POSTERIOR REVERSIBLE ENCEPHALOPATHY SYNDROME

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POSTERIOR REVERSIBLE ENCEPHALOPATHY SYNDROME (PRES):

POSTERIOR REVERSIBLE ENCEPHALOPATHY SYNDROME (PRES) Dr Prashant Makhija

HISTORICAL BACKGROUND:

HISTORICAL BACKGROUND In 1897, Vaquez and Nobecourt pointed out the correlation of toxemia of pregnancy and HTN In1928, Oppenheimer and Fishberg introduced the term hypertensive encephalopathy In 1996, Hinchey and colleagues first described the clinical condition- as reversible posterior leukoencephalopathy ( RPLE) Semin Neurol 2011;31:202–215 Crit Care & Shock (2009) 12:135-143

POSTERIOR REVERSIBLE ENCEPHALOPATHY:

POSTERIOR REVERSIBLE ENCEPHALOPATHY Is a Clinicoradiological entity Clinical features - headache, mental confusion, seizures and visual disturbances Radiological features - pattern of bilateral white matter abnormalities in the posterior regions of both cerebral hemispheres Other terms reversible posterior leukoencephalopathy reversible posterior cerebral edema syndrome reversible occipital parietal encephalopathy “potentially reversible encephalopathy syndrome” J Intensive Care Med 2012 27: 11 S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

Dynamics of Cerebral Blood Flow:

Dynamics of Cerebral Blood Flow The normal cerebral blood flow ~ 50 ml/100gm/min Cerebral blood flow varies directly with the cerebral perfusion pressure and inversely with the cerebral vascular resistance CPP = MAP – CVP CBF=(MAP – CVP) / CVR Cerebral resistance arterioles respond to the MAP rises with compensatory vasoconstriction that maintains a relatively constant cerebral blood flow There is relative paucity of sympathetic innervation in posterior circulation Semin Neurol 2011;31:202–215

PowerPoint Presentation:

Wide range of mean arterial pressures (MAP; 50 mm Hg to 150 mm Hg) With chronic HTN, the resistance arterioles undergo proliferation of the muscular media adapting to the chronically high perfusion pressures This results in a shift of the autoregulation curve to the right This adaptation allows the maintenance of normal CBF at higher mean arterial pressures The shift also limits vascular dilation and makes the CBF vulnerable to rapid lowering of the MAP Semin Neurol 2011;31:202–215

NORMAL CEREBRAL AUTOREGULATION:

NORMAL CEREBRAL AUTOREGULATION Semin Neurol 2011;31:202–215

DYNAMICS OF CBF IN PTS WITH CHRONIC HTN:

DYNAMICS OF CBF IN PTS WITH CHRONIC HTN Semin Neurol 2011;31:202–215

PATHOPHYSIOLOGY:

PATHOPHYSIOLOGY Pathophysiology of PRES is poorly understood Disruption of BBB → Vasogenic Edema Cerebral Hyperperfusion - breakdown of Cerebral autoregulation due to rapid ↑ in BP Cerebral Hypoperfusion - endothelial dysfunction Pract Neurol 2011; 11: 136–144 S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

Pathogenesis of PRES:

Pathogenesis of PRES

COMORBID CONDITIONS/TRIGGERS:

COMORBID CONDITIONS/TRIGGERS Pregnancy-related conditions Eclampsia Hydatidiform mole Major medical illness Organ transplantation Thrombotic thrombocytopenic purpura Henoch-Scho¨nlein purpura Autoimmune inflammatory disease: systemic lupus, scleroderma, Wegener’s, periarteritis nodosa Sepsis/systemic inflammatory response syndrome/multiple organ failure Alcohol and drug withdrawal Hypomagnesemia , hypercalcemia , hypocholesterolemia Semin Neurol 2011;31:202–215

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Neurologic illness Guillain-Barre ´ ’s syndrome Spinal cord injury with autonomic dysreflexia Head injury Drugs that cause endothelial dysfunction Immunosuppressant agents - Cyclosporine A Chemotherapeutic agents, especially high-dose multidrug - Tacrolimus (FK506), Cisplatin , Gemcitabine , Bevacizumab Erythropoietin Blood transfusion Indinavir Cytarabine IVIg Semin Neurol 2011;31:202–215

CLINICAL FEATURES:

CLINICAL FEATURES Epidemiology Age- 4 to 90 years, most cases occur in young to middle-aged adults, the mean age ranging across case series from 39 to 47 years Female predominance Consciousness impairment severity from confusion, somnolence, and lethargy to coma reported in 13 % to 90 % of cases Seizure Up to 92 % of cases rarely focal (23 %-28 %) ,Secondary generalized seizures are common (53–62 %) Status epilepticus , has been described in 3 % to 13 % of patients Annual Update in Intensive Care and Emergency Medicine 2011

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Headache s and nausea/vomiting were reported in 26 % to 53 % of patients Visual abnormalities found in 26 % to 67 % of patients blurred vision (7 % -18 %) visual neglect (4 %-27 %) homonymous hemianopsia (4 % -20 %) visual hallucinations (3 % -5 %) cortical blindness (8 %-33 %) Focal neurological signs None to 3-17% cases Annual Update in Intensive Care and Emergency Medicine 2011

Distribution of clinical features in cohort studies of PRES:

Distribution of clinical features in cohort studies of PRES Clinical Features Hinchey 1996 (N=13) Bartynski 2007(N=136) McKinney 2007(N=76) Lee 2008(N=36) Burnett 2010(N=79) Consciousness impairment 10 (67 %) 39 (26 %) 10 (13 %) 34 (94 %) 76 (90 %) Seizure 11 (73 %) 97 (71 %) 58 (76 %) 33 (92 %) 56 (70 %) Headaches 8 (53 %) 39 (26 %) 3 (4 %) 19 (53 %) 26 (31 %) Visual abnormalities 10 (67 %) 39 (26 %) 3 (4 %) 13 (36 %) 24 (29 %) Nausea/vomiting 8 (53 %) 39 (26 %) NR NR NR Focal neurological signs NR NR 2 (3 %) 1 (3 %) 14 (17 %) Acute hypertension 12 (80 %) 91 (67 %) NR NR 62 (78 %) Annual Update in Intensive Care and Emergency Medicine 2011

RADIOLOGICAL CHARACTERISTICS OF PRES:

RADIOLOGICAL CHARACTERISTICS OF PRES 1. Holohemispheric watershed pattern (23 %) watershed zone between the anterior and posterior cerebral arteries, on the one hand, and the middle cerebral artery, on the other confluent vasogenic edema extends through the frontal, parietal, and occipital lobes S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

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2. Superior frontal sulcus pattern (27 %) Patchy edema predominates in the frontal lobes along the superior frontal sulci parietal and occipital lobes are variably involved S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

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3. Dominant parietal-occipital pattern (22 %) previously thought to be typical of PRES posterior part of the parietal and occipital lobes is predominantly involved S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

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4. Partial / asymmetric expression of the primary patterns (28 %) absence of involvement of either the parietal or the occipital lobes and asymmetric abnormalities in the affected parietal or occipital lobes S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

Complications diagnosed radiologically:

Complications diagnosed radiologically Cerebral ischemia Reported to occur in 10 to 23% of pts. non-reversible damage associated with adverse outcomes Cerebral herniation Posterior edema, particularly when located in the cerebellum and brainstem, may cause transtentorial cerebral herniation S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

PowerPoint Presentation:

Cerebral hemorrhage uncommon in PRES- 5 to 17% of pts. parenchymal hematoma, subarachnoid hemorrhage, and focal intraparenchymal hemorrhage measuring less than 5mm in diameter more common among patients with allogeneic bone marrow transplantation or anticoagulant treatment S. Legriel, F. Pico, and E. Azoulay. Annual Update in Intensive Care and Emergency Medicine 2011

Radiological features in cohort studies of PRES:

Radiological features in cohort studies of PRES Radiological Features Hinchey 1996 (N=13) Casey 2000 N = 16 Bartynski 2007(N=136 McKinney 2007(N=76) Lee 2008(N=36) Burnett 2010(N=79) Bilateral 15 (100 %) 11 (69 %) > 98 (> 72 %) NR 36 (100 %) NR Asymmetric 10 (67 %) NR 21 (15 %) 2 (3 %) NR NR Confluent NR 2 (13 %) 31 (23 %) 44 (58 %) 2 (13 %) 12 (16 %) Gray matter 4 (27 %) NR NR 22 (29 %) 16 (44 %) NR Posterior > anterior 14 ( 93 % ) 15 ( 94 % ) 30 (22 %) NR NR NR Occipital 14 (93 %) NR 134 (99 %) 75 (99 %) NR NR Parietal 13 (87 %) 8 (50 %) 134 (99 %) 75 (99 %) NR 50 (67 %) Frontal 7 (47 %) 14 (88 %) 93 (68 %) 60 (89 %) 22 (61 %) 61 (81 %) Temporal 9 (60 %) 16 (100 %) 55 (40 %) 52 (68 %) NR 62 (83 %) Brainstem 2 (13 %) NR 17 (13 %) 14 (18 %) 21 (58 %) NR Cerebellum 1 (7 %) NR 41 (30 %) 26 (34 %) 21 (58 %) NR Basal ganglia 1 (7 %) 3 (19 %) 19 (14 %) 9 (12 %) NR NR

DIFFERENTIAL DIAGNOSIS:

DIFFERENTIAL DIAGNOSIS Posterior circulation stroke usually no seizures infarction shows( cytotoxic oedema ) hyperintensity on DWI with low signal on the corresponding ADC map while, in contrast, PRES ( vasogenic edema) shows the exact opposite on ADC mapping Pract Neurol 2011; 11: 136–144

PowerPoint Presentation:

Reversible cerebral vasoconstriction syndrome Thunderclap headache PRES quickly progresses over a few hours, complications may occur for several days with the RCVS Imaging PRES- Bilateral parieto -occipital lesions on MRI, typical for PRES Imaging RCVS- classic pattern of ‘string of beads’ on Angiography, at least two narrowings per artery on two different cerebral arteries at brain magnetic resonance angiography (MRA) or at conventional angiography in about 10% of cases there seems to be overlap between this syndrome and PRES Pract Neurol 2011; 11: 136–144

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Primary CNS vasculitis Symptoms usually come on more insidiously CSF is abnormal, with more than 95% of cases showing an inflammatory reaction MRI may show multiple infarcts of different ages Encephalitis in PRES there are no systemic features of inflammation (fever, blood tests, CSF) Pract Neurol 2011; 11: 136–144

MANAGEMENT:

MANAGEMENT Principles of Management General measures- aimed at maintaining ABC of the patient Symptomatic therapy Antihypertensives Anticonvulsants Correction/Removal of the underlying cause Withdrawl of offending drug Termination of pregnancy

MANAGEMENT OF BLOOD PRESSURE:

MANAGEMENT OF BLOOD PRESSURE No empirically established guidelines are available for the optimal degree of BP lowering A 20% reduction in the MAP is a reasonable goal for immediate reduction in hypertensive crises The above goal should be reached within the first 2 hours and to bring the blood pressure down to 160/100 mmHg within the first 6 hours Ideal agent - IV administration, has a rapid onset and short duration of action allowing rapid titration to effect, and be free of limiting side effects- labetolol , hydralazine , nicardipine , or fenoldopam Semin Neurol 2011;31:202–215 Annual Update in Intensive Care and Emergency Medicine 2011

PROGNOSIS:

PROGNOSIS Brain lesions are reversible Most studies- excellent short term and long term outcome symptoms usually seem to resolve in about 3–8 days while recovery of the MRI abnormalities takes longer—several days to weeks The ideal timing of repeat MRI is about 7–10 days after onset of symptoms when there should usually be clear improvement of the MRI abnormalities Pract Neurol 2011; 11: 136–144

PowerPoint Presentation:

Occasionally poor neurological outcome has been mentioned as being due to conversion from primary vasogenic into cytotoxic oedema Poor outcome may also be related to associated comorbidity (sepsis) or intracerebral haemorrhage A retrospective review of PRES cases between 1998 and 2005 suggested recurrent PRES episodes occur in ~ 4% of cases Studies report up to 15 % mortality rate Pract Neurol 2011; 11: 136–144 Annual Update in Intensive Care and Emergency Medicine 2011

CONCLUSION:

CONCLUSION PRES is a clinicoradiological syndrome and its symptoms and signs develop over hours —a combination of seizures, disturbed vision, altered mental function and headache MRI is the diagnostic gold standard . There is predominant affection of parieto -occipital subcortical white matter of both hemispheres.Typical PRES lesions on MRI are thought to represent vasogenic oedema There are many different trigger factors , most commonly abrupt hypertension , renal failure, immunosuppressive therapy, eclampsia , autoimmune disease and infections

PowerPoint Presentation:

The prognosis is good and recurrence rare . Symptoms generally resolve within a week. MRI lesions resolve somewhat more slowly Treatment consists of antihypertensive drugs, withdrawal of medication such as chemotherapy, and treatment of any underlying disease

PowerPoint Presentation:

THANK YOU

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