Application of Upper Extremity Radionuclide Venography as a Diagnostic Approach for Port-A Catheter Thrombosis

To investigate the role of upper extremity radionuclide venography as a potential diagnostic modality in the assessment of venous thrombosis associated with a Port-A catheter. Methods: Fourteen symptomatic patients who had received Port-A catheter implantation were enrolled. A dynamic nuclear medicine flow study was performed with intravenous administration of Technetium-99m macroaggregated albumin to both upper extremities. Imaging patterns of the venous system were categorized as patency, partial obstruction, and total occlusion. Results: The findings of the dynamic images clearly demonstrated clinical problems. Three patients were free of a definite venous flow change. Three patients had partial obstruction of venous return. A significant cut-off of venous return was demonstrated in 8 patients, and total occlusions were hence diagnosed. All patients underwent this procedure smoothly without any complication. Conclusion: These results suggest that upper extremity radionuclide venography is an easily performed and effective method for diagnosing Port-A catheter thrombosis in clinical practice

Congenital Central Hypoventilation Syndrome with PHOX2B Gene Mutation in a Taiwanese Infant

Congenital central hypoventilation syndrome (CCHS) is a rare disease that is characterized by failure in the autonomic control of breathing. Recent reports have identified mutation of the paired mesoderm homeobox protein 2b (PHOX2B) gene as playing a major role in CCHS. Increasing polyalanine repeat number is associated with a more severe clinical phenotype. We report a newborn male infant with the clinical manifestations of apnea and cyanosis requiring immediate endotracheal intubation at the age of 1 day. Recurrent hypoventilation with hypercapnia and hypoxemia occurred during sleep after weaning from the ventilator. No primary cardiopulmonary disease was identified. These clinical manifestations are compatible with CCHS. PHOX2B gene mutation analysis performed at the age of 4 months revealed expanded alleles containing polyalanine 26 repeats, further supporting the diagnosis of CCHS. Continuous ventilator support was necessary and tracheostomy was ultimately performed at the age of 5 months due to ventilator dependence. He was discharged with home ventilator support at the age of 6 months. [J Formos Med Assoc 2007;106(1):69-73