The para-thyreoid glands—usually two on each side—lie in the external capsule along the posterior edge of the lobes of the thyreoid. They are flattened, elliptical bodies, averaging a quarter of an inch in length and an eighth of an inch in width, of a light brown colour, smooth and glistening on the surface, and of a soft, flabby consistence (W. G. MacCallum). When tetany follows operations for goitre it is due to the removal of these glands.
Physiological Hyperæmia.—The 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, pyæmia, 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 œsophagus 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 dyspnœa.
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 œsophagus.
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.