Introduction
Nocturia arises from a fundamental mismatch between nocturnal urine production, storage capacity, and sleep architecture, which may be driven by abnormalities of the genitourinary tract, but also by sleep disorders, medical diseases, patient actions/lifestyle factors, or medications. This article introduces a novel system for organizing the complex differential diagnosis for nocturia, as proposed by an international collective of practicing urologists, physician specialists, and sleep experts: “Sleep CALM”—Sleep Disorders, Comorbidities, Actions, Lower Urinary Tract Dysfunction, and Medications.
Methods
Narrative review of current evidence regarding the relevance of each “Sleep CALM” factor to nocturia pathogenesis, evaluation, and management.
Results
Nocturia and sleep disorders are highly intertwined and often bidirectional, such that nocturnal awakenings for reasons other than a sensation of bladder fullness should not be used as grounds for exclusion from nocturia treatment, but rather leveraged to broaden therapeutic options for nocturia. Nocturia is an important potential harbinger of several serious medical conditions beyond the genitourinary tract. Urologists should have a low threshold for primary care and medical specialty referral for medical optimization, which carries the potential to significantly improve nocturnal voiding frequency in addition to overall health status. Adverse patient actions/lifestyle factors, lower urinary tract dysfunction, and medication use commonly coexist with disordered sleep and comorbid medical conditions, and may be the primary mediators of nocturia severity and treatment response, or further exacerbate nocturia severity and complicate treatment.
Conclusion
“Sleep CALM” provides a memorable and clinically relevant means by which to structure the initial patient history, physical exam, and clinical testing in accordance with current best-practice guidelines for nocturia. Although not intended as an all-encompassing diagnostic tool, the “Sleep CALM” schema may also be useful in guiding individualized ancillary testing, identifying the need for specialty referral and multidisciplinary care, and uncovering first-line treatment targets.
Nocturia is defined as the number of times urine is passed during the main sleep period and is one of the most bothersome of all lower urinary tract symptoms. It is a symptom that often leads to urological consultation but can pose a considerable diagnostic and treatment challenge, as the underlying pathophysiology is multifactorial. The cause may be unrelated to the lower urinary tract, and as such, management of this condition requires awareness of all the possible urological and non-urological causes, as well as multidisciplinary input, for the most effective management. At its most basic level, nocturia arises from an imbalance between nocturnal urine production and functional bladder storage capacity, that is intricately linked to sleep quality.
This review article has been written by a group of medical, urological and sleep specialists. It provides a framework for evaluating the potential causes of nocturia, with an easy-to-remember system that has direct relevance to its treatment. The authors recommend using the acronym ‘Sleep C.A.L.M’ when considering the causes of nocturia: Sleep disorders, Comorbidity, Actions, Lower urinary tract dysfunction, Medications. This framework allows clinicians to provide a structured evaluation and management based on best-practice standards. This is a useful tool for all healthcare practitioners that are faced with managing this condition.