Medical Minute: Pneumorrhachis

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July 23, 2015 by dailybolusoflr

By Michael Ehmann, MD MPH MS



Images courtesy of Michael Ehmann, MD
I.                Definition
a.      Air within the spinal canal
b.     Also called epidural pneumatosis, intraspinal pneumocele, spinal emphysema, pneumosaccus, aerorrhachia
II.             Etiology
a.      Most often trauma (spinal fracture) or spinal instrumentation (LP, epidural)
b.     Pneumomediastinum (spontaneous or aerodigestive tract injury)
                                                    i.     Spontaneous alveolar rupture secondary to acute increase in transalveolar pressure gradient
1.     Valsalva, coughing, vomiting, hyperpnea, asthma, drugs, exertion
                                                  ii.     Air tracks along bronchovascular sheaths to hilum & mediastinum (pneumomediastinum) then extends along submandibular & retropharyngeal fascial planes through neural foramina into epidural space (pneumorrhachis)
c.      Infectious (epidural abscess)
III.           Epidemiology
a.      Rare!
b.     Spontaneous pneumomediastinum in 1:30,000 ED patients
c.      Pneumorrhachis in only 9.5% of those with pneumomediastinum
IV.           Prognosis
a.      Trauma and infectious: bad
b.     Iatrogenic and spontaneous: good
                                                    i.     Spontaneous: 64 patients
1.     4 had neuro findings
a.      1 required laminectomy; all made full recovery
V.              ED Evaluation
a.      Signs & symptoms of pneumomediastinum
                                                    i.     Neuro exam, CT neck & chest
                                                  ii.     Differentiate spontaneous & aerodigestive tract injury
b.     Trauma
                                                    i.     Search for occult injury, image liberally
c.      Infectious
                                                    i.     Treat as epidural abscess
d.     Iatrogenic
                                                    i.     Neuro exam
VI.           Disposition
a.      No published guidelines for ED management
b.     Observation & supportive care
                                                    i.     Iatrogenic & spontaneous
c.      Admit
                                                    i.     Trauma, infectious & aerodigestive tract injury
References
Belotti EA, et al. Chest. 2010;137(5):1197-200.
Jung H, et al. Korean J Thorac Cardiovasc Surg. 2014;47(6):569-71.
Kono T, et al. Pediatr Int. 2007;49(6):923-7.
Migeot M, et al. Rev Neurol(Paris). 2013;169(2):173-4.
Murayama S, et al. World J Radiol. 2014;6(11):850-4.
Newcomb AE, et al. Chest. 2005;128(5):3298-302.

Song KJ, et al. Spine J. 2009;9(2):e16-18

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