Pneumomediastinum is a rare condition defined as free air in the mediastinum. It is usually spontaneous but can be traumatic. Spontaneous pneumomediastinum occurs when alveoli rupture due to high pressure, allowing air to track along tissue planes into the mediastinum. Traumatic pneumomediastinum results from injuries like pulmonary interstitial emphysema or ruptured bronchus/esophagus. It is diagnosed using chest x-ray or CT scan and usually resolves with conservative treatment like analgesia. Rarely tension pneumomediastinum can occur requiring surgical drainage.

1. Pneumomediastinum

2. * More Common Among Children
and Neonates
• First Described By Laennec 1819 as
a consequence of Traumatic Injury
• Then Spontaneous
Pneumomediastinum was described
by Hamman in 1939
* Rare Condition

3. It is defined as free air or gas
contained within the mediastinum,
which almost invariably originates
from the alveolar space or the
conducting airways.

4. Pneumomediastinum
Spontaneous
Traumatic

5. Spontaneous
• Rupture of Marginally Situated
Alveoli (high intraalveolar
pressure)
• Erosion of a Tracheal Or
Esophageal Tumor
•Pneumoperitoneum,
Pneumoretroperitoneum

6. Traumatic
• pulmonary interstitial
emphysema (positive pressure
ventilation)
• ruptured bronchus (commonly
associated with pneumothorax)
• ruptured esophagus (diabetic
acidosis, alcoholic, Boerhaave)

7. Pathophysiology
The Macklin Effect 1944
o alveolar rupture
o air dissection along the
bronchovascular sheath
o free air reaching the
mediastinum

8. Complications
Rarely leads to significant
complications by it self
Significant Illness
Comorbid
Disease
Trauma

9. Tension
Pneumomediastinum
• Rare
• Elevated Mediastinal pressure leads to
diminished cardiac output, either by:
• When extensive subcutaneous and
mediastinal gas is present, airway
compression may also occur.
direct cardiac compression
reduced venous return

10. Statistics
• SPM
from 1 per 800 to 1 per 42,000 pediatric
patients presenting to ER.
from 1 per 12,000 to 1 per 30,000
admission to the hospital.
0.3% incidence of PM in association with
asthma over a 10-year period.
• TPM
10% of blunt chest injury patients will
develop PM.

11. Mortality & Morbidity
SPM is a self limited condition
are generally attributable to underlying
disease states.
as high as 50-70% as seen in
Boerhaave syndrome
is not associated with an
increased mortality rate in
patients with sepsis-induced
ARDS

12. Gender
29 cases of SPM over a 10-year
period, 69% were males
Is a body habitus favoring a tall thin build is
an additional risk factor for the
development of SPM?
TPM is more common in males,
reflecting the male
predominance among those
who experience trauma and
accidents.

13. Age
The peak prevalence of SPM is seen in the second
to fourth decades of life.
reflects involvement in activities that
increase the risk of developing SPM
the force of an individual's cough, vomit, and Valsalva
maneuvers (all of which may lead to PM) attenuates with age
The age distribution for PM occurring in
conjunction with specific disease
processes reflects the age profile of the
particular disease.

14. Clinically
• Chest pain
• Dyspnea
• Fever
• Dysphonia
• Throat pain
• Jaw pain
• Miscellaneous :
Dysphagia, neck swelling, and torticollis

15. Chest pain
IN SPM said to be a feature in 50-90% of cases
• retrosternal in location
• worsened by inspiratory maneuvers
• may radiate to the shoulders or back thus
suggesting MI or pericarditis
in 27% of persons with
asthma with PM

16. Dyspnea
may reflect associated illnesses such
as asthma, a coexistent pneumothorax,
or a tension PM.

17. Fever
Low-grade fever may be present
following cytokine release that is
associated with air leak.
mediastinitis or infectious/inflammatory
disorders should be included in the
differential diagnosis
Dysphonia

18. Signs
• Subcutaneous air
•The Hamman sign
•Associated pneumothorax
•Other diseases
•Oxygen saturation

19. • not pathognomic of PM
•subcutaneous emphysema in 73% of
patients presenting with asthma
subsequently found to have PM.
•The positive predictive value of this sign
for PM in the previous series was 100%.
Subcutaneous air

22. The Hamman sign
• pathognomic of PM
• precordial systolic crepitations
and diminution of heart sounds
• prevalence of 10% to 50% PM
patients

23. Oxygen saturation
• Pulse oximetry is mandatory in
all patients with suspected PM
•In a series of children with
asthma presenting to an
emergency department, those
with PM had a significant
difference in oxyhemoglobin
saturation (90% vs 94% of
those without PM, p = 0.03).

24. Work Up
Chest X-Ray
usually reveals a pneumomediastinum.
• thymic sail sign
•"ring around the artery"
sign
•double bronchial wall sign
•continuous diaphragm sign
•the extrapleural sign

27. spinnaker sail
sign

28. Subcutaneous
air

29. continuous diaphragm sign

30. CT-Scan
• provide additional diagnostic
information regarding the
presence of coexisting illness
•in diagnosing small
pneumomediastinum not visible
on chest radiography.
chest radiography alone
may result in a missed
diagnosis in 10% of
patients presenting with
pneumomediastinum.

31. Contrast radiography
suspected esophageal perforation
ABG
ECG

32. Spirometry
?
should not be undertaken in
patients with
pneumomediastinum
because the increased
alveolar pressures may
further exacerbate the air
leak.

33. Treatment
Medical Care
• Most are Asymptomatic
Spontaneously resolve
• Adequate analgesia
• Some Points
 mechanical ventilation & PM?
 high-frequency oscillatory ventilation
Children with ARDS and PM?
 Nitrogen washout with inhalation of
100% oxygen

34. • The use of the lowest pressures or tidal
volumes necessary to achieve satisfactory
carbon dioxide removal and oxygenation.
Mechanical Ventilation & PM?
• Permissive hypercapnia, a ventilatory strategy that
is based on maintaining adequate oxygenation and
blood pH while allowing high partial pressure of
carbon dioxide, allows for ventilatory support while
minimizing barotrauma.

35. Treatment
Surgical Care
Mediastinoscopy
Mediastinal drainage

36. http://emedicine.medscape.com/
http://LearningRadiology.com
http://chorus.rad.mcw.edu/doc/00964.html
http://www.mypacs.net/