Salivary aldosterone as a diagnostic aid in primary aldosteronism

Adrenocortical function in hypotensive patients with end stage renal disease

BACKGROUND

Sustained hypotension among patients with end stage renal disease on dialysis (ESRDh) varies from 5.0% to 12.0%. Despite their role in the regulation of blood pressure (BP) corticoadrenal hormones have been poorly investigated.

OBJECTIVES

This study aims to detect adrenal insufficiency in ESRDh and follow their clinical outcome.

METHODS

Fifty ESRDh and 30 healthy volunteers were studied. In all cases basal blood and saliva were obtained. Synthetic ACTH (25μg) was injected intramuscularly and at 30min saliva was collected. Circulating ACTH, renin, cortisol and aldosterone were measured and steroids were also assessed in saliva by immunoassay.

RESULTS

Fifteen ESRDh achieved steroid responses not different than healthy volunteers; four had primary adrenal insufficiency; six had secondary adrenal insufficiency; nine had selective hypoaldosteronism and sixteen secondary hyperaldosteronism. The years on dialysis did not differ among subgroups. ROC analysis defined the following cut-offs for basal cortisol to predict adrenal insufficiency: in serum ⩽232.0nM (sensitivity (S) 100.0% and specificity (E) 90.0%); in saliva ⩽4.4nM (100.0% S and E). Basal aldosterone cut-off values to predict hyperaldosteronism were: in serum >500.0pM and saliva >60.0pM (100.0% S and E, for both). For the prediction of hypoaldosteronism the basal serum aldosterone was ⩽260.0pM (100% S; 53% E) and in saliva it was ⩽20.1pM (100% S; 58.5% E). Three patients with primary adrenal insufficiency and six with secondary adrenal insufficiency improved general clinical condition and normalized BP on steroids. One patient died before initiation of steroid therapy.

CONCLUSION

Adrenal function should be assessed in ESRDh in order to unmask adrenal insufficient states.

Saliva as a diagnostic fluid

Salivary diagnostics is a dynamic and emerging field utilizing nanotechnology and molecular diagnostics to aid in the diagnosis of oral and systemic diseases. In this article the author critically reviews the latest advances using oral biomarkers for disease detection. The use of oral fluids is broadening perspectives in clinical diagnosis, disease monitoring, and decision making for patient care. Important elements determining the future possibilities and challenges in this field are also discussed.

A patient with concurrent primary aldosteronism and Page kidney

The ratio of aldosterone-to-renin activity is currently recommended as a screening test for primary aldosteronism (PA). There are many factors interfering the interpretation of aldosterone-renin ratio (ARR) and could hamper in-time diagnosis of PA. Here, we first report a patient with underlying Page phenomenon and an accidentally disclosed adrenal incidentaloma. High renin secretion from Page phenomenon had masked higher ARR into normal ARR obscuring the diagnosis of PA. However, adrenal venous sampling (AVS) confirmed the autonomous aldosterone secretion with left adrenal vein plasma aldosterone concentration (PAC) 124.1 ng/dl and a lateralization ratio 3.3. AVS may discriminate masked PA due to high renin secretion from Page kidney. It is suggested that clinicians should cautiously interpret aldosterone-renin ratio and consider diagnostic AVS if hyperaldosteronism is highly suspected especially in the background of other secondary hypertension.