Primary Aldosteronism.

Primary aldosteronism is the underlying cause of hypertension in primary care settings in approximately 6% of cases, and it is even more common in patients with resistant hypertension. However, it is estimated that only about 2% of patients who have risk factors for primary aldosteronism have been formally tested or diagnosed. The first step in the diagnosis of primary aldosteronism is case detection and involves testing patients who are at risk, including individuals with resistant hypertension, as well as those with well-controlled hypertension and a first-degree relative with primary aldosteronism, hypokalemia, an adrenal nodule, atrial fibrillation, obstructive sleep apnea, or a family history of an early stroke (i.e., younger than 40 years). Initial case detection is performed by simultaneously measuring plasma aldosterone concentration and plasma renin activity; an elevated aldosterone-renin ratio (greater than 30) indicates independent aldosterone secretion (i.e., aldosteronism). After a positive case detection, confirmatory testing should be performed. Confirmatory tests include the captopril challenge, oral or intravenous salt loading, or fludrocortisone suppression. Results are positive if aldosterone levels remain high after interventions that suppress or interrupt physiologic production of aldosterone. If the confirmatory test is positive, adrenal computed tomography and adrenal vein sampling should be performed to differentiate unilateral from bilateral adrenal production of aldosterone. Patients with unilateral primary aldosteronism should undergo adrenalectomy, whereas those with bilateral production should be treated with mineralocorticoid receptor antagonists, such as spironolactone or eplerenone.

Unusual Pheochromocytoma Presentation: From Dysuria to Catecholamine Crisis.

Pheochromocytomas are catecholamine-secreting tumors that can present as a surgical emergency, with a mortality rate as high as 15%. When these lesions present as a crisis, diagnosis and management can be very challenging, given the profound physiologic consequences, such as cardiovascular collapse or multiple organ failure, occurring over a rapid time frame. We describe an unusual case of a pheochromocytoma presenting with urinary frequency and subsequent shock and tumor hemorrhage following a urological procedure. Our patient was successfully managed with resuscitation and appropriate blood pressure control to stabilize hemodynamics prior to proceeding with open adrenalectomy. Furthermore, our patient presented initially with urinary symptoms, which has not been described as an initial presentation of pheochromocytoma. This case brings important learning points regarding unusually presenting pheochromocytomas and emergency management to improve patient survival.

Diagnosis and Management of Nodular Thyroid Disease.

Thyroid nodules are common and often asymptomatic. However, patients may seek treatment for nonfunctional benign nodules that cause compressive symptoms or cosmetic problems. Additionally, many patients with autonomously functioning nodules also seek treatment. As minimally invasive thermal ablation techniques become more wide spread, providers offering these treatments should be familiar with the pathophysiology of thyroid nodules, and with how to work up a patient with nodular thyroid disease.

Postmortem molecular screening in unexplained sudden death.

OBJECTIVES: We examined the prevalence of defects in arrhythmia-related candidate genes among patients with unexplained sudden cardiac death (SCD). BACKGROUND: Patients with unexplained sudden death may constitute up to 5% of overall SCD cases. For such patients, systematic postmortem genetic analysis of archived tissue, using a candidate gene approach, may identify etiologies of SCD. METHODS: We performed analysis of KCNQ1 (KVLQT1), KCNH2 (HERG), SCN5A, KCNE1, and KCNE2 defects in a subgroup of 12 adult subjects with unexplained sudden death, derived from a 13-year, 270-patient autopsy series of SCD. Archived, paraffin-embedded myocardial tissue blocks obtained at the original postmortem examination were the source of deoxyribonucleic acid for genetic analysis. RESULTS: Two patients were found to have the same HERG defect, a missense mutation in exon 7 (nucleotide change G1681A, coding effect A561T). The mutation was heterozygous in Patient 1, but Patient 2 appeared to be homozygous for the defect. Patch-clamp recordings showed that the A561T mutant channel expressed in human embryonic kidney cells failed to generate HERG current. Western blot analysis implicated a trafficking defect in the protein, resulting in loss of post-translational processing from the immature to the mature form of HERG. No mutations were detected among the remaining four candidate genes. CONCLUSIONS: In this autopsy series, only 2 of 12 patients with unexplained sudden death were observed to have a defect in HERG among five candidate genes tested. It is likely that elucidation of SCD mechanisms in such patients will await the discovery of multiple, novel arrhythmia-causing gene defects.

The effect of citalopram on midbrain CRF receptors 1 and 2 in a primate model of stress-induced amenorrhea.

We have demonstrated marked differences in the neurobiology of the serotonin system between stress-sensitive (SS) and stress-resilient (SR) cynomolgus macaques characterized in a model of stress-induced amenorrhea, also called functional hypothalamic amenorrhea (FHA). Dysfunction of the serotonin system in SS monkeys suggested that administration of a selective serotonin reuptake inhibitor (SSRI) might correct FHA. This study examines the effect of escitalopram (CIT) administration to SS and SR monkeys on corticotrophin-releasing factor (CRF) receptor 1 (CRF-R1) and CRF receptor 2 (CRF-R2) gene expression in the serotonin cell body region of the midbrain dorsal raphe. CRF-R1 was not significantly different between groups. There was a significant effect of treatment and a significant interaction between treatment and stress sensitivity on the average CRF-R2-positive pixel area (P < .004 and P < .006, respectively) and on the average number of CRF-R2-positive cells (P < .023 and P < .025, respectively). CIT significantly increased CRF-R2-positive pixel area and cell number in the SS group (pixel area P < .001; cell number P < .01; Bonferoni) but not in the SR group. In summary, CIT administration tended to decrease CRF-R1, but the small animal number precluded significance. CIT administration significantly increased CRF-R2 only in SS animals. These data suggest that the administration of CIT reduces anxiogenic components and increases anxiolytic components of the CRF system in the midbrain serotonin network, which in turn leads to improved ovarian function. Moreover, these data raise the possibility that SSRIs may be effective in the treatment of stress-induced infertility.

Effects of citalopram on serotonin and CRF systems in the midbrain of primates with differences in stress sensitivity.

This chapter reviews the neurobiological effects of stress sensitivity and s-citalpram (CIT) treatment observed in our nonhuman primate model of functional hypothalamic amenorrhea (FHA). This type of infertility, also known as stress-induced amenorrhea, is exhibited by cynomolgus macaques. In small populations, some individuals are stress-sensitive (SS) and others are highly stress-resilient (HSR). The SS macaques have suboptimal secretion of estrogen and progesterone during normal menstrual cycles. SS monkeys also have decreased serotonin gene expression and increased CRF expression compared to HSR monkeys. Recently, we found that CIT treatment improved ovarian steroid secretion in SS monkeys, but had no effect in HSR monkeys. Examination of the serotonin system revealed that SS monkeys had significantly lower Fev (fifth Ewing variant, rodent Pet1), TPH2 (tryptophan hydroxylase 2), 5HT1A autoreceptor and SERT (serotonin reuptake transporter) expression in the dorsal raphe than SR monkeys. However, CIT did not alter the expression of either Fev, TPH2, SERT or 5HT1A mRNAs. In contrast, SS monkeys tended to have a higher density of CRF fiber innervation of the dorsal raphe than HSR monkeys, and CIT significantly decreased the CRF fiber density in SS animals. In addition, CIT increased CRF-R2 gene expression in the dorsal raphe. We speculate that in a 15-week time frame, the therapeutic effect of S-citalopram may be achieved through a mechanism involving extracellular serotonin inhibition of CRF and stimulation of CRF-R2, rather than alteration of serotonin-related gene expression.