Magnetic resonance imaging (MRI) findings in children surviving extremely premature delivery and extremely low birthweight with cerebral palsy.

To delineate the frequency, severity, and characteristics of the brain injury occurring in children surviving extremely premature birth, we reviewed brain magnetic resonance images (MRIs) of children with cerebral palsy whose birthweight was less than 1000 g and whose gestational age was less than 28 weeks. The patients were all enrolled in the state Children's Rehabilitative Services clinic, where cerebral palsy is an automatic qualifying condition. We tabulated the MRI findings with respect to the cerebellum, periventricular white matter, and corpus callosum. The inclusion criteria were met by 157 children; 94 had an MRI. The available scans were reviewed by the authors, and the findings were tabulated. Fifty scans were available for review. There were 4 totally normal scans, 18 scans had normal cerebellar imaging, and 8 scans were felt to have normal cerebral findings. The common cerebral abnormalities included decreased white-matter volume without gliosis (n = 36), periventricular leukomalacia (n = 16), and a thin corpus callosum (n = 18). Cerebellar abnormalities were found in 32. The cerebellar findings included destruction of major portions of the cerebellum (usually the inferior vermis and hemispheres) (n = 23) and focal or unilateral loss of cerebellar tissue (n = 4). The high incidence of injury to the cerebellum has not been previously appreciated. The most common cerebral injury is decreased volume of white matter in the periventricular regions without gliosis. The pattern of cerebellar injury suggests a vascular insult, and the deficient white matter without gliosis suggests immaturity of oligodendrogliocytes with limited response to injury. Both lesions are more or less unique to the age at which the insult occurred and represent an emerging, newly recognized type of cerebral palsy.

Navajo neurohepatopathy is caused by a mutation in the MPV17 gene.

Navajo neurohepatopathy (NNH) is an autosomal recessive disease that is prevalent among Navajo children in the southwestern United States. The major clinical features are hepatopathy, peripheral neuropathy, corneal anesthesia and scarring, acral mutilation, cerebral leukoencephalopathy, failure to thrive, and recurrent metabolic acidosis with intercurrent infections. Infantile, childhood, and classic forms of NNH have been described. Mitochondrial DNA (mtDNA) depletion was detected in the livers of two patients, suggesting a primary defect in mtDNA maintenance. Homozygosity mapping of two families with NNH suggested linkage to chromosome 2p24. This locus includes the MPV17 gene, which, when mutated, causes a hepatocerebral form of mtDNA depletion. Sequencing of the MPV17 gene in six patients with NNH from five families revealed the homozygous R50Q mutation described elsewhere. Identification of a single missense mutation in patients with NNH confirms that the disease is probably due to a founder effect and extends the phenotypic spectrum associated with MPV17 mutations.

Leukoencephalopathy with bilateral anterior temporal lobe cysts.

Recently, several reports describing patients with a nonprogressive clinical course, increased signal in the cerebral white matter, and cystic changes in the anterior temporal lobes on magnetic resonance imaging (MRI) have appeared. To date, 25 patients with this very distinctive condition have been described. We report four new cases of this newly recognized entity. All have been identified primarily because of the distinctive MRI features consisting of the very unusual anterior temporal lobe cystic changes. The clinical features are characterized by severe, disabling, but nonprogressive mental and motor retardation. Magnetic resonance spectroscopy has shown increased myo-inositol and decreased N-acetylaspartate in the cerebral white matter. This is a distinctive, probably genetic, condition with characteristic neuroimaging and clinical features. In the appropriate clinical situation, the neuroimaging features are diagnostic.

The thalamus and midbrain in Reye syndrome.

A previously healthy 5 1/2-year-old male had Reye syndrome. He presented in coma with apnea 1 week after a viral infection and following 2 days of vomiting and progressive obtundation. He was in coma with dystonic posturing and intact brainstem function. Laboratory evaluation revealed initial hypoglycemia, and markedly elevated liver enzymes, prolonged clotting times, and elevated ammonia levels. No underlying metabolic disorder was present, and the patient completely recovered. On a modified diffusion-weighted image magnetic resonance imaging scan, restriction of diffusion in the thalamus and midbrain was observed. While abnormalities of the thalamus and midbrain have previously been reported, this is the first report of diffusion-weighted imaging indicating early impairment of water diffusion, a finding more commonly observed with stroke.

Frequency and nature of cerebellar injury in the extremely premature survivor with cerebral palsy.

We report on the frequency and variable nature of magnetic resonance imaging-documented injury to the cerebellum in children with cerebral palsy who had survived a birth with a weight under 1000 g and/or a gestational age under 28 weeks. Thirty of 67 patients who had magnetic resonance images were found to have injury to the cerebellum. Those with cerebellar injury were much more likely to be microcephalic and to be unable to walk or talk. They did not demonstrate a greater frequency of observed injury to the cerebrum. From a larger collection of children with known cerebellar injury and cerebral palsy who had a history of being extremely premature, we found that 35 of 47 patients had prominent injury to the inferior cerebellum, suggesting infarction, whereas the remainder demonstrated varying degrees of cerebellar atrophy with or without asymmetry and four also had enlarged 4th ventricles. Injury to the cerebellum in the extremely premature survivor who has cerebral palsy is common and associated with a more adverse clinical picture. The etiology of this injury is obscure.

Cerebellar injury in the extremely premature infant: newly recognized but relatively common outcome.

Severe injury to the cerebellum as a complication of extreme prematurity with extremely low birthweight was recently described in 13 children with the clinical diagnosis of cerebral palsy. We report another 10 cases of this syndrome. The clinical features include striking motor impairment and variable degrees of ataxia and athetosis or dystonia, which represent a distinct clinical type of cerebral palsy. Most are severely damaged, with cognitive, language, and motor delays. All are microcephalic, except one with hydrocephalus. Neuroimaging studies demonstrate the absence of major portions of the cerebellum involving both the inferior vermis and hemispheres. Most also have injury of a less severe nature in the cerebrum. This report indicates that this is not an uncommon outcome of extremely low birthweight infants, and we hope to encourage further investigations into the relative frequency and likely etiologies of the condition.

Cerebellar infarction: an unrecognized complication of very low birthweight.

We evaluated 13 children with cerebral palsy who had birthweights under 1085 g. A magnetic resonance image (MRI) of the head was obtained, the findings were compared, and the neonatal records were reviewed. The individual children were classified as to the type of cerebral palsy. On MRI, all had severe injury to the inferior cerebellar hemispheres, mostly symmetric, and in some there was injury to the inferior vermis. The average birthweight was 668 g, and the gestational ages were 24 to 27 weeks. No other outstanding prenatal or postnatal problems were identified. The children had different types of severe cerebral palsy, with only 3 being able to walk. Almost all were mentally retarded and microcephalic. All had visual problems. This report defines a previously underappreciated injury to the cerebellum in extremely premature infants. Further clinical, laboratory, and pathologic studies are needed to better define the underlying mechanisms.