A variety of disorders can cause pleuritic chest pain, oftenwith a pleural rub, but without a pleural effusion. Some ofthese conditions remain ‘dry’ but in most fluid may accumulate,and therefore many of the causes of a pleural effusionmust be considered in the differential diagnosis of drypleurisy.
Pleuritic pain is a common feature of many radiologicallyobvious pneumonias, but can also occur with minorbacterial and viral pulmonary infections not radiologically apparent. Epidemic myalgia (Bornholm’s disease), mostcommonly due to the Coxsackie B virus, is primarily aninfection of intercostal muscle but occasionally the pleurais involved. The intercostal muscles are tender. There maybe associated pericarditis, myocarditis or orchitis. Pain mayrelapse and remit several times before finally settling.
Pneumothorax is air in the pleural space, as a consequenceof which there is partial or complete collapse of the lung.Owing to the recoil of the chest wall and the lung, the pressurewithin the pleural space is normally negative. Whenthe pleural membrane (visceral or parietal) is breached, airis sucked into the pleural cavity and the lung collapses.When the defect in the pleura seals, the pneumothorax isclosed and there is no movement of air in or out of thepleural cavity. When there is a persistent defect in thepleura the pneumothorax is open. When this defect is ofthe visceral pleura there is then a bronchopleural fistula,and air moves in and out of the pleural space duringbreathing. Occasionally the damaged visceral pleura actsas a valve, permitting air to enter the pleural space oninspiration but not to leave it on expiration, leading to atension pneumothorax.
A pneumothorax may be spontaneous, or follow chesttrauma, mechanical ventilation, ruptured oesophagus, orartificial induction. Causes of traumatic pneumothoraxinclude blunt trauma to the chest, commonly externalcardiac massage, and penetrating chest injuries (e.g. stabwounds or needle aspiration biopsies that breach thevisceral pleura from without) and transbronchial biopsyand positive-pressure ventilation that breach the visceralpleura from within.
Clinical featuresCharacteristically, there is a sudden onset of chest painlaterally, sometimes radiating to the shoulder. With substantialcollapse of the lung there is associated breathlessness,and a dry, irritating cough is common. Sometimes thepatient is aware of the partially collapsed lung floppingabout within the thorax. On examination the most strikingfindings are of reduced breath sounds and hyperresonantpercussion. A small left-sided pneumothorax may be associatedwith a clicking noise with each heartbeat, noted bythe patient and on occasions loud enough to be heard byothers. A large pneumothorax in a normal person causesbreathlessness, and in the presence of pre-existing pulmonarydisease a small one may cause severe respiratorydistress.Tension pneumothorax is a medical emergency. Thevalve action of the pleural tear results in a progressiveincrease in the size and pressure of the pneumothorax. Theunderlying lung is totally collapsed. The mediastinum isshifted to the contralateral side, compromising the functionof the opposite lung, and the high intrathoracic pressureelevates the jugular venous pressure, reduces venousreturn and causes tachycardia, low cardiac output, andeventually circulatory collapse and death.