Pleurisy implies inflammation of the pleural
surfaces, whether (1) fibrinous, (2) serous with effusion or (3) purulent. The
most important single' cause of pleurisy, whether acute or chronic, dry or with
effusion, is tuberculosis. Pneumonic consolidation—whatever
the causative organism—single or multiple pulmonary abscess and primary or
secondary neoplasia may also be accompanied by pleurisy, as may complicated
bronchiectasis. Rarely, pleurisy complicates acute rheumatism. It may occur in
nephritis, often terminally, or during the course of blood diseases such as
leukaemia. Diaphragmatic pleurisy, with shoulder-tip pain, and mediastinal
pleurisy—both localizations with
or without effusion—have been described; as
isolated phenomena they are rare.
It
is probable that many of the cases of so-called simple or primary pleurisy are,
in reality, due to underlying foci of inflammation in the lung, whilst others
are tuberculous. The latter aetiology should always be suspected if the pain or
rub lasts more than a few days. It is very doubtful whether pleurisy ever
follows mere exposure to cold—" Pleuritis a frigore "
of the older writers. Epidemics of primary pleurisy have been described
(Scadding, 1946) and are probably to be distinguished from Bornholm disease. Pleurisy, evidenced by friction, occurs with varying frequency
in the latter, and there is still doubt whether the primary site of
inflammation is in the pleura or in the muscles and fasciae of the parietes. It
is the epidemic, sometimes explosive, nature of an outbreak which stamps it as
something distinct. In most outbreaks of Bornholm disease, relatively few of
the individuals who have the severe, sudden chest pain actually show friction.
