ER: A Shift in the Night

each post gonna contain a bunch of cases i visited on ER or Clinic a week before

Monday, April 20, 2009

pneumomediastinum & Pneumopericardium

35-year-old alcoholic man came to ER with Chest pain & dyspnea..


Pneumopericardium is rare - defined as a collection of air or gas in the pericardial space.

The amount of air required to produce haemodynamic changes depends on the volume and rate of introduction:

  • haemodynamic changes may occur with as little as 60 ml of air if it is introduced rapidly
  • up to 500 ml may accumulate into the pericardium without marked effect if introduced slowly into the pericardial space (1)

Aetiology can be divided into three broad categories.

  • most common cause is trauma:
    • blunt or penetrating chest injury and barotrauma are included in this category:
      • barotrauma is usually secondary to positive pressure ventilation (both invasive and noninvasive)
        • most commonly occurring in neonatal practice
        • however cases associated with severe asthma, prolonged labour and cocaine inhalation may occur
  • second category - fistulation between pericardium and a hollow or air-containing structure e.g. pleural space, pulmonary substance, bronchial tree, gastrointestinal tract
    • examples include
      • staphylococcal lung abscess rupture
      • erosion into the pericardium as a result of a bronchial carcinoma
      • gastropericardial fistula complicating peptic ulcer disease
  • third category - much less common is secondary to gas production de novo by microorganisms invading the pericardial sac e.g. Clostridium perfringens and Klebsiella

Two distinctive clinical signs associated with pneumopericardium.

  • splashing ‘mill wheel’ murmur - this was described in the first description of this condition by Bricketeau in 1844. The case was in fact one of pyopneumopericardium. The 'mill wheel' murmur described was a result of the combination of fluid and gas in the pericardial space
  • presence of shifting tympany - revealed when the precordium is percussed in the recumbent and upright positions

Investigations in pneumopericardium include:

  • ECG - may reveal signs of pericarditis; at the point of tamponade then bradycardia is said to be common
  • CXR - may allow differentiation between pneumopericardium and pneumomediastinum
    • may show ‘transverse band of air’ sign - represents air within the transverse sinus of the pericardium.
      • 'transverse band of air' sign is not present in pure pneumomediastinum or medial pneumothorax
  • CT scan - demonstrates pericardial air; also may provide diagnostic clues to the aetiology of the pneumopericardium
  • barium contrast swallow - may demonstrate an oesophagopericardial fistula
    • negative result cannot completely exclude this diagnosis
  • echocardiography - may reveal pathognomonic spontaneous contrast within the pericardial space; also may show features of cardiac tamponade if present

Management:

Seek expert advice.

  • in the absence of tension then, in general, treatment is aimed at the specific cause
  • if signs of tamponade develop then
    • urgent pericardiocentesis is required
    • a pericardial catheter should be left in place in order to prevent the development of further tension

Prognosis:

  • pneumopericardium - one review revealed a 57% all-cause mortality
  • pyopneumopericardium - has an even higher associated mortality rate
  1. Stacey S et al. A case of spontaneous tension pneumopericardium. Br J Cardiol 2004;11:32-14.


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