the initial MRI markers (percentage of ADC reduction, DWI extent, or FLAIR extent) with the clinical outcome. Three patients had histologic correlation. However, moderate correlation was seen between the extent of abnormality on initial FLAIR and the extent on follow-up FLAIR (r = 0.441, p = 0.047). Of the 13 patients who underwent repeat MRI at 21 days or longer, the reduced diffusion resolved in all but one. Significant differences were noted between ADC values in affected white matter versus unaffected periventricular white matter on initial (p < 0.0001) but not on follow-up MRI (p = 0.13), and in affected white matter on initial versus follow-up (p = 0.0014) in those individuals who underwent repeat imaging on the same magnet (n = 9), confirming resolution of the DWI abnormalities.

CONCLUSION

Acute toxic leukoencephalopathy with reduced diffusion may be clinically reversible and radiologically reversible on DWI, and may also be reversible, but to a lesser degree, on FLAIR MRI. None of the imaging markers measured in this study appears to correlate with clinical outcome, which underscores the necessity for prompt recognition of this entity. Alerting the clinician to this potentially reversible syndrome can facilitate treatment and removal of the offending agent in the early stages.

Atypical imaging findings in a renal transplant patient with reversible posterior leukoencephalopathy syndrome: a case report

Background

Atypical clinical and imaging findings in Reversible Posterior Leukoencephalopathy Syndrome are recognized with increasing frequency.

Case report

We report a case of an adult in his 5^th decade immunosupressed with methilprednisolone, tacrolimus and micophenolate who two months after renal transplantation, multiple infections and an episode of humoral rejection became hypertensive with severe headaches, visual field abnormalities, seizures, left hemiparesis and hemineglect.

Computed Tomography scan of the brain showed a hypo dense lesion in the left occipital lobe. Ischemic stroke was diagnosed and aspirin and permissive hypertension were indicated. Twelve hours later he developed left sided motor seizures and cortical blindness. Magnetic Resonance Image showed hyper intensity in T2 and FLAIR in both occipital lobes and a small area of cortical restricted diffusion in Diffuson Weighted Images in the left occipital lobe. With a diagnosis of Reversible Posterior Leukoencephalopathy Syndrome his blood pressure was controlled with intravenous labetalol, and two days later the neurologic findings returned to baseline and most Computed tomography findings resolved.

Conclusion

This case underscores that in the appropriate setting Reversible Posterior Leukoencephalopathy Syndrome should be suspected and the clinician should not be misled by atypical clinical or imaging findings. In contrast to other pathologies that resemble Reversible Posterior Leukoencephalopathy Syndrome, with the right and timely treatment, signs, symptoms and images can be completely reversible.

Posterior reversible encephalopathy syndrome associated with hemorrhage

BACKGROUND

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico-radiological entity characterized by headache, encephalopathy, visual disturbances, and seizures in association with reversible vasogenic edema on neuroimaging. Intracerebral hemorrhage associated with PRES (PRES-ICH) is generally considered an atypical finding.

METHODS

Retrospective case series.

RESULTS

Seven patients were identified with PRES-ICH, four males and three females. The presenting clinical symptoms included headache (2), encephalopathy (5), vision changes (2), seizures (2), and hemiparesis (1). The co-morbid conditions included acute renal dysfunction (3), solid organ transplantation (3), bone marrow transplant (1), use of calcineurin inhibitor agents (4), and pre-eclampsia (1). Neuroimaging revealed intraparenchymal hemorrhage in six patients and subarachnoid hemorrhage in one patient. Six of the seven patients with PRES-related ICH had underlying bleeding diathesis, including one patient who was anti-coagulated with a heparin drip. The mean platelet count was 82.1 x 10(3)/microl (range, 4-232 x 10(3)/microl), and the mean INR value was 2.18 (range, 0.9-6.7). Two patients died during the acute hospitalization. Among the five survivors, only two patients had good functional outcome (pre-defined as mRS < or = 1).

CONCLUSION

In our series, the majority of patients with PRES-ICH (85%) had an underlying bleeding diathesis or coagulopathy. Although PRES is typically considered to have a favorable prognosis, the clinical outcome of PRES with associated ICH can be more variable.

Posterior reversible encephalopathy syndrome after combined general and spinal anesthesia with intrathecal morphine

We describe a patient who was in a stupor for several days after combined general-spinal anesthesia. Both clinical manifestations and magnetic resonance imaging findings were consistent with posterior reversible encephalopathy syndrome and resolved after the patient recovered spontaneously.

Posterior reversible encephalopathy syndrome

PURPOSE OF REVIEW

The ophthalmologist may be called upon to evaluate visual loss in a patient with posterior reversible encephalopathy syndrome. Familiarity with presentation and clinical management is imperative, as visual loss is often reversible with prompt treatment directed at causative factors.

RECENT FINDINGS

Since its initial description in 1996, the predisposing factors, clinical presentation and radiographic variation of posterior reversible encephalopathy syndrome continue to expand. Case reports of newly uncovered associations of the syndrome appear frequently. Originally considered a subcortical disease of the posterior cerebrum, posterior reversible encephalopathy syndrome has been shown to affect gray matter and can involve both the anterior and posterior cortex, brainstem, cerebellum or even the spinal cord. The pathophysiologic basis of cerebral edema and molecular mechanisms of edema underlying the syndrome are currently being revealed.

SUMMARY

Acute hypertension, eclampsia, immunosuppressive medication, infection or autoimmune diseases can all result in the clinical syndrome of vasogenic edema in the central nervous system leading to headache, seizure, confusion and frequent visual loss. The biologic basis for the syndrome is likely an insult to cerebral vascular autoregulation. MRI is essential in diagnosing a cerebral cause for visual loss. The ophthalmologist may have the initial opportunity to diagnose the syndrome. Treatment may reverse clinical deficits, and is based on eliminating the etiologic causation.

Reversible unilateral brain edema presenting with major neurologic deficit after valve repair

Brain edema after cardiac surgery is unusual and often asymptomatic. We encountered a 34-year-old man who had postoperative left flaccid hemiplegia and anosognosia after undergoing composite root replacement and closure of a patent foramen ovale. Computed tomographic and magnetic resonance imaging (MRI) scans showed profound white matter changes indicative of brain edema predominantly in the right hemisphere. His symptoms resolved spontaneously within 3 days with resolution of MRI abnormality. No evidence of cerebral infarction was documented on diffusion-weighted imaging and apparent diffusion coefficient mapping, or on the follow-up MRI obtained 25 days after presentation. The cause for the unilateral brain edema is unknown, but the patient's clinical course and imaging are supportive for a variant of a hyperperfusion syndrome or reversible encephalopathy. The outcome was excellent.

Posterior reversible encephalopathy syndrome, part 1: fundamental imaging and clinical features

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique CT or MR imaging appearance. Recognized in the setting of a number of complex conditions (preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune disease and high dose chemotherapy) the imaging, clinical and laboratory features of this toxic state are becoming better elucidated. This review summarizes the basic and advanced imaging features of PRES, along with pertinent features of the clinical and laboratory presentation and available histopathology. Many common imaging/clinical/laboratory observations are present among these patients, despite the perception of widely different associated clinical conditions.

Atypical reversible posterior leukoencephalopathy syndrome in thrombotic thrombocytopenic purpura

A 32-year-old man with an atypical form of reversible leukoencephalopathy syndrome (RPLS) caused by thrombotic thrombocytopenic purpura (TTP) is reported. In this particular case, a timely diagnosis of TTP was established primarily on the clinical findings, which led to the early initiation of plasmapheresis and resulted in excellent clinical recovery. The pathophysiological aspects of the relationship between TTP and RPLS are discussed in light of the clinical and radiological features (including diffusion- and perfusion-weighted magnetic resonance imaging studies) of this case. The mechanism for TTP-associated, or TTP-induced, leukoencephalopathy is suggested to be independent of hypertension and vasoconstriction. TTP-associated endothelial injury can play a major role as the inciting mechanism for the development of RPLS.