|
●診断：Posterior reversible
encephalopathy
●Diagnostic Keys
・Clinical
During chemotherapy
Increased blood pressure
・Imaging
Bilateral occipital
Subcortical white matter
Symmetrical
Mild mass effect
Posterior reversible encephalopathy (PRES)
●Anonymous
・Reversible posterior leukoencephalopathy
・Reversible posterior cerebral edema syndrome
●Etiologies (numerous!)
・Hypertensive encephalopathy
・HT, eclampsia, cyclosporine toxicity
・Uremic encephalopathy
・Uremia, GN, HUS,TTP
Mechanism of PRES (1)
 Overaction
of cerebral autoregulation system
↓
Reversible vasospasm
↓
Potentially reversible ischemia
 Breakthrough of cerebral
autoregulation system
↓
Arterial dilatation
↓
Brain hyperperfusion
↓
Extravasation of fluid & macromolecules
Mechanism of PRES (2)
 Toxins associated with uremia
↓
Endothelial injury
↓
Breakdown of the BBB
↓
Concentration of intracranial ‘uremic toxins’
 Intravascular microthrombi
↓
Occlude cerebral arterioles
↓
Hypoxia & associated edema
↓
Infarction with or w/o hemorrhage
Imaging findings of PRES
●Location
・White matter > gray matter
・Posterior circulation > anterior circulation
・Poorer sympathetic innervation (?)
・Basal ggl, int. et ext. capsule
・Fed by small fragile end-arteries
●Generally symmetric
●Decreased SI in T1, increased SI in T2
●Mild mass effect
●Contrast enhancement can be seen
●Completely resolves without any sequelae
第18病日
 
この時はほぼ ‘reversible’ …
同一患者の後日談（付録）
左副腎原発神経芽細胞腫 stage II
化学療法第２クール。第9日に熱発と一過性血圧上昇あり。第13日、数日前より骨髄抑制強く感染徴候あり。朝再び意識レベル低下に続き間代性痙攣出現。
今回は血圧上昇なし
発症当日CT, 第２病日MRI
  
第38病日 MRI
必ずしも ‘reversible’ ではない！
References
1. Port JD, Beauchamp NJ, Jr. Reversible intracerebral pathologic
entities mediated by vascular autoregulatory dysfunction. Radiographics
1998;18(2):353-67.
2. Casey SO, Sampaio RC, Michel E, Truwit Cl. Posterior reversible
encephalopathy syndrome: utility of fluid-attenuated inversion
recovery MR imaging in the detection of cortical and subcortical
lesions. Am J Neuroradiol 2000; 21(7): 1199-206.
3. Ito Y, Arahata Y, Goto Y, Hirayama M, Nagamutsu M, Yasuda
T, et al. Cisplatin neurotoxicity presenting as reversible posterior
leukoencephalopathy syndrome. Am J Neuroradiol 1998;19(3):415-7.
|