Hiponatremia in the practice of a psychiatrist. Part 1: SIADH syndrome and drug-induced hyponatremia

Introduction. Hyponatremia is an important part of psychiatric practice. In order to analyze its causes and symptoms, the literature on hyponatremia in psychiatric patients has been reviewed. The work has been divided into two separate manuscripts. In the first one the authors discuss the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and hyponatremia occurring with the use of psychotropic drugs (antidepressants, antipsychotics, normotimics), while the second paper discusses research on psychogenic polydipsia. The causes of hyponatremia in patients treated in psychiatric wards include: water intoxication associated with polydipsia, somatic comorbidities, side effect of internal medicine and psychiatric drugs. The most common mechanism leading in these cases to hyponatremia is the syndrome of inappropriate secretion of vasopressin (SIADH). The SIADH syndrome is a group of symptoms, first described in 1967 by Schwartz and Bartter in The American Journal of Medicine, which results from the hypersecretion of antidiuretic hormone, also called vasopressin, which causes patients to develop normovolemic hyponatremia. The phenomenon of drug-induced hyponatremia in psychiatric practice is generally observed with the use of antidepressants, antipsychotics and anti-epileptic drugs (used in psychiatry as normotimic drugs).

Aim and method. The first manuscript includes a review of literature on the syndrome of inappropriate secretion of vasopressin (SIADH) and hyponatremia occurring after the use of psychotropic drugs, and is divided into two subsections: 1. The syndrome of inappropriate secretion of vasopressin (SIADH), 2. Hyponatremia and psychotropic drugs (antidepressants, antipsychotics, normotimics).

Conclusion. In the view of the reviewed literature it is extremely important to control the natremia level during pharmacotherapy using the above mentioned drugs, especially in the initial period of therapy.

Endocrine check-up in adolescents and indications for referral: A guide for health care providers

The American Academy of Pediatrics recommends that young people between the ages of 11 and 21 years should be seen annually by their pediatricians, since annual checkups can be an important opportunity for health evaluation and anticipatory guidance. Parents of infants and young children are accustomed to regularly visiting a pediatrician for their child's checkups. Unfortunately, when children reach the teen years, these annual checkups may decrease in frequency. In routine check-ups and medical office visits, particular attention should be paid to the possibility of a developmental or endocrine disorder. Early diagnosis and treatment may prevent medical complications in adulthood and foster age-appropriate development. Our purpose is to acquaint readers with the concept, based on current scientific understanding, that some endocrine disorders may be associated with a wide range of deleterious health consequences including an increased risk of hypertension and hyperlipidemia, increased risk of coronary artery disease, type 2 diabetes, significant anxiety and lack of self-esteem. Understanding the milestones and developmental stages of adolescence is essential for pediatricians and all other health providers who care for adolescents. Treating adolescents involves knowledge of a variety of medical, social and legal information; in addition, close working relationships must be established within the adolescent's network to create an effective care system. In summary, we underline the importance of a periodic endocrine checkup in adolescents in order to identify endocrine problems early and develop an approach to treatment for those patients who need help during this time. Indications for endocrine referral for professional and other healthcare providers are also included. These lists are clearly not intended to be comprehensive, but will hopefully serve as a guide for specific clinical circumstances.

[New frequent adverse reaction of PPI in older adults: mild hyponatremia]

Hyponatremia is a rare side effect described in the product characteristics of proton pump inhibitors (PPIs). Hyponatremia in the elderly (>65 years) was assessed in patients with exposure to PPIs for at least one year compared to controls not exposed to PPIs counterparts. Included 145 patients, twenty-four patients (16.6%) had moderate hyponatremia ([120-134] mEq/L). Forty-eight patients (33.1%) were treated with PPIs. In the end, 31.3% [18.7%-46.3%] of the treated population for more than a year by PPI suffered moderate hyponatremia against only 9.3% [14.3%-16.9%] in the rest of the population, giving an odds ratio of 4.4 ([1.8-11.1], p=0.001). The relationship between hyponatremia dose was not significant (R2=0.05, p=0.74). By our study, we show that the risk of moderate hyponatremia is increased by chronic use of PPI in the elderly population. We also specify a notion of prevalence between 18.7% and 46.3%.

[Moderate potentially drug-induced hyponatremia in older adults: benefit in drug reduction]

OBJECTIVE

This study aimed at evaluating the benefit of changing drug therapy in elderly patients with moderate, potentially drug-induced hyponatremia.

METHODS

Hospitalized older adults, with moderate hyponatremia, potentially induced by drugs, were randomized into two arms: an interventional group, whose drug therapy was changed, and a reference group, which received standard care. The effectiveness of the intervention was evaluated by the normalization of serum sodium after four weeks and by the incidence of falls three months later.

RESULTS

Nineteen patients were randomized, fourteen evaluated at 4 weeks. Serum sodium was normalized more frequently in the interventional group than in the reference group: 75% (6/8) IC95% [35-97] versus 0% (0/6) IC95% [0-46]; p=0.01. A greater reduction in falls occurred in the therapeutic intervention group 75% (3/4) IC95% [19-99] versus 0% (0/5) IC95% [0-52]; p=0.048.

CONCLUSION

This study showed the biological and clinical benefit of a pharmalogical intervention. Registration number of the study: ID RCB 2010-A00778-31.