Health Supervision Guidance for Achondroplasia Patients Updated

By Lisa Rappaport

May 29, 2020

(Reuters Health) - New clinical guidance from the American Academy of Pediatrics (AAP) on health supervision across the lifespan of people with achondroplasia focuses on recent advances in technology that can help diagnose and manage patients with short stature.

The new guidance, which adds an emphasis on patient needs in adolescence and adulthood, updates recommendations issued in 1995, and updated in 2005, that were focused more on children.

The latest guidance reflects advances in technology including better MR imaging resolution and techniques to improve visualization and shorten imaging time as well as the greater clinical presence and use of assessment tools like polysomnography, said Dr. Julie Hoover-Fong, lead author of the new guidelines and director of the Greenberg Center for Skeletal Dysplasias at Johns Hopkins University in Baltimore.

"It was important to outline all the tests, studies and physical examination maneuvers that could be employed to identify potential serious complication in infants and children with achondroplasia, hopefully empowering families and healthcare providers to pursue them when medically indicated," Dr. Hoover-Fong said by email.

"Childhood medical issues, such as obstructive sleep apnea exacerbated by obesity, will remain and likely intensify in adulthood if not recognized and treated as soon as possible," Dr. Hoover-Fong added. "We felt it was important to include adult-specific health and psychosocial issues in the expanded prenatal and adolescent/adult sections of this updated document."

On the possibility of using supplemental growth hormone treatment to treat short stature, the AAP guidelines note that some recent studies have found an insignificant impact on stature with growth hormone, as well as a potential risk for worsening scoliosis and kyphosis associated with this intervention.

Another possible intervention, limb lengthening, is a long and costly process that can have variable outcomes depending on individual patient characteristics and the surgeon involved, the guidelines note. The AAP recommends that parents discuss this with children and involve children in the consent process before engaging in these procedures.

The long-term benefits and harms of surgery are not clear, and research to date also hasn't shown how surgical interventions might impact pain and function over time, Dr. Hoover-Fong said. The optimal timing for surgery is also unclear.

A third option for treatment includes investigational drug therapies with the potential to increase long bone growth or address skeletal complications caused by achondroplasia. Here, too, the AAP urges parents to fully vet clinical trials and ensure that clinicians participating in any trials have enough experience with achondroplasia to distinguish medication side effects from any symptoms that may result from the underlying medical condition.

"All three interventions have widely variable levels of acceptance by the short stature patient population and medical providers, and many individuals in the short stature community do not feel these are necessary to their health or well-being," said Dr. Hoover-Fong. "It was important to present these as options but not obligatory or recommended treatments."

While pediatricians will likely remain the main and most frequent point of contact for children who need ongoing care for achondroplasia, the new guidelines also recognize that improvements in imaging and prenatal testing for this condition may also require some clinical consultations even before babies are born.

A prenatal diagnosis of achondroplasia can be made with more certainty when one or both parents have the condition, according to the AAP guidance.

When both parents have average stature, achondroplasia may be suspected in late gestation when the long bone appears shortened on ultrasound.

"The diagnosis of achondroplasia is usually straight forward, with characteristic clinical features including short stature, relatively large head, and short arms and legs," said Dr. Svein Fredwall of the TRS National Resource Centre for Rare Disorders and Sunnaas Rehabilitation Hospital in Nesodden, Norway.

Characteristic radiological findings on x-rays can confirm the diagnosis, supplemented by a genetic test if necessary, Dr. Fredwall, who wasn't involved in the guidelines, said by email.

The challenge for clinicians and parents is navigating a wide range of possible interventions, some of which don't have a clearly proven track record of long-term benefits and harms, Dr. Fredwall said.

"Children with achondroplasia are as every other kid, they want to have friends, play and have fun, and when growing up getting an education, find a job and a partner," Dr. Fredwall added. "The clinical guidelines are important to inform healthcare providers what to anticipate, and to prevent medical complications, to ensure that these kids can live their lives as normal as possible."

SOURCE: Pediatrics, online May 26, 2020.