Definitive diagnosis and treatment
An abdominal ultrasonographic examination revealed an enlarged right adrenal gland measuring 1.23 x 1.48 cm. The left adrenal
gland was visualized and measured 3.2 mm (normal width) in a dorsoventral plane. The kidney size and architecture appeared
normal, with no evidence of renal pelvic or ureteral dilatation. The liver, spleen, gastrointestinal tract, and urinary bladder
appeared normal ultrasonographically. No enlarged mesenteric lymph nodes were seen, and the remainder of the study findings
Spironolactone (1.5 mg/kg orally every 12 hours) was added to the treatment plan. The dose of potassium gluconate was increased
to 4 mEq given orally every eight hours because the potassium concentration was rechecked and remained below the reference
range. Serial recheck electrolyte profiles revealed progressively increasing potassium concentrations. The cat's generalized
weakness improved along with resolution of the cervical ventroflexion. The resting plasma aldosterone concentration (PAC)
was > 3,864 pmol/L (reference range = 194 to 388 pmol/L). This value, along with the ultrasonographic findings and interpretation
of minimum database diagnostics excluding other differentials for hypokalemia and hypertension, confirmed a diagnosis of hyperaldosteronism.
Surgical excision of the adrenal mass was recommended to the owners, but it was declined because of financial considerations.
Medical management was implemented. The cat was discharged with amlodipine (0.625 mg orally every 24 hours), spironolactone
(6.25 mg orally every 12 hours), amoxicillin trihydrate-clavulanate potassium (62.5 mg total orally every 12 hours for seven
days) and potassium gluconate (6 mEq orally every 12 hours).
An initial recheck evaluation 10 days after discharge revealed a potassium concentration of 4.13 mEq/L and a systolic blood
pressure of 130 mm Hg. The cat's owner reported improvement in the cat's weakness and lethargy, as well as return of usual
jumping behaviors and normal gait and stance. A urine culture sample collected by cystocentesis was repeated after the antibiotics
were discontinued, and the results were negative for growth.
Subsequent evaluations were performed every two months, and the cat remained normotensive with normal potassium concentrations.
At the time of this manuscript, 19 months after diagnosis, the cat is reported to be doing well.