ULTRASONOGRAPHY OF ADRENAL GLANDS IN NORMAL FERRETS

Point of Care Ultrasound in Exotic Animal Emergency and Critical Care

Exotic pets are presented to veterinary clinics with increasing frequency for routine, urgent, and emergency needs. With these increased visits, owners' expectations for high-quality veterinary care are also increasing. Many presenting complaints of reptiles, birds, and small mammals can benefit from the use of point of care ultrasound (POCUS) to establish a minimum database, aid in triage, and help guide further diagnostics, treatment, and prognostic discussions with the owner. Hospitalized exotic patients can also have their progress tracked and better assessed with the aid of POCUS.

Evidence-Based Advances in Ferret Medicine

This literature review covers approximately 35 years of veterinary medicine. This article develops the current state of knowledge in pet ferret medicine regarding the most common diseases according to evidence-based data and gives insight into further axis of research. Literature review was conducted through identification of keywords (title + ferret) with Web-based database searching. To appreciate the methodological quality and the level of evidence of each article included in the review, full-text versions were reviewed and questions addressed in the articles were formulated. Analysis of the articles' content was performed by the authors, and relevant clinical information was extracted.

Radiographic and ultrasonographic findings of the spleen and abdominal lymph nodes in healthy domestic ferrets

Objective

To describe the radiographic and ultrasonographic characteristics of the spleen and abdominal lymph nodes in clinically healthy ferrets.

Materials and Methods

Fifty‐five clinically healthy ferrets were prospectively recruited for this cross‐sectional study. Three‐view whole body radiographs and abdominal ultrasonography were performed on awake (23 out of 55) or sedated (32 out of 55) ferrets. On radiographs splenic and abdominal lymph node visibility was assessed. Splenic thickness and echogenicity and lymph node length, thickness, echogenicity, number and presence of cyst‐like changes were recorded.

Results

The spleen was radiographically detectable in all ferrets. On ultrasound the spleen was hyperechoic to the liver (55 out of 55) and mildly hyperechoic (28 out of 55), isoechoic (15 out of 55) or mildly hypoechoic (12 out of 55) to the renal cortices. Mean splenic thickness was 11.80 ±0.34 mm. Lymph nodes were radiographically discernible in 28 out of 55 ferrets and included caudal mesenteric and sublumbar nodes. An average of 9 ±2 lymph nodes (mean± standard deviation; mode 10) were identified in each ferret using ultrasound. A single large jejunal lymph node was identified in all ferrets and had a mean thickness of 5.28 ± 1.66 mm. For other lymph nodes the mean thickness measurements plus one standard deviation were less than 4.4 mm (95% confidence interval: ≤ 3.72 mm).

Clinical Significance

The information provided in this study may act as a baseline for evaluation of the spleen and lymph nodes in ferrets.

Ultrasonographic visualization of the adrenal glands of healthy ferrets and ferrets with hyperadrenocorticism

A protocol was developed to compare the ultrasonographic characteristics of the adrenal glands of 21 healthy ferrets and 37 ferrets with hyperadrenocorticism. By using specific landmarks, the adrenal glands were imaged in 97% of the cases. The adrenal glands of ferrets with hyperadrenocorticism had a significantly increased thickness, with changes in shape, structure, and echogenicity compared to the adrenal glands of healthy ferrets. Based on the findings of the study, adrenal glands may be classified as abnormal when they have a rounded appearance, increased size of the cranial/caudal pole (thickness >3.9 mm), a heterogeneous structure, increased echogenicity, and/or signs of mineralization.

Effects of melatonin administration on the clinical course of adrenocortical disease in domestic ferrets

OBJECTIVE

To evaluate the effect of oral administration of melatonin on clinical signs, tumor size, and serum steroid hormone concentrations in ferrets with adrenocortical disease.

DESIGN

Noncontrolled clinical trial.

ANIMALS

10 adult ferrets with clinical signs of adrenocortical disease (confirmed via serum steroid hormone concentration assessments).

PROCEDURES

Melatonin (0.5 mg) was administered orally to ferrets once daily for 1 year. At 4-month intervals, a complete physical examination; abdominal ultrasonographic examination (including adrenal gland measurement); CBC; serum biochemical analyses; and assessment of serum estradiol, androstenedione, and 17alpha-hydroxyprogesterone concentrations were performed. Serum prolactin and dehydroepiandrosterone sulfate concentrations were evaluated at the first, second, and last examinations, and serum cortisol concentration was evaluated at the first and last examinations.

RESULTS

Daily oral administration of melatonin greatly affected clinical signs of adrenocortical disease in ferrets; changes included hair regrowth, decreased pruritus, increased activity level and appetite, and decreased vulva or prostate size. Mean width of the abnormally large adrenal glands was significantly increased after the 12-month treatment period. Recurrence of clinical signs was detected in 6 ferrets at the 8-month evaluation. Compared with pretreatment values, serum 17alpha-hydroxyprogesterone and prolactin concentrations were significantly increased and decreased after 12 months, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that melatonin is a useful, easily administered, palliative treatment to decrease clinical signs associated with adrenocortical disease in ferrets, and positive effects of daily treatment were evident for at least an 8-month period. Oral administration of melatonin did not decrease adrenal gland tumor growth in treated ferrets.

Retrospective review of the ultrasonographic features of adrenal lesions in 21 ferrets

Clinical signs and follow-up information were recorded. Histopathologic diagnoses were obtained for 25 adrenal glands in 21 ferrets. Adrenal lesions included ten adenocarcinomas, nine adenomas, one hyperplasia and one cortical cyst. Four adrenal glands (all right-sided) were diagnosed as unspecified adrenal tumors but lacked a definite histopathologic diagnosis (adenoma vs. adenocarcinoma) due to incomplete surgical resection and consequent small sample sizes. Bilateral adrenal lesions were identified in 4 ferrets (19%). Adrenal shape, size, echogenicity, laterality, and the presence of vascular invasion were evaluated with ultrasound. Size and shape were variable and not specific to lesion type. Both benign and malignant adrenal tumors (adenomas, adenocarcinomas) appeared most often as masses with increased thickness and a normal length (11/23), less frequently as larger masses with increased thickness and length (4/23) or as nodules focally deforming the normal adrenal shape (6/23). The only cortical cyst appeared as a nodule. Three adrenal glands had a normal size and shape and were diagnosed as adenomas (2) or hyperplasia (1). Therefore treatment may be warranted based solely on clinical signs if adrenal glands are ultrasonographically normal. Vascular invasion was not identified ultrasonographically. However, focal absence of periglandular fat resulting in contact of 8 adrenal glands with either caudal vena cava (6), aorta (1) or liver (1) identified ultrasonographically, correlated with incomplete surgical resectability (6/8) and histopathologic diagnoses of carcinoma (4/8) or unspecified tumors (4/8). Therefore, a focal absence of periglandular fat between the adrenal gland and the large vessels or liver, deviation or compression of the large vessels by the adrenal lesion may indicate malignancy. Adrenal tumors (benign and malignant) were often associated with a prominent uterus, uterine stump or prostate with or without prostatic cysts.

Emergency and critical care of ferrets

Gastrointestinal disease, neoplasia, cardiac disease, and endocrinopathy are among the most common syndromes affecting the ferret that presents in an emergency situation. Knowledge of these and other disease processes, indicated diagnostic testing, and immediate treatment protocols are critical to provide efficient and effective care to the ferret in crisis.

Ultrasonography of the adrenal glands in the dog, cat, and ferret

Ultrasonography has become an important modality for imaging adrenal glands in small animals. Normal adrenal glands and structural abnormalities, such as changes in size, shape, and echogenicity, can be identified. In the case of adrenal tumors, ultrasonography is a valuable tool for identifying neoplastic masses with local and regional involvement, as well as potential abdominal metastases. When correlated with clinical findings and results of hematologic, serum biochemical and endocrine tests, ultrasonographic findings make a substantial contribution to the diagnosis of adrenal diseases in dogs, cats, and ferrets.