Parathyroid scintigraphy findings in chronic kidney disease patients with recurrent hyperparathyroidism

Background Parathyroidectomy (PTX), either subtotal or total with forearm autografting, is a well-established treatment for refractory renal hyperparathyroidism (RHPT). However, 20–30% of patients develop persistent or recurrent disease. Obtaining accurate localization before reoperation is difficult. Patients and methods The study group comprised 21 consecutive adult patients (18 undergoing haemodialysis and 3 with a renal graft) imaged using 99mTc-sestamibi/123I subtraction scintigraphy. Of the 21 patients, 12 had undergone one previous PTX and the other 9 between two and four parathyroid operations. All patients had symptoms and signs of severe RHPT. The mean serum PTH level was 1,142 pg/ml. 99mTc-Sestamibi and 123I images were recorded simultaneously. Imaging views comprised a planar view of the neck and mediastinum, followed by a magnified pinhole view over the thyroid bed area. If parathyroid ectopy was detected, SPECT or SPECT-CT was performed. The forearm was imaged in case of autograft. Results Parathyroid scintigraphy was negative in one patient and positive in the other 20 (sensitivity 95.2%). One patient had uptake corresponding to two unresected parathyroid glands. Recurrence at the site of the partially resected gland or autograft was seen in 11 patients. However, six of them had a second 99mTc-sestamibi focus corresponding to a supernumerary parathyroid gland. Seven other patients had a supernumerary parathyroid gland as the sole cause of relapse. Three of the supernumerary glands showed major ectopy (intrathyroidal, low mediastinal, undescended within the vagus nerve). One patient had parathyromatosis with multiple parathyroid nodules scattered over the left side of the neck. Reoperation was possible in 13 patients, with no false-positive findings. Conclusion Many patients referred with the hypothesis of hyperplasia of a subtotally resected parathyroid gland or autograft were found to harbour a supernumerary parathyroid gland missed at the initial surgery

Impfungen für Auslandreisen [Vaccinations for travel abroad]

Travel to the developing world by Swiss citizens has been increasing. Vaccine-preventable diseases challenges the physician to provide pre-travel advice. Each traveler's itinerary, duration of stay and medical history, including previous immunization, should be reviewed. Vaccinations are required or recommended according to the requirements and the epidemiology of countries being visited. This article summarizes updated recommendations to individual vaccines and immunoglobulins

Cognitive load and mental rotation : structuring orthographic projection for learning and problem solving

Cognitive load theory was used to generate a series of three experiments to investigate the effects of various worked example formats on learning orthographic projection. Experiments 1 and 2 investigated the benefits of presenting problems, conventional worked examples incorporating the final 2-D and 3-D representations only, and modified worked examples with several intermediate stages of rotation between the 2-D and 3-D representations. Modified worked examples proved superior to conventional worked examples without intermediate stages while conventional worked examples were, in turn, superior to problems. Experiment 3 investigated the consequences of varying the number and location of intermediate stages in the rotation trajectory and found three stages to be superior to one. A single intermediate stage was superior when nearer the 2-D than the 3-D end of the trajectory. It was concluded that (a) orthographic projection is learned best using worked examples with several intermediate stages and that (b) a linear relation between angle of rotation and problem difficulty did not hold for orthographic projection material. Cognitive load theory could be used to suggest the ideal location of the intermediate stages