Epidemiology, Symptoms, and Treatment Characteristics of Hyponatremic Psychiatric Inpatients

Abstract

Hyponatremia is a common phenomenon in psychiatry occurring as an adverse effect to drugs or following polydipsia. We performed a retrospective in-depth analysis of hyponatremia cases in a large unselected population of psychiatric inpatients. During a 3-year period, all cases of hyponatremia were identified among patients admitted to a large psychiatric state and university hospital by the institution's electronic laboratory database. Demographic, treatmentrelated, and laboratory data were obtained by consecutive chart review, respectively. Hyponatremia occurred in 347 (4.9%) of 7113 cases, of which the majority (78%) displayed only a mild manifestation. Symptoms were recorded in 28.8% of cases, already occurred in mild forms, and comprised gait impairment (45%, including falls), confusion (30%), sedation (26%), and dyspepsia (41%). Age, female sex, nonpsychiatric drug polypharmacyVparticularly with thiazides and/or angiotensinconverting enzyme inhibitorsVand diagnosis of a mood disorder were associated with more severe hyponatremia, respectively. The proportion of hyponatremic patients treated with venlafaxine, trazodone, carbamazepine, oxcarbazepine, and first-generation antipsychotics, respectively, was significantly higher in the hyponatremia sample than in the normonatremic population. This was, surprisingly, not the case with selective serotonin reuptake inhibitors or any other antidepressant drug class. We found prescription with second-generation antipsychotics to be significantly associated with less severe hyponatremia.Hyponatremia may be mainly attributed to the syndrome of inappropriate antidiuretic hormone secretion, as indicated by decreased serum osmolarity in our sample. Besides old age and female sex, treatment with certain drugsVrather than whole drug classesVcarries a substantially increased risk. ] is maintained within tight limits through a complex homeostatic system involving hypothalamic osmoreceptors and peripheral baroreceptors regulating water intake and urine output via changes in thirst and the neurohypophyseal secretion of the antidiuretic hormone arginine-vasopressin (AVP).8 Thus, excessive water intake or inappropriate release of AVP in the absence of osmotic stimuli, respectively are among the most common pathomechanisms of hyponatremia. The latter condition is known as the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and occurs, among an array of other causes, as an adverse effect of a large number of psychotropic and other drugs. 7,9,10 Above all, a wealth of case reports, casecontrol, and population-based studies have implicated antidepressants, such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), selective serotonin and norepinephrine reuptake inhibitors (SNRIs), and certain anticonvulsantsVmainly carbamazepine and oxcarbazepineV in hyponatremia of this origin. 11Y13 The most prevalent nonpsychiatric drugs associated with SIADH-induced hyponatremia are thiazide diuretics and angiotensin-converting enzyme inh...

Hiponatremia associada a antidepressivos: uma revisão

“…A hiponatremia normalmente ocorre nas primeiras 10 semanas de tratamento e 79% dos casos nas primeiras três semanas 9 . Entre os fatores de risco de hiponatremia, encontram-se idade, sexo feminino, utilização de medicação concomitante que provoque hiponatremia (antidiabéticos, anti-inflamatórios não esteroides, anticonvulsivantes e, principalmente, os diuréticos tiazídicos e inibidores da enzima conversora de angiotensina -IECA), história de pneumonia recente e perturbação do humor, estando os três primeiros associados também a hiponatremia mais severa 1,6,10 . Na população idosa, provaram ser fatores de risco independentes a história de hiponatremia, o peso inferior a 60 kg e os sintomas psicóticos 8 .…”

“…O Na + sérico é mantido dentro do limite por um sistema homeostático que envolve osmorreceptores hipotalâmicos e barorreceptores periféricos que regulam a absorção de água e o débito urinário por meio de mudanças na sede e na secreção do hormônio antidiurético (ADH) 6 . Esse hormô-nio é segregado pela hipófise posterior e atua nos túbulos coletores do rim para promover a reabsorção de água 1 .…”

“…Esse hormô-nio é segregado pela hipófise posterior e atua nos túbulos coletores do rim para promover a reabsorção de água 1 . A hiponatremia pode ter várias causas, sendo as mais comuns a ingestão excessiva de água, a hipovolemia, a insuficiência renal e a síndrome da secreção inapropriada do hormônio antidiurético (SIADH), cujo mecanismo exato ainda não está totalmente esclarecido 3,6,11 . A SIADH ocorre como efeito colateral de um grande número de fármacos psicotrópicos ou outros, sendo os fármacos não psicotrópicos mais associados os diuréticos tiazídicos e aos IECA 6 .…”

“…A hiponatremia pode ter várias causas, sendo as mais comuns a ingestão excessiva de água, a hipovolemia, a insuficiência renal e a síndrome da secreção inapropriada do hormônio antidiurético (SIADH), cujo mecanismo exato ainda não está totalmente esclarecido 3,6,11 . A SIADH ocorre como efeito colateral de um grande número de fármacos psicotrópicos ou outros, sendo os fármacos não psicotrópicos mais associados os diuréticos tiazídicos e aos IECA 6 . A dieta com restrição de sódio concomitante também pode potenciar o desenvolvimento de hiponatremia 12 .…”

Hyponatraemia – presentations and management

“…30,31 SIAD has been reported as an adverse effect of many drugs, including psychotropic medications 32 and chemotherapeutic drugs. 33 The cardinal diagnostic criteria for SIAD, originally described by Bartter and Schwartz in 1967, are outlined in Box 1 .…”