January 2023 Medical Image of the Month: Abnormal Sleep Study and PFT with Supine Challenge Related to Idiopathic Hemidiaphragmatic Paralysis

Figure 1. Results of a sleep study demonstrating a correlation between body position and oxygen saturation.  When the patient moved into right lateral decubitus positioning, their SaO2 dropped (red), when they moved into left lateral decubitus positioning, their SaO2 recovered (Green).  This position-dependent change in SaO2 during sleep suggests right hemidiaphragmatic paralysis.

Figure 2.  Flow-volume loop from pulmonary function testing demonstrates a significant reduction in forced vital capacity (FVC) and forced expiratory volume 1s (FEV1) with supine positioning (green line) compared to upright baseline (red line) suggestive of diaphragmatic dysfunction. 

Figure 3.  Fluoroscopic images from a sniff test at end tidal (A) and “sniffing” (B) portions of exam demonstrating normal depression of the left hemidiaphragm (down arrowhead) and paradoxical elevation of the right hemidiaphragm (up arrowhead) consistent with right hemidiaphragmatic paralysis. Sagittal reconstruction from a noncontrast chest CT (C) demonstrating an elevated but otherwise normal appearing right hemidiaphragm (arrows).

A 71-year-old man presented to our pulmonary clinic with a complaint of worsening dyspnea, which seems to be positional in nature.  Symptoms were exacerbated by bending over or laying down too quickly.  The patient was known to our practice, having had a kidney transplant 17 years ago, a left upper lobectomy for squamous cell carcinoma 6 years ago (no recurrence), and has been on fluconazole for 4 years due to disseminated coccidioidomycosis (cocci) with cavitary pulmonary involvement.  The patient had recurrent DVTs 2 years ago and is on Eliquis.  On top of that, the patient had COVID 1 year ago, but had recovered.  An outside sleep study was remarkable for overnight hypoxia.  Outside pulmonary function testing (PFTs) demonstrated a combined restrictive and obstructive picture.  An outside chest CT failed to demonstrate any findings that would suggest COVID-related changes or progression of cocci as a potential cause.  A V/Q scan was low probability for pulmonary embolism.

 The positional nature of the patient’s symptoms and suspicious physical exam findings suggested abnormal diaphragmatic motion as a potential etiology.  The astute pulmonologist ordered a home sleep study to evaluate for any positional nature to the overnight hypoxia (Fig. 1), PFTs with supine challenge (Fig. 2) and a fluoroscopic sniff test to evaluate diaphragmatic motion (Figure 3).  The sleep study did indeed demonstrate a strong correlation between patient position and SaO2 (dropped when right side down or supine).  The PFTs demonstrated a significant drop in pulmonary function with supine challenge.  The sniff test demonstrated an elevated right hemidiaphragm with paradoxical motion during sniffing maneuvers (Fig. 3A,3B).  Results were consistent with right hemidiaphragmatic paralysis.  Of note, several months later repeat PFTs and sniff test demonstrated some interval improvement in right hemidiaphragmatic paralysis suggesting a reversible process, probably inflammatory and perhaps related to a viral neuritis.

Diaphragmatic paralysis can be further categorized into unilateral or bilateral with these entities each having a somewhat different set of potential etiologies. Distinguishing between unilateral vs. bilateral paralysis is important. Potential causes of unilateral hemidiaphragmatic paralysis can be separated into trauma/iatrogenic causes (such as following CABG), compression (such as cervical spondylosis or tumor along phrenic nerve), neuropathic (such as in multiple sclerosis) or inflammation (such as in the setting of a viral neuritis) (1).  Viral neuritis affecting the phrenic nerve has been reported with COVID-19 (2).  Up to 20% of cases of unilateral hemidiaphragmatic paralysis may be considered idiopathic (3).

The diagnostic approach to suspected hemidiaphragmatic paralysis is actually pretty well demonstrated by this case report.  CXR, in combination with physical exam, is often good as an initial screening exam.  Diaphragmatic motion can be assessed with sniff testing using fluoroscopy (or ultrasound if there is a desire to limit exposure to ionizing radiation).  Evaluation for causes of compression can be done with cross-sectional imaging, particularly CT or MRI.  Pulmonary function testing with supine challenge and a sleep study can also provide useful information, as demonstrated by this case.

Clinton Jokerst MD¹, Carlos Rojas MD¹, Michael Gotway MD¹, and Philip Lyng MD²

Department of Radiology¹

Mayo Clinic Arizona, Scottsdale, AZ USA

Division of Pulmonology²

Mayo Clinic Arizona, Scottsdale, AZ USA

References

1. O'Toole SM, Kramer J. Unilateral Diaphragmatic Paralysis. [Updated 2022 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557388/ (accessed 12/12/22).
2. FitzMaurice TS, McCann C, Walshaw M, Greenwood J. Unilateral diaphragm paralysis with COVID-19 infection. BMJ Case Rep. 2021 Jun 17;14(6):e243115. [CrossRef] [PubMed]
3. Kokatnur L, Vashisht R, Rudrappa M. Diaphragm Disorders. 2022 Aug 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. [PubMed] 

Cite as: Jokerst C, Rojas C, Gotway MB, Lyng P. January 2023 Medical Image of the Month: Abnormal Sleep Study and PFT with Supine Challenge Related to Idiopathic Hemidiaphragmatic Paralysis. Southwest J Pulm Crit Care Sleep. 2023;26(1):5-7. doi: https://doi.org/10.13175/swjpccs057-22 PDF

Medical Image of the Week: Prozac Eyes

Figure 1. 60-second epoch shows the slow rolling eye movements (red arrow) and rapid eye movements (green arrows) seen during NREM stage 2 sleep.

A 59-year-old man with a past medical history significant for hypertension, obesity and depression underwent an overnight polysomnogram for high clinical suspicion for obstructive sleep apnea. His current medications include doxepin, fluoxetine, bupropion, ambien and amlodipine. A snapshot during NREM sleep is shown (Figure 1).

Fluoxetine (Prozac®) is a potent selective serotonin reuptake inhibitor (SSRI).“Omnipause” neurons in the brainstem inhibit saccadic eye movements. NREM eye movements result from the potentiation of serotonergic neurons that inhibit these neurons (1). These eye movements occur during all stages of NREM sleep. These atypical eye movements have been reported to be present with a lower incidence with use of other antidepressants, benzodiazepines and neuroleptics and they tend to persist even after discontinuation of the medication (2). The clinical significance of these eye movements is unknown.

Safal Shetty MD, Sarah Patel MD, Kenneth S. Knox MD

Section of Pulmonary, Allergy, Critical Care & Sleep Medicine

Banner University Medical Center

Tucson, AZ USA

References

1. Schenck CH, Mahowald MW, Kim SW, O'Connor KA, Hurwitz TD.Prominent eye movements during NREM sleep and REM sleep behavior disorder associated with fluoxetine treatment of depression and obsessive-compulsive disorder. Sleep. 1992;15(3):226-35. [PubMed]
2. Geyer JD, Carney PR, Dillard SC, Davis L, Ward LC. Antidepressant medications, neuroleptics, and prominent eye movements during NREM sleep. J Clin Neurophysiol. 2009;26(1):39-44. [CrossRef] [PubMed] 

Cite as: Shetty S, Patel S, Knox KS. Medical image of the week: prozac eyes. Southwest J Pulm Crit Care. 2015;11(6):284. doi: http://dx.doi.org/10.13175/swjpcc128-15 PDF

Medical Image of the Week: Alpha Intrusion into REM Sleep

Figure 1. 30-second epoch during NREM sleep (Stage N3). The red arrows show alpha waves (8-12 Hz frequency) on delta waves (0.5-2 Hz), most prominently seen in the frontal and central EEG leads.

Figure 2. 30 second epoch during REM sleep showing bursts of alpha activity during REM sleep (red arrow) with hypersynchronous theta wave activity (4-7 Hz) (blue arrow).

A 45-year-old woman with a past medical history of hypertension and chronic headaches was referred to the sleep laboratory for high clinical suspicion for sleep apnea based on a history of snoring, witnessed apnea and excessive daytime sleepiness. An overnight sleep study was performed. Images during N3 Sleep and REM sleep are shown (Figures 1 and 2).

Alpha intrusion in delta sleep is seen in patients with fibromyalgia, depression, chronic fatigue syndrome, anxiety disorder, and primary sleep disorders like psychophysiological insomnia, obstructive sleep apnea, circadian disorders and narcolepsy (1).

Bursts of alpha waves during REM sleep may be more common during phasic REM than tonic REM. The REM alpha bursts (alpha activity lasting at least 3 seconds without an increase in EMG amplitude) may represent microarousals (2).  

Hypersynchronous theta activity should be differentiated from the spike and waveform activity seen in seizures.

Safal Shetty MD, Tam Le, MD

Banner University Medical Center

Tucson, AZ

References

1. Jaimchariyatam N, Rodriguez CL, Budur K. Prevalence and correlates of alpha-delta sleep in major depressive disorders. Innov Clin Neurosci. 2011;8(7):35-49. [PubMed]
2. Cantero JL, Atienza M. Alpha burst activity during human REM sleep: descriptive study and functional hypotheses. Clin Neurophysiol. 2000;111(5):909-15. [CrossRef] [PubMed] 

Cite as: Shetty S, Le T. Medical image of the week: alpha intrusion into REM sleep. Southwest J Pulm Crit Care. 2015;11(6):273-4. doi: http://dx.doi.org/10.13175/swjpcc126-15 PDF

Medical Image of the Week: PSG Sweat Artifact

Figure 1. A 30 second epoch suggestive of sweat artifact and incidentally noted snore artifact on the M1 channels.

Figure 2: Sweat artifact as seen in a 10 second epoch.

Figure 3.  30 second epoch after removal of the M1 channels.

A 61-year-old man, with a past medical history significant for hypertension, COPD and morbid obesity with a body mass index (BMI) of 45.81 is referred for an overnight sleep study for suspicion of obstructive sleep apnea. Artifact was noted on the polysomnogram recording as shown above (Figures 1-3).

Sweat artifact is characterized by slow undulating movement of the baseline recording in the affected channels due to perspiration altering the potential of the involved electrodes (1). Sweat artifact may mimic delta waves and scored as non-rapid eye movement (NREM) stage 3 sleep. Lowering the room temperature, using a fan on the scalp or replacing the conductive paste on the electrodes may help eliminate the artifact.

Safal Shetty, MD¹ and John Roehrs, MD²

¹Banner University Medical Center Tucson, AZ

²Southern Arizona VA Health Care System

Tucson, AZ

Reference

1. Siddiqui F, Osuna E, Walters AS, Chokroverty S. Sweat artifact and respiratory artifact occurring simultaneously in polysomnogram. Sleep Med. 2006;7(2):197-9. [CrossRef] [PubMed] 

Cite as: Shetty S, Roehrs J. Medical image of the week: PSG sweat artifact. Southwest J Pulm Crit Care. 2015;11(4):171-2. doi: http://dx.doi.org/10.13175/swjpcc097-15 PDF 

Medical Image of the Week: Polysomnogram Artifact

Figure 1. Thirty second polysomnogram epoch showing artifact in lead O1M2 (black arrow).

Figure 1. Ten second polysomnogram epoch showing artifact in lead O1M2 (black arrow).

A 54 year-old man with a past medical history of attention deficit hyperactivity disorder (ADHD), low back pain, and paroxysmal supraventricular tachycardia presented to the sleep laboratory for evaluation of sleep disordered breathing. Pertinent medications include fluoxetine, ambien, and clonazepam. His Epworth sleepiness score was 18. He had a total sleep time of 12 min. On the night of his sleep study, the patient was restless and repeatedly changed positions in bed. 

Figures 1 and 2 show the artifact determined to be lead displacement of O1M2 after the patient shifted in bed, inadvertently removing one of his scalp electrodes. The sine waves are 60 Hz in frequency. Once the problem was identified, the lead was quickly replaced to its proper position.

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

¹University of Arizona Medical Center

²Southern Arizona VA Health Care System

Tucson, AZ

Reference as: Bartell J, Shetty S, Roehrs JD. Medical image of the week: polysomnogram artifact. Southwest J Pulm Crit Care. 2015;10(2):95-6. doi: http://dx.doi.org/10.13175/swjpcc014-15 PDF

Medical Image of the Week: Cheyne-Stokes Respiration on Overnight Polysomnography

Figure 1. 300 second polysomnogram window showing crescendo-decrescendo pattern of Cheyne-Stokes respiration (solid black arrows). Cycle length is approximately 60 seconds in duration (Outlined black arrows).

A 75 year old man with a significant past medical history of atrial fibrillation, hypertension, complete heart block status-post pacemaker implantation, thoracic aortic aneurysm, and ischemic cardiomyopathy, was referred to the sleep laboratory for evaluation for suspected sleep disordered breathing. The patient had subjective complaints of morning headaches, reported apnea, un-refreshing sleep, nocturnal urination, and intermittent snoring. The diagnostic polysomnogram was significant for periodic breathing, Cheyne-Stokes pattern, with a cycle length that ranged from 60-65 seconds (Figure 1). Oxygen saturation nadir was 79% as measured by pulse oximetry. Electrocardiogram showed a persistently paced rhythm.

Cheyne-Stokes respiration is a periodic breathing pattern characterized by crescendo-decrescendo episodes of respiratory effort that are interspersed between periods of apnea. It is typically seen in individuals with systolic heart failure, but can also be seen in those with intracerebral hemorrhage or infarction. The mechanism for Cheyne-Stokes respiration involves increased central controller gain causing increased central nervous system sensitivity to changes in arterial blood gas PCO₂ and PO₂. Increased circulation time results in circulatory delay between gas exchange occurring at the alveolar capillary membrane and the central chemoreceptors in the medulla. The result is instability in respiration (1).

Ryan Nahapetian, MD, MPH and Sairam Parthasarathy, MD

Pulmonary, Allergy, Critical Care, & Sleep Medicine

University of Arizona, Tucson, AZ

Reference

1. Quaranta AJ, D'Alonzo GE, Krachman SL. Cheyne-Stokes respiration during sleep in congestive heart failure. Chest. 1997;111(2):467-73. [CrossRef] [PubMed]

Reference as: Nahapetian R, Parthsarathy S. Medical image of the week: Cheyne-Stokes respiration on overnight polysomnography. Southwest J Pulm Crit Care. 2014;8(6):328-9. doi: http://dx.doi.org/10.13175/swjpcc055-14 PDF