Radiotherapy in the management of thyroid orbitopathy. Computed tomography and clinical outcomes.

OBJECTIVE: We investigated the long-term outcome of patients with thyroid orbitopathy treated with orbital radiotherapy using quantitative clinical measurements and orbital computed tomographic morphometric changes. DESIGN: Patients who had undergone orbital radiotherapy for thyroid orbitopathy at least 1 year previously were retrospectively recalled for follow-up examination and computed tomography. Controls were patients with similar disease activity but who had not undergone radiotherapy. SETTING: Subspecialty clinic in a university teaching hospital. PATIENTS: Twenty-one patients (42 orbits) who underwent radiotherapy and six clinically comparable patients who had not undergone radiotherapy (12 orbits). INTERVENTION: Standardized, super-voltage, orbital radiotherapy. MEASUREMENTS: Five clinical indexes of orbitopathy and six computed tomographic indexes were examined for interval changes. RESULTS: The orbital computed tomographic muscle-diameter index enlargement ratio did not change in either group (radiotherapy group, 1.54 to 1.51, not significant; nonradiotherapy group, 1.37 to 1.36, not significant). The mean (+/- SEM) number of muscles with low-density areas increased in both groups (radiotherapy group, 1.1 [+/- 1.9] muscles per orbit; P < .001). Soft-tissue signs improved significantly with lesser improvements in extraocular muscle function in both groups. Proptosis, visual acuity, and intraocular pressure rise on upgaze did not improve significantly in either group. CONCLUSIONS: No changes in muscle size measured with computed tomography were found in either patients undergoing radiotherapy or patients not undergoing radiotherapy after long-term follow-up. Clinical indexes of thyroid orbitopathy, especially soft-tissue signs, improved on follow-up, but this was not influenced by the method of treatment.

Erosive spondylo-arthropathy and tertiary hyperparathyroidism.

A patient on long term haemodialysis for analgesic nephropathy, with known teriary hyperparathyroidism developed a rapidly evolving, erosive, non-infective spondylo-arthropathy at two vertebral levels. In addition, erosions were noted adjacent to the right sacroiliac joint. Subsequent postmortem material from the affected vertebral levels demonstrated changes consistent with hyperparathyroidism alone and this is suggested as the possible aetiology underlying this recently recognised destructive spondyloarthropathy.

Peripheral vision suppression of melatonin.

The suppression of melatonin by bright light is probably mediated by the suprachiasmatic nucleus (SCN) in humans. In animals, SCN cells have broad visual receptive fields, suggesting that peripheral bright light could be effective for melatonin suppression. Twelve healthy subjects were subjected to 1000 lux illumination for 2 hr from 0100 to 0300 on two occasions: once lighting the central visual field 5 degrees from the center of gaze and once lighting the peripheral visual field 60 degrees lateral to the direction of gaze. Six subjects were observed on a third occasion in dim light. The three conditions differed significantly, with less melatonin secreted in 1000 lux, but melatonin levels with central and peripheral illumination did not differ. This suggests that phototherapy using bright light in the visual periphery may be effective.