I can only underline the study results reported by Zieschang et al. (1).
Patients in a confusional state who are mostly older and over 65 years of age are transferred by relatives, emergency physicians, but also other somatic wards to optional protected gerontopsychiatric wards because they “can’t be controlled.”
A very common cause is hyponatremia of unclear etiology. Clinically, the dominant symptoms in addition to pronounced cognitive deficits are agitation, fear/anxiety, perplexity/helplessness, and depressive symptoms.
The clientele of patients with hyponatremia is extremely heterogeneous and diagnoses at admission vary. In my opinion, however, one aspect of the etiology was not given enough room: pharmacogenic hyponatremia.
The authors did discuss that hyponatremia is often facilitated, or even triggered by (in many cases) inadequate pharmacotherapy (for example, with thiazide diuretics), but they did not provide a detailed list/explanation of the potentially risky medications. Especially antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), entail a fivefold risk for hospital admission subsequent to hyponatremia (2).
Antipsychotic drugs are also associated with an increased risk for hyponatremia—and they are used particularly often in geriatric and gerontopsychiatric patients (3).
Furthermore, diverse anticonvulsive drugs, analgesics (especially non-steroidal anti-inflammatory drugs), and cytotoxic substances range among the medications associated with a high risk. Rastogi et al. (4) summarize typical at-risk patients for hyponatremia as follows:
Receiving treatment with thiazide diuretics
Older age
Hypoglycemia
Type 2 diabetes
Receiving treatment with ACE inhibitors
Reflux esophagitis, and
Urinary tract infections.
If we extend the spectrum to also include gerontopsychiatric patients, who may be treated with an SSRI or antipsychotic drug, the risk probably rises further.
For this reason, a careful risk-benefit analysis should be done in at-risk patients before initiating pharmacotherapy.
References
- 1.Zieschang T, Wolf M, Vellappallil T, Uhlmann L, Oster P, Kopf D. The association of hyponatremia, risk of confusional state, and mortality—a prospective controlled longitudinal study in older patients. Dtsch Arztebl Int. 2016;113:855–862. doi: 10.3238/arztebl.2016.0855. [DOI] [PMC free article] [PubMed] [Google Scholar]
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