Authors: Curtis Duffield Jennifer Jocson Sandra L WoottonGorges
Publish Date: 2009/08/11
Volume: 39, Issue: 12, Pages: 1357-
Abstract
Brainstem disconnection is a very rare neonatal abnormality with only seven cases reported We report a unique case of a neonate who presented at delivery with hypertonia dysmorphic facial features and respiratory distress as well as numerous musculoskeletal and genitourinary abnormalities MRI of the brain showed disconnection between the pons and medulla with cerebellar hypoplasia and absent cerebellar peduncles It aided in the description of the neurological and vascular anomalies associated with this diagnosisBrainstem disconnection is a rare entity described only in the neonate Seven prior neonates have been reported in the English literature with all dying by 7 weeks of age 1 The etiology of brainstem disconnection remains uncertain Proposed theories include variants of pontocerebellar hypoplasia or other mid and hindbrain malformations such as Joubert syndrome Mobius syndrome etc as well as vascular insult with brainstem necrosis 1 2 3Brainstem disconnection is generally unrecognized prenatally although cerebellar hypoplasia can be seen on prenatal US 1 2 Neonatal clinical findings vary but generally involve dense neurologic dysfunction Advances in imaging especially MRI have allowed more detailed evaluation of the anatomic anomalies that make up this disorderA girl was born at term to a 23yearold woman A secondtrimester US had shown bilateral ventriculomegaly left hydronephrosis a 2vessel cord vertebral segmentation anomalies and polyhydramnios At delivery the infant was dysmorphic and had a poor cry and increased tone with jitteriness The infant weighed 3125 g 35th percentile and had an occipitalfrontal circumference of 355 cm 65th percentile Physical examination revealed right microophthalmia hypertelorism an asymmetrically smaller right face with elevated nasal bridge and a thin and downturned upper lip A lower lumbar deformity was noted as well as a heart murmur The neurologic exam found hypertonia cortical thumb posturing poor suck exaggerated reflexes and seizurelike activity similar to myoclonic jerks EEG showed abnormal baseline activity but did not specifically correlate with the myoclonic jerks Echocardiogram showed only a small muscular ventricular septal defect Highresolution chromosome studies were normalBrain MRI at 1 day old Sagittal T1W a and axial T2W b images show disconnection between the midbrain and medulla with absence of the pons between white arrowheads Platelike ectopic neuronal tissue/white matter is seen at the ventral aspect of the midbrain and medulla arrowheads There is absence of the vermis cerebellar hemisphere symmetrical hypoplasia and absence of the cerebellar peduncles and a prominent cisterna magna There is kinking of the brainstem black arrow Colpocephaly is noted on axial T2inversionrecovery images c Additional findings include right anophthalmia with an absent right optic nerve curved arrowAngiography Sagittal a and axial b MIP 3D timeofflight MRA show absence of the basilar artery white arrow The carotid arteries and circle of Willis are intact with patent posterior communicating arteries and P1 segments of the posterior cerebral arteries arrowheads A tiny right PICA is seen MR venography was normalPlain radiography demonstrated multiple thoracic spine segmentation anomalies and hypoplasia of the distal sacrum and coccyx MR of the spine demonstrated kinking of the brainstem but otherwise normal cord contour and signal The conus was at the L23 level
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