Hamman's Sign
Radiology Cases in Pediatric Emergency Medicine
Volume 1, Case 7
Robert J. Butts, MD
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     A 20 year old male presents to the emergency 
department at 2:15 a.m. after awakening late at night 
with difficulty breathing.  He initially experienced severe 
difficulty, but upon arrival in the ED he reported some 
improvement.  He had some mild chest pain.  He was 
not very communicative and declined to describe the 
chest pain further.  He was brought in by his father who 
noted he was behaving differently than usual.  The 
patient admitted to smoking crack cocaine on the day 
prior to arrival.  He denied other illicit drug or alcohol 
use.  His father was aware of the substance abuse and 
attributed his unusual behavior to this.
     Exam:  VS T36.6, P82, R22, BP 144/84.  His 
oxygen saturation in room air was 100%.  He was 
awake and alert, although he was noted to exhibit a 
somewhat flattened affect.  He ambulated well.  He 
exhibited a dry cough.  Pertinent physical findings 
revealed clear lung fields.  Auscultation of the heart 
revealed normal S1 and S2 with what was thought to be 
a friction rub.  This was described as a fine grating 
sound similar to the dehiscence of Velcro.  It was very 
brief and was noted to occur regularly with each heart 
beat in systole.  There was no chest wall tenderness.  
His peripheral pulses were good.  His color and 
perfusion were good.  The remainder of the exam was 
unremarkable.  A normal EKG was obtained.  A chest 
radiograph was obtained to look for evidence of 

View CXR:  AP view

View CXR:  Lateral view

     The patient returned from the Imaging department 
40 minutes later.  His CXR showed no cardiomegaly.  
His aortic shadow appeared to be normal.  At this time, 
his symptoms had spontaneously resolved.  He was no 
longer short of breath.  His chest pain had also 
resolved.  His vital signs showed improvement.  Cardiac 
auscultation at this time was normal.  The fine grating 
sound could no longer be heard.  The patient was 
discharged at 3:30 a.m. in good condition with a 
diagnosis of transient shortness of breath with a history 
of substance abuse.  He was advised to rest and refrain 
from further drug use.  He was instructed to return if his 
symptoms worsened.
     Later that morning, a radiologist reading his CXR 
noted a pneumomediastinum.  On the PA film, air is 
seen dissecting along the superior mediastinum 
bilaterally, and shadows consistent with subcutaneous 
emphysema were noted apically over the left lung.  
Note the vertical air densities extending upward from 
the mediastinum more noticeable on the left than on the 
right.  There is also air superimposed over the inferior 
aspect of the aortic arch.
     More impressively, the lateral radiograph revealed 
mediastinal air trapping with thymic demarcation.  Note 
the oblique air space present above (anterior and 
superior to) the heart.  You may have to adjust the 
brightness and contrast controls on your monitor to 
visualize these findings.  There are also vertical air 
densities outlining the trachea.
     The patient was called to notify him of the findings.  
His symptoms had resolved.  He was instructed to 
follow up with his private physician.

Teaching points:
     1.  The abuse of crack cocaine has become 
epidemic among adolescents in many areas.  The 
possibility of drug abuse in any adolescent who arrives 
with chest or pulmonary complaints should be 
considered (1).
     2.  Abnormal chest radiographs are quite common in 
cocaine users admitted with respiratory complaints, 
ranging from 12-55% (2).  Both pneumomediastinum 
and pneumothorax are relatively common after illicit 
cocaine use, and the incidence is higher for those who 
smoke crack cocaine, a relatively pure, extremely 
addictive, intensely euphoric alkaloid form of cocaine.   
Of those with pneumomediastinum, one series reported 
73% with detectable subcutaneous emphysema and 
50% with Hamman's sign, an unusual systolic crunch 
heard over the cardiac apex and the left sternal border 
     The mechanism of air leaks is felt to be related to 
exertional inhalation with Valsalva maneuvers.  Drug 
users do this to accomplish the highest delivery of drug 
to the bloodstream.  Irritants in the inhalant and the 
higher temperatures of the inhalant may induce reflex 
coughing, resulting in even greater intrathoracic 
pressure surges. In most cases, air is allowed into the 
mediastinum by spontaneous rupture of distended 
alveoli into the pulmonary vascular sheath (4).
     3.  The peculiar crackling, bubbling, or churning 
sounds heard usually during systole (Hamman's sign) 
are considered, by some, to be pathognomonic for 
mediastinal emphysema, and were first described in 
1945 by Hamman (5), who also attributed interstitial 
emphysema to trauma, increased intrapulmonary 
pressure (Valsalva maneuvers and cough), or 
spontaneous rupture of alveoli.  Hamman's sign is often 
noted to be transient, as in this case.  Hamman's sign 
has also been well described with isolated 
pneumothoraces and may represent free pleural air 
cyclically channeled through a lung fissure (6).
     4.  Retrospective reviews of young children with 
tracheobronchial foreign body aspiration have revealed 
a relatively high frequency of pneumomediastinum on 
initial chest radiographs.  The radiographic finding of 
pneumomediastinum should lead to the consideration of 
foreign body aspiration in any child in a high risk age 
group (7,8).
     5.  Pneumomediastinum is seen not uncommonly as 
a relatively late complication of cystic fibrosis (9), and if 
noted in any steroid-dependent child with unexplained 
fevers, esophageal rupture should be considered (10).  
Rarely, pneumomediastinum may signal 
tracheobronchial disruption in any patient with blunt 
thoracic trauma (11).
     6.  Pneumomediastinum and/or pneumothorax 
should be considered as an etiology for respiratory 
complaints or chest pain in any young person whose 
daily activities may include an unusual frequency of 
Valsalva maneuvers or increased intrathoracic 
pressure.  Examples include a young trombonist (12) 
and a Chinese martial arts expert (13).
     7.  Complete recovery within days is expected for 
drug- and Valsalva-related pneumomediastinum.

     1.  Luque MA, Cavallaro DL, Torres M, Emmanual 
P, Hillman JV.  Pneumomediastinum, pneumothorax, 
and subcutaneous emphysema after alternate cocaine 
inhalation and marijuana smoking.  Pediatric 
Emergency Care 1987:3(2): 107-109.
     2.  McCarroll KA, Roszler MH.  Lung disorders due 
to drug abuse.  Journal of Thoracic Imaging 
     3.  Seaman ME.  Barotrauma related to inhalational 
drug abuse.  Journal of Emergency Medicine 
     4.  Brody SL, Anderson GV, Gutman JB.  
Pneumomediastinum as a complication of crack 
smoking.  American Journal of Emergency Medicine 
     5.  Hamman L.  Mediastinal emphysema.  Journal of 
the American Medical Association 1945;128:1-6.
     6.  Baumann MH, Sahn SA.  Hamman's sign 
revisited.  Pneumothorax or pneumomediastinum?  
Chest 1992;102(4):1281-1282.
     7.  Burton EM, Riggs W Jr, Kaufman RA, Houston 
CS.  Pneumomediastinum Caused by Foreign Body 
Aspiration in Children. Pediatric Radiology 
     8.  Ramadan HH, Bu-Saba N, Baraka A, Mroueh S.  
Management of an Unusual Presentation of Foreign 
Body Aspiration.  Journal of Laryngology and 
Otolaryngology.  1992;106(8):751-752.
     9.  Grum CM, Lynch JP.  Chest radiographic 
findings in cystic fibrosis.  Seminars in Respiratory 
Infections 1992;7(3):192-209.
     10.  Klygis LM, Jutabha R, McCrohan MB, 
Vanagunas AD.  Esophageal Perforations Masked by 
Steroids.  Abdominal Imaging 1993:18(1):10-12.
     11.  Baumgartner F, Sheppard B, deVirgilio C, Esrig 
B, Harrier D, Nelson RJ, Robertson JM.  Tracheal and 
Main Bronchial Disruptions After Blunt Trauma.  Annals 
of Thoracic Surgery 1990;50(4):569-574.
     12.  Ito S, Takada Y, Tanaka A, Ozeki N, Yazaki Y.  
A case of spontaneous pneumomediastinum in a 
trombonist.  Kokyu To Junkan 1989;37(12):1359-62.  
     13.  Yoneyama H, Matsushima T, Nakamura J, 
Yano T, Adachi M, Tano Y.  Two cases of spontaneous 
pneumomediastinum due to Xiao-lin Temple boxing 
vocal exercise.  Nippon Kyobu Shikkan Gakkai Zasshi 

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Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine