K.E.M.

Radiology

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Department of Radiology 

  Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India

Case of the Month

< Case No. 47 : March 2024 >

Crouzon syndrome

Contributed by: Asad Agwan

Clinical Profile:

A A one year old girl child was brought by her parents with an abnormal shape of the head since birth. The baby had bulging of the eyes.

On clinical examination, there was bilateral proptosis, hypertelorism, a flattened forehead, a beaked nose and an underdeveloped upper jaw.

             Fig. 1:The photograph of the patient shows abnormal shape of the skull with proptosis

(reproduced with parent's consent) 

Radiological findings:

AP and lateral radiographs of skull show multiple round lucencies in the skull with scalloping of the inner table giving the copper beaten appearance.There is abnormal shape of the skull with fused coronal and sagittal sutures.

There is proptosis on both sides. (Fig, 2)

FIG 2 FIG 2A & 2B: AP and lateral radiographs of the skull show multiple round lucencies in the skull with scalloping of the inner table giving a copper beaten appearance

The images of the skull from a CT scan are shown below.

Fig. 3 : FIG 3A 3B & 3C:

The CT scan of the head  shows moderate to severe thinning of the cranial bones with prominent convolutional markings along the inner table of the skull and abnormal shape of the skull with fused coronal and sagittal sutures.

MRI of the brain shows findings of intracranial hypertension. there is tonsillar herniation suggestive of Chiari I malformation. (fIG. 4)

Fig. 4  MRI brain shows features of intracranial hypertension. There is tonsillar herniation indicative  of Chiari I malformation.

Radiological diagnosis:

Crouzon syndrome with Chiari I malformation

Treatment:

The patient will undergo neurosurgical treatment for craniosynostosis

 Timeline:     

Discussion

Crouzon syndrome is a genetically inherited syndrome characterized by craniosynostosis (premature fusion of coronal sutures) resulting inskull and facial deformities.

Crouzon syndrome is inherited in an autosomal dominant pattern and is caused by a mutation in the fibroblast growth factor receptor (FGFR-2 and FGFR-3) on chromosome 10. (1) (2) The syndrome has complete variable penetrance expressivity resulting in phenotypically unaffected children to children with severe deformities.

Crouzon syndrome is a fairly rare entity and is estimated to occur in 1 in 60,000 newborns; however, it is the second most common craniosynostosis syndrome behind only the more recently described Muenke syndrome.[4][5]

FGFR-2 and FGFR-3 are two of the four transmembrane protein receptors responsible for osteoblast differentiation during embryological development.

Missense mutations in these two receptors result in gain-of-function signalling and subsequent acceleration in the differentiation of osteoblasts.[6][7] In Crouzon syndrome brachycephaly (widened and shortened skull) is the most common presentation due to bi-coronal suture fusion. However, trigonocephaly (triangular) and scaphocephaly (long and narrow) are not uncommon. In the most severe cases, a “cloverleaf” skull known as a Kleeblattschadel deformity can be seen due to the closure of multiple sutures. (8) (9)  The evaluation for Crouzon syndrome is relatively straightforward in the setting of known family history as the characteristic physical examination findings confirm the diagnosis. However, in cases where there is a spontaneous mutation, and the clinical presentation is not clear initially, these patients may require genetic testing for diagnosis. Additional tests in these situations may include imaging techniques such as magnetic resonance imaging (MRI) and computed tomographic (CT) imaging of the brain to detect craniosynostosis or other skeletal abnormalities. The most common imaging findings on X-ray-based techniques are peri sutural sclerosis, reduced serration, and bony bridging and/or the absence of the suture altogether. A beaten bronze appearance of the skull is also a common finding on CT in this syndrome due to multiple radiolucencies of the skull bones. These imaging modalities can also help identify sequelae of the syndrome such as radiographic findings suggestive of increased intracranial pressure that may be otherwise difficult to detect in uncooperative children. Surgical management is the treatment modality of choice to correct the   ldevelopment of the midface and orbits to prevent blindness and intellectual disability related to the restriction of the brain and orbital development

It requires long-term follow up to monitor ocular development due to the propensity to develop strabismic amblyopia and the need for strabismus surgery. These examinations should also monitor for optic nerve oedema that would raise concerns for elevated intracranial pressure. Due to airway changes, sleep apnoea is also of concern. A team-based approach helps monitor for these vision and life-threatening complications.

Complications:

 Raised intracranial pressure

 Mental subnormality

 Problems with vision

 Exposure keratitis

 Aspiration pneumonia

 Breathing problems and stridor

Conclusion :

Crouzon syndrome is a genetically inherited syndrome characterized by craniosynostosis resulting in skull and facial deformities. The prognosis of patients with Crouzon syndrome depends on early diagnosis and treatment. If treated promptly, the patients may have a near-normal lifespan.

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