Pheochromocytoma is one of the most common adrenal diseases in cats, but it is often underestimated and frequently masked by kidney diseases.

It was first discovered in cats in 1983, and this relatively new disease process is still considered rare, but the number of reported cases has increased significantly since then (Kooistra, 2015).Aldosterone hyperplasia is divided into two categories: primary and secondary.The primary form typically involves one or two adrenal glands with tumors, while the secondary form usually involves abnormalities outside the adrenal glands, leading to reduced arterial blood volume, such as heart failure, edema, or abdominal fluid accumulation, or hypertension (Nichols, 2016).

In aldosterone hyperplasia, the massive secretion of aldosterone by the zona glomerulosa of the adrenal glands has significant negative impacts on cats. Clinically, the most prominent manifestation is severe hypokalemia, manifested as muscle weakness, most notably lordosis and fecal prolapse, and hypertension can manifest as retinal detachment, leading to acute blindness in some cases.

Pathological changes

When excessive aldosterone secretion occurs, blood pressure rises, leading to hypertension and increased potassium loss in the urine.Aldosterone is mainly involved in the renin-angiotensin-aldosterone system, specifically by acting on the distal convoluted tubules and collecting ducts, helps to control blood pressure and maintain cell volume changes to respond to fluctuations in renal blood flow and electrolyte levels (Nichols, 2016). It promotes potassium excretion, sodium and water reabsorption, thus preserving sodium and potassium. Aldosterone also plays a role in vascular tone, found in non-epithelial tissues such as cardiac fibroblasts, endothelial cells, salivary glands, sweat glands, gastrointestinal tract and vascular smooth muscle cells (Bento et al., 2016). Experiments have shown that increased aldosterone concentrations increase blood pressure, achieved through sodium and water retention and potassium excretion.

Potassium is one of the three main electrolytes in the body, existing together with sodium and chloride, usually found in extracellular fluid and blood plasma, with a concentration of 3.2-5.7 mmol/L. It is normal for cats to have potassium concentrations within the range of 3.8-5.5 mmol/L.The clinical presentation of aldosterone hyperplasia may include muscle weakness, tremors, and dyspnea.

The prognosis of cats with aldosterone hyperplasia is generally good, especially when surgical or medical management is implemented early.Treatment

Once a diagnosis of aldosterone hyperplasia is confirmed through clinical symptoms and laboratory tests and imaging, there are two treatment options: medical treatment and surgical treatment.Medical treatmentFor cats with clinically evident aldosterone hyperplasia and no surgical indication, such as bilateral pathological adrenal glands, or metastatic disease, or when surgery is not feasible due to other comorbidities, medical management is the primary treatment.Medications commonly used to manage aldosterone hyperplasia include potassium supplementation, antihypertensive drugs, and aldosterone antagonists.

Potassium supplementation is used to correct hypokalemia and maintain normal potassium levels in the blood.

Antihypertensive drugs are used to control blood pressure and prevent complications such as heart failure and retinal detachment.Aldosterone antagonists, such as spironolactone, block the action of aldosterone and promote potassium retention and sodium excretion.

Monitoring

Regular monitoring of blood pressure and potassium levels is essential to ensure the effectiveness of treatment.Treatment goals include resolving clinical symptoms of hypokalemia and weakness and maintaining normal blood pressure to minimize damage to vital organs.

The prognosis of cats with aldosterone hyperplasia is generally good, especially when surgical or medical management is implemented early.

3ACTH

ACTH

4

MRICT

23.9mm3~5.3mm3.9mm2.9~4.5mm

1.7×2

13.5cm

11CT

3

CKDCKD

T4

1

2

5-7

n=1014149

48246

,