More than two dozen cases of cortical proliferation in neonates receiving PGE 1 have been reported in the medical literature to date. The reaction appears to involve hyperostosis in the diaphyses of the long tubular bones and, less commonly, in the ribs, scapulae, and clavicles. Widening of the cranial sutures has also been observed. The mechanism of this effect is not known. The diagnosis of hyperostosis may be made by clinical examination revealing joint swelling or loss of motion, or radiographically.
Cortical proliferation begins to regress after discontinuing therapy.
23 Gastric outlet obstruction, resulting from mucosal hyperplasia in the antrum, has been also reported after long-term use of PGE 1 . Among the 74 patients evaluated, five had both clinical and radiologic or pathological evidence of gastric obstruction, another four had clinical signs only, and the remaining 65 were considered normal. Another potential consequence of long-term PGE 1 exposure is the development of intimal tears within the pulmonary arteries and changes in vessel muscularity. Aneurysmal dilatation and vessel wall edema have recently been reported in infants who have received PGE 1 . It has been suggested that these changes may be dose-related, occurring more frequently when higher infusion rates are used to maximize pulmonary blood flow.