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Pearl of the Month

Nocturia and sleep apnea

Publish date: June 28, 2017

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Author’s note: I have been writing “Myth of the Month” columns for the last several years. I will try to continue to write about myths when possible, but I would like to introduce a new column, “Pearl of the Month.” I want to share with you pearls that I have found really helpful in medical practice. Some of these will be new news, while some may be old news that may not be well known.

A 65-year-old man comes to a clinic concerned about frequent nocturia. He is getting up four times a night to urinate, and he has been urinating about every 5 hours during the day. He has been seen twice for this problem and was diagnosed with benign prostatic hyperplasia and started on tamsulosin.

He found a slight improvement when he started on 0.4 mg qhs, reducing his nocturia episodes from four to three. His dose was increased to 0.8 mg qhs, with no improvement in nocturia.

Exam today: BP, 140/94; pulse, 70. Rectal exam: Prostate is twice normal size without nodules. Labs: Na, 140; K, 4.0; glucose, 80; Ca, 9.6.

He is frustrated because he feels tired and sleepy from having to get up so often to urinate every night.

What is the best treatment/advice at this point?

A. Check hemoglobin A_1C.

B. Start finasteride.

C. Switch tamsulosin to terazosin.

D. Evaluate for sleep apnea.

^{©David Cannings-Bushell/iStockphoto.com}

Sleep apnea sufferer being treated by CPAP via mask and air tube from machine.

At this point, I think an evaluation for sleep apnea is the next appropriate step. It is unlikely that he has diabetes with high enough blood sugars to cause polyuria, with a random glucose of 80. His daytime sleepiness is a clue to a possible sleep disorder, and his nocturia is a symptom that is often overlooked or not appreciated in patients with sleep apnea.

Umpei Yamamoto, MD, of Kyushu University Hospital, Japan, and colleagues studied the prevalence of sleep-disordered breathing among patients who presented to a urology clinic with nocturia and in those who visited a sleep apnea clinic with symptoms of excessive daytime sleepiness.¹ Sleep-disordered breathing was found in 91% of the patients from the sleep apnea clinic and 70% of the patients from the urology clinic. The frequency of nocturia was reduced with continuous positive airway pressure (CPAP) in both groups in the patients who had not responded to conventional therapy or nocturia.

The symptom of nocturia as a symptom of sleep apnea might be even more common in women.² Ozen K. Basoglu, MD, and Mehmet Sezai Tasbakan, MD, of Ege University, Izmir, Turkey, described clinical similarities and differences based on gender in a large group of patients with sleep apnea. Both men and women with sleep apnea had similar rates of excessive daytime sleepiness, snoring, and impaired concentration. Women had more frequent nocturia.

Nocturia especially should be considered a possible clue for the presence of sleep apnea in younger patients who have fewer other reasons to have nocturia. Takahiro Maeda, MD, of Keio University, Tokyo, and colleagues found that men younger than 50 years had more nocturnal urinations the worse their apnea-hypopnea index was.³ Overall in the study, 85% of the patients had a reduction in nighttime urination after CPAP therapy.

Treatment of sleep apnea has been shown in several studies to improve the nocturia that occurs in patients with sleep apnea. Hyoung Keun Park, MD, of Konkuk University, Seoul, and colleagues studied whether surgical intervention with uvulopalatopharyngoplasty (UPPP) reduced nocturia in patients with sleep apnea.⁴ In the study, there was a 73% success rate in treatment for sleep apnea with the UPPP surgery, and, among those who had successful surgeries, nocturia episodes decreased from 1.9 preoperatively to 0.7 postoperatively (P less than .001).

Minoru Miyazato, MD, PhD, of University of the Ryukyus, Okinawa, Japan, and colleagues looked at the effect of CPAP treatment on nighttime urine production in patients with obstructive sleep apnea.⁵ In this small study of 40 patients, mean nighttime voiding episodes decreased from 2.1 to 1.2 (P less than .01).

Dr. Douglas S. Paauw

I think that this information helps us increase our recognition of sleep apnea and also counsel patients on the benefits of treatment.

Pearl: Sleep apnea should be considered in the differential diagnosis of patients with nocturia, and treatment of sleep apnea may decrease nocturia.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at dpaauw@uw.edu.