JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
Image 1
Upon further questioning, the patient mentioned early morning headaches which typically resolved after sitting or standing for several hours. A magnetic resonance imaging (MRI) of the brain with dynamic pituitary imaging was performed in light of this history coupled with the patient’s laboratory abnormalities and a high suspicion for Cushing’s disease. The MRI demonstrated a macroadenoma of the pituitary measuring 8mm x 19mm x 8mm, eroding the sella as well as invading into the sphenoid sinus. The patient was diagnosed with Cushing’s disease, and Neurosurgery was consulted. The patient underwent successful endoscopic transsphenoidal resection of the macroadenoma, which was felt to be complete. Pathology demonstrated a monomorphic population of mononuclear cells compatible with a pituitary adenoma. The patient was doing very well when seen post-operatively by the neurosurgery service.
DISCUSSION
Image 2
While our patient did have a classic presentation of Cushing’s disease, without a high level of suspicion he may have gone undiagnosed for quite some time and instead started on traditional management for hypertension and diabetes. In order to diagnose Cushing’s disease, it is important to first diagnose Cushing’s syndrome and then look for the underlying cause. The Endocrine Society advises against widespread testing for Cushing’s syndrome, rather testing when there is a high level of suspicion, such as patients with unusual features for age (hypertension and osteoporosis, as seen in our patient), children with decreasing height percentile and increasing weight, patients with progressive features predictive of Cushing’s syndrome, and patients with an adrenal incidentaloma. 4 First, exogenous glucocorticoid exposure must be excluded by obtaining a thorough drug history including skin creams, herbal medications, joint injections, and megestrol acetate. Then, for initial testing, the Society recommends one of the following first line tests: 24-hour urinary free cortisol, late night salivary cortisol, or low dose (1mg) dexamethasone suppression test. 4 Abnormal results include high cortisol levels with loss of the expected diurnal pattern of cortisol secretion and failure of normal feedback inhibition. If testing reveals abnormal results, physiologic causes of hypercortisolism (including obesity, pregnancy, psychologic stress, poorly controlled diabetes, and chronic alcoholism) should be excluded, and an endocrinologist should be consulted. Confirmation of abnormal cortisol levels should be made by repeating the same test initially found to be abnormal. 4 Once an elevated cortisol level is confirmed, the next step is to determine if the cause isACTH-dependent or ACTH-independent by measuring the plasma ACTH level. If the ACTH level is <5pg/ mL, an ACTH-independent cause should be suspected, such as adrenal adenomas or carcinomas, as well as adrenal hyperplasia. At this point, adrenal imaging should be performed. On the other hand, ATCH is elevated (>20pg/mL), as with our patient, an ACTH-dependent cause of Cushing’s syndrome is suggested. A pituitary MRI is then performed to look for the source of ACTH secretion, as pituitary adenomas are the most common source
Image 3
The above images display typical features of Cushing’s syndrome as seen in our patient, including moon faces (Image 1), increased dorsocervical fat pad (Image 2), and abdominal striae and central obesity (Image 3).
26 J La State Med Soc VOL 170 JANUARY/FEBRUARY 2018
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