✓ Cushing's disease is associated with brain atrophy and cognitive deficits. Excess glucocorticoids cause retraction and simplification of dendrites in the hippocampus, and this morphological change probably accounts for the hippocampal volume loss. Mechanisms by which glucocorticoids affect the brain include decreased neurogenesis and synthesis of neurotrophic factors, impaired glucose utilization, and increased actions of excitatory amino acids. In this review, the timing, pathology, and pathophysiology of the brain atrophy in Cushing's disease are discussed. The correlation of atrophy with cognitive deficits and its reversibility is also reviewed.
Chirag G. Patil, Shivanand P. Lad, Laurence Katznelson and Edward R. Laws Jr.
Shivanand P. Lad, Chirag G. Patil, Edward R. Laws Jr. and Laurence Katznelson
✓ Cushing's syndrome can present a complex problem of differential diagnosis. Of cases in which hypercortisolemia results from an adrenocorticotropic hormone (ACTH)–dependent process, approximately 80% are due to a pituitary adenoma (Cushing's disease [CD]), 10% are due to adrenal lesions, and the remaining 10% are secondary to ectopic ACTH secretion. For patients with CD, surgical removal of the pituitary adenoma is the treatment of choice. Thus, localization of the source of ACTH secretion is critical in guiding timely treatment decisions.
Inferior petrosal sinus sampling (IPSS) is considered to be the gold standard for confirming the origin of ACTH secretion in patients with Cushing's syndrome.
The authors present an overview of IPSS—both the technique and its interpretation—as well as a summary of recent studies. A number of other techniques are discussed including sampling from the cavernous sinus, the jugular vein, and multiple sites to aid the diagnosis and lateralization of ACTH-producing pituitary adenomas. Management is best undertaken by a comprehensive multidisciplinary team taking into account the results of all the biochemical and imaging studies available, to provide the best advice in patient treatment decisions.