R. Nehgme et al., CARDIOVASCULAR-ABNORMALITIES IN PATIENTS WITH X-LINKED HYPOPHOSPHATEMIA, The Journal of clinical endocrinology and metabolism, 82(8), 1997, pp. 2450-2454
Treatment for X-linked hypophosphatemia (XLH; vitamin D metabolites an
d phosphate salts) may result in hypercalcemia, hypercalciuria, nephro
calcinosis, and hyperparathyroidism. Cardiovascular abnormalities occu
r in association with these complications, but have not been reported
in XLH. We hypothesized that such abnormalities may occur in XLH and e
valuated cardiovascular status in 13 patients with this disease. All p
atients were asymptomatic and had normal cardiovascular physical exami
nations and Holter studies. Serum calcium and creatinine clearance wer
e normal in all. However, all patients had mild to moderate nephrocalc
inosis. Left ventricular hypertrophy was diagnosed by electrocardiogra
m in three and by ultrasonography in seven children. Baseline blood pr
essure (BP) was normal (mean +/- SD, +/- 15/74 +/- 6 mm Hg). During ex
ercise stress testing, systolic BP increased in all patients, but the
maximal systolic pressure was less than that in healthy age- and sex-m
atched controls (156 +/- 20 vs. 175 +/- 23; P = 0.002, by t test). An
abnormal increase in diastolic BP occurred at all levels of work load
in XLH patients; their peak exercise diastolic BP was 91 +/- 12 cs. 72
+/- 6 mm Hg in controls (P < 0.0001, by t test). Whether these abnorm
al findings are primaly defects in XLH or represent complications of t
reatment is unclear. Patients with XLH should be monitored closely for
the development of hypertension and left ventricular hypertrophy. Inv
estigation of the mechanisms involved and establishment of therapeutic
guidelines are indicated.