PEDIATRICS Vol. 102 No. 6 December 1998, pp. 1407-1414
Acid-base Homeostasis in Children With Growth Hormone Deficiency
Received Apr 30, 1998; accepted Jun 18, 1998.
From the * Department of Pediatrics, Section of Endocrinology,
University of California, Davis School of Medicine, Sacramento,
California; and the Department of Pediatrics, Section of
Endocrinology, University of California, San Diego School of Medicine,
San Diego, California.
Background. Although the primary use of growth hormone (GH) is to promote linear growth, it is also known to affect many metabolic processes and to influence renal function. In laboratory animals, growth hormone deficiency (GHD) causes a mild metabolic acidosis that is corrected by GH treatment. We observed a patient with GHD who initially presented with acidosis of unclear etiology and corrected the acidosis with GH treatment.
Objectives. To determine: 1) whether children with GHD have lower mean serum bicarbonate concentrations than do children with short stature because of other causes; and 2) whether the presence of a low serum bicarbonate concentration increases the probability of GHD among children with short stature.
Methods. We collected data from the medical records of 143 children with short stature who had serum electrolyte concentrations measured as part of their initial evaluations, 66 with GHD and 77 with short stature as a result of other causes. We compared mean serum bicarbonate concentrations and bicarbonate standard deviation scores (SDS) between these two groups and determined the probability of GHD for patients according to bicarbonate SDS.
Results. The mean serum bicarbonate concentration was
significantly lower in patients with GHD (mean standard deviation
[SD]; 23.9 [0.4] mEq/L vs 25.2 [0.3] mEq/L) as was the
bicarbonate SDS (
0.12 [0.14] SD vs 0.38 [0.10] SD). Twelve (75%)
of 16 patients with bicarbonate SDS 
1 SD had GHD compared with 7 (28%) of 25 patients with bicarbonate SDS >1 SD. Patients with
bicarbonate SDS between 1 SD and 1 SD had an intermediate probability
of GHD, 46/102 (45%), similar to the overall prevalence of GHD in the
study population (46%). Mean bicarbonate concentrations and
bicarbonate SDS increased significantly in 9 patients who had repeat
electrolyte measurements during treatment with GH (mean bicarbonate;
21.7 [1.1] mEq/L vs 26.9 [0.59] mEq/L, mean bicarbonate SDS; 1.24
[0.43] SD vs 0.55 [0.27] SD).
Conclusions. Serum bicarbonate concentrations are lower in
patients with GHD than in patients with short stature as a result of
other causes. In addition, serum bicarbonate concentrations rise with
GH treatment in patients with GHD. The probability of GHD is increased
for patients with bicarbonate SDS 1 SD and decreased for patients with bicarbonate SDS >1 SD. These findings indicate a role for GH in
maintaining normal acid-base homeostasis and suggest that GHD should be
considered in children whose growth failure is attributed to other
causes of acidosis.
Key words:
growth hormone,
short stature,
acidosis,
bicarbonate.
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