Hypokalemia associated with mifepristone use in the treatment of Cushing's syndrome

SUMMARY

Mifepristone is a promising option for the management of hypercortisolism associated with hyperglycemia. However, its use may result in serious electrolyte imbalances, especially during dose escalation. In our patient with adrenocorticotropic hormone-independent macro-nodular adrenal hyperplasia, unilateral adrenalectomy resulted in biochemical and clinical improvement, but subclinical hypercortisolism persisted following adrenalectomy. She was started on mifepristone. Unfortunately, she missed her follow-up appointments following dosage escalation and required hospitalization at an intensive care level for severe refractory hypokalemia.

LEARNING POINTS

Mifepristone, a potent antagonist of glucocorticoid receptors, has a high risk of adrenal insufficiency, despite high cortisol levels. Mifepristone is associated with hypokalemia due to spill-over effect of cortisol on unopposed mineralocorticoid receptors. Given the lack of a biochemical parameter to assess improvement, the dosing of mifepristone is based on clinical progress. Patients on mifepristone require anticipation of toxicity, especially when the dose is escalated. The half-life of mifepristone is 85 h, requiring prolonged monitoring for toxicity, even after the medication is held.

Utilisation of gonadotrophin-releasing hormone (GnRH) analogue to differentiate ovarian from adrenal hyperandrogenism in postmenopausal women

Postmenopausal hyperandrogenism is a relatively rare diagnosis resulting from excess androgen production from the adrenals or ovaries. The exclusion of malignant causes is a priority. Laboratory tests and imaging are utilised to help differentiate the source of excess androgens. We report two cases of postmenopausal hyperandrogenism in women aged 75 and 67 years. Both cases presented with clinical features suggestive of hyperandrogenism which had developed gradually over the previous 2 years. Laboratory investigations confirmed a significant elevation in their serum testosterone levels. In both cases, imaging did not reveal any abnormality of the adrenals or ovaries. To help differentiate an adrenal vs ovarian source a single-dose GnRH analogue was given with measurement of testosterone and gonadotrophin levels pre and post. The reduction in gonadotrophins achieved by the GnRH analogue resulted in suppression of testosterone levels which suggested an ovarian source. Both patients proceeded to bilateral oophorectomy. Histology revealed a benign hilus cell tumour in one case and a benign Leydig cell tumour in the other.

Addison's disease in antiphospholipid syndrome: a rare complication

Addison’s disease (AD) is the most common endocrine manifestation of antiphospholipid syndrome (APS), but it remains a very rare complication of the syndrome. It is caused by adrenal venous thrombosis and consequent hemorrhagic infarction or by spontaneous (without thrombosis) adrenal hemorrhage, usually occurring after surgery or anticoagulant therapy. We present a clinical case of a 36-year-old female patient with a previous diagnosis of APS. She presented with multiple thrombotic events, including spontaneous abortions. During evaluation by the third episode of abortion, a CT imaging revealed an adrenal hematoma, but the patient was discharged without further investigation. A few weeks later, she presented in the emergency department with manifestations suggestive of adrenal insufficiency. Based on that assumption, she started therapy with glucocorticoids, with significant clinical improvement. After stabilization, additional investigation confirmed AD and excluded other etiologies; she also started mineralocorticoid replacement. This case illustrates a rare complication of APS that, if misdiagnosed, may be life threatening. A high index of suspicion is necessary for its diagnosis, and prompt treatment is crucial to reduce the morbidity and mortality potentially associated.

Adrenal insufficiency, be aware of drug interactions!

SUMMARY

A 42-year-old man with complaints of muscle soreness and an increased pigmentation of the skin was referred because of a suspicion of adrenal insufficiency. His adrenocorticotropic hormone and cortisol levels indicated a primary adrenal insufficiency (PAI) and treatment with hydrocortisone and fludrocortisone was initiated. An etiological workup, including an assessment for anti-adrenal antibodies, very long-chain fatty acids, 17-OH progesterone levels and catecholamine secretion, showed no abnormalities. 18Fluorodeoxyglucose positron emission tomography/CT showed bilateral enlargement of the adrenal glands and bilateral presence of an adrenal nodule, with 18fluorodeoxyglucose accumulation. A positive tuberculin test and positive family history of tuberculosis were found, and tuberculostatic drugs were initiated. During the treatment with the tuberculostatic drugs the patient again developed complaints of adrenal insufficiency, due to insufficient dosage of hydrocortisone because of increased metabolism of hydrocortisone.

LEARNING POINTS

Shrinkage of the adrenal nodules following tuberculostatic treatment supports adrenal tuberculosis being the common aetiology. The tuberculostatic drug rifampicin is a CYP3A4 inducer, increasing the metabolism of hydrocortisone. Increase the hydrocortisone dosage upon initiation of rifampicin in case of (adrenal) tuberculosis. A notification on the Addison's emergency pass could be considered to heighten physician's and patients awareness of hydrocortisone drug interactions.