Elevated intracranial pressure
When the ICP is elevated the following symptomes may occur: vomiting, visual disturbance, bulging of the anterior fontanel, altered mental status, papilledema and headache.The main risks of prolonged elevated intracranial pressure may include cognitive impairment and impaired vision through prolonged papilledema and subsequent optic atrophy. These are the main reasons why fundoscopy should be performed during the physical examination of children with craniosynostosis.The causes of an elevation of the intracranial pressure are best understood using the Monro-Kellie doctrine. The Monro-Kellie doctrine reduces the cranial vault to a box with rigid walls. This box contains three elements: brain, intracranial blood and cerebrospinal fluid. The sum of volumes of these three elements is constant. An increase in one should cause a decrease in one or both of the remaining two, thereby preventing an elevation of the intracranial pressure.A compensatory mechanism involves the movement of cerebrospinal fluid from the cranial vault towards the spinal cord. The volume of blood in the cranial vault is auto-regulated by the brain, and will therefore not decrease that easily.Intracranial pressure will rise as a result of continued brain growth within the rigid skull. It appears that in children with craniosynostosis, the expected decrease of intracranial blood is probably not occurring as it should according to the Monro-Kellie hypothesis. This is shown when the brain expands in the fixed skull, which gives a faster rise in intracranial pressure than would be expected. Obstructive sleep apnea
The short stops in breathing during the sleep are the mainstay of OSA.
observed a FGFR3 mutation in as many as 31% of the cases with nonsyndromic coronal synostosis, thus showing that FGFR abnormalities play an important role in nonsyndromic craniosynostosis.In terms of syndromic craniosynostosis not only do FGFR3 and TWIST genes feature, but also FGFR1 and in particular FGFR2, which has been reported in 90% of the syndromic craniosynostoses such as Apert, Crouzon, Peiffer and Jackson–Weiss. The mutations can be divided into mutations that lead to gain of function (in FGFR genes) and mutations that lead to loss of function (in TWIST genes). Craniosynostosis is therefore likely the result of a disturbance in the fine balance that regulates the multiplication and maturation of the precursor bone cells in the cranial sutures.The familial rate, which is different for nonsyndromic and syndromic cases, provides an important clue. In the nonsyndromic cases, a positive family history is found in 2% of the cases with sagittal suture closure and in 6% to 11%  of the cases with coronal suture closure. Cranial sutures
The mesenchyme above the meninges undergoes intramembranous ossification forming the neurocranium. The neurocranium consists of several bones, which are united and at the same time separated by fibrous sutures. This allows movement of the separate bones in relation to one another; the infant skull is still malleable.