Medical Image of the Week: Cheyne-Stokes Respiration

Figure 1. Cheyne-Stokes Breathing pattern seen. The red arrow indicates the cycle time which is defined as the duration of the central apnea (or hypopnea) + the duration of a respiratory phase.

A 62 year-old male with a past medical history congestive heart failure, chronic obstructive pulmonary disease, and obesity with a body mass index of 38.02 kg/m² underwent an overnight polysomnogram for clinical suspicion for obstructive sleep apnea. He was found to have a periodic breathing as seen in the image above.

Cheyne-stokes respiration (CSR) is a type of periodic breathing characterized by crescendo-decrescendo pattern of respiration separated by central sleep apneas (CSA) or hypopneas (1). CSR-CSA may be seen in up to 15-37% of systolic heart failure patients (2,3). A longer cycle length, usually between 45-90 seconds, as well as the waxing and waning breathing pattern differentiate CSR from other forms of cyclic central apnea. CSA leads to chronically increased sympathetic activity and exerts multiple deleterious effects on the failing heart (2). The presence of CSR has been associated with higher mortality and rapid deterioration in cardiac function (4).

Jared Bartell and Safal Shetty, MD

University of Arizona Medical Center

Tucson, AZ

References

1. Berry RB, Budhiraja R, Gottlieb DJ, Gozal D, Iber C, Kapur VK, Marcus CL, Mehra R, Parthasarathy S, Quan SF, Redline S, Strohl KP, Davidson Ward SL, Tangredi MM; American Academy of Sleep Medicine. Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine. J Clin Sleep Med. 2012;8(5):597-619. [CrossRef]  [PubMed]
2. Yumino D, Bradley TD. Central sleep apnea and Cheyne-Stokes respiration. Proc Am Thorac Soc. 2008;5(2):226-36. [CrossRef] [PubMed]
3. Garcia-Touchard A, Somers VK, Olson LJ, Caples SM. Central sleep apnea: implications for congestive heart failure. Chest. 2008;133(6):1495-504. [CrossRef] [PubMed]
4. Hanly PJ, Zuberi-Khokhar NS. Increased mortality associated with Cheyne-Stokes respiration in patients with congestive heart failure. Am J Respir Crit Care Med. 1996;153(1):272-6. [CrossRef] [PubMed] 

Reference as: Bartell J, Shetty S. Medical image of the week: Cheyne-Stokes respiration. Southwest J Pulm Crit Care. 2015;10(3):145-6. doi: http://dx.doi.org/10.13175/swjpcc017-15 PDF

Medical Image of the Week: Sleep Bruxism

Figure 1. Hypnogram and polysomnographic tracing showing an episode of rhythmic masticatory muscle activity (RMMA) during sleep. RMMA is defined when at least 3 consecutive EMG bursts (frequency 1 Hz) lasting greater than or equal to 0.25 seconds are scored on the masseter and temporalis channels.

Figure 2. Thirty second epoch of polysomnogram showing phasic sleep-bruxism during stage N2 sleep.

A 42 year-old man with a past medical history of insomnia, post-traumatic stress disorder, depression and both migraine and tension headaches was referred for an overnight sleep study. He had presented to the sleep clinic with  symptoms  of obstructive sleep apnea. Medications included sumatriptan, amitryptiline, sertraline, and trazodone. His sleep study showed: sleep efficiency of 58.2%, apnea-hypopnea index  of 33 events per hour, and arousal index of 14.5/hr. Periodic limb movement index was 29.2/hr. The time spent in the sleep stages included N1 (3.6%), N2 (72.5%), N3 (12.9%), and REM (10.9%). Figure 1 is representative of the several brief waveforms seen on his EEG and chin EMG. Sleep bruxism (SB) is a type of sleep-related movement disorder that is characterized by involuntary masticatory muscle contraction resulting in grinding and clenching of the teeth and typically associated with arousals from sleep (1,2).

The American academy of sleep medicine (AASM) criteria for sleep related bruxism diagnosis:

1. The patient reports or is aware of tooth-grinding sounds or tooth clenching during sleep.
2. One or more of the following is present: A. Abnormal wear of the teeth; B. Jaw muscle discomfort, fatigue, or pain and jaw lock upon awakening; and C. Masseter muscle hypertrophy upon voluntary forceful clenching.
3. The jaw muscle activity is not better explained by another current sleep disorder, medical or neurological disorder, medication use, or substance use disorder.

The exact etiology of SB is unknown. It is associated with sleep arousals, genetic factors, stress, anxiety and behavioral factors and medications like selective serotonin receptor inhibitors, tobacco, alcohol and recreational drug use and sleep disordered breathing (2).

The electromyogram (EMG) activity pattern in patients with SB is known as rhythmic masticatory muscle activity (RMMA) and involves the masseter and temporalis muscles in patterns of phasic and/or tonic contractions, most typically during stages N1 and N2 of sleep (2,3). Clinically, bruxism can result in abnormal tooth wear, masseter muscle hypertrophy, reduced salivation, and morning headaches (1,2).

Sleep bruxism has been shown to be strongly associated with tension and migraine headaches (4). Treatment of the underlying sleep disordered breathing with positive airway pressure may eliminate bruxism during sleep (5). Treatment involves oral appliances such as occlusal splints or mandibular advancement devices (2). There is insufficient evidence to support pharmacotherapy in the treatment of sleep bruxism (1).

Jared Bartell¹, Safal Shetty, MD^1,2, and John Roehrs, MD^1,2

¹University of Arizona Medical Center, Tucson, AZ

²Southern Arizona VA Health Care System, Tucson, AZ

References

1. Macedo CR, Macedo EC, Torloni MR, Silva AB, Prado GF. Pharmacotherapy for sleep bruxism. Cochrane Database Syst Rev. 2014;10:CD005578. [CrossRef] [PubMed] 
2. Carra MC, Huynh N, Lavigne G. Sleep bruxism: a comprehensive overview for the dental clinician interested in sleep medicine. Dent Clin North Am. 2012;56(2):387-413. [CrossRef] [PubMed]
3. Valiente López M, van Selms MK, van der Zaag J, Hamburger HL, Lobbezoo F. Do sleep hygiene measures and progressive muscle relaxation influence sleep bruxism? Report of a randomised controlled trial. J Oral Rehabil. 2014 Nov 21. [CrossRef] [PubMed]
4. De Luca Canto G, Singh V, Bigal ME, Major PW, Flores-Mir C. Association between tension-type headache and migraine with sleep bruxism: a systematic review. Headache. 2014;54(9):1460-9. [CrossRef] [PubMed]
5. Oksenberg A, Arons E. Sleep bruxism related to obstructive sleep apnea: the effect of continuous positive airway pressure. Sleep Med. 2002;3(6):513-5. [CrossRef] [PubMed]

Reference as: Bartell J, Shetty S, Roehrs J. Medical image of the week: sleep bruxism. Southwest J Pulm Crit Care. 2015;10(3):140-2. doi: http://dx.doi.org/10.13175/swjpcc016-15 PDF