Study objectives: There have been many studies on the physical characteristics at the time of contraction of a primary spontaneous pneumothorax (PSP), but it has not been shown when and how such physical characteristics develop. These issues were investigated.
Patients and design: Physical development of 27 male patients with PSP were examined. Their physical records were collected with the patients' permission, and standard curves, estimated from the Japanese nationwide records in the year corresponding to the ages of the patients, were plotted as control values.
Results: The height of patients was already greater at 6 years of age. It showed a marked increase from 11 to 14 years. The body weight was more than the standard until 9 years, but it became less after age 11, and this difference increased after age 15. Rohrer's index was significantly lower than the standard at all ages, and the difference was particularly large from 11 to 15 years. In the standard group, there was a balance between the annual height and weight gain. In the patient group, annual weight gain was similar to that in the standard group whereas height began to increase 2 years earlier, and as a result, ectomorphy, which was also observed before this age, became marked at this age.
Conclusions: The rapid increase in the vertical dimension of the thorax compared with the horizontal dimension during the period of rapid physical development is considered to affect intrathoracic pressure at the apex of lung, which would have some influence on enhancing cyst formation.