History and Physical Examination
Infants with hydrocephalus develop an enlarging head with bulging fontanelle, enlarged scalp veins, macrocrania, suture diastasis, and positive Macewen (ie, cracked pot) sign. If the hydrocephalus is not treated, these infants develop sunset eyes, recurrent vomiting, and, later, respiratory arrest. Persistent leakage of cerebrospinal fluid (CSF) from the repaired spinal wound almost invariably indicates active hydrocephalus, even if the ventricular size is only modestly enlarged and the anterior fontanelle is not bulging.
Complications
The particular concern in children with myelomeningocele is the presence of hindbrain hernia in the context of the Arnold-Chiari II malformation, which can cause early clinical symptoms of bulbar palsy due to compression of the brainstem and can remain unnoticed by inexperienced observers or be confused with symptoms of shunt malfunction or untreated hydrocephalus.
Manifestations of brainstem dysfunction caused by hindbrain hernia and aggravated by ventricular dilatation include the following:
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Poor feeding
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Recurrent vomiting
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Poor sucking
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Generally subdued behavior with poor crying
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High-pitched cry or stridor caused by vocal cord paralysis - A predictor of poor outcome
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Episodes of apnea
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Extremity weakness in older children
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Recurrent aspiration - Often manifesting as recurrent pneumonia
Approximately 20% of children with myelomeningocele who also have an Arnold-Chiari II malformation develop brainstem symptoms. Myelomeningocele is also a contributor to mortality and morbidity in the first two decades of life.
Older children with closed fontanelles develop clinical signs of intracranial hypertension without progressive head enlargement. They develop headaches, blurred vision, decline in intellectual performance, and gradual drowsiness, which, if left untreated, lead to coma and death due to respiratory arrest.
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The lumbar region of a newborn baby with myelomeningocele. The skin is intact, and the placode-containing remnants of nervous tissue can be observed in the center of the lesion, which is filled with cerebrospinal fluid (CSF).
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Axial T1-weighted MRI scan of an 8-week-old girl who presented with enlarging head circumference. Considerable ventricular dilatation is shown on the lateral and third ventricles. Periventricular lucency is observed around the frontal horns, indicating raised intraventricular pressure.
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Sagittal T1-weighted MRI scan of an 8-week-old girl who presented with enlarging head circumference. The third and lateral ventricles are dilated, whereas the fourth ventricle is of normal size. Aqueductal stenosis is shown. The appearance is typical of this condition.
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Phase-contrast MRI scan of an 8-week-old girl who presented with enlarging head circumference, obtained 3 months after endoscopic third ventriculostomy. A large signal void is shown in the prepontine region, corresponding to the flow through the stoma in the floor of the third ventricle, indicating that the ventriculostomy is functioning well.
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Axial T1-weighted MRI scan of a 15-year-old girl who was born with thoracic myelomeningocele, hydrocephalus, and Arnold-Chiari II syndrome. She was treated with a ventriculoperitoneal shunt. The ventricular system has a characteristic shape, with small frontal and large occipital horns, which are typical in patients with spina bifida. The shunt tube is shown in the right parietal region.
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Sagittal T1-weighted MRI scan of a 15-year-old girl who was born with thoracic myelomeningocele, hydrocephalus, and Arnold-Chiari II syndrome. Significant hindbrain hernia and low-lying fourth ventricle are shown in the context of the Arnold-Chiari II syndrome.
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Damaged shunt valve removed during shunt revision from a 22-year-old woman with hydrocephalus and spina bifida. The material of the valve has dramatically disintegrated.
