Phaeochromocytoma in the Hong Kong Chinese population.

OBJECTIVE: To review the clinical manifestations of phaeochromocytoma in a Hong Kong Chinese population. DESIGN: Retrospective review. SETTING. Five public hospitals in Hong Kong. PATIENTS: Seventeen patients with operated phaeochromocytoma between 1994 and 2003 were reviewed retrospectively. RESULTS: Six patients (35%) were men, 11 (65%) were women. The mean age at presentation was 47 (range, 17-72) years. The diagnosis post-presentation was delayed by 1 to 132 months. Over 70% of the patients had hypertension. The most frequent symptoms were headache (53%), palpitations (53%), and sweating (41%); all these symptoms were present in 24% of the patients. Four (24%) had hereditary phaeochromocytoma/paraganglioma syndrome. The sensitivity of 24-hour urinary catecholamine measurements was 82%. Mean urinary adrenaline and noradrenaline concentrations were respectively 7- and 8-fold greater than the upper reference limits. Computed tomography and metaiodobenzylguanidine scintigraphy were the most widely used means for tumour localisation (sensitivity, 100% and 87% respectively). Approximately 65% of the patients had intra-adrenal tumours; 53% were on right side, 18% were bilateral. All the patients were prescribed phenoxybenzamine (dosage range, 20-120 mg/day) preoperatively. Two thirds of the patients had improved blood pressure 1 year after the operation. No malignancy was reported after a mean follow-up period of 7 years. CONCLUSION: Our series of patients with phaeochromocytomas commonly had a high frequency of normotension and extra-adrenal tumours. A high index of clinical suspicion and appropriate biochemical investigations are necessary to make the diagnosis, especially for patients manifesting adrenal incidentaloma and extra-adrenal lesion.

Usage of a fixed dose of radioactive iodine for the treatment of hyperthyroidism: one-year outcome in a regional hospital in Hong Kong.

OBJECTIVES: To evaluate the efficacy of a fixed dose of radioactive iodine (131-I) in the treatment of thyrotoxicosis, and to identify risk factors associated with treatment failure. DESIGN: Retrospective study. SETTING: Thyroid Clinic of a regional hospital in Hong Kong. PATIENTS: Patients receiving their first dose of radioactive iodine for the treatment of thyrotoxicosis during the inclusive period September 1999 to August 2004. MAIN OUTCOME MEASURES: Relapse rate and time to relapse. RESULTS: A total of 113 patients received a fixed dose of 5 mCi (185 MBq), 6 mCi (222 MBq), 8 mCi (296 MBq), and 10 mCi (370 MBq) 131-I in a proportion of 1:6:71:35. At 1 year, 42 (37%) of the patients had relapsed, of which 69% received a second 131-I dose. The median time to relapse after first receiving 131-I was 4 months. At 1 year, the remaining 71 (63%) of the patients were successfully treated; 46 (41%) were euthyroid, and 25 (22%) had became permanently hypothyroid. Basal free thyroxine level and goitre size were significantly associated with a relapse rate after a single dose of 131-I; larger goitres showed a trend towards high rates of relapse. Patients pretreated with propylthiouracil had a higher rate of relapse during the first year after radioactive iodine than those pretreated with carbimazole, but the difference was not significant when combined with other pretreatment variables. CONCLUSIONS: A single fixed dose of radioactive iodine is a simple, safe, and effective treatment for hyperthyroidism. High basal free thyroxine concentration and large goitre size are associated with higher chance of relapse. Higher radioiodine doses may be considered to improve the cure rate.