thyreoid varies greatly in size even
within normal limits, and may become engorged and swollen from
physiological causes, particularly in the female. Before the onset of
menstruation at puberty, for example, the thyreoid frequently becomes
engorged, and the enlargement may recur with each period for months or
even years. During pregnancy also the gland may become swollen.

#Acute Thyreoiditis# may occur in a healthy thyreoid or in one that is
the seat of goitre, and may end within a few days in resolution, or go
on to suppuration. It is due to infection with pyogenic bacteria,
which usually gain access to the gland by the blood stream, as, for
example, in typhoid fever, pyaemia, influenza, and other acute
infective diseases. Direct infection sometimes occurs from an abscess,
a cellulitis, or an infected wound in the neck; it has also occurred
from a foreign body impacted in the oesophagus ulcerating through and
perforating the gland.

One lobe is usually more involved than the other, but the condition
may be diffused. When pus forms it may infiltrate the stroma of the
gland, or may be collected into several small foci.

_Clinical Features._--The usual signs of inflammation are present;
there is severe headache of a congestive nature, and sometimes
vertigo. The swelling takes the shape of the thyreoid, and although
the skin may not be red, the subcutaneous veins are dilated. In severe
cases there is pain and difficulty in swallowing and dyspnoea.

When suppuration ensues, all the symptoms are aggravated, and repeated
rigors occur. The pus may burst into the cellular tissue of the neck,
or into the air-passage or the oesophagus.

_Treatment._--In the non-suppurative stage the ordinary treatment of
acute inflammatory conditions is employed; if pus forms, the abscess
should be opened and drained.

#Tuberculous and syphilitic affections# of the thyreoid are very rare.

PARENCHYMATOUS GOITRE OR BRONCHOCELE

The term goitre is applied clinically to any non-inflammatory
enlargement of the thyreoid gland.

_Etiology._--Parenchymatous goitre, sometimes called also simple, or
non-toxic goitre, is endemic in certain hilly districts in
England--particularly Derbyshire and Gloucestershire--and in various
parts of Scotland. It is exceedingly common in certain valleys in
Switzerland. It is met with less frequently in men than in women, and
it occurs chiefly during the child-bearing period of life. The toxic
agent that caus