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At a glance

It is a rare medical condition characterized by accelerated growth and osseous maturation, unusual craniofacial appearance, hoarse and low pitched cry, camptodactyly, and hypertonia. Most patients have muscle spasticity and exaggerated knee reflexes. There is an estimated risk in these children of less than or equal to 1.09% of rhabdomyolysis or malignant hyperpyrexia. The craniofacial abnormalities that cause difficulty with tracheal intubation may improve, worsen, or remain unchanged as craniofacial structures mature.

Synonyms

Weaver-Smith Syndrome; WSS.

History

It was first described in 1974 by David D. Weaver, an American physician and David Weyhe Smith, an American pediatrician.

Incidence

The exact incidence remains unknown. It affects males three times more often than females. It is often diagnosed prenatally.

Genetic inheritance

Isolated cases. It is believed to be inherited as an autosomal dominant inheritance presumed.

Pathophysiology

Caused by mutation in the nuclear receptor binding Su-var (NSD1 gene), which is located on 5q35.

Diagnosis

Clinically by characteristic facies associated with tall stature, large head, ears, and hands, and a low-pitched voice.

Clinical aspects

Increased prenatal weight and height. Development and speech are delayed; there are mental retardation and behavioral problems. Other features involve head and neck (flattened occiput, short broad neck, long philtrum, retrognathia, anterior and cephalad position of the larynx, strabismus, hypertelorism, epicanthal folds, down-slanting palpebral fissures, depressed nasal bridge), skeleton (short ribs, disharmonic and advanced bone age, scoliosis, kyphosis, small iliac wings, coxa valga, limited elbow and knee extension, flared metaphyses, camptodactyly, clinodactyly, broad thumbs, feet malformations), genitourinary (GU) (inverted nipples, inguinal hernia, hydrocele, cryptorchism), skin (loose skin, thin hair and nails), and central nervous system (CNS) (hypertonia, spasticity, seizures, absent septum pellucidum, lateral ventricle dilatation). Congenital cardiac defects may occur.

Precautions before anesthesia

Children presenting for muscle biopsy have a 10 to 20% chance of a positive finding, and around half of these have a diagnosis of muscular dystrophy. Evaluate carefully the oropharyngeal anatomy for eventual direct laryngoscopy and tracheal intubation (clinical, radiographs), neurological function (clinical, CT/MRI, EEG), renal function (clinical, echography, lab), and cardiac function (clinical, ECG, echography). Clinical assessment of functional capacity must be obtained especially when there is a high suspicion of coexisting cardiac or respiratory diseases.

Anesthetic considerations

The craniofacial abnormalities that cause difficulty with tracheal intubation may improve, worsen, or remain unchanged as craniofacial structures mature. Tracheal intubation can be difficult because of retrognathia, short broad neck, and an anterior and cephalad position of the larynx. It may require adapted anesthetic management. Fiberoptic intubation can be useful. The accessibility to a laryngeal mask airway in case of failed tracheal intubation may also ...

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