Hypertension in the emergency department: A missed opportunity to screen for primary aldosteronism?

OBJECTIVES: Primary aldosteronism (PA) is a common but underdiagnosed secondary cause of hypertension. Emergency departments (EDs) often assess patients with severe hypertension or its sequelae, some of whom have underlying PA. We aimed to determine the proportion of patients presenting to the ED with hypertension who meet the Endocrine Society criteria for PA testing and the proportion who were screened. METHODS: We performed a structured retrospective chart review of adults who presented to three EDs in an Australian tertiary health network between August 2019 and February 2020, with a coded presenting complaint of hypertension. Clinical parameters to determine whether the patients met the criteria for PA testing were extracted from electronic medical records. RESULTS: Of the 418 patients who presented to the EDs with documented elevated blood pressure (BP), 181 patients (43.3%) fulfilled PA screening criteria and nine patients (2.2%) underwent PA testing. Individuals who fulfilled screening criteria were older; had higher prevalence of Type 2 diabetes, coronary artery disease, and congestive heart failure; took more antihypertensive medications; and had lower estimated glomerular filtration rate. Individuals who were tested for PA were younger and had higher BP on presentation. Screening for PA was more frequent in patients who were referred to medical teams. CONCLUSIONS: As far as we are aware, our study is the first to evaluate PA testing in hypertensive patients who present to ED. More than 40% of adults presenting to the EDs with hypertension met the current criteria for testing for PA but only few were tested. These results emphasize that increased awareness of PA in the ED is needed to encourage opportunistic testing, referral, and treatment, especially in patients who present with hypertensive emergencies. Prospective studies are required to determine the feasibility and effectiveness of this.

Altered EEG power spectrum, but not sleep-wake architecture, in HCN1 knockout mice.

Sleep is a complex biological state characterized by large populations of neurons firing in a rhythmic or synchronized manner. HCN channels play a critical role in generating and sustaining synchronized neuronal firing and are involved in the actions of anaesthetics. However, the role of these channels in sleep-wakefulness per se has yet to be studied. We conducted polysomnographic recordings of Hcn1 constitutive knockout (Hcn1 KO) and wild-type (WT) mice in order to investigate the potential role of HCN1 channels in sleep/wake regulation. EEG and EMG data were analysed using the Somnivore™ machine learning algorithm. Time spent in each vigilance state, bout number and duration, and EEG power spectral activity were compared between genotypes. There were no significant differences in the time spent in wake, rapid eye movement (REM) or non-REM (NREM) sleep between Hcn1 KO and WT mice. Wake bout duration during the inactive phase was significantly shorter in Hcn1 KO mice whilst no other bout parameters were affected by genotype. Hcn1 KO mice showed a reduction in overall EEG power which was particularly prominent in the theta (5-9 Hz) and alpha (9-15 Hz) frequency bands and most evident during NREM sleep. Together these data suggest that HCN1 channels do not play a major role in sleep architecture or modulation of vigilance states. However, loss of these channels significantly alters underlying neuronal activity within these states which may have functional consequences.