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: Empyema Necessitans

Figure 1. Panel A: chest radiograph on admission showed mass like lesion centered at the right upper lobe. Panel B: Coronal CT cut showing loculated fluid collection demonstrating peripheral rim enhancement. There is extension of pleural fluid into the soft tissues of the adjacent right chest wall (white arrow).

Figure 2. Panel A: chest radiograph after VATS decortication and antibiotic course shows resolution. Panel B: axial CT cut after completion of therapy shows complete resolution.

A previously healthy 46-year-woman was evaluated for two week history of right shoulder pain, associated pleuritic chest pain and dyspnea.

Chest radiograph showed right apical mass (Figure 1A). Imaging  showed loculated fluid collection with extension into the soft tissues of the adjacent right chest wall suggestive of empyema necessitans (Figure 1B).

Chest Tube placement was done along with broad spectrum antibiotics. Blood and pleural fluid cultures showed methicillin-resistant Staphylococcus aureus (MRSA). Due to persistence of loculation despite antibiotics, she underwent a video-assisted-thoracoscopic surgery (VATS) for decortication and further drainage of the effusion.

Symptoms and radiologic findings improved and she was discharged with intravenous antibiotics to complete a six week course. Chest imaging at six week period showed complete resolution (Figure 2).

Empyema necessitans, defined by the extension of an empyema through the parietal pleura, into surrounding tissue is becoming rare with the routine drainage of empyema and antibiotics use. Common causative pathogens include Mycobacterium tuberculosis, Actinomyces israelii, Streptococcus pneumoniae, and Staphylococcus aureus (1). Surgical treatments for thoracic empyema include chest tube drainage, debridement via VATS, decortication, open window thoracostomy, and thoracoplasty (2).

Kai Rou Tey MD¹, Bhupinder Natt MD²

¹Department of Internal Medicine - South Campus and ²Department of Pulmonary, Critical Care, Allergy and Sleep

University of Arizona College of Medicine

Tucson, AZ USA

References

1. Kono SA, Nauser TD. Contemporary empyema necessitatis. Am J Med. 2007;120(4):303-5. [CrossRef] [PubMed]
2. Molnar TF. Current surgical treatment of thoracic empyema in adults. Eur J Cardiothorac Surg. 2007;32(3):422-30. [CrossRef] [PubMed] 

Cite as: Tey KR, Natt B. Medical image of the week: empyema necessitans. Southwest J Pulm Crit Care. 2015;11(6):271-2. doi: http://dx.doi.org/10.13175/swjpcc139-15 PDF