344 DISEASES OF THE THYROID GLANDS 



Symptoms. —Both the acute and chronic forms have been 

 observed. In the acute form the disease develops very 

 rapidly. The following symptoms are most prominent: 



(a) Exophthalmos. — A prominence of the eyes which may 

 be unilateral or bilateral. . This symptom is readily recog- 

 nized by the protrusion of the eyeballs, and the prominence 

 of the sclera of the eye. The lids do not cover the eye 

 completely. It is important to note that in some breeds of 

 dogs the eyes are very prominent and this should not be 

 mistaken for exophthalmos. The normal sight is retained 

 in most cases. In severe rases it is possible to have a pan- 

 ophthalmitis which would destroy the sight temporarily or 

 permanently. Ulceration of the cornea is common. 



(b) Enlargement of the Thyroid Glands. — Some enlarge- 

 ment of the glands is present in practically all cases. The 

 common expression "inward goiter" has been given to this 

 condition when the glands are not much enlarged and the 

 other symptoms are prominent. The enlargement may be 

 general or only one lobe affected. 



(c) Tachycardia. — The heart action is rapid and the pulse- 

 rate is usually so much increased that it cannot be counted 

 accurately. The action of the heart at first is regular, but 

 during the later stages of the disease becomes very irregular. 

 The throbbing of the heart is often so intense as to shake the 

 animal's body. Acute dilatation of the heart with dyspnea, 

 cough, etc., is a prominent symptom in the later stages. 



Distention of the arteries and pulsation of the entire gland 

 is easily seen from a distance. On palpation a distinct 

 throbbing can be felt. The gland may be more or less firm, 

 or soft and flabby, depending on the degree of involvement. 



(d) Tremors. —Tremors or trembling of the muscles is 

 often observed. General symptoms of restlessness, whining 

 and crying, and spasms are present in some cases. Emacia- 

 tion comes on rapidly, and general exhaustion is very 

 common. 



The chronic form is characterized by similar symptoms 

 but milder in character and lasting for several weeks or 

 months. 



