Difficult physician-patient encounters.

Consultant physicians encounter patients, and families and carers of patients, who leave us feeling helpless, frustrated, irritated and even angry. There are limited opportunities for trainees and physicians to discuss how to recognize, manage, learn from and prevent these difficult physician-patient encounters. This paper addresses factors, including physician factors, that may contribute to making encounters difficult, categorizes the types of difficult encounters and provides generic and specific suggestions (based in part on published literature and in part on our personal experience) about prevention and management of many of them.

Cautionary tales in the interpretation of studies of tools for predicting risk and prognosis.

Assessing future risk or prognosis in individual subjects is an often difficult and humbling task for clinicians. In recent times numerous prediction tools have been developed to make the task more accurate and thereby render management decisions more appropriate. If these tools are to be used effectively, an understanding is needed of their method of development, performance characteristics, ease of use and applicability in clinical settings, and potential impact on clinical decision-making. In this fourth article in a series on critical appraisal, we discuss questions that need to be asked of any new risk prediction tool.

Cautionary tales in the clinical interpretation of studies of diagnostic tests.

The use of investigational tests in making a diagnosis is a core activity of physicians and one that requires an understanding of the accuracy and usefulness of specific tests in discriminating between several diagnostic possibilities. Studies of diagnostic tests are frequently methodologically flawed and their results are often not well understood or applied in clinical practice. This article defines the performance characteristics of diagnostic tests, describes several commonly encountered deficiencies in study design which may invalidate reports of new diagnostic tests, and explains a Bayesian approach to interpreting test results in terms of disease probability.

Cautionary tales in the clinical interpretation of therapeutic trial reports.

Practising clinicians are assailed daily with reports of new therapeutic clinical trials. The evidence-based medicine movement has developed critical appraisal methods for assessing the validity and impact of such studies. However, challenges persist in regards to the appropriate interpretation and application of trial results within everyday clinical settings. Using selected examples from recently published literature, we illustrate 15 cautionary themes for translating research evidence from therapeutic trials into clinical practice.

Laser therapy for rhegmatogenous retinal detachment.

Traditional techniques for managing uncomplicated macula-sparing rhegmatogenous retinal detachments include scleral buckling and pneumatic retinopexy. Demarcation laser photocoagulation is associated with less morbidity than these techniques and may be equally as effective in stabilizing selected macula-sparing retinal detachments.

A pigmented adenoma of the ciliary epithelium examined by magnetic resonance imaging.

PURPOSE: We studied a case of a pigmented adenoma of the ciliary epithelium. METHODS: We used magnetic resonance imaging in the clinical diagnosis of this tumor. RESULTS: The tumor was successfully treated by local excision. CONCLUSIONS: Magnetic resonance imaging is most useful in evaluating a ciliary body mass for local extension. It cannot clinically distinguish a pigmented adenoma of the ciliary epithelium from a uveal melanoma.

Osteomalacia due to unusual causes presenting in adults.

Severe osteomalacia due to causes other than malabsorption and, where renal function was impaired, disproportionate to the degree of renal failure, is described in 15 adults. Only one was younger than 46 years, the median age being 59 years. The diagnosis was not made for months in most patients. After investigation, the patients were grouped as follows: nutritional three cases, "renal" six cases, hypophosphataemia three cases, neurofibromatosis and primary hyperparathyroidism one each. The last patient was poorly nourished and had taken anticonvulsants and analgesics. Most patients responded well to treatment with calciferol. These cases indicate the need to be aware that osteomalacia may occur in previously healthy middle-aged or elderly subjects.

Calcium metabolism in cancer. Studies using calcium isotopes and immunoassays for parathyroid hormone and calcitonin.

Studies of calcium metabolism in 38 patients with cancer indicated that: 1) intestinal absorption of calcium was reduced in patients with skeletal metastases and in those with hypercalcemia; 2) calcium-47 space (a measurement of bone turnover rate) was high in the patients with skeletal metastases; 3) hypercalcemic patients had higher urinary and endogenous fecal excretion of calcium than those who were normocalcemic; 4) levels of plasma immunoreactive parathyroid hormone were similar in normo- and hypercalcemic patients, but the levels for a given serum calcium in malignant disease were lower than those in primary hyperparathyroidism; and 5) some patients had elevated calcitonin levels. Hypercalcemia complicating malignant disease is therefore not due to hyperabsorption or diminished excretion of calcium, and a low calcium diet is unlikely to benefit these patients. Measurement of 47Ca space could be of use in monitoring therapy of patients with skeletal metastases, and measurement of plasma parathyroid hormone could be useful in the differential diagnosis of hypercalcemia.

Whisky: a new provacative test for calcitonin secretion.

Oral whisky is a potent stimulus of calcitonin secretion. Peak increments of immunoreactive calcitonin are observed within 15 min after the ingestion of 50 ml of whisky; the magnitude of the response is similar to that observed during a four-hour calcium infusion. This procedure has several advantages over standard methods of stimulating calcitonin release in patients at risk of developing medullary carcinoma of the thyroid, and this is shown by a study in a large family with familial chromaffinomatosis.

Calcitonin in breast and lung cancer.

Immunoreactive calcitonin was found in extracts of seven out of eight consecutive breast carcinomas and four selected lung carcinomas, but not in extracts of benign breast lesions or normal tissues. This suggests that the high plasma calcitonin levels observed in patients with a wide variety of cancers reflect ectopic production of calcitonin by cancer tissue, and that the radioimmunoassay for calcitonin could prove to be of value in the detection and management of malignant disease, particularly breast cancer.

Immunoreactive calcitonin production by human lung carcinoma cells in culture.

Monolayer cultures have been established from a poorly differentiated carcinoma of the lung. Homogeneous cell growth and morphology have been maintained for over 18 months through more than 80 subculture passages, and the cells have been found to produce both immunoreactive calcitonin and an immunoreactive carcinoembryonic antigen-like material.