The external aspect of a myxedematous patient is characteristic. The puffed and expressionless face together with the general attitude reflect both mental inertia and profound disorder of general nutrition.
These consist chiefly in symptoms indicating a blunting and torpor of cerebral activity - psychic paralysis; there is extreme sluggishness of association of ideas demonstrable by simple clinical examination as well as by psychometry; the attention is difficult to obtain and to fix; there are also retrograde amnesia by default of reproduction and anterograde amnesia by default of fixation; permanent indifference; aboulia.
The indifference is occasionally interrupted by transient attacks of irritability. Myxedematous patients are often sulky and ill-natured.
Sleep is diminished, replaced by permanent somnolence, and disturbed by nightmares.
The reflexes are diminished or abolished; all movements are sluggish and clumsy.
But the most striking changes are those of the integuments and of the thyroid gland.
The skin is thickened and infiltrated; its surface is smooth and of a dull whiteness. On palpation it gives the sensation of waxy tissue. There is no pitting on pressure, this being a point of distinction between myx-cedematous infiltration and anasarca.
The features are dull, eyes sunken, lips thickened; the wrinkles of the forehead disappear, and the naso-labial folds become effaced. The physiognomy is immovable and stupid. The hair of the head, eyebrows, and beard is scant, discolored, and atrophied. These characteristics are pathognomonic of the myxcedematous facies.
The hair over the entire body is atrophied. The nails become deformed and brittle.
The mucous membranes present thickening analogous to that of the skin. They are pale, anaemic, and in places cyanotic.
On palpation one finds atrophy or even complete absence of the gland.
Sometimes the thyroid gland is increased in size, causing an abnormal prominence in front of the neck. This hypertrophy, true or false, is generally transitory, and occurs chiefly in the early stages of the disease. When the swelling persists through the entire duration of the affection, it is usually the result of cystic degeneration of the gland.
The visceral disorders are not characteristic; they indicate general atony and diminished vitality of the organism: small, compressible pulse, sluggish and painful digestion, and constipation.
The course of myxcedema is progressive, but interrupted by frequent remissions.
If no appropriate treatment is instituted, the stock of ideas becomes diminished, psychic inertia becomes extreme and complete dementia is established; also the physical symptoms become accentuated and death supervenes either from cachexia or from some complication (pulmonary tuberculosis).
It is possible to supply, to a certain extent, the deficiency caused by atrophy of the thyroid gland by the administration of the thyroid substance of animals (almost exclusively that of the sheep), either in the crude form or in the form of pharmaceutical preparations. The thyroid substance may be administered in tablets, pills, or capsules containing it either in the fresh state or dried and reduced to a powder.
A glycerine extract of thyroid gland is also prepared and is known by the name of thyroidine.
Finally, Baumann and Proos have extracted from the sheep's thyroid a substance, iodothyrine, which seems to be the active principle. This substance is "triturated with sugar of milk in such proportions that 1 gram of the mixture represents 1 gram of the fresh gland." 1
Thyroid medication must be employed with great caution. Toxic symptoms are easily produced: acceleration of the pulse and respiration, headache, attacks of vertigo, and, in severe cases, a tendency to collapse. Therefore it is advisable to begin the treatment with small doses, which should be gradually increased, and promptly reduced or suspended entirely on the appearance of alarming symptoms.
The mental and physical effects of thyrotherapy are very rapid. In a few days the cerebral torpor becomes less marked, the skin reassumes its normal aspect, and the other myxoedematous symptoms become abated.