Treatment of aldosterone-secreting adrenocortical tumors in cats by unilateral adrenalectomy: 10 cases (2002-2012)

Surgical findings and outcomes after unilateral adrenalectomy for primary hyperaldosteronism in cats: a multi-institutional retrospective study

CASE SERIES SUMMARY

Twenty-nine cats from different institutions with confirmed or highly suspected primary hyperaldosteronism treated by unilateral adrenalectomy were retrospectively included in this study. The most frequent clinical signs were lethargy (n = 20; 69%) and neck ventroflexion (n = 17; 59%). Hypokalaemia was present in all cats, creatinine kinase was elevated in 15 and hyperaldosteronism was documented in 24. Hypertension was frequently encountered (n = 24; 89%). Preoperative treatment included potassium supplementation (n = 19; 66%), spironolactone (n = 16; 55%) and amlodipine (n = 11; 38%). There were 13 adrenal masses on the right side, 15 on the left and, in one cat, no side was reported. The median adrenal mass size was 2 × 1.5 cm (range 1-4.6 × 0.4-3.8); vascular invasion was present in five cats, involving the caudal vena cava in four cats and the renal vein in one. Median duration of surgery was 57 mins. One major intraoperative complication (3%) was reported and consisted of haemorrhage during the removal of a neoplastic thrombus from the caudal vena cava. In 4/29 cats (14%), minor postoperative complications occurred and were treated medically. One fatal complication (3%) was observed, likely due to disseminated intravascular coagulation. The median duration of hospitalisation was 4 days; 97% of cats survived to discharge. The potassium level normalised in 24 cats within 3 months of surgery; hypertension resolved in 21/23 cats. Follow-up was available for 25 cats with a median survival of 1082 days. Death in the long-term follow-up was mainly related to worsening of comorbidities.

RELEVANCE AND NOVEL INFORMATION

Adrenalectomy appears to be a safe and effective treatment with a high rate of survival and a low rate of major complications. Long-term medical treatment was not required.

Ultrasonographic Detected Adrenomegaly in Clinically Ill Cats: A Retrospective Study

This retrospective study aimed to assess the prevalence of ultrasonographic detected adrenomegaly in clinically ill cats, evaluating the final established diagnosis, describe adrenal ultrasound findings and if the adrenomegaly was suspected or incidental. Abdominal ultrasonography reports of cats presenting to a veterinary teaching hospital between October 2018 and February 2021 were retrospectively reviewed. Cats showing adrenomegaly (one or both glands having a dorsoventral axis >4.8 mm) were selected and medical records respectively evaluated. Nine-hundred and eighty-three ultrasonographical reports were selected, of which, 68 (7%) disclosed adrenomegaly. European/Domestic Short-Hair (62/68; 91%) male (44/68; 65%) castrated (35/44; 80%) cats were overrepresented. Adrenomegaly was an incidental finding in 62/68 (91%) cats while in 6/68 (9%) it was identified in the context of investigating a potential adrenal disease. Concerning established diagnosis, chronic kidney disease was overrepresented (25/68; 37%), followed by endocrinopathies (20/68; 29%). Adrenomegaly was bilateral in 53% (36/68) of cases. In unilateral cases (32/68; 47%), it was more prevalent on the left side (23/32; 72%), with a normal-sized contralateral adrenal gland. Left adrenal demonstrated a larger size and a tendency to oval shape. This study assesses the prevalence of adrenomegaly in clinically ill cats, reinforcing it can be an incidental ultrasound finding.

Retrospective study of aldosterone and progesterone secreting adrenal tumors in 10 cats

Background

Primary hyperaldosteronism caused by adrenal neoplasia has been well described in cats. Multiple corticosteroid abnormalities occur in a subset of affected cats, but characterizations of this syndrome are limited to several case reports.

Objectives

To describe a series of cats with adrenal tumors secreting aldosterone and additional corticosteroids.

Animals

Ten cats with multiple corticosteroid secreting adrenocortical tumors.

Methods

Retrospective case series. Medical records of cats with adrenal tumors secreting both aldosterone and progesterone were identified. Data concerning historical findings, clinicopathologic features, treatments, and outcomes were retrieved from medical records.

Results

All 10 cats had diabetes mellitus in addition to biochemical features of hyperaldosteronism such as hypokalemia. High corticosterone concentrations were observed in all 3 cats in which this corticosteroid was measured. Ultrasound examinations revealed unilateral adrenal tumors in all 10 cases, and the contralateral adrenal gland was either atrophied or not identified in 5 cats. Three of 4 cats developed hypoadrenocorticism after surgical adrenalectomy. Three cats achieved diabetic remission after adrenalectomy. Two cats treated with adrenalectomy survived >1 year, 1 cat survived 6.5 months, and 1 cat was alive 5.5 months after diagnosis. Survival >1 year occurred in 2 of 4 cats treated with medical management alone. Two cats were not treated.

Conclusions and Clinical Importance

The presence of multiple corticosteroid abnormalities should be considered in cats with aldosterone secreting adrenal tumors, especially those with concurrent diabetes mellitus. Both surgical and medical management can result in long‐term survival, although diabetic remission was documented only in cats undergoing adrenalectomy.

Multiple corticosteroid abnormalities in cats with hyperaldosteronism

Background

The frequency with which multiple corticosteroid abnormalities occur in cats with aldosterone secreting adrenocortical tumors is unknown.

Objectives

To evaluate adrenal‐derived corticosteroids in cats in which blood samples were submitted for measure of aldosterone.

Animals

Two hundred ninety‐seven cats.

Methods

Retrospective study. Analysis of a convenience sample of previously submitted serum or plasma. Progesterone, corticosterone, and cortisol were measured in feline serum or plasma samples submitted to an endocrinology laboratory for aldosterone measurements. Demographics and clinical history were retrieved from submittal forms when provided. Statistical testing was performed to investigate associations among the adrenal corticosteroids.

Results

Progesterone and corticosterone concentrations were strongly correlated (ρ = 0.74; P < .001). Progesterone (median, 5 nmol/L; interquartile range, 3‐10 nmol/L) and corticosterone (113 nmol/L, 38‐250 nmol/L) in cats with markedly increased aldosterone concentrations (≥3000 pmol/L) were higher than progesterone (1 nmol/L, 1‐2 nmol/L) and corticosterone (12 nmol/L, 3‐25 nmol/L) in cats with normal aldosterone concentrations (P < .001 for both comparisons). Progesterone concentrations ≥10 nmol/L (normal, ≤2 nmol//L) occurred in 24 of 76 (32%) cats with aldosterone concentrations ≥3000 pmol/L. Cortisol was lower in cats with aldosterone concentrations ≥3000 pmol/L as compared to those with aldosterone concentrations <500 pmol/L (59 nmol/L, 27‐103 nmol/L vs 103 nmol/L, 49‐182 nmol/L; P = .002).

Conclusions and Clinical Importance

Multiple corticosteroid abnormalities occur in a subset of cats with hyperaldosteronism. The magnitude of increases in progesterone and corticosterone in some cats with hyperaldosteronism is likely to be clinically relevant.

A case of behavioral changes in a castrated male cat due to a functional adrenocortical adenoma producing testosterone and androstenedione

Case summary

This case report describes a 9-year-old neutered male cat with a functional adrenal tumor showing aggression toward other cats in the household, excessive meowing and urine spraying. The diagnosis was made based on the clinical signs, an enlarged right adrenal gland on ultrasound, penile spines and elevated sex hormones on an adrenocorticotropic hormone stimulation test. The cat was submitted to celiotomy and adrenalectomy. Histopathological examination confirmed the adrenocortical adenoma. Three months after surgery the penile spines disappeared and urine spraying, as well as excessive meowing, had greatly decreased; however, aggressive behavior took much longer to stop and required behavior therapy.

Relevance and novel information

Functional adrenal tumors producing only sex hormones and behavioral changes are uncommon. The cat reported herein started showing behavioral changes before spines appeared on the penis, and structural alterations in the adrenal gland at the abdominal ultrasonography were detected. Considering all the possible implications resulting from severe behavior problems such as cat-cat aggression, from a permanent separation of the cats to relinquishment, a detailed investigation of underlying medical mechanisms in these animals is crucial from the start. Examinations may need to be repeated later in the course.

Feline comorbidities: Recognition, diagnosis and management of the cushingoid diabetic

PRACTICAL RELEVANCE

Diabetes mellitus (DM) is a common feline endocrinopathy, and is often driven by underlying insulin resistance with associated pancreatic beta (β)-cell dysfunction. Although spontaneous hyperadrenocorticism (HAC) with hypercortisolemia (hypercortisolism) is relatively uncommon in cats, it is a well-established cause of insulin resistance and is routinely associated with DM in this species.

CLINICAL CHALLENGES

Many of the clinical signs associated with feline HAC are subtle and may be attributed to concurrent DM or the aging process. Failure to recognize HAC in the diabetic cat can impact patient wellbeing and predispose the patient to progressive compromise. Unfortunately, it can be difficult to establish a diagnosis of HAC, as test results may be influenced by poor diabetic regulation, and protocols are different to those used in canine patients. Treatment options depend on the underlying cause, and often require careful, ongoing assessment and modulation of both adrenal function and insulin requirements. However, various approaches have been shown to either improve glycemic control in cats with sustained insulin dependence, or facilitate diabetic remission.

EVIDENCE BASE

This review summarizes the current literature on feline HAC, with a particular focus on cats with concurrent DM. The clinical findings that suggest HAC are discussed, along with an outline of diagnostic options and their limitations. Published outcomes for various medical options, surgical procedures and radiation therapy are provided. The authors also share their thoughts on the safe and effective management of cats with HAC and DM, with an emphasis on the anticipation and recognition of changing insulin requirements.

Feline abdominal ultrasonography: what's normal? what's abnormal? The adrenal glands

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the adrenal glands can provide important information pertaining to several conditions including hyperaldosteronism and hyperadrenocorticism.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings, such as adrenal mineralisation, and clinically significant pathological changes can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the ultrasonographic examination of the normal and diseased adrenal glands. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although the use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Acute adrenal haemorrhage in two cats with aldosterone-secreting adenocarcinomas

Case summary

Two 13-year-old domestic shorthair cats were diagnosed with unilateral right adrenocortical carcinomas (ACCs) and primary hyperaldosteronism (PHA). Both had polyuria, polydipsia and weight loss, and developed severe anaemia from an episode of acute adrenal haemorrhage. In one case, this occurred during hospitalisation and treatment of severe muscle weakness with cervical ventroflexion, while the other cat had acute collapse at home. A diagnosis of PHA was confirmed in both cases based on measurement of plasma aldosterone and renin activity. In one case, basal progesterone was also measured and was elevated. On ultrasonography and CT in one case, haemorrhage into the right retroperitoneal space was identified. Unilateral adrenalectomy was performed in both cases and there was no evidence of venous tumoral invasion in either. On histopathology of the excised adrenal glands both were ACCs with tumour necrosis, and one had extensive intratumoral haemorrhage. Both cats were diagnosed with International Renal Interest Society stage 2 or 3 chronic kidney disease postoperatively; one survived for 18 months and the other was well 8 months postoperatively.

Relevance and novel information

Acute adrenal haemorrhage secondary to adrenal neoplasia has been reported in only one other cat, in which tumour type and function were not specified. Acute adrenal haemorrhage can occur as a consequence of tumour necrosis and rupture and can cause severe hypovolaemia and anaemia in cats with primary hyperaldosteronism.

Hypertensive ocular disease in cats: A guide to fundic lesions to facilitate early diagnosis

PRACTICAL RELEVANCE

Systemic hypertension is common in older cats and can result in damage to organs with a rich arteriolar supply such as the eyes, kidneys, myocardium and brain. Hypertensive disease in these organs is known as target organ damage (TOD). Disease in the eye resulting from hypertension is the most easily identifiable form of TOD and can often be the reason the cat is presented to the veterinarian. Routine blood pressure measurement and fundic examination allows cats with hypertensive ocular lesions to be detected early in the course of the disease, when the lesions have the best chance of responding to treatment.

CLINICAL CHALLENGES

Detecting early evidence of TOD in the fundus requires a veterinarian to be competent in recognising lesions associated with mild hypertensive disease, as well as the more easily recognised advanced lesions that frequently result in impaired vision and blindness.

AUDIENCE

This review is written for all veterinarians who treat cats. It provides information and images to facilitate and guide veterinarians performing fundoscopy in cats, in particular in those over 7 years of age, with the aim of diagnosing hypertensive ocular lesions when they are present.

EQUIPMENT

The clinical manifestations of hypertensive ocular disease can be detected non-invasively with inexpensive equipment. A summary of the equipment available for general practitioners to perform fundoscopy is provided.

EVIDENCE BASE

This is a comprehensive review of the literature on hypertensive ocular disease in cats. The author has also included images of hypertensive ocular lesions taken in general practice to highlight the variety of lesions that can be detected.

Peculiarities of feline hyperadrenocorticism: Update on diagnosis and treatment

Practical relevance: Hyperadrenocorticism (HAC) is a relatively uncommon endocrinopathy of older cats, with a mean age at diagnosis of 10 years. In addition to pituitary-dependent and adrenal-dependent hypercortisolism, clinical signs of HAC can result from adrenal sex steroid-producing tumours. Clinical challenges: While HAC in cats has many similarities to canine HAC, there are key differences in presentation, diagnosis and response to therapy. Most, but not all, cats with HAC have concurrent diabetes mellitus, which is often insulin resistant. Up to a third of cats with HAC have extreme skin fragility and are at high risk of debilitating iatrogenic skin tears during diagnostic or therapeutic interventions. Infections of the skin and nail beds, and urinary, respiratory and gastrointestinal tract, secondary to cortisol-induced immune suppression, are also common. Cats respond differently to dogs to adrenal function tests including adrenocorticotropic hormone (ACTH) stimulation and dexamethasone suppression tests; a 10-fold higher dose of dexamethasone is recommended in cats to screen for HAC. Curative treatment options include adrenalectomy or transsphenoidal hypophysectomy. Radiation or medical treatment may improve clinical signs. The response to mitotane therapy is poor. While trilostane is the medical treatment of choice based on retrospective studies, investigations into the pharmacokinetics of this drug in cats are lacking. Global importance: Feline HAC occurs worldwide and is not associated with any purebreed predisposition. Although uncommon, adrenal sex steroid-producing tumours have a higher prevalence in cats than in dogs. Evidence base: The information in this review is drawn from over 180 reported cases of feline HAC. Reports investigating clinical presentation, clinicopathological findings and treatment outcomes are observational, retrospective multiple case series (EBM grade III) or single case reports (EBM grade IV). While most endocrine testing studies for diagnosis are cohort controlled analytical studies (EBM grade III), prospective, randomised, placebo-controlled studies have been performed (EBM grade I).

Clinical findings, diagnostics and outcome in 33 cats with adrenal neoplasia (2002-2013)

OBJECTIVES

The objective of this retrospective study was to describe the clinical signs and diagnostic findings in cats with histopathologically confirmed adrenal neoplasms, and to assess correlations with survival data.

METHODS

Study data were acquired by reviewing medical records for all cats diagnosed with adrenal neoplasms at seven referral institutions between 2002 and 2013. Inclusion criteria required a histopathologic diagnosis of an adrenal neoplasm (ante-mortem or on necropsy).

RESULTS

Thirty-three cats met the inclusion criteria for the study. The most common presenting complaints included weakness (n = 12), respiratory signs (n = 4), blindness (n = 4) or gastrointestinal signs (n = 3). Laboratory abnormalities included hypokalemia (n = 18), alkalemia (n = 12), elevated creatine kinase (>3000, n = 5) and azotemia (n = 4). In addition, hypertension was noted in 13 cats. Thirty cats were diagnosed with cortical tumors (17 carcinomas, 13 adenomas) and three cats were diagnosed with pheochromocytomas. Twenty-five cats underwent tests to evaluate the function of the adrenal tumors; 19/25 cats had functional tumors (hyperaldosteronism [n = 16], hypercortisolemia [n = 1], high estradiol [n = 1], and hypersecretion of aldosterone, estradiol and progesterone [n = 1]). Twenty-six cats underwent adrenalectomy, one cat was medically managed and six were euthanized without treatment. Long-term survival postoperatively ranged from 4-540 weeks, with 20 (77%) cats surviving the perioperative period of 2 weeks. The only variable that was found to be negatively associated with survival was female sex. The most common complications noted during the perioperative period were hemorrhage and progressive lethargy and anorexia.

CONCLUSIONS AND RELEVANCE

Surgical treatment for feline adrenal tumors (regardless of tumor type) resulted in good long-term survival. Given that pre- and postoperative hypocortisolemia was identified in this study, and, in addition, hypersecretion of more than one adrenal hormone occurred in one cat, adrenal panels prior to surgery may be beneficial as part of the preoperative work-up.

Adrenocortical tumor in a cat secreting more than one type of corticosteroid

CASE SUMMARY

A 14-year-old, spayed female domestic shorthair cat was evaluated because of a right adrenal mass. The referring veterinarian had started treatment for hypokalemia and systemic arterial hypertension. During the initial evaluation the cat was alert and responsive, and serum potassium concentration was within the reference range. Serum concentrations of aldosterone and progesterone were increased. Atrophy of the contralateral adrenal and an exaggerated response of cortisol to stimulation with adrenocorticotropic hormone suggested hypersecretion of cortisol. Unilateral adrenalectomy was performed and recovery was uneventful. Histologic examination of the mass revealed an adrenocortical tumor. After surgery, clinical signs of hypercortisolism, hyperaldosteronism and hyperprogesteronism were no longer observed, and neither potassium supplementation nor antihypertensive treatment were needed.

RELEVANCE AND NOVEL INFORMATION

In cases with an adrenocortical tumor, clinicians should investigate whether the tumor hypersecretes glucocorticoids, mineralocorticoids, sex steroids or combinations of these. Hypersecretion of more than one adrenal hormone may occur in a cat with an adrenocortical tumor.