Chromatin-negative Klinefelter's syndrome with focal megalencephaly

Brain metabolism after recurrent insulin induced hypoglycaemic episodes: a PET study

Neuropsychological testing was carried out and the rate of oxygen metabolism in the brain was measured by PET in 15 highly selected patients with type 1 diabetes. The aim was to investigate the impact on the brain of hypoglycaemic comas resulting from insulin treatment. No significant difference was found between nine patients with a history of more than 10 hypoglycaemic comas and six others who denied any history of such events. These data suggest that intensified insulin treatment, although increasing the frequency of hypoglycaemic coma, may not always be harmful for the brain. This may be explained by the limited duration of hypoglycaemic coma induced by conventional insulin treatment.

Unilateral megalencephaly associated with neonatal high output cardiac failure

High-flow cerebral arteriovenous fistulae are well known to present in the neonatal period with macrocephaly, cranial bruits and high-output cardiac failure. This report describes a newborn infant with such a clinical presentation, who had unilateral megalencephaly without macroscopic arteriovenous shunts. Ultrasound Doppler examination of the carotid and cerebral vessels showed diastolic flow, or a decreased pulsatility index, consistent with decreased intracranial vascular resistance. The ipsilateral cerebral arteries and veins were markedly enlarged at angiography and at post-mortem examination, but there was no arteriovenous malformation. The infant expired from high-output cardiac failure and hypoglycemia. It is postulated that the high-output cardiac failure was due to increased blood flow through the enlarged, dysplastic cerebral hemisphere.

Megalencephaly: definition and classification

The various definitions and classifications of megalencephaly are reviewed, and numerous diseases and syndromes associated with megalencephaly are listed. A new definition of megalencephaly based on quantitative radiographic features is proposed. We define megalencephaly as a brain volume which exceeds the mean by more than twice the standard deviation. Furthermore, a modified etiopathogenic classification of megalencephaly results in three main groups, viz anatomic, metabolic and dynamic megalencephaly. The clinical pictures in these main groups of megalencephaly, and the largest subgroup of anatomic megalencephaly, familial anatomic megalencephaly, appear to be quite different.

Megalencephaly: types, clinical syndromes, and management

The differential diagnosis of megalencephaly poses a challenge to the clinician. The two major categories, metabolic and anatomic, include a number of conditions, many of them rare. This article provides a systematic approach to the patient with megalencephaly.