Linear catch-up growth.

Chronic diseases and malnutrition cause growth failure in childhood and adolescence. Correction of the cause of a growth deficiency is usually followed by catch-up growth. Capacity to catch-up is not only variable in different phases of growth, it is also different in different diseases and among different individuals suffering from the same disease. Catch-up growth is of three types. In type 1 catch-up growth, height deficit is swiftly eliminated after the growth restriction ceases. In type 2, after growth restriction ceases growth continues for longer than usual and growth arrest is compensated. Type 3 is a mixture of type 1 and type 2. Repeated episodes of growth inhibitory conditions result in lower catch-up rates in the subsequent periods. Although the exact mechanism regulating catch-up growth still remains a mystery, monitoring catch-up growth remains an important measure of the efficacy of the therapy and therefore of immense clinical importance.