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.

Clinical safety of percutaneous ultrasound-guided fine-needle aspiration of adrenal gland lesions in 19 dogs.

OBJECTIVE: To evaluate the safety of fine-needle aspiration of adrenal gland lesions in dogs and to characterise the risks in a subset of patients with cytologically or histopathologically diagnosed phaeochromocytoma. MATERIALS AND METHODS: Retrospective review of medical records of dogs that underwent percutaneous ultrasound-guided fine-needle aspiration of adrenal gland lesions between August 2014 and December 2016. Nineteen dogs were identified, with three undergoing bilateral adrenal gland aspiration and one dog undergoing aspiration twice, yielding 23 cytology samples in total. Data collected included signalment, concurrent medical conditions, current medications, blood pressure and heart rate before adrenal fine-needle aspiration, imaging characteristics of the adrenal gland lesions and any clinically apparent procedure-related complications. RESULTS: Phaeochromocytoma was diagnosed in nine of 19 dogs, including one dog with bilateral phaeochromocytoma. One dog developed ventricular tachycardia following aspiration of an adrenal gland lesion cytologically consistent with a phaeochromocytoma. CLINICAL SIGNIFICANCE: Percutaneous ultrasound-guided fine-needle aspiration of adrenal gland lesions appears to be relatively safe, even in phaeochromocytoma, but further data are required to lend more weight to this finding. Minimally invasive aspirates could be considered as part of the diagnostic algorithm in the investigation of an incidentally detected adrenal gland lesion of uncertain clinical significance.

Lymphocytic adrenal medullitis and lymphocytic thyroiditis in a laboratory beagle dog.

Lymphocytic adrenal medullitis characterized by inflammation and atrophy in the medulla of the bilateral adrenal glands was observed in an 18-month-old male laboratory beagle dog. It might be that the present lymphocytic adrenal medullitis is an autoimmune-mediated disease as the histological characteristics are consistent with an autoimmune pathogenesis. However, the actual cause remains unclear as the existence of serum autoantibodies against the adrenal medulla could not be confirmed. Although this dog also contracted lymphocytic thyroiditis along with serum thyroglobulin autoantibodies, indicating that the thyroiditis occurred with an autoimmune basis; the relation between the adrenal medullitis and thyroiditis is unknown.

Retained fetal adrenal cortex in a cynomolgus macaque (Macaca fascicularis).

An incidental, bilateral, retained fetal adrenal cortex was detected in a male cynomolgus macaque (age, approximately 2.4 y) used in a 4-week toxicology study. Microscopic examination of the adrenal gland cortex zone revealed the presence of additional solid sheets and columns of cells supported by vascular capillary bed and composed of large polyhedral cells with abundant eosinophilic, slightly finely vacuolated cytoplasm that surrounded the entire circumference of the medulla. Nuclei were vesicular, round to oval with prominent small nucleoli. There was no evidence for inflammation or cellular degeneration. Based on the microscopic examination, a diagnosis of retained fetal cortex of the adrenal gland was made. This morphologic change resembles fetal cortex in human infants. To our knowledge, this case description is the first report of a cynomolgus macaque with the rare entity of retained fetal cortex, which should not be misinterpreted as a test article-related change.

Morphological changes and parasite load of the adrenal from dogs with visceral leishmaniasis.

The objective of this study was to analyze morphological changes and parasite loads in the adrenal gland from 45 dogs with visceral leishmaniasis (VL). The animals were from the Zoonosis Control Center of Araçatuba, state of São Paulo, which is an endemic region for the disease. These animals were euthanized due to positive diagnoses of VL. The dogs were classified into asymptomatic, oligosymptomatic and symptomatic groups. The parasite load was determined by immunohistochemistry, using VL-positive dog hyperimmune serum. Nine dogs showed an inflammatory infiltrate composed, predominantly, of plasma cells and macrophages. However, only eight dogs showed macrophages with amastigote forms of the parasite, immunolabeled in the cytoplasm. The medullary and reticular layers were the most affected areas, possibly due to a favorable microenvironment created by hormones in these regions. The density of parasites in the glandular tissue was not associated with clinical signs of VL (P > 0.05). However, the presence of the parasite was always associated with the presence of a granulomatous inflammatory infiltrate. This gland may not be an ideal place for the parasite's multiplication, but the presence of injuries to the glandular tissue could influence the dog's immune system, thus favoring the parasite's survival in the host's different organs.

Morphological changes and parasite load of the adrenal from dogs with visceral leishmaniasis / Alterações morfológicas e carga parasitária da adrenal de cães com leishmaniose visceral

The objective of this study was to analyze morphological changes and parasite loads in the adrenal gland from 45 dogs with visceral leishmaniasis (VL). The animals were from the Zoonosis Control Center of Araçatuba, state of São Paulo, which is an endemic region for the disease. These animals were euthanized due to positive diagnoses of VL. The dogs were classified into asymptomatic, oligosymptomatic and symptomatic groups. The parasite load was determined by immunohistochemistry, using VL-positive dog hyperimmune serum. Nine dogs showed an inflammatory infiltrate composed, predominantly, of plasma cells and macrophages. However, only eight dogs showed macrophages with amastigote forms of the parasite, immunolabeled in the cytoplasm. The medullary and reticular layers were the most affected areas, possibly due to a favorable microenvironment created by hormones in these regions. The density of parasites in the glandular tissue was not associated with clinical signs of VL (P > 0.05). However, the presence of the parasite was always associated with the presence of a granulomatous inflammatory infiltrate. This gland may not be an ideal place for the parasite's multiplication, but the presence of injuries to the glandular tissue could influence the dog's immune system, thus favoring the parasite's survival in the host's different organs.

O objetivo deste estudo foi analisar as alterações morfológicas e a carga parasitária da glândula adrenal de 45 cães com leishmaniose visceral (LV). Os animais eram provenientes do Centro de Controle de Zoonoses (CCZ) de Araçatuba (SP), região endêmica para a doença. Esses animais são submetidos à eutanásia, devido ao diagnóstico positivo para LV. Os cães foram classificados nos grupos assintomático, oligossintomático e sintomático. A determinação da carga parasitária foi feita por imuno-histoquímica, com utilização de soro hiperimune de cão positivo para LV. Em nove cães, verificou-se um infiltrado inflamatório, composto predominantemente por plasmócitos e macrófagos. Entretanto, apenas oito cães apresentaram macrófagos com formas amastigotas do parasito imunomarcadas em seu citoplasma. As camadas medular e reticulada foram as mais afetadas, possivelmente por um microambiente favorável criado pelos hormônios nestas regiões. A densidade de parasitos no tecido glandular não foi relacionada com os sinais clínicos de LV (P > 0,05). No entanto, a presença do parasito sempre esteve associada à presença de infiltrado inflamatório granulomatoso. Possivelmente, essa glândula não é um sítio ideal para a multiplicação do protozoário, mas a presença de injúrias no tecido glandular poderia influenciar o sistema imune do cão, favorecendo a sobrevivência do parasito nos diferentes órgãos do hospedeiro.

Ultrasonographical examination of feline adrenal glands: intra- and inter-observer variability.

Interpretation of ultrasonographical measurements requires an understanding of the source and the magnitude of variation. A substantial part of the variation can be attributed to the observer, the equipment or the animal. The aim of this study was to evaluate which adrenal gland measurement is the least variable within and between observers. Three experienced ultrasonographers examined six cats at three different times on the same day, more than 1 h apart, according to a strict scanning protocol. Seven ultrasonographical measurements were performed on each adrenal gland (maximal length on sagittal images, maximal height at the cranial and caudal poles on sagittal and transverse images, and maximal width of the cranial and caudal poles on transverse images). Height measurements in both planes showed the lowest variability within and between observers compared with length and width measurements. Descriptive ultrasonographical features, such as echogenicity of the gland, presence of hyperechoic spots or layering assessment, demonstrated satisfactory-to-good intra- and inter-observer agreement, whereas the shape assessment showed very poor inter-observer agreement. The results of this study describe a reliable scanning protocol that can be the basis for future adrenal ultrasonographical examinations for cats suspected of adrenal disease (eg, hyperaldosteronism, hyperadrenocorticism, sex hormone-producing tumours).

Correlation of inflammation with adrenocortical atrophy in canine adrenalitis.

Hypoadrenocorticism or Addison's disease (AD) is a functional disorder in which insufficient mineralocorticoid and glucocorticoid hormones are produced by the adrenal cortex. Human AD is usually attributed to lymphoplasmacytic adrenalitis with autoimmune destruction of the adrenal cortex. Lymphoplasmacytic adrenalitis is also reported in some descriptions of canine AD; however, the histological aspects of adrenalitis or adrenocortical atrophy have not been well characterized because microscopical examination is not required for diagnosis of AD. In this study, sections of adrenal glands from 33 dogs with adrenalitis were compared with those of 37 dogs without adrenal lesions. The affected dogs were classified clinically as having AD (n = 3), being suspected of having AD (n = 17), not having AD (n = 11) or were unclassified (n = 2). The adrenal inflammation was lymphoplasmacytic in 17 dogs, lymphocytic in four, lymphohistiocytic in one, granulomatous in three and neutrophilic in eight cases. Adrenal glands from control dogs lacked leucocyte infiltration and had a cortical to medullary area ratio of 1.1-7.2. All three dogs with AD, 8/17 dogs with suspected AD and 1/11 dogs without AD had a cortical to medullary area ratio <1.1. Because the area ratio was correlated (r = 0.94) with a linear cortical to medullary thickness ratio, a thickness ratio <1.1 could also indicate severe adrenocortical atrophy. Severe adrenocortical atrophy was associated typically with lymphoplasmacytic infiltration and nearly complete loss of cortical cells; however, the zona glomerulosa was partially spared in three dogs with lymphoplasmacytic adrenalitis and severe cortical atrophy. In contrast, non-lymphoid inflammation was generally part of systemic disease, multifocal and was unaccompanied by severe adrenocortical atrophy.

Ultrasonographic appearance of adrenal glands in healthy and sick cats.

The first part of the study aimed to describe prospectively the ultrasonographic features of the adrenal glands in 94 healthy cats and 51 chronically sick cats. It confirmed the feasibility of ultrasonography of adrenal glands in healthy and chronically sick cats, which were not statistically different. The typical hypoechoic appearance of the gland surrounded by hyperechoic fat made it recognisable. A sagittal plane of the gland, not in line with the aorta, may be necessary to obtain the largest adrenal measurements. The reference intervals of adrenal measurements were inferred from the values obtained in the healthy and chronically sick cats (mean ± 0.96 SD): adrenal length was 8.9-12.5 mm; cranial height was 3.0-4.8 mm; caudal height was 3.0-4.5 mm. The second part of the study consisted of a retrospective analysis of the ultrasonographic examination of the adrenal glands in cats with adrenal diseases (six had hyperaldosteronism and four had pituitary-dependent hyperadrenocorticism) and a descriptive comparison with the reference features obtained in the control groups from the prospective study. Cats with hyperaldosteronism presented with unilateral severely enlarged adrenal glands. However, a normal contralateral gland did not preclude a contralateral infiltration in benign or malignant adrenal neoplasms. The ultrasonographic appearance of the adrenal glands could not differentiate benign and malignant lesions. The ultrasonographic appearance of pituitary-dependent hyperadrenocorticism was mainly a symmetrical adrenal enlargement; however, a substantial number of cases were within the reference intervals of adrenal size.

Diabetic ketoacidosis with concurrent pancreatitis, pancreatic ß islet cell tumor, and adrenal disease in an obese ferret (Mustela putorius furo).

A 5.5-y-old spayed female ferret (Mustela putorius furo) with a history of adrenal disease, respiratory disease, and chronic obesity was evaluated for progressive lethargy and ataxia, diminished appetite, and possible polyuria and polydipsia. Physical examination revealed obesity, lethargy, tachypnea, dyspnea, a pendulous abdomen, significant weakness and ataxia of the hindlimbs, prolonged skin tenting, and mild tail-tip alopecia. Clinicopathologic analysis revealed severe hyperglycemia, azotemia, an increased anion gap, glucosuria, ketonuria, proteinuria, and hematuria. Abdominal ultrasonography showed hyperechoic hepatomegaly, bilateral adrenomegaly, splenic nodules, mild peritoneal effusion, and thickened and mildly hypoechoic limbs of the pancreas with surrounding hyperechoic mesentery. Fine-needle aspirates of the liver were highly suggestive of hepatic lipidosis. In light of a diagnosis of concurrent diabetic ketoacidosis and pancreatitis, the ferret was treated with fluid therapy, regular and long-acting insulin administration, and pain medication. However, electrolyte derangements, metabolic acidosis, dyspnea, and the clinical appearance of the ferret progressively worsened despite treatment, and euthanasia was elected. Necropsy revealed severe hepatic lipidosis, severe suppurative pancreatitis and vacuolar degeneration of pancreatic islet cells, a pancreatic ß islet cell tumor, bilateral adrenal cortical adenomas, and myocardial fibrosis. To our knowledge, this case represents the first report of concurrent diabetes mellitus, pancreatitis, pancreatic ß islet cell tumor (insulinoma), and adrenal disease in a domestic ferret. The simultaneous existence of 3 endocrine diseases, pancreatitis, and their associated complications is a unique and clinically challenging situation.

Associations among systemic blood pressure, microalbuminuria and albuminuria in dogs affected with pituitary- and adrenal-dependent hyperadrenocorticism.

BACKGROUND: Hypertension and proteinuria are medical complications associated with the multisystemic effects of long-term hypercortisolism in dogs with hyperadrenocorticism (HAC). METHODS: This study investigated the relationships among adrenocorticotropic hormone (ACTH)-stimulation test results, systemic blood pressure, and microalbuminuria in clinically-healthy dogs (n = 100), in dogs affected with naturally occurring pituitary-dependent (PDH; n = 40), or adrenal-dependent hyperadrenocorticism (ADH; n = 30). RESULTS: Mean systemic blood pressure was similar between clinically healthy dogs and dogs with HAC (p = 0.803). However the incidence of hypertension was highest in dogs with ADH (p = 0.017), followed by dogs with PDH, with the lowest levels in clinically healthy dogs (p = 0.019). Presence of microalbuminuria and albuminuria in clinically healthy dogs and dogs affected with HAC was significantly different (p < 0.001); incidences of albuminuria followed the same pattern of hypertension; highest incidence in dogs with ADH, and lowest level in clinically healthy dogs; but microalbuminuria showed a different pattern: clinically healthy dogs had highest incidences and dogs with ADH had lowest incidence. The presence of albuminuria was not associated with blood pressure values, regardless of whether dogs were clinically healthy or affected with ADH or PDH (p = 0.306). CONCLUSIONS: Higher incidence of hypertension and albuminuria, not microalbuminuria was seen in dogs affected with HAC compared to clinically healthy dogs; incidence of hypertension and albuminuria was significantly higher in dogs affected with ADH compared to PDH. However, presence of albuminuria was not correlated with systemic blood pressure.

Comparison of the VIDAS and IMMULITE-2000 methods for cortisol measurement in canine serum.

BACKGROUND: Serum cortisol concentration is often measured in dogs for the diagnosis and monitoring of adrenal disease. An enzyme-linked fluorescent assay (VIDAS method) on the MiniVidas analyzer has been validated for the measurement of cortisol concentration in human serum and could have applications for canine samples. OBJECTIVE: The aim of this study was to compare canine cortisol results obtained using the VIDAS method with those obtained using the IMMULITE-2000 immunoassay, which has previously been validated for canine serum. METHODS: The concentration of cortisol in 40 canine serum samples was determined concurrently with the VIDAS and IMMULITE methods, the latter as the reference method. Pearson's correlation coefficient, linear, and Deming regression analyses and Bland-Altman analysis were used to compare the 2 methods. Acceptability of the new method was judged using a medical decision chart (MEDx chart). RESULTS: Cortisol concentrations obtained with the IMMULITE method ranged from 23.1 to 1380 nmol/L. Correlation (r=.977) and simple linear regression (slope=1.0722, confidence interval [CI] 0.996-1.148; intercept=-4.799, CI -42.838 to 33.240) revealed no proportional or constant error. Based on Deming regression and a Bland-Altman plot the 2 methods gave comparable results. The MEDx chart indicated that performance of the new method was good at decision limits of 40, 132, and 480 nmol/L. CONCLUSION: Results of the VIDAS method were comparable to those of the IMMULITE-2000 reference method such that the VIDAS may be used as an alternative assay to evaluate serum cortisol concentration in dogs for the diagnosis of adrenal disease.

Adrenal steroid metabolism in birds: anatomy, physiology, and clinical considerations.

The hypothalamo-pituitary-adrenal system in birds is anatomically and functionally different from that in mammals. The adrenal gland structure and corticosteroid hormone physiology of birds will be reviewed. The anatomy and physiology sections of this article will be important for better understanding the pathogenesis, diagnosis, and possible treatment of primary or secondary adrenal gland disease. Causes of hyper- and hypoadrenocorticism in birds also will be reviewed. The article will conclude with current indications and complications to the clinical use of glucocorticoids in birds.

Adrenal gland disease in ferrets.

Adrenal gland disease in ferrets is unique to this species, with clinical signs and pathophysiology different from those seen in the dog. Its prevalence is increasing; 70% of pet ferrets in the United States were affected in 2003. The exact causes of the adrenal gland changes that lead to the disease are not known. Early oophorohysterectomies and neutering, combined with the artificially prolonged photoperiod experienced by indoor pet ferrets, and a possible genetic component, may be contributing factors. Signs of adrenal gland disease include progressive hair loss, pruritus, lethargy, atrophy, and, in female ferrets, vulvar swelling. An understanding of the signs and physiologic changes is necessary for diagnosis and treatment. A review of anatomy, physiology, and current surgical and medical options is presented.

Adrenal diseases in ferrets in Japan.

Adrenal diseases are quite common in Japanese pet ferrets; however, there have been no reports concerning the epidemiology of ferret adrenal disease in Japan. The purpose of this study was to collect epidemiological data on ferret adrenal disease in Japan by sending a questionnaire to veterinarians throughout Japan. Among the 521 cases that met the criteria for this study, 307 were adrenocortical carcinoma (58.9%), 117 were adrenocortical adenoma (22.5%) and 87 were adrenocortical hyperplasia (16.7%), respectively. Sex, clinical signs, concurrent diseases, age and the sites of the affected adrenal gland in these cases were similar to those reported in North America. Most pet ferrets in Japan are imported from North America, and their husbandry in Japan is similar to that in North America, which may be the cause of the similarity in ferret adrenal disease between North America and Japan. Because a difference in the incidence of ferret adrenal diseases among countries has been reported, further research is necessary to investigate the factors related to the similarities and how to decrease the incidence of adrenal diseases in ferrets in Japan.

Outcomes of adoption of adult laboratory ferrets after gonadectomy during a veterinary student teaching exercise.

We surveyed 27 people who had adopted a total of 43 adult domestic ferrets after their use in a series of veterinary student surgery teaching laboratories to assess the success of those adoptions and to determine the rate of occurrence of common maladies of domestic ferrets after adult gonadectomy as compared with the usual practice of early-age gonadectomy. The adoptions took place 1-7 y prior to the survey. The response rate was 48% of adopters, covering 53% of the ferrets. Overall the success of former breeding and instructional ferrets as pets were rated as 91% good or excellent and 4.5% poor. Behavioral issues (for example, nipping, failure to litter train) were noted as the most common problems (36% of ferrets). Adrenal gland disease, insulinoma, or lymphosarcoma occurred in 23% of all ferrets and accounted for 57% of those ferrets that had died prior to the time of the survey.

Feline adrenal disorders.

Although only recently discovered, feline adrenal disorders are becoming increasingly more recognized. Feline adrenal disorders include diseases such as hyperadrenocorticism (Cushing's syndrome) and hyperaldosteronism (Conn's syndrome). The clinical signs of feline hyperadrenocorticism, which include unregulated diabetes mellitus and severe skin atrophy, are unique to the cat. Other signs of feline hyperadrenocorticism, such as potbellied appearance, polydipsia, polyuria, and susceptibility to infections are also seen in dogs with hyperadrenocorticism. Conn's syndrome has only recently been described in the cat and is in fact more common in cats than in dogs. Characterized by severe hypokalemia, hypertension, and muscle weakness, Conn's syndrome may be misdiagnosed as renal failure. The clinician should become familiar with the clinical signs of adrenal disorders in cats and the common diagnostic tests used to diagnose these syndromes in cats as they differ from those in the dog. Treatment of feline adrenal disorders may be challenging; the clinician should become familiar with common drugs used to treat adrenal disorders in cats.

Computed tomographic quantification of canine adrenal gland volume and attenuation.

We conducted a retrospective study in presumed normal dogs to determine the adrenal gland attenuation and volume values. Multidetector computer tomography (MDCT 16) analysis of the gland was carried out in 48 adult dogs without evidence of adrenal gland disease that underwent CT examination for acute spinal injuries. The mean nonenhanced attenuation value +/- SD of the left adrenal gland was 36.0 +/- 5.3 HU (range: 22.0-42.0 HU). The mean nonenhanced attenuation value +/- SD of the right gland was 34.3 +/- 7.0 HU (range: 20.4-48.6HU). The mean enhanced attenuation value +/- SD were: left gland 101.5 +/- 10.6HU (range: 86.8-128.0 HU), and right gland 97.4 +/- 12.4 HU (range: 58.9-123.6 HU). The mean CT volume +/- SD were: left gland was 0.60 cm3 (range: 0.20-0.95; SD 0.17), and right gland (0.55cm3, range: 0.22-1.01; SD 0.19). Attenuation values and volume data were related to age, weight, and gender, using ANOVA. There was no statistically significant difference between the left and right side or in adrenal measurements, because of body weight class effects. The animal effect was the most important source of variation for all adrenal measurements. Based on our study, CT is an effective method for assessing adrenal characteristics in the dog. Normative CT data are provided to allow estimation of normal adrenal gland size and volume.