A Closer Look at Short Stature
Published on in Endocrinology and Diabetes Update
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Published on in Endocrinology and Diabetes Update
When is a child “short enough” to be referred to an endocrinologist for evaluation? “It depends on how you define short stature, and that’s a matter for debate,” says Vaneeta Bamba, MD, medical director, Diagnostic and Research Growth Center at The Children’s Hospital of Philadelphia. “While the term traditionally refers to children with height 2 standard deviations or more below the mean, any child with persistent deceleration of height velocity should be evaluated for poor growth.”
CHOP’s Growth Center is dedicated to the clinical evaluation, diagnosis, and treatment of children with disorders of growth and puberty and sees more than 6,500 patients a year. Besides the usual suspects that include constitutional growth delay and familial short stature, growth hormone deficiency (GHD) may be a cause for growth retardation. CHOP has the ability to complete the entire process — from assessment to diagnosis to initiation of growth hormone therapy — all under one roof. Routine lab testing, provocative growth hormone testing, and magnetic resonance imaging of the pituitary gland can all be performed at CHOP, as well as family education.
Once the diagnosis of GHD is confirmed, a referral is made to CHOP’s Family Learning Center, where family members are carefully instructed in proper growth hormone administration. This free service is offered to all patients regardless of insurance status, and CHOP nurses experienced in use of various GH devices conduct the education. Since patients come to CHOP from Pennsylvania, New Jersey, Delaware, and beyond, sometimes it is challenging for a family to come to the Family Learning Center. In these instances, a CHOP Home Care nurse may be sent to the home to teach parents or care providers.
One barrier to treatment of GHD is GH contract negotiation by insurance companies. While a child may be required to use a particular brand of GH based on coverage by his or her insurer, this brand may change 6 to 12 months later. Attention must be given to how these different brands of growth hormone can impact dosing. “Families can use additional support when their child’s brand is changed,” says Bamba, “since administration protocols vary slightly with each manufacturer. It’s stressful for them.”
Parental height and ethnic/cultural norms should be considered when evaluating a child for abnormal growth, but these factors may not exclude an underlying treatable reason for a child’s short stature. While in most cases, majority of growth is genetically determined, it is possible a child’s short stature may be due to an underlying condition or genetic abnormality. In some cases, the child may benefit from evaluation and treatment.
In addition to routine screening for chronic disease, endocrine, and GI conditions, many children have genetic testing performed to identify those who may present with subtle or even no clinical features, such as a girl with mosaic Turner syndrome or a child with haploinsufficiency of the short stature homeobox gene on the X chromosome (SHOX deficiency). Because genetic testing is performed on-site at CHOP, the Genetics team is consulted when an abnormality is identified.
In addition to otherwise healthy children with short stature, CHOP has subspecialty clinics that are designed to evaluate children with specific diagnoses, such as Turner syndrome, 22q deletion syndrome, celiac disease, and oncological diagnoses. These children are typically evaluated within their subspecialty program in a multidisciplinary environment. “This allows the children to see many or all of the subspecialists they need at one time,” says Bamba, “which reduces anxiety for both families and children.”
Many children being assessed for growth retardation have challenges in other areas as well, such as weight gain and psychosocial issues revolving around self-confidence, particularly during adolescence. The CHOP team collaborates with nutritionists, feeding team, GI specialists, and behavioral health specialists when necessary to address these aspects of a child’s well-being. Joint appointments between these specialties are not uncommon.
Regardless of the reason for growth patterns, focus on positive character traits is critical to building self-confidence and self-esteem in some children, especially during the sensitive adolescent period. It is important to remember that a child may be significantly shorter than his or her peers, but still be very healthy and happy. Research indicates that clinicians may need to remind parents of this fact.
Adda Grimberg, MD, scientific director of the Growth Center, has been studying patterns in the referral and treatment of children with short stature. Pediatric growth hormone registries have documented an almost 2:1 male-to-female ratio among U.S. growth hormone recipients, a ratio close behind Japan’s, but exceeding that of many European countries.
Pediatric endocrinologists are the principal prescribers of growth hormone in the pediatric population, and boys were found to outnumber girls, again about 2:1, among children referred to the Growth Center for evaluation of short stature or poor growth. Further, the girls who were referred were shorter than the boys, relative to both the general population and their parents’ heights, and were found to have a greater frequency of underlying disease. Taking it one step back, to the patient population of general pediatric practices, the prevalence of growth faltering did not differ between boys and girls, indicating the 2:1 ratio seen in endocrine practices reflects a gender-based referral bias. A racial bias was also found, with African American patients relatively underrepresented among the children with growth faltering who saw an endocrinologist versus those who saw a gastroenterologist or no specialist.
The majority of patients with growth faltering were managed by their primary care clinician without seeing a specialist. Among diagnostic tests ordered by primary pediatricians for patients with growth faltering, tests of the growth hormone axis were ordered twice as frequently for boys than girls.
Current NIH-funded studies aim at understanding the origins of the disparities in the management of short stature — from the perspectives of both primary care clinicians and parents. Because short stature is not a disease, both parents and clinicians share in the clinical decision-making process, and the degree of parental concern often influences the management pursued by clinicians.
Factors influencing parental attitudes and knowledge about childhood growth and its treatment, such as the Internet, thereby play a role in shaping healthcare practice. Grimberg’s work ultimately strives to understand how social pressures for tallness are impacting pediatric care and how we can address the disparities to improve clinical care for children with growth problems. Also, Grimberg is chairing the Pediatric Endocrine Society taskforce that is drafting new guidelines for pediatric growth hormone and IGF-I therapy.
Medically underserved girls receive less evaluation for short stature. Grimberg A, Feemster KA, Pati S, Ramos M, Grundmeier R, Cucchiara AJ, Stallings VA. Pediatrics. 2011;127(4):696-702.
Internet informs parents about growth hormone. Cousounis P, Lipman TH, Ginsburg KR, Grimberg A. Horm Res Paediatr. 2013;80(2):86-91.
Categories: Endocrinology and Diabetes Update Winter 2015