What are the associated medical problems?

• Foramen magnum stenosis - as mentioned above, essentially all children with achondroplasia have a smaller than average foramen magnum. The foramen magnum is the opening thru which the spinal cord leads the head to travel down the spinal column. For the vast majority of children this does not present a problem. There are however approximately 5% or fewer of children with achondroplasia in whom this opening is so small that there is not adequate room for the spinal cord to function properly. These children have what is termed cord compression or compressive myelopathy. This is a very serious medical problem and requires surgical correction. Cord compression due to foramen magnum stenosis has been implicated as the cause of sudden death in a very small proportion of infants with achondroplasia. As with all surgeries performed on Little People, we suggest that care be taken to assure that the physician has experience not only with the procedure, but also performing the procedure on Little People.
• Hydrocephalus - Enlargement of head circumference occurs invariably in achondroplasia but does not require treatment unless pressure within the skull (intracranial pressure) increases and interferes with brain function. Standard charts for normal head circumference throughout childhood in achondroplasia are available. If there is any deviation from average, an opinion should be obtained from a neurosurgeon regarding the need for a ventriculo-peritoneal shunt (a tube that drains excess fluid from the brain into the abdominal cavity).
• Sleep apneas or Sleep-disordered breathing - 2 types: Sleep disordered breathing is common in achondroplasia with studies demonstrating a very wide range of affected children ranging from 22% - 85%. As many as 20% of children could be severely affected(6). There are 2 types of apneas or disordered breathing and they will be discussed separately.
  • Obstructive apnea - results from the blockage of airflow into and out of the lungs with normal respiratory drive. This is the most common type of apnea in achondroplasia because of the mid-face hypoplasia and hypotonia of the pharyngeal muscles. The end result is a "smaller pipe" for the air to travel thru. Many children with achondroplasia adopt an open mouth habitus with the tongue resting on the lower lip to create maximum airway space. This commonly manifests as snoring and causes disturbed sleep. Symptoms can include tiredness, irritability, daytime sleeping, etc.Treatment for obstructive apnea can include weight reduction measures, adenoidectomy-tonsillectomy, continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) at night by nasal mask to keep the airways open. A tracheostomy may be necessary in the most severe cases.
  • Central apnea - results from failure of the respiratory centers in the brain to properly control the process of breathing. In the brainstem, the respiratory centers are in close proximity to the foramen magnum. Therefore, if the foramen magnum is compressing the spinal cord central apnea can result.

• What are the physical characteristics of Achondroplasia?
• How is the diagnosis made?
• What are the associated medical problems?
• Problems in the musculoskeletal system
• Problems elsewhere in the body
• What are things to watch out for?
• References