Marshall-Smith Syndrome

At a glance

It is a genetic disorder characterized by the association of facial dysmorphism, failure to thrive, and accelerated osseous maturation and linear growth. Accompanied by severe respiratory problems that are often fatal during the first year of life, mental retardation, hypotonia, muscle weakness, and psychomotor retardation. Craniofacial abnormalities include prominent forehead and eyes, maldevelopment of the epiglottis, and laryngomalacia. Patients with this syndrome have a high risk of developing anesthetic complications, especially concerning the maintenance of the airways.

History

This medical condition was first described in 1971 by Richard E. Marshall, an American pediatrician, and David W. Smith, an American pediatrician and dysmorphologist.

Incidence

This is a very rare disorder. The exact incidence remains unknown. Twenty-five cases have been described in the literature. It seems to affect males and females equally. The onset of the disease is prenatal and therefore present at birth.

Genetic inheritance

There is no evidence that it is genetically related. All cases reported were sporadic mutations.

Pathophysiology

Unknown.

Diagnosis

Based on clinical aspect and typical radiograph of bones: markedly advanced osseous maturation, widening of the middle and proximal phalanx, and multileveled platyspondylia (thin anterior part of vertebral bodies).

Clinical aspects

Orofacial dysmorphism: prominent forehead, shallow orbits with prominent eyes, megalocornea, micrognathia caused by hypoplastic mandibular ramus, upturned nose with anteverted nostrils, large overflexed ears. Stridor caused by laryngeal anomalies or hypoplasia with rudimentary epiglottis. Scoliosis. Atlantoaxial instability. Hypoplastic thorax. The presence of choanal atresia and functional obstruction of the upper airway are associated with obstructive sleep apnea. Mental retardation. Most patients die before age 2 years as a consequence of recurrent pulmonary infections (chronic aspiration).

Precautions before anesthesia

Check for presence or history of stridor and/or laryngomalacia; probable sleep apnea syndrome: consider insertion of a nasopharyngeal airway before sleep during a few days before anesthesia; echocardiography to rule out associated cardiac malformation and pulmonary hypertension caused by chronic upper airway obstruction. Check patency of both nostrils. A cervical spine radiograph must be obtained to assess the atlantoaxial stability. A chest radiograph is indicated to eliminate the presence of lung infection (recurrent infection with this disorder) and hypoplasia of part of the lungs.

Anesthetic considerations

A difficult face-mask ventilation must be expected. At the time of induction of anesthesia, it is highly recommended to maintain spontaneous ventilation until the trachea has been intubated and lung ventilation is confirmed. Difficult tracheal intubation should be anticipated. Direct laryngoscopy may be complicated by the presence of macroglossia, malformed epiglottis, and laryngomalacia. Upper airway collapse at the beginning of the induction of anesthesia can be expected, which ...