The approach to the child with unusual physical features, multiple congenital anomalies, or a dysmorphic syndrome is a complex one. Careful physical measurements are not only important for determining the child's condition and present status, but are important as well for establishing baseline measurements in order to follow the affected individual over time and in order to define the natural history of the condition. If a child is seen repeatedly, careful serial measurements are invaluable for demonstrating the disproportionate growth of different parts of the body and the changing proportions that may occur with time.
As stated earlier in the book, a measurement really has meaning only in comparison with other measurements; therefore, all measurements need to be taken and recorded in a way that allows them to be compared with the norms for chronological age, the norms for height age, the bone-age-related norms, or the age-related measurement of some other part of the body. In each area of the body, there is a standard against which other measurements should be compared. For example, in the craniofacial area, the age-related head circumference (OFC) is used for the comparison with other measurements. Are the ears small or large for the age that corresponds to the head size? For example a six-year-old boy, who is 50th percentile for height with a head size that is 50th percentile for a two-year-old and an ear size that is 50th percentile for a four-year-old will appear to have large ears even though they are small for his age.
It is a general rule of thumb that any measurements that deviate more than two standard deviations from each other are considered to be outside the range of normal and need an explanation. Thus, if height is at the 10th percentile and weight is at the 90th percentile, although both measurements are normal, the child will be relatively overweight, and the physician should ask why. Similarly, if head circumference is at the 10th percentile and inner canthal distance is at the 90th percentile, the child will appear to have relative ocular hypertelorism, and the physician should ask why. Other measurements around and of the eye in such a child may allow the delineation of small palpebral fissures (as seen in the fetal alcohol spectrum disorder and blepharophimosis syndrome) or the delineation of laterally displaced inner canthus or telecanthus (as seen in Waardenburg syndrome).
As with any other medical evaluation a careful prenatal, medical, developmental, and family history; a thorough general physical examination, and appropriate laboratory evaluations should be obtained on any child with dysmorphic features or congenital anomalies. This book is aimed at providing data which allow the physician to describe and quantify physical anomalies as a meaningful and useful part of the evaluation. Most chapters deal with particular parts of the body. They outline the ways to describe and measure that area and provide graphs of normal values for frequently used measurements. Practically speaking, there are about 36 measurements that should be performed on all children being evaluated for dysmorphic features. These 36 measurements take less than 10 minutes to record. If a particular area seems to be disproportionate or abnormal, there are additional measurements or studies that can be performed. Photographs should be taken as well.
Figure 18.1 gives an example of an outline form for recording measurements. If the child is quiet, they can be done in a logical way. If the child is crying or agitated, it often pays to obtain distal measurements such as hands, feet and OFC first, before moving in toward the face and chest.
After the measurements are obtained,they should be compared with the normal age- and sex-related standards. Percentiles for the individual are generated. The measurements are then analysed. Any deviating percentile is evaluated. The next step is to compare the measurements with the norms for height age of that child. For example, if the chronological age of the child is four years but the child's height is that of the average (e.g., 50th percentile) two-year-old,the other body measurements need to be compared to the two-year-old standards. They may be completely normal for two years, suggesting that the child is growing like a two-year-old, or there may be marked disproportion. It may then be useful to compare particular parts of the body, such as comparing hand and foot measurements to the "age-related" or "height-related" hand and foot standards. These comparisons allow the physician to define better which body area, if any, is disproportionate. Finally, the child's measurements should be compared to bone-age-related norms. If the bone age was advanced in the four-year-old described above, the disparity between chronological age and height would be even greater.
In subsequent examinations, repeated measurements may be taken in the same way, allowing the construction of a longitudinal growth curve for various areas of the body. In many syndromes with disproportionate growth, the growth curves have not yet been defined. The definition of disproportionate growth in various body areas in these conditions should allow better understanding of the pathogenetic mechanisms leading to the disproportionate growth.
Chapter 18 An Approach to the Child with Dysmorphic Features
Patient name- Date of birth- Hospital no. —
Paternal ethnic origin_ Height_ Date of examination
Maternal ethnic origin- Height- Examiner-
Patient age_ Height age_ Bone age_
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