What is the prognosis of hypophosphatemic rickets?

Updated: May 18, 2020
  • Author: James CM Chan, MD; Chief Editor: Sasigarn A Bowden, MD  more...
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Apart from the short stature of most affected adults, the prognosis for a normal lifespan and normal health is good.

The chief aspects of morbidity in X-linked hypophosphatemia are the metabolic processes linked to phosphate. Clinically, the most obvious of these aspects is the effect on bone formation and growth that causes very severe rickets, especially in affected males. The early development of rickets indicates alterations in the orderly processes of bone growth and remodeling that cause bone deformation. Abnormal dentine formation causes late dentition and spontaneous abscess formation.

In a study of 59 adult patients with X-linked hypophosphatemia, Chesher et al found that 42% required at least one osteotomy, while dental disease, nephrocalcinosis, and hearing impairment were found in 63%, 42%, and 14% of the patients, respectively. [25]

Hypercalcemia, nephrocalcinosis, and hypertension

Acute hypercalcemia (with resulting irritability, confusion, and potential seizures) can occur during treatment. Nephrocalcinosis, the long-term result of overaggressive therapy, may be more damaging. Aside from hypercalcemia from vitamin D supplementations, the phosphate supplementations need to be approached with caution. A long-term study in XLH patients treated with combination therapy demonstrated a distinct relationship between mean phosphate dose and the grade of nephrocalcinosis; if the phosphate supplementations are kept to below 60 mg/kg body weight per day, the risk of nephrocalcinosis is minimized. [26] Although ultrasonography reveals that 47% of properly treated patients show evidence of nephrocalcinosis, this condition in X-linked hypophosphatemia apparently does not usually progress to renal failure.

Hypertension has been reported in older children under treatment as a consequence of persistent hyperparathyroidism. [27] Nephrocalcinosis did not need to be present for hypertension to occur. Consequently, patients under treatment should be carefully monitored for laboratory signs of hyperparathyroidism.

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