Multivariable Model to Predict an ACTH Stimulation Test to Diagnose Adrenal Insufficiency Using Previous Test Results.

Context: The adrenocorticotropin hormone stimulation test (AST) is used to diagnose adrenal insufficiency, and is often repeated in patients when monitoring recovery of the hypothalamo-pituitary-adrenal axis.

Objective: To develop and validate a prediction model that uses previous AST results with new baseline cortisol to predict the result of a new AST.

Methods: This was a retrospective, longitudinal cohort study in patients who had undergone at least 2 ASTs, using polynomial regression with backwards variable selection, at a Tertiary UK adult endocrinology center.

Radionuclide shuntogram demonstrating migration of distal ventriculoperitoneal shunt tubing out of the peritoneal cavity.

An 81-year-old man with a history of ventriculoperitoneal (V-P) shunt placement for symptomatic normal pressure hydrocephalus presented with recurrence of confusion and gait disturbance. Radionuclide cisternography demonstrated loculation of In-111 DTPA in the abdominal wall. A soft tissue mass palpated at the location of tracer accumulation was confirmed to be extraperitoneal pooling of fluid at the site of coiling of the distal shunt tip.