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a 71-year - old female patient ( height : 143 cm and weight : 48 kg ) was scheduled for posterior decompression and posterolateral fusion of l4 - 5-s1 under general anesthesia for spinal stenosis .
she never has been diagnosed with any disease , including hypertension . on the preoperative evaluation ,
the ecg showed right bundle branch block ; cardiomegaly and pulmonary vascular congestion were noted on the chest plain radiography .
the bp after entering operating room was 175/87 mmhg and the heart rate ( hr ) was 68 beats / min ( bpm ) .
anesthesia was induced with 100 mg of propofol , 50 mg of rocuronium and 40 g of remifentanil .
a 20-g catheter was placed on the left radial artery and a 16-g intravenous catheter was inserted .
the surgical team moved the patient in the prone position for the surgical position , and after that , the bp was elevated to 175/87 mmhg and the hr was 68 bpm . during the surgery , the vital signs were maintained within the normal ranges . on completion of surgery , glycopyrrolate 0.2 mg and pyridostigmine 10 mg were administrated to reverse the residual muscle relaxation .
the endotracheal tube was removed after confirming that the patient was awake and the muscle function had been fully restored .
the operation time was 3 h 15 min , and the duration of anesthesia was 3 h 50 min . in the recovery room , the initial bp was 128/73 mmhg , the hr was 91 bpm , the respiratory rate was 15 breaths / min and the pulse oximetry was 100% .
after 30 minutes , she responded to her name , but she was drowsy and answered incoherent words to verbal questions .
after several minutes , she vomited two times and then generalized tonic - clonic seizure occurred .
her bp was elevated , but the systolic bp remained at 140 to 165 mmhg , and the diastolic bp was 60 to 90 mmhg .
the patient was evaluated with computed tomography ( ct ) and magnetic resonance imaging ( mri ) .
the t2 weighted mri showed swelling and an increased signal intensity at the deep gray nuclei , cerebral cortex and cerebellum ( fig .
she was transferred to the intensive care unit ( icu ) for close monitoring and conservative management . in the icu , 900 mg / day of prophylactic sodium valproate was given intravenously to prevent the recurrence of seizure until postoperative day 13 .
her blood pressure is slightly above the normal range with a systolic bp of 130 to 160 mmhg and a diastolic bp of 70 to 90 mmhg .
on postoperative day 4 , the patient 's trachea was intubated due to a decreased mental status and possible aspiration pneumonia . on postoperative day 7 , mri was repeated and prominent subcortical lesions were mainly distributed in the posterior part of the brain ( fig .
at this time , pres was diagnosed according to the neuroimaging findings and the medical condition of her high blood pressure . on the 8th day
she was transferred to a general ward and oral antihypertensive medication with amlodipine 5 mg was started .
pres was first described in 1996 as a combination of neurological abnormalities and imaging findings that develop in patients with acute medical illness or in those who are being treated with immunosuppressive drugs .
the syndrome was initially recognized in association with severe hypertension , autoimmune disease , malignancy , immunosuppressive therapy or pregnancy .
clinically , the most common symptom is generalized seizure associated with brain edema . according to roth and ferbert 's report ,
other frequent symptoms were visual changes ( 60% ) , altered mental function ( 56% ) , headache ( 52% ) and nausea and vomiting ( 28% )
. there were 22 cases with elevated blood pressure , and the mean systolic blood pressure for all the patients was 170  37 mmhg .
the neuroimaging abnormalities seen on ct and mri typically show focal regions of symmetric white matter edema that most commonly affect the parietal and occipital lobes , and the posterior aspect of the frontal lobes might also be affected .
the posterior circulation supplied by the vertebro - basilar system has poor sympathetic innervation and so it is believed to be frequently involved .
two opposing hypotheses are commonly cited : 1 ) the current more popular theory suggests that severe hypertension exceeds the limits of autoregulation , leading to breakthrough brain edema and 2 ) the earlier original theory suggests that hypertension leads to cerebral autoregulatory vasoconstriction , ischemia and subsequent brain edema . the hypertension / hyperperfusion theory
is primarily based on the blood pressure exceeding the autoregulation limits of the brain . however , the problems with this theory is that pres is commonly seen without hypertension or with only a minor increase of blood pressure , as noted in the larger studies [ 10 - 12 ] .
further investigations will be needed to more clearly understand the pathogenesis of pres . reducing the blood pressure and seizure control are very important to treat and
magnesium sulfate has been the first line treatment for the patients who have eclampsia with pres .
antihypertensive drugs , including hydralazine and labetalol , and antiseizure medication with close monitoring are recommended for the other patients with pres . in our case ,
the acute elevation of blood pressure such as occurred after position change was regarded as the major trigger factor for pres . owing to the brain edema and swelling , our patients showed generalized seizure and a stuporous mentality in the recovery room .
we left much to be desired concerning the untreated preoperative hypertension and the delayed diagnosis .
as seen in this case , we should consider the possibility of pres in patients with delayed emergence from general anesthesia , and especially for the patients with hypertension and/or eclampsia , or those who are receiving immunosuppressive therapy .
having a clinical suspicion is most important for the early recognition and diagnosis of pres .
so , we recommend early brain imaging evaluation for the suspected patients and strict blood pressure control because the latter is an important factor to prevent further brain damage .
posterior reversible encephalopathy syndrome ( pres ) is an unfamiliar term to anesthesiologists , and this is characterized by neurologic symptoms that include mental change , headache , seizure and visual disturbance and also abnormal neuroimaging finding . 
 a 71-year - old female patient was operated on for posterior decompression and total laminectomy under general anesthesia for the spinal stenosis . 
 after the operation , she developed generalized tonic - clonic seizure and a stuporous mentality in the recovery room . 
 the magnetic resonance imaging ( mri ) revealed swelling and increased signal intensity at the deep gray nuclei , cerebral cortex and cerebellum . 
 after one week , she returned to an alert mentality and then she was diagnosed with pres . 
 she was discharged without any neurologic deficit on postoperative day 20 . 
 this report describes our experience with pres after spinal surgery was performed under general anesthesia on a suspected untreated hypertensive patient .