CASE CONFERENCES Sleep Fragments Section Editors: Mihaela Teodorescu, M.D., and Shirin Shafazand, M.D.
Fluctuating Flow Vibrato, Tremolo, or Upper Airway Oscillation Mudiaga O. Sowho1, Erica Wolfe1, Emi Z. Murano2, and Jason P. Kirkness1 1 Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine; and 2The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland
In Brief We describe a case of a 48-year-old woman with an incidental finding on a research polysomnogram, which posed an interesting differential diagnosis elucidated with the aid of advanced diagnostic methods. This case illustrates the utility of quantitative airflow assessment during sleep in the evaluation of involuntary upper airway phasic activity.
consciousness after trauma but had no other neurologic symptoms. The polysomnogram revealed a sleep latency of 5 minutes, which included decreased slow wave and REM sleep, with a slightly decreased sleep efficiency (74.9%). The total, non–REM (NREM), and REM apnea–hypopnea index values were 6.2, 1.2, and 47 events per hour, respectively.
Wake
Case Vignette A 48-year-old African-American woman presented for an overnight polysomnography study as part of participation in a research protocol. Although the patient had no prior complaints, on the screening questionnaire she acknowledged loud snoring and mouth dryness upon awakening. Her screening physical examination was significant for narrowed lateral pharyngeal arch, Mallampati grade IV airway, and audible staccato breathing during expiration. The rest of her examination was unremarkable. She had a traumatic incident 16 years ago that required hospitalization for splenic repair. She admits that there was brief loss of
Similarly, the total, NREM, and REM arousal indices were 11.3, 12.7, and 26.1 events per hour, respectively. All of the respiratory events were obstructive. The minimum O2 saturation was 84% during NREM sleep and 88% during REM sleep. Airflow tracing showed rhythmic phasic oscillations during wakefulness and sleep. Oscillations persisted during NREM and
NREM
REM
EEG
EKG O2 SAT
Chin EMG
Flow
Thorax Abdomen Leg EMG
Figure 1. Two-breath cycles in wakefulness (Wake) and in non–REM (NREM) and REM sleep. Polysomnogram includes EEG, EKG, oxygen saturation, airflow, thoracic effort, abdominal effort, and leg EMG channels. Flow oscillations persist during wakefulness and sleep as well as during inspiration and expiration.
(Received in original form September 25, 2014; accepted in final form February 26, 2015 ) This study was supported by American Heart Association grant 12SDG8100000. Correspondence and requests for reprints should be addressed to Mudiaga O. Sowho, M.D., M.P.H., Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, 5501 Hopkins Bayview Circle, Asthma & Allergy Building, Baltimore, MD 21224. E-mail: [email protected] Ann Am Thorac Soc Vol 12, No 4, pp 613–615, Apr 2015 Copyright © 2015 by the American Thoracic Society DOI: 10.1513/AnnalsATS.201409-437CC Internet address: www.atsjournals.org
Case Conferences: Sleep Fragments
613
CASE CONFERENCES
Video 1. Three-dimensional dynamic MRI showing the sagittal view of the upper airway, extending from the nasopharynx to the glottic folds of the larynx. The cardiac rhythm (1.4 Hz) and upper airway movement frequency (2.2 Hz) are identical to the findings on the EKG and airflow channels of the polysomnogram.
REM sleep with similar frequency and amplitude and were only absent in apnea (Figure 1). We noticed subtle quivers in the patient’s speech during sustained phonation, and she subsequently had a dynamic MRI of the upper airway, obtained as part of research. The MRI did not show any aberrant upper airway tissue or mass; however, bilateral rhythmic movements of the palatal, pharyngeal, and laryngeal walls were noted. The MRI findings are shown in Video 1.
Question Based on the clinical vignette, polysomnogram, and MRI findings, what is the diagnosis?
to synchronously oscillate with the larynx (3). This kind of upper airway involvement can lead to rapid intermittent changes in airway resistance with continuous interruption in airflow (4). Persistent Oscillations in Airflow Signal
In this patient, the airflow tracing from the polysomnograph showed oscillations at a rate of 2.2 Hz during inspiratory and expiratory phases (Figure 1). Airflow oscillations continued throughout the study, except during apneas, although rapid phasic bursts in chin EMG signal persisted at the same frequency as the fluctuations in flow. At first, we ruled out artifacts that could affect the airflow tracing, such as
humming (50–60 Hz), cardioballistic airflow (frequency most commonly ,1.5 Hz), and channel cross-talking between ECG (1.33 Hz or 80 bpm) and EMG channels (Figure 2). Salas and colleagues described a case of idiopathic palatal myoclonus with demonstrable flow oscillations from polysomnography (7). Conditions in the differential, such as ShyDrager syndrome and other extrapyramidal disorders, may also result in flow oscillations during wakefulness (8) but have not been shown to persist during sleep. Evaluation and Diagnosis
A three-dimensional dynamic MRI of the upper airway performed during wakefulness at 18 frames per second, as part of research, 28 cycles
EKG
1.4 Hz
Discussion 44 Peaks
Voice tremor is the phonatory manifestation of the essential tremor syndrome, characterized by involuntary skeletal muscle contraction that leads to oscillatory movement of laryngeal muscles at a rate of 4 to 10 Hz (1). There is wide disparity in symptom severity, with severe forms presenting as audible dysphonia and mild cases undetected or detected as mere incidental findings (2). In some cases, the muscles of the palate and pharynx are seen 614
Flow
2.2 Hz
Time
20 seconds
Figure 2. Twenty-second epoch displaying the EKG and airflow channel. The frequency of the cardiac rhythm (1.4 Hz) is shown to be slower than the flow oscillations (2.2 Hz).
AnnalsATS Volume 12 Number 4 | April 2015
CASE CONFERENCES
Low Frequency Oscillations
Inspiratory phase EMG
Chin EMG* Chin EMG DESATURATION
02 SAT
Airflow* Inspiratory High frequency >30Hz Airflow APNEA
*Low cut frequency 10Hz applied
Inspiratory and Expiratory oscillations
Fluctuating Flow Vibrato, Tremolo, or Upper Airway Oscillation Mudiaga O. Sowho1, Erica Wolfe1, Emi Z. Murano2, and Jason P. Kirkness1 1 Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine; and 2The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland
In Brief We describe a case of a 48-year-old woman with an incidental finding on a research polysomnogram, which posed an interesting differential diagnosis elucidated with the aid of advanced diagnostic methods. This case illustrates the utility of quantitative airflow assessment during sleep in the evaluation of involuntary upper airway phasic activity.
consciousness after trauma but had no other neurologic symptoms. The polysomnogram revealed a sleep latency of 5 minutes, which included decreased slow wave and REM sleep, with a slightly decreased sleep efficiency (74.9%). The total, non–REM (NREM), and REM apnea–hypopnea index values were 6.2, 1.2, and 47 events per hour, respectively.
Wake
Case Vignette A 48-year-old African-American woman presented for an overnight polysomnography study as part of participation in a research protocol. Although the patient had no prior complaints, on the screening questionnaire she acknowledged loud snoring and mouth dryness upon awakening. Her screening physical examination was significant for narrowed lateral pharyngeal arch, Mallampati grade IV airway, and audible staccato breathing during expiration. The rest of her examination was unremarkable. She had a traumatic incident 16 years ago that required hospitalization for splenic repair. She admits that there was brief loss of
Similarly, the total, NREM, and REM arousal indices were 11.3, 12.7, and 26.1 events per hour, respectively. All of the respiratory events were obstructive. The minimum O2 saturation was 84% during NREM sleep and 88% during REM sleep. Airflow tracing showed rhythmic phasic oscillations during wakefulness and sleep. Oscillations persisted during NREM and
NREM
REM
EEG
EKG O2 SAT
Chin EMG
Flow
Thorax Abdomen Leg EMG
Figure 1. Two-breath cycles in wakefulness (Wake) and in non–REM (NREM) and REM sleep. Polysomnogram includes EEG, EKG, oxygen saturation, airflow, thoracic effort, abdominal effort, and leg EMG channels. Flow oscillations persist during wakefulness and sleep as well as during inspiration and expiration.
(Received in original form September 25, 2014; accepted in final form February 26, 2015 ) This study was supported by American Heart Association grant 12SDG8100000. Correspondence and requests for reprints should be addressed to Mudiaga O. Sowho, M.D., M.P.H., Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, 5501 Hopkins Bayview Circle, Asthma & Allergy Building, Baltimore, MD 21224. E-mail: [email protected] Ann Am Thorac Soc Vol 12, No 4, pp 613–615, Apr 2015 Copyright © 2015 by the American Thoracic Society DOI: 10.1513/AnnalsATS.201409-437CC Internet address: www.atsjournals.org
Case Conferences: Sleep Fragments
613
CASE CONFERENCES
Video 1. Three-dimensional dynamic MRI showing the sagittal view of the upper airway, extending from the nasopharynx to the glottic folds of the larynx. The cardiac rhythm (1.4 Hz) and upper airway movement frequency (2.2 Hz) are identical to the findings on the EKG and airflow channels of the polysomnogram.
REM sleep with similar frequency and amplitude and were only absent in apnea (Figure 1). We noticed subtle quivers in the patient’s speech during sustained phonation, and she subsequently had a dynamic MRI of the upper airway, obtained as part of research. The MRI did not show any aberrant upper airway tissue or mass; however, bilateral rhythmic movements of the palatal, pharyngeal, and laryngeal walls were noted. The MRI findings are shown in Video 1.
Question Based on the clinical vignette, polysomnogram, and MRI findings, what is the diagnosis?
to synchronously oscillate with the larynx (3). This kind of upper airway involvement can lead to rapid intermittent changes in airway resistance with continuous interruption in airflow (4). Persistent Oscillations in Airflow Signal
In this patient, the airflow tracing from the polysomnograph showed oscillations at a rate of 2.2 Hz during inspiratory and expiratory phases (Figure 1). Airflow oscillations continued throughout the study, except during apneas, although rapid phasic bursts in chin EMG signal persisted at the same frequency as the fluctuations in flow. At first, we ruled out artifacts that could affect the airflow tracing, such as
humming (50–60 Hz), cardioballistic airflow (frequency most commonly ,1.5 Hz), and channel cross-talking between ECG (1.33 Hz or 80 bpm) and EMG channels (Figure 2). Salas and colleagues described a case of idiopathic palatal myoclonus with demonstrable flow oscillations from polysomnography (7). Conditions in the differential, such as ShyDrager syndrome and other extrapyramidal disorders, may also result in flow oscillations during wakefulness (8) but have not been shown to persist during sleep. Evaluation and Diagnosis
A three-dimensional dynamic MRI of the upper airway performed during wakefulness at 18 frames per second, as part of research, 28 cycles
EKG
1.4 Hz
Discussion 44 Peaks
Voice tremor is the phonatory manifestation of the essential tremor syndrome, characterized by involuntary skeletal muscle contraction that leads to oscillatory movement of laryngeal muscles at a rate of 4 to 10 Hz (1). There is wide disparity in symptom severity, with severe forms presenting as audible dysphonia and mild cases undetected or detected as mere incidental findings (2). In some cases, the muscles of the palate and pharynx are seen 614
Flow
2.2 Hz
Time
20 seconds
Figure 2. Twenty-second epoch displaying the EKG and airflow channel. The frequency of the cardiac rhythm (1.4 Hz) is shown to be slower than the flow oscillations (2.2 Hz).
AnnalsATS Volume 12 Number 4 | April 2015
CASE CONFERENCES
Low Frequency Oscillations
Inspiratory phase EMG
Chin EMG* Chin EMG DESATURATION
02 SAT
Airflow* Inspiratory High frequency >30Hz Airflow APNEA
*Low cut frequency 10Hz applied
Inspiratory and Expiratory oscillations
