CME *-*-0 Evaluating tall children ALEXANDER K.C. LEUNG, MIBBS, FRCP(Edin) SUMMARY W LANE M. ROBSON, NID, FRCPC The causes of tall stature are numerous; genetic tall stature and constitutional tall stature are the most common. Diagnosis can usually be established from ALI SlATURE IN CHILDREN IS * precocious puberty, the history and physical defined as a * pituitary growth hormone excess, examination. An estimation of arbitrarily bone age can help to confirm height greater than two * cerebral gigantism (Sotos syndrome), diagnosis and to determine the standard deviations above * hyperthyroidism, child's growth potential. No the mean torr- a populatlonI ot1r.l1the same * Marfan's syndrome, treatment is usually necessary. sex, age, and race.' According to this hhomocystinuria, Hormonal therapy can be definition, approximately 2.30% of chil- * Klinefelter's syndrome, considered for individuals for dren have tall stature. The most com- * XYY syndrome, whom the predicted height is mon cause of tall stature is genetic * hypogonadal syndromes, excessive if the psychosocial and medical advantages predisposition. * Beckwith-Wiedemann syndrome, outweigh the risks of treatment. Several pathologic conditions also * Weaver syndrome, present with tall stature. Excessively * Proteus syndrome, and RESUMEI I tall stature, especially of girls, can * congenital generalized lipodystrophy. ll existe de nombreuses causes cause serious psychologic problems.2 a la grande taille; les plus This article reviews the causes of tall Familial or genetic tall stature. frequentes sont les etiologies stature and suggests an approach to Familial or genetic tall stature is the genetique et constitutionnelle. management. most common cause of tall stature. l'histoire et l'examen physique These children are usually tall from permettent habituellement de preciser le diagnostic. Causes and clinical early childhood (Figure 1) and have La determination de l'age manifestations tall parents. Genetically tall children osseux peut contribuer a The causes of tall stature are: have a high normal growth rate, nor- confirmer le diagnostic et a * familial or genetic tall stature, mal results from physical examina- determiner le potentiel de * constitutional tall stature, tion, and a bone age that is croissance de l'enfant. * exogenous obesity, compatible with chronologic age. La majorite des cas ne Comparing the growth of the patient necessitent aucun traitement. Dr is Clinical Associate in the the on a chart On pourra envisager le recours Leung Professor and parents growth a I'hormonotherapie chez les Department ofPediatrics at the University of reveals that the tall stature is appro- individus a qui l'on predit une Calgary and is a Pediatric Consultant at the priate for that family. taille excessive, a la condition Alberta Children's Hospital. Dr Robson is toutefois de bien soupeser les Medical Director ofPediatric JVNephrology at the Constitutional tall stature. avantages medicaux et Children's Hospital in Greenville, SC, and is Constitutional tall stature is the second psychosociaux, ainsi que les Clinical Associate Professor in the Department of most common cause of tall stature. risques inherents au traitement. Pediatrics ofthe Faculy ofMedicine at the Children with constitutional tall stature Can Fam Physician 1995;41:457-468. University ofSouth Carolina in Columbia. have a normal length at birth. The (anadian Family Plhsician VO1. 1 IOAlarc(h 199. 457 CME Evaluating tall children growth velocity accelerates in early Precocious puberty. An etiologic childhood, and the tall stature is usu- classification helps to manage preco- ally evident by the age of 3 to 4 years cious puberty.5 In affected children, (Figure 2).3 Growth velocity slows acceleration of linear growth invariably down after the child reaches 4 or 5 occurs simultaneously with signs of pre- years; thereafter the growth curve is mature sexual development or inappro- parallel to and above the normal priate virilization. Rapid growth is curve.3 Constitutionally tall children accompanied by a rate of osseous matu- have a slightly or moderately ad- ration that is greater than expected for vanced bone age. Puberty usually the chronologic age. The advanced develops in the early range of bone age results in early epiphyseal clo- .3 normal, and final adult height is in sure; consequently, the ultimate height is the upper range of normal. There is less than it would have been otherwise.5 usually a family history of a similar growth pattern. Pituitary growth hormone excess. Growth hormone hypersecre- Exogenous obesity. Children with tion in children is usually caused by a exogenous obesity are usually tall for growth hormone-producing or null- their age.4 In these children, bone age cell adenoma of the pituitary gland. is advanced and proportional to height Before the epiphyses close, an excess of age, and the adolescent growth spurt growth hormone produces accelerated begins and ends early. These children linear growth and results in gigantism.6 are only slightly taller than average Bone age is often advanced.7 An excess as adults.4 of growth hormone after the epiphyses Id - ao r11 I 2W _ 10 0 I V A ,,I A y Ir 1/1 5.1. A A Yi x lzi v y 0 ;o 458 Canadian Family Physician VOL 41: March 1995 CME fuse results in acromegaly, a disorder mental retardation, large elongated Evaluating tall children characterized by large hands and feet, head, large ears and jaws, high overgrowth of the mandible and supra- arched palate, prominent jaw, anti- orbital ridges, and coarse facial fea- mongoloid slant to the eyes, large tures. Pituitary tumours are associated hands and feet, and increased arm with headache, decreased visual acuity, span compared with height.9 The visual field defects (typically bitemporal bone age is often advanced and com- hemianopsia), and symptoms or signs patible with the height of the patient.9 suggesting increased intracranial pres- The serum level of growth hormone sure. Tumours are also associated with and the results of other endocrine deficiency of other pituitary hormones, studies are normal. In most patients, such as thyrotropin, corticotropin, and the lateral and third ventricles are gonadotropin. mildly dilated. Encephalograms are often abnormal.9 Most cases are spo- Cerebral gigantism (Sotos syn- radic. Familial cases are usually con- drome). Children with Sotos syn- sistent with an autosomal dominant drome are often large at birth, and mode of inheritance.9 their growth is most rapid during the first few years of life.8 Thereafter, the Hyperthyroidism. Excessive thyroid growth velocity slows, and the growth hormone in early childhood causes an curve remains parallel to and above acceleration in linear growth and pro- the normal curve. Other features portional osseous maturation. include frontal bosselation, coarse facial Craniosynostosis sometimes develops features, hypertelorism, clumsiness, when hyperthyroidism appears in very 90 _ !} s so~~~~~~~~~~~~~~~~~~~~~~ -1 S Sl 70~~~~~~~i _ 6 7-- - 5~~~~~~ 30_ !B 2 30t - 7 A ~~~~~~~ITA A] to~~_Yi Vl**I 4 ° _ t1 lL 20 2[r-1r ~~~~~~~~~~AC Canadian Family Physician VOL 41: March 1995 461 CME Evaluating tall children early life. The ultimate adult height Homocystinuna. Homocystinuria is is unaffected.'0 an autosomal recessive disorder caused by a deficiency of cystathionine Marfan's syndrome. Marfan's syn- P-synthase with resultant excretion of drome is characterized by arachno- large amounts of homocystine in the dactyly, tall stature, superior lens urine.'2 Patients with this disorder have subluxation or dislocation, and aortic a phenotypic appearance similar to or mitral regurgitation." The arm those with Marfan's syndrome (Figure 4). span is greater than height, and the Additional features of homocystinuria upper to lower body segment ratio is include mental retardation, malar flush, diminished (Figure 3). Other clinical inferior lens subluxation or dislocation, features include joint hyperextension, and an increased incidence of seizures, inguinal or femoral hernia, pectus arterial and venous thrombosis, osteo- excavatum, scoliosis, megalocornea, porosis, and vertebral collapse.'3 and myopia." Retinal detachment and aortic aneurysm and rupture are Klinefelter's syndrome. Klinefelter's the important complications. The syndrome is due to the presence of condition is inherited as an autosomal more than one X chromosome in a dominant trait. male patient."' The most common Fzgure 3. Child with Marfan's syndrome: Figure 4. Child with homocystinuria: The disproportionatey long limbs make the arm span The thin, long limbs and sparse subcutaneous tissue exceed the height ofthepatient. are evident. 462 Canadian Family Physician VOL 41: March 1995 CME abnormal karyotype is 47 XXY. which include a small jaw, widely sepa- Evaluating tall children Affected children are tall and have rated eyes, large and dysplastic ears, eunuchoid proportions with a long arm broad forehead, long philtrum, mega- span and legs and a decreased upper to cephaly, strabismus, depressed nasal lower body segment ratio. Genital bridge, and flat occiput. 16"17 abnormalities, such as hypogonadism, cryptorchidism, and a small phallus, Proteus syndrome. Proteus syn- are sometimes present.'3 Gynecomastia drome is characterized by overgrowth is common during adolescence. Mental of various body parts, megacephaly, retardation and behavioural difficulties, multiple hyperpigmented warty nevi, such as excessive shyness, aggres- and subcutaneous vascular tumours.18'19 siveness, and antisocial behaviour,