Page 888 - Small Animal Internal Medicine, 6th Edition

860 PART VI Endocrine Disorders

TABLE 50.1 event of severe compression of the hypothalamus, abnor-
malities related to dysfunction of the autonomic nervous
VetBooks.ir Clinical Signs and Physical Examination Findings in system, including adipsia, loss of temperature regulation,
erratic heart rate, and inability to be roused from a sleep-
Dogs With Hyperadrenocorticism
PHYSICAL EXAMINATION like state, may develop. Identification of a pituitary mac-
rotumor requires computed tomography (CT) or magnetic
CLINICAL SIGNS FINDINGS resonance imaging (MRI; Fig. 50.4). No biochemical or
endocrine test results reliably correlate with the size of the
Polyuria, polydipsia* Endocrine alopecia*
Polyphagia* Epidermal atrophy (thin pituitary tumor.
Panting* skin)*
Abdominal distention* Failure of hair regrowth* MEDICAL COMPLICATIONS:
Endocrine alopecia* Abdominal distention* THROMBOEMBOLISM
Weakness* Hepatomegaly* Several medical complications can develop secondary to
Lethargy Muscle wasting* prolonged cortisol excess (Box 50.1). The most worrisome is
Calcinosis cutis Cutaneous
Cutaneous hyperpigmentation
hyperpigmentation Comedones
Urine dribbling Calcinosis cutis BOX 50.1
Persistent anestrus Bruising
(female) Testicular atrophy Medical Complications Associated With
Decreased libido (male) Neurologic signs (PMA) Hyperadrenocorticism in Dogs
Neurologic signs (PMA) Facial nerve paralysis
Stupor Respiratory distress— Systemic hypertension
Ataxia tachypnea (PTE) Pyelonephritis
Circling Myotonia Cystic calculi (calcium phosphate, oxalate)
Aimless wandering Lameness (ligament laxity, Glomerulonephropathy, proteinuria
Pacing torn) Congestive heart failure
Behavioral alterations Pancreatitis
Respiratory distress— Insulin resistant diabetes mellitus
tachypnea (PTE) Steroid hepatopathy
Lameness (ligament Pulmonary thromboembolism
problems) Persistent anestrus
Stiff gait (myotonia) Pituitary macrotumor syndrome
Degenerative myopathy
PMA, Pituitary macroadenoma; PTE, pulmonary thromboemboli. Pseudomyotonia
*Common findings.

A B

FIG 50.4
(A) Postgadolinium administration magnetic resonance imaging (MRI) scan of a 9-year-old
male castrated German Shepherd dog with pituitary-dependent hyperadrenocorticism
(PDH) and a pituitary mass (arrow). No neurologic signs were present at the time the MRI
scan was performed. (B) Postgadolinium administration MRI scan of an 8-year-old Boston
Terrier with PDH, a large pituitary mass invading the brainstem, and signs of
disorientation, ataxia, and circling. (From Feldman EC, Nelson RW: Canine and feline
endocrinology and reproduction, ed 3, St Louis, 2004, WB Saunders.)