Page 921 - Small Animal Internal Medicine, 6th Edition

CHAPTER 50 Disorders of the Adrenal Gland 893

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A B

C

FIG 50.20
(A) An 11-year-old male castrated Doberman Pinscher mix presented for clinical signs
consistent with acute gastroenteritis. Abdominal ultrasound identified a 1.4-cm-diameter
adrenal mass (arrow) and a normal-size contralateral adrenal gland. The history, physical
examination findings, and results of routine blood and urine tests were not supportive of
adrenal disease, and the dog responded to symptomatic therapy for acute gastroenteritis.
The adrenal mass was periodically evaluated with ultrasound. Over the ensuing 2 years,
the dog remained healthy, and minimal growth or change was noted in the echogenicity
of the adrenal mass. (B) The adrenal mass 1 year after presentation; maximum diameter
was 1.8 cm. (C) The adrenal mass 2 years after presentation; maximum diameter was
2.0 cm.

or catecholamines. Aldosterone-secreting tumors causing in size and shape. An increased baseline plasma aldos-
primary hyperaldosternism (Conn’s syndrome) are more terone concentration is documented and used to establish
common in cats than dogs. Excessive secretion of aldos- the diagnosis.
terone causes sodium retention and potassium depletion Progesterone-secreting adrenal tumors are identified
which manifests as increased serum sodium (>155 mEq/L) most commonly in cats. Excessive progesterone secretion in
and decreased serum potassium (<3.0 mEq/L) concentra- affected cats causes diabetes mellitus and feline fragile skin
tions. Hypokalemia causes lethargy and weakness which syndrome (Fig. 50.21). Clinical features mimic feline hyperad-
are the most common clinical signs of primary hyperal- renocorticism. Results of tests of the pituitary adrenocortical
dosteronism. Hypernatremia causes systemic hypertension. axis are normal to suppressed in cats with a progesterone-
An adrenal mass should be identified on abdominal ultra- secreting adrenal tumor. Diagnosis requires documentation
sound, and the contralateral adrenal gland should be normal of an increased plasma progesterone concentration.