Mild influenza encephalopathy with biphasic seizures and late reduced diffusion

Two Japanese infants with influenza A infection presented with a brief febrile seizure, followed by secondary seizures and disturbance of consciousness on day 5. Magnetic resonance imaging revealed reduced subcortical diffusion around day 5. Both were diagnosed with mild form of acute encephalopathy syndrome characterized by biphasic seizures and late reduced diffusion. It is important for clinicians in Asian countries to recognize and to inform parents that secondary progression may occur even after a brief febrile seizure with influenza.

Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions

OBJECTIVE

Reversible lesion in the central area of the splenium of the corpus callosum (SCC) is a unique phenomenon occurring particularly in patients with encephalitis or encephalopathy and in patients receiving antiepileptic drugs (AED). We report MR imaging findings, clinical courses, and outcomes in eight patients with various diseases and conditions.

MATERIALS AND METHODS

Eight patients with a reversible SCC lesion with transiently restricted diffusion were reviewed retrospectively. Diseases and conditions that were associated with a reversible lesion included epilepsy receiving AED (n=1), seizure from eclampsia receiving AED (n=1), mild infectious encephalitis (n=2), hypernatremia resulting in osmotic myelinolysis (n=1), and neoplasm (n=3) such as acute lymphocytic leukemia, spinal meningeal melanocytoma, and esophageal cancer. We evaluated MR imaging findings and clinical findings.

RESULTS

Seven patients had isolated SCC lesions; one patient with osmotic myelinolysis showed additional parenchymal lesions. The reversible SCC lesion shape was oval (n=6) or extended (n=2). The mean apparent diffusion coefficient value of the splenial lesion was 0.40+/-0.16 x 10-3 mm2/s, ranging from 0.22 to 0.64 x 10-3 mm2/s. In a patient with osmotic myelinolysis, additional white matter lesions, shown as restricted diffusion, were revealed as not reversible on follow-up MR imaging. Neurological courses and outcomes were good in seven patients with isolated SCC lesions, but poor in one with osmotic myelinolysis.

CONCLUSION

Reversible SCC lesion with restricted diffusion is apparent in a wide spectrum of diseases and conditions. Neurological courses and outcomes are good, particularly in patients with isolated SCC lesions. Knowledge of MR imaging findings and the associated spectrum of diseases and conditions might prevent unnecessary invasive examinations and treatments.

Reversible restricted diffusion of entire corpus callosum

MR imaging of a 31-year-old man with bacterial meningo-encephalitis associated with infectious endocarditis demonstrated T2 prolongation and restricted diffusion involving the entire corpus callosum and symmetrically involving the cerebral hemispheric white matter. His neurological signs and symptoms were mild, and recovery was complete within a week. Follow-up MR imaging with a 9-day interval revealed complete resolution of these lesions. The clinical and radiological courses were identical to those previously reported with a reversible lesion isolated to the splenium, or to the splenium and peripheral fronto-parietal white matter. This suggests that such reversible lesions are not necessarily restricted to the splenium, but may involve the entire corpus callosum.

14-3-3 protein detection in the cerebrospinal fluid of patients with influenza-associated encephalopathy

Influenza-associated encephalopathy is characterized by high fever, convulsions, and loss of consciousness associated with influenza infection in children, but its pathophysiology remains to be clarified. We examined 14-3-3 proteins, which are acidic brain proteins, in cerebrospinal fluid by immunoblotting in four patients with influenza-associated encephalopathy, four patients with influenza without encephalopathy, and four patients with another encephalopathy. Interestingly, we detected 14-3-3 proteins in all four patients with influenza-associated encephalopathy (100%) but not in any of the other patients. 14-3-3 isoforms, including beta, gamma, epsilon, xi, and theta, were found in the cerebrospinal fluid of the patients with influenza-associated encephalopathy, suggesting extensive damage to the brain. We conclude that 14-3-3 proteins in cerebrospinal fluid are highly detectable in influenza-associated encephalopathy and thus can be used as a rapid diagnostic marker.

Finger cold-induced vasodilatation, sympathetic skin response, and R-R interval variation in patients with progressive spinal muscular atrophy

To elucidate autonomic function in spinal muscular atrophy, we evaluated finger cold-induced vasodilatation, sympathetic skin response, and R-R interval variation in 10 patients with spinal muscular atrophy: 7 of type 1, 2 of type 2, and 1 of type 3. Results of finger cold-induced vasodilatation, sympathetic skin response, and R-R interval variation were compared with those of healthy children. Finger cold-induced vasodilatation was abnormal in 6 of 10 patients with spinal muscular atrophy; it was normal in the healthy children. The mean sympathetic skin response latency and amplitude did not differ significantly from those of the healthy children. Amplitudes of sympathetic skin response to sound stimulation were absent or low in all six patients with spinal muscular atrophy. No significant difference was found in the mean R-R interval variation of patients with spinal muscular atrophy and healthy children. Results show that some patients with spinal muscular atrophy have autonomic dysfunction, especially sympathetic nerve hyperactivity, that resembles dysfunction observed in amyotrophic lateral sclerosis.

Magnetic resonance imaging confirms periventricular venous infarction in a term-born child with congenital hemiplegia

Magnetic resonance imaging (MRI) of a 5-day-old female born at term with congenital leftsided hemiplegia revealed T2 shortening and T2* signal dropout lining the lateral wall of a focally enlarged right lateral ventricle, reflecting the deposition of haemosiderin or ferritin derived from periventricular venous infarction in utero. This observation strengthens the hypothesis that congenital hemiplegia in children born at term can result from a clinically silent periventricular venous infarction in utero. The loss of shortening of T2 in the right posterior limb of the internal capsule at birth was followed by prolongation of T2 at 1 year. It is important to evaluate the asymmetry of the posterior limb shown by MRI to predict future hemiplegia and enable early therapy.

Pituitary cysts in childhood evaluated by MR imaging

BACKGROUND AND PURPOSE

Pituitary cysts are common findings on pathologic examination and imaging studies. They are generally considered to be rarer in children than in adults; however, no good data exist to substantiate this opinion. We reviewed MR imaging studies to evaluate the frequency and imaging features of pituitary cysts in children.

METHODS

We retrospectively reviewed T1-weighted sagittal images in 341 patients <15 years of age to evaluate for pituitary cysts. Paramagnetic contrast was administered in 86 of the 341 patients. Sagittal or coronal fast spin-echo T2-weighted images were performed in 166 patients. For patients having pituitary cysts, pituitary function was examined by assessing blood levels of pituitary hormones.

RESULTS

A cystic pituitary lesion was recognized in 4 patients (1.2%) aged 1-4 years. None of the 4 manifested endocrinologic signs or symptoms or were the results of their laboratory studies abnormal. All the lesions were sharply demarcated and situated just posterior to the anterior pituitary lobe. All were iso- or hypointense compared with the pons on T1-weighted images without contrast enhancement, suggesting a Rathke cleft cyst. MR imaging of a patient with probable low-grade gliomas in the left hypothalamic region and optic chiasma showed complete resolution of a pituitary cyst at a 1-year follow-up study.

CONCLUSION

The frequency of pituitary cysts on MR imaging in childhood is almost equal to that of Rathke cleft cysts, as assessed in autopsy studies of subjects aged 10 to 29 years. These cysts are common in children and should be considered, in the absence of signs or symptoms of pituitary dysfunction, as incidental findings.

Recurrent meningitis associated with a petrous apex cephalocele

We present the case of a 6-year-old girl with recurrent bacterial meningitis and cerebrospinal fluid (CSF) rhinorrhea associated with a petrous apex cephalocele (PAC). We diagnosed her by means of three-dimensional computed tomography (CT) and heavily T2-weighted magnetic resonance imaging (MRI). Petrous apex cephaloceles are usually an asymptomatic incidental finding in adults; however, they should be considered as a possible cause of CSF rhinorrhea, otorrhea, and recurrent meningitis in children.

Episodic hyponatremia in mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS)

Various organ involvements and endocrinologic abnormalities associated with electrolyte imbalance, including hyponatremia, are seen in patients with mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS); however, the clinical significance of hyponatremia in these patients is rarely reported. We analyzed the serum sodium concentration profiles and clinical and laboratory data of seven patients with MELAS. We found that hyponatremia occurred episodically in four of the seven patients from an early stage of the disease. We identified excessive sodium loss in urine to be associated with the hyponatremic episodes and the causes of hyponatremia in two patients as relative adrenal insufficiency, acute renal failure, and serious paralytic ileus. However, even extensive examinations failed to reveal the cause in other patients. Because severe hyponatremia can cause serious complications, clinicians should pay attention to serum sodium levels and maintain them properly in patients with MELAS.

Intracranial dural venous anomalies in familial cervical cystic hygroma

This report describes a 3-year-old male with a familial cervical cystic hygroma and intracranial dural venous abnormalities consisting of a falcine sinus between the superior sagittal and the straight sinus with a rudimentary posterior part of the superior sagittal sinus; a prominent occipital sinus with narrowed transverse sinuses; and no intraparenchymal vascular abnormality. We hypothesize that a genetic factor that resulted in familial cervical cystic hygromas may also have caused the intracranial dural venous anomalies.

Reversible white matter lesion in methionine adenosyltransferase I/III deficiency

A 5-year-old boy with methionine adenosyltransferase (MAT) I/III deficiency, under treatment for the tentative diagnosis of homocystinuria, presented with mildly decreased appetite and sleepiness. MR imaging showed abnormal T1 and T2 prolongations and reduced diffusion in the cerebral white matter. Clinical symptoms and MR imaging findings improved after discontinuation of therapy. We speculate that inappropriate treatment might enhance CNS lesions of MAT I/III deficiency by causing a reversible vacuolating myelinopathy.

Influenza-associated encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum: a case report and literature review

We report the cases of two patients with influenza-associated encephalitis/encephalopathy (IAEE) who presented with mild CNS manifestations and complete recovery within a few days. Initial MR imaging at days 4 and 5 revealed a lesion in the central portion of the splenium of the corpus callosum with a reduced apparent diffusion coefficient (ADC) value, which completely resolved on follow-up studies at day 10. We postulate two possible mechanisms for decreased ADC; namely, intramyelinic edema and an inflammatory infiltrate.

Partitioning of 13C-labelled photosynthate varies with growth stage and panicle size in high-yielding rice

A super-high-yielding rice (Oryza sativa L.) cultivar, Takanari, and a traditional japonica rice cultivar, Nakateshinsenbon, were grown under field conditions to compare partitioning of ¹³C-labelled photosynthate to different plant organs during the period of reproductive development. The flag leaf and the two leaves immediately below it on the main culm were exposed individually to ¹³CO₂ and the movement of the heavy carbon isotope to grains, hull, panicle branches and vegetative parts of plant was assessed. Also, the effect of a reduction of sink size on the partitioning of ¹³C to different organs was studied by removing some of the primary branches of the panicle. ¹³C taken up by the three leaves in the post-heading period, moved mostly to the grains and hull of the panicle. At this stage, the uppermost three leaves and the panicle consisted of a single source-sink unit. Partitioning of ¹³C to the rest of the vegetative structures of the plant was minimal. In the case of Nakateshinsenbon, the flag leaf supplied most of the carbon assimilates for the grains and contributions from the other two leaves were much smaller. However, in Takanari, the contribution of ¹³C to grains from the second leaf was equivalent to that of the flag leaf. In Takanari, removal of more than one third of the primary branches of the panicle significantly reduced partitioning from the third leaf of the culm, but partitioning from the flag leaf was not significantly changed. In contrast, branch removal treatment significantly depressed transport of carbon assimilates from the flag leaf in Nakateshinsenbon. The obligatory nature of the source-sink relationship in rice is discussed. It is concluded that in lower-yielding traditional rice, photosynthesis in the flag leaf supplies carbon assimilates to the developing grains. But in the super-yielding rice Takanari, the main source area is extended to include the two leaves below the flag leaf so as to sustain an extra large panicle. Even greater grain-filling is possible in super-yielding rice, if the source area is increased further.

Gorlin syndrome with ulcerative colitis in a Japanese girl

We present the case of a 14-year-old Japanese girl who had both Gorlin syndrome and ulcerative colitis. She had complained of blood stools for 6 months and severe scoliosis from her infancy. Physical examination revealed multiple nevi, palmar and plantar pits, jaw cysts, and calcification of the falx cerebri, leading to the diagnosis of Gorlin syndrome. Total colonoscopy revealed an edematous and spotty bleeding mucosa extending from the anus to the transverse colon. Histological examination was also compatible with ulcerative colitis. Thus, we diagnosed her as having Gorlin syndrome with ulcerative colitis. Gene analysis revealed a mutation, 1247InsT, in the human patched gene (PTCH), resulting in the truncation of PTCH protein. Since Gorlin syndrome and ulcerative colitis are rare disorders in childhood, this association is interesting, suggesting a correlation between the hedgehog signaling and intestinal disorders.

Decreased cerebrospinal fluid hypocretin-1 levels near the onset of narcolepsy in 2 prepubertal children

We present 2 cases of narcolepsy with prepubertal onset. Although excessive daytime sleepiness and cataplexy had appeared early in both patients, the presence of sleep-onset rapid eye movement periods was detected several months after the onset of hypersomnia. The levels of hypocretin in the cerebrospinal fluid were reduced when measured 3 weeks (Patient 1) and 2 months (Patient 2) after the appearance of hypersomnia, before the presence of sleep-onset rapid eye movement periods was confirmed. Because the symptoms of narcolepsy in children are often obscure and easily mistaken as other diseases, and the electrophysiologic studies may not be specific in the early stage, the definite diagnosis tends to be delayed. Measurement of hypocretin-1 levels in the cerebrospinal fluid is useful for the early diagnosis of narcolepsy with prepubertal onset.

Brain MR imaging in neonatal hyperammonemic encephalopathy resulting from proximal urea cycle disorders

We present brain MR images in three patients with neonatal-onset hyperammonemic encephalopathy resulting from urea-cycle disorders (two sisters with deficiency of the carbamyl phosphate synthetase I reaction step and one boy with an ornithine transcarbamylase deficiency). MR imaging revealed almost identical findings of injury to the bilateral lentiform nuclei and the deep sulci of the insular and perirolandic regions; to our knowledge, this pattern has not been previously reported. We hypothesize that these lesions presumably reflect the distribution of brain injury due to hypoperfusion secondary to hyperammonemia and hyperglutaminemia in the neonatal period.

The changing MR imaging appearance of polymicrogyria: a consequence of myelination

BACKGROUND AND PURPOSE

During the review of MR studies of multiple patients with polymicrogyria (PMG), it was noted that the patterns of cortical abnormality differed significantly among affected patients. In particular, the cortex appeared very thin in some patients, but was thick in others. The purpose of the present study was to attempt to clarify the cause of the different imaging appearances.

METHODS

T1- and T2-weighted images obtained in 17 patients (age range, 3 days to 43 years) with PMG diagnosed on the basis of imaging characteristics were retrospectively reviewed. One patient was examined four times over a period of 21 months. Particular attention was paid to the thickness and signal intensity of the cortex and underlying white matter and how these features varied with maturation of the cortex and white matter.

RESULTS

T2-weighted images revealed two patterns of PMG. Pattern 1 showed small, fine, and undulating cortex with normal thickness (3-4 mm) in seven patients, all younger than 12 months; and pattern 2, a bumpy cortex that appeared abnormally thick (6-8 mm) and had an irregular cortical-white matter junction in seven patients older than 18 months. Both patterns were observed in four patients between 15 months and 2 years of age (ie, pattern 1 in the anterior frontal region and pattern 2 in the posterior frontal, parietal, or perisylvian regions). A layer of T2 prolongation (2-3 mm) was recognized between pattern 1 PMG and underlying myelinated white matter in four patients 11 months to 2 years of age. T1-weighted images showed either poor differentiation of the cortex and underlying white matter or pattern 2. Serial MR imaging in one patient depicted longitudinal changes of the PMG from pattern 1 to pattern 2.

CONCLUSION

These findings suggest that the two appearances (thin and thick) of the cortex seen in PMG likely represent the same process, with the apparent difference being the result of myelination in subcortical and intracortical fibers that cause a change of the appearance and apparent thickness of PMG on T2-weighted images.

T1 hyperintensity in the pulvinar: key imaging feature for diagnosis of Fabry disease

BACKGROUND AND PURPOSE

Fabry disease (FD) is an inborn error of glycosphingolipid metabolism. To date, no specific neuroimaging features have been elucidated to help in making the diagnosis of this disorder. The purpose of this study was to determine whether the finding of T1 shortening in the lateral pulvinar is a useful finding in the imaging diagnosis of FD and to deduce the relationship of this finding to the pathophysiology of the disease.

METHODS

We studied T1- and T2-weighted images obtained in ten patients (nine male and one female) with FD with an age range of 19-59 years. The images were examined for anatomic aberrations and areas of abnormal signal intensity (SI) in both gray matter and white matter. The SI of deep gray matter was evaluated qualitatively and semiquantitatively, relative to the SI of CSF or the genu of the corpus callosum. Gradient echo MR images and axial noncontrast CT images were available for one patient.

RESULTS

Seven of 10 patients showed small areas of T2 prolongation in the white matter of the cerebral hemispheres. Despite the known propensity for vascular disease in these patients, only one had cortical infarction. Bilateral T1 shortening in the lateral pulvinar was recognized in at least seven patients, all over the age of 30 years, who also had small areas of T2 prolongation in the white matter. CT and gradient echo images in one patient revealed no evidence of calcification or metallic deposits in the pulvinar.

CONCLUSION

Bilateral T1 shortening in the lateral pulvinar is a common finding in FD and may be useful in suggesting this diagnosis.

Slit ventricle syndrome after cyst-peritoneal shunting for temporal arachnoid cyst in children--a clinical entity difficult to detect on neuroimaging study

Slit ventricle syndrome, known to occur from malfunction of the shunt procedure for hydrocephalus, is reported after cyst-peritoneal shunt for temporal arachnoid cyst. Two children aged 12 and 10 years, who underwent cyst-peritoneal shunting for a large temporal arachnoid cyst at the age of 10 and 5 years, respectively, recently experienced several episodes of severe headache. Prior to admission, repeated CT scans did not reveal any morphological change in either of these two patients. Evidence of high intracranial pressure by lumbar tap revealed shunt malfunction. Both patients became free of neurological complaints and deficits after shunt revision. Despite elevated intracranial pressure due to shunt malfunction, neuroimaging studies showed no morphological changes in slit ventricle syndrome. Delay in both the diagnosis and prompt treatment may result in complete loss of visual acuity and even death. It is important to suspect this complication in patients with persistent elevated intracranial pressure symptoms and signs after any shunting procedure, regardless of unchanged neuroimaging studies. Once this is suspected, lumbar tap may be necessary and the choice of treatment is shunt revision.

Retrocerebellar arachnoid cysts in siblings with mental retardation and undescended testis

Arachnoid cysts comprise approximately 1% of all intracranial space-occupying lesions and usually occur sporadically. We report retrocerebellar arachnoid cysts in two male siblings with mental retardation and undescended testis, suggesting the possibility of a genetic basis for at least some cases of retrocerebellar arachnoid cysts.

A case of acute disseminated encephalomyelitis presenting hypersomnia with decreased hypocretin level in cerebrospinal fluid

A 12-year-old girl was diagnosed as having acute disseminated encephalomyelitis and manifested hypersomnia as the main clinical feature. Magnetic resonance imaging (MRI) revealed lesions in the bilateral hypothalamus in addition to other multifocal brain lesions involving the cerebral white matter, brain stem, and basal ganglia. The level of hypocretin in cerebrospinal fluid was decreased in this patient. Corticosteroid treatment resulted in improvement of the hypersomnia and resolution of MRI lesions in the hypothalamus and other regions. This case suggests that the arousal state control mechanism related to the hypocretin peptide/receptor system may be impaired in some patients with acute disseminated encephalomyelitis.

Detection of UV-induced K-ras codon 12 mutation by PCR and differential dot-blot hybridization in cells from Down syndrome and Cockayne syndrome

By means of the polymerase chain reaction (PCR) and differential dot-blot hybridization, base substitution mutations of K-ras codon 12 were investigated in skin fibroblast cells from Down syndrome (DS) patients. Mutations were identified in DS cells after UV irradiation, predominantly in cells from younger patients. In contrast, no mutation was detected in cells from Cockayne syndrome (CS) patients who had the same features of premature aging as in DS but were not prone to cancer. This association of DS cells, but not CS cells, with inducibility of the K-ras codon 12 mutation may imply the proneness of DS patients to cancer development but a lack of proneness of CS patients.

Evaluation of magnetic resonance angiography with selective maximum intensity projection in patients with childhood moyamoya disease

To determine whether magnetic resonance angiography with selective maximum intensity projection can facilitate the detection of cerebral moyamoya vessels in patients with childhood moyamoya disease, six patients with moyamoya disease (6 to 9 years old) and ten controls (4 to 16 years old) were evaluated by means of high resolution magnetic resonance angiography (matrix 512x384) with/without selective maximum intensity projection, and conventional angiography. In the patients with moyamoya disease, moderate or marked moyamoya vessels were detected but underestimated in 2/12 hemispheres on magnetic resonance angiography without selective maximum intensity projection. On magnetic resonance angiography with selective maximum intensity projection, moyamoya vessels were correctly assessed in 11/12 hemispheres (92%). In the controls, bilateral mild moyamoya vessels were detected in eight of 20 hemispheres (four of ten patients, under 7 years old), which were compatible with normal lenticulostriate arteries. Magnetic resonance angiography with selective maximum intensity projection is an accurate modality for assessing moyamoya vessels in moyamoya disease.