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Home , Brachycephaly, Scaphocephaly, Spina bifida

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Recognising congenital anomalies of the

E Wegoye, MB ChB (MUST) Registrar, Division of Neurosurgery, University of Cape Town and Groote Schuur Hospital, Cape Town

L Padayachy, MB ChB, FCS (Neurosurg) (SA), MMed Consultant, Division of Neurosurgery, University of Cape Town, and Institute for Child Health, Red Cross War Memorial Children’s Hospital, Cape Town

Correspondence to: L Padayachy (L.Padayachy@ Fig. 1. Fronto-nasal . uct.ac.za) Fig. 3. Lumbo-sacral myelomeningocele. A wide array of neurological abnor- malities occur in childhood, with a nutrition and periconceptional vitamin significant proportion of these attributable supplementation, particularly . The to congenital causes. The classic congenital simple primary prevention strategy of folate neurosurgical condition is open spina supplementation has been shown to reduce bifida or myelomeningocele, but this is the incidence by 80%. There is mandatory just one example of a wide spectrum of in South Africa, but conditions commonly referred to as neural clinical experience has suggested that this tube defects or, more correctly in clinical is insufficient and anyone who may become practice, as dysraphism. pregnant must consume supplemental folate before conception! Dysraphism This is a broad term used to describe a range Clinically, myelomeningocele presents as of conditions that arise owing to errors a fluid-filled sac of varying size, which in the early development of the nervous Fig. 2. Occipital encephalocele. usually occurs in the lumbo-sacral system, either during closure of the neural region, but can occur anywhere along the tube (also called primary , The depth of extension is variable, with most midline spinal axis (Fig. 3). It contains from conception to day 28) or subsequent lesions located occipitally, close to the union. neural tissue with a delicate meningeal embryological development (or secondary These abnormalities should be borne in layer. neurulation). mind when children present with recurrent , remembering that they may be There is invariably some form of Cranial dysraphism found anywhere along the midline from the neurological deficit in the lower limbs, Encephalocele tip of the nose to the gluteal cleft. ranging from to mild weakness, This group of malformations is characterised depending on the level and size of the lesion. by defects of the skull resulting in herniation Spinal dysraphism (or ) These are often accompanied by spinal and of the brain. They are classified according to Myelomeningocele lower limb deformities. is their anatomical location, with the majority Myelomeningocele is caused by defective seldom present at birth, but occurs in 75 - occurring either occipitally or frontally (Figs closure of the , a process that 85% of cases. 1 and 2). Clinical presentation depends on is completed within 28 days of conception. the location, but features include a skin- The incidence of myelomeningocele in Once diagnosed, the with a covered sac, which may increase in size on live births is 1 - 2/1 000 (0.1 - 0.2%), myelomeningocele must be referred to a Valsalva. Surgical closure is the mainstay of with marked regional variation. Prenatal specialist centre for closure within 24 hours. treatment. Often, patients are not referred diagnosis is possible with maternal serum Surgical treatment involves prompt closure until very late owing to a mistaken belief alfa-fetoprotein, confirmed by of the lesion, usually followed by insertion that the condition will be fatal. and . of a ventriculoperitoneal shunt.

Cranial dermal sinus Recently, a significant decline has been Occult spinal dysraphism (OSD) Congenital cranial dermal sinuses are noted in many parts of the world, This is a group of disorders resulting from midline tracts lined by squamous epithelium. largely as a result of improved maternal malformation of the during

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secondary neurulation. This group comprises Sagittal many different, but individually rare, This is the most common type of variants, but the key feature is that almost all . The skull is typically have obvious cutaneous stigmata including elongated with a palpable bony ridge, subcutaneous lipoma, hypertrichosis (a usually with frontal and occipital bossing hairy patch), caudal appendage, capillary (Fig. 5). The cranial base, orbits and face are haemangioma or dermal sinus (Fig. 4). usually spared. with It is important to differentiate the rare should be referred to a specialist centre dermal sinus, which always needs further before the age of 6 months. investigation, from the much more common sacral pit or dimple (Table 1). Unilateral coronal synostosis Premature fusion of the coronal suture may Patients may be asymptomatic or have occur unilaterally (anterior ) or lower limb weakness, sphincter problems bilaterally (). Unilateral fusion and/or skeletal deformities due to is usually non-syndromic. Coronal suture Fig. 5. Sagittal synostosis. myelodysplasia, neural compression or synostosis is accompanied by flattening spinal cord tethering, neural compression of the ipsilateral forehead, compensatory facial due to ipsilateral involvement and myelodysplasia. contralateral bossing, shortening and of the nasal bone, zygoma and maxilla. upwards displacement of the greater sphenoid Surgical indications are patient specific wing with a flattened vertically elongated Children diagnosed with anterior plagio- and depend on the natural history of the orbit (harlequin eye) (Fig. 6). There is also a cephaly should be referred early, as surgery disease, but usually involve untethering of the spinal cord. Table 1. Differentiating dermal sinuses from sacral dimples Craniosynostosis Dermal sinus Sacral dimple Craniosynostosis occurs in 1 in 2 100 Location Anywhere from tip of the nose to Usually in the natal cleft, children. The condition involves premature coccyx, slightly off the midline directed caudally towards tip closure of the cranial sutures, either single of coccyx or multiple, and may be simple or part of a Appearance Punctuate, may be almost Much larger, almost crater-like syndrome (Table 2). The most commonly invisible encountered single suture synostoses are Associated features Often skin discoloration or tuft Nil the sagittal suture (scaphocephaly) and the of hair coronal suture (plagiocephaly). Complications Meningitis (often recurrent), Mainly cosmetic dermoid tumour Investigation MRI mandatory Seldom necessary

Table 2. Classification of craniosynostosis Non-syndromic Suture involved Simple Scaphocephaly Sagittal Anterior plagiocephaly Unilateral coronal Posterior plagiocephaly Unilateral lambdoid Metopic Compound Variable More than 1 suture Brachycephaly Bilateral lambdoid Turribrachycephaly Bilateral coronal Syndromic Crouzon’s syndrome Typically bilateral coronal Apert’s syndrome Usually coronal, often lambdoid Fig. 4. Typical punctate dermal sinus Multiple suture involvement surrounded by hyperpigmentation just above Other, e.g. Saethre-Chotzen, Jackson-Weiss, the natal cleft (yellow arrow), with more Carpenter’s, cloverleaf skull rostral punched-out cutaneous lesion.

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Table 3. Diagnostic criteria for NFI and NFII Neurofibromatosis I (NFI) Neurofibromatosis II (NFII) The diagnostic criteria are met if a patient has 2 or more of the The diagnostic criteria are met if a person has either of the following: following: 1. Six or more café au lait macules that have a maximum diameter 1. Bilateral 8th nerve masses seen with appropriate imaging of >5 mm in prepubertal patients and >15 mm in postpubertal techniques, such as MRI or CT patients 2. A first-degree relative with NF II and unilateral 8th nerve mass or 2 2. Two or more neurofibromas of any type , or one plexiform of the following: neurofibroma Neurofibroma, meningioma, glioma, neurilemoma or juvenile 3. Freckling in the axillary or inguinal regions posterior subcapsular cataract 4. Optic glioma 5. Two or more Lisch nodules (iris hamartomas) 6. A characteristic osseus lesion, such as sphenoid wing dysplasia or thinning of the long bone cortex, with or without pseudoarthrosis 7. A first-degree relative (i.e. parent, sibling, or child) with NFI by the above criteria

neurofibromatosis, tuberous sclerosis and Sturge-Weber syndrome.

Neurofibromatosis (NF) NF remains the most common and surgically important of the neurocutaneous disorders. NF can be divided into two distinct types – NFI, which accounts for around 90% of cases, and NFII. The diagnosis is made on clinical grounds Fig. 8. Increased head circumference in (Fig. 7), using the diagnostic criteria listed hydrocephalus. in Table 3. Conclusion Tuberous sclerosis (TS) While neuro-imaging is extremely helpful Fig. 6. Left anterior coronal synostosis. TS is characterised by hamartomatous lesions in planning the management of the involving multiple organs. In the brain they usually abovementioned conditions, virtually all manifest as cortical tubers and/or subependymal can be diagnosed on clinical grounds at the giant cell astrocytomas. The most common primary care level, enabling prompt referral clinical features include intractable seizures, for definitive management. developmental delay, behavioural impairment and raised intracranial pressure due to obstructive hydrocephalus.

Hydrocephalus ‘Congenital hydrocephalus’ is often associated with myelomeningocele, but may also be caused by aqueduct stenosis, Dandy- Walker malformation, intrauterine infection, germinal matrix haemorrhage and rarely by Fig. 7. Café au lait lesion in neurofibromatosis. an X-linked inherited disorder. The classic clinical sign is increasing head circumference (Fig. 8), while other clinical features include: is optimal if performed before the age of 1 • irritability year. • poor appetite • vomiting Neurocutaneous syndromes • poor head control These conditions have specific • bulging anterior fontanelle neurological findings with associated • thin shiny scalp with distended scalp cutaneous lesions, often with dysplasia veins of other organ systems. The most • upward gaze paresis commonly recognised conditions include • cranial nerve palsies (III and VI).

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