Page 797 - Small Animal Internal Medicine, 6th Edition

CHAPTER 48 Disorders of the Thyroid Gland 769

TABLE 48.1
VetBooks.ir Dog Breeds Reported to Have an Increased Prevalence of
Thyroid Hormone Autoantibodies
BREED ODDS RATIO*

Pointer 3.61
English Setter 3.44
English Pointer 3.31
Skye Terrier 3.04
German Wirehaired Pointer 2.72
A Old English Sheepdog 2.65

Boxer 2.37
Maltese 2.25
Kuvasz 2.18
Petit Basset Griffon Vendéen 2.16
American Staffordshire Terrier 1.84
Beagle 1.79
American Pit Bull Terrier 1.78
Dalmatian 1.74
Giant Schnauzer 1.72
Rhodesian Ridgeback 1.72
B Golden Retriever 1.70
Shetland Sheepdog 1.69
Chesapeake Bay Retriever 1.56
Siberian Husky 1.45
Brittany Spaniel 1.42
Borzoi 1.39
Australian Shepherd 1.28
Doberman Pinscher 1.24
Malamute 1.22
Cocker Spaniel 1.17
Mixed 1.05
C *Odds of serum thyroid hormone autoantibodies (THAA) among
breeds with an increased risk of having THAA, compared with
FIG 48.2 dogs of all other breeds.
Histologic section of a thyroid gland from a healthy dog From Nachreiner RF et al: Prevalence of serum thyroid hormone
(A), from a dog with lymphocytic thyroiditis and autoantibodies in dogs with clinical signs of hypothyroidism, J Am
hypothyroidism (B), and from a dog with idiopathic atrophy Vet Med Assoc 220:466, 2002.
of the thyroid gland and hypothyroidism (C). Note the
mononuclear cell infiltration, disruption of the normal
architecture, and loss of colloid-containing follicles in (B) Seborrhea and pyoderma may be focal, multifocal, or gener-
and the small size of the gland, decrease in follicular size alized. Because both frequently result in pruritus, hypothy-
and colloid content, and lack of cellular infiltration in (C), roid dogs with secondary pyoderma or seborrhea initially
compared with (A). (A and B, Hematoxylin and eosin
stain; ×250; C, Hematoxylin and eosin stain; ×40.) (From may be brought to the veterinarian because of a pruritic skin
Feldman EC, Nelson RW: Canine and feline endocrinology disorder.
and reproduction, ed 4, St Louis, 2015, WB Saunders.) The haircoat in dogs with hypothyroidism is often dull,
dry, and easily epilated. Hair regrowth is slow. Hyperkerato-
sis leads to the development of scales and dandruff. Variable
degrees of hyperpigmentation may be noted. Chronic otitis
externa has been noted in some dogs with hypothyroid-
ism. In severe cases of hypothyroidism, acidic and neutral