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Internal Medicine

Periventricular leukomalacia (PVL)

Introduction

White-matter brain injury, characterized by the necrosis (more often coagulation) of white matter near the lateral ventricles.

  • Also known as “encephalodystrophy”, “ischemic necrosis”, “periventricular infarction”, “coagulation necrosis”, “leukomalacia,” “softening of the brain”, “infarct periventricular white matter”, “necrosis of white matter”, “diffuse symmetrical periventricular leukoencephalopathy”
  • Leading known cause of cerebral palsy and cognitive deficits in premature infants
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Oxygen Deprivation Around. (2019) Periventricular Leukomalacia (PVL) | Birth Injury Attorneys. Retrieved March 20, 2019, from https://www.abclawcenters.com/practice-areas/neonatal-birth-injuries/periventricular-leukomalacia/

Pathophysiology

Pathogenesis:

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Pathogenesis of periventricular leukomalacia (PVL) | McMaster Pathophysiology Review. Retrieved March 20, 2019, from http://www.pathophys.org/cerebralpalsy/ivh-pvl/

Neuropathologic hallmarks:

  • Microglial activation
  • Focal & diffuse periventricular depletion of premyelinating oligodendroglia (premyelinating oligodendroglia are highly vulnerable to death caused by glutamate, free radicals, and proinflammatory cytokines)
    • Focal component (located deep in the cerebral white matter)
      • Characterized by localized necrosis of all cellular elements with subsequent cyst formation
    • Diffuse component (less severe injury, apparently cell-specific, categorized by diffuse injury to oligodendroglial precursors)
      • Oligodendroglial precursors → Mature oligodendroglial cells (form the myelin of the cerebral white matter)
        • This process is principally a post-term event in human brain. Thus, not unexpectedly, the principal neuropathologic sequela of PVL is a diminution of WM volume and ventriculomegaly, secondary to the deficiency of myelin.
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Schematic depiction of coronal section of cerebrum with the focal and diffuse components of PVL shown in one hemisphere and the cerebral vascular supply in the other hemisphere. The focal necrotic component of PVL is depicted by the black circles, and the diffuse OL-specific component, in the gray shading. The long and short penetrating arteries supply the cerebral WM, as shown. | Volpe, J. J. (2001). Neurobiology of Periventricular Leukomalacia in the Premature Infant. Pediatric Research, 50, 553. Retrieved from https://doi.org/10.1203/00006450-200111000-00003
brain-injury-hypoxia-ischemia-due-to-periventricular-leukomalacia-pvl
Hypoxia ischemia due to periventricular leukomalacia (PVL) | Oxygen Deprivation Around. (2019) Periventricular Leukomalacia (PVL) | Birth Injury Attorneys. Retrieved March 20, 2019, from https://www.abclawcenters.com/practice-areas/neonatal-birth-injuries/periventricular-leukomalacia/

Clinical features

  • Spastic diplegia (M/C motor sequelae)
    • Related primarily to the deep periventricular locus of the focal component of the lesion
  • Cognitive and behavioural deficits (related to the diffuse component of the lesion)
    • Motor function more impaired than cognitive & language functions

Diagnosis

Imaging

Cranial ultrasonography:

  • Increased periventricular white matter echogenicity ± cystic abnormalities (cystic abnormalities visible after ≥ 1 week after birth)

Diffusion-weighted magnetic resonance imaging:

  • Visualize PVL earlier in the neonatal period than ultrasonography
  • Can provide prognostic information by documenting:
    • Gray matter atrophy
    • Tract degenerations
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Periventricular leukomalacia (PVL). Sagittal (A) and coronal (B) cranial untrasonograms obtained at age 2 days. Images exemplify extensive bilateral cystic PVL. This twin born at 29 weeks of gestation had fetal heart rate decelerations and Apgar scores of 4 and 7 at 1 and 5 minutes, respectively, related to his role as donor in twin-twin transfusion syndrome. C, Magnetic resonance image (fluid-attenuated inversion recovery) obtained at age 10 days in an infant born at 34 weeks of gestation. Image shows bilateral enlarged, blood-filled ventricles and prominent bilateral periventricular high-signal areas in the white matter lateral to the ventricles, consistent with PVL. The mother, who had diabetes, had pregnancy-induced hypertension, which was treated with magnesium sulfate. The baby, with Apgar scores of 2 and 2 at 1 and 5 minutes, respectively, developed status epilepticus that responded to treatment with phenobarbital sodium. Shortly after birth, he developed severe bilateral intraventricular hemorrhages with posthemorrhagic hydrocephalus, a frequent concomitant of PVL. D, T2-weighted magnetic resonance image (fluid-attenuated inversion recovery) in a 9-year-old girl with intractable complex seizures since infancy. There are peritrigonal high-signal areas, consistent with PVL. She had been born at 37 weeks of gestation to a mother with diabetes, and developed severe hypoxia, which was treated with extracorporeal membrane oxygenation. | Deng, W., Pleasure, J., & Pleasure, D. (2008). Progress in Periventricular Leukomalacia. Archives of Neurology, 65(10), 1291–1295. https://doi.org/10.1001/archneur.65.10.1291

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