Evidence-Based Advances in Rodent Medicine

Therapies in Exotic Animal Gastroenterology

This article reviews treatment of gastrointestinal (GI) disorders in exotic companion mammal species, birds, reptiles, amphibians, and fish. Treatment of GI stasis involves fluids, nutrition, and analgesia; there is minimal evidence suggesting prokinetics are useful. Research has evaluated the efficacy of various appetite stimulants in several exotic animal species. Although rabbits and rodents cannot vomit, maropitant may be beneficial by providing visceral analgesia. Gastroprotectants may be indicated for patients at risk for GI ulceration, such as anorexic psittacine birds. Immunosuppressives may be indicated for GI neoplasia and inflammatory bowel disease.

Gastroenterology in Rodents

Gastrointestinal (GI) diseases are frequently diagnosed in rodents. Clinical signs are usually nonspecific and include anorexia, weight loss, chronic wasting, abdominal discomfort, gas accumulation in the intestine and stomach, and diarrhea. Malabsorption associated with GI dysfunction or gastroenteritis quickly leads to negative energy balance and metabolic acidosis. Therefore, all disorders of the GI tract should be treated as soon as possible. The article describes selected disorders of the GI tract in guinea pigs (Cavia porcellus), chinchillas (Chinchilla lanigera), degus (Octodon degus), and rats (Rattus norvegicus).

Adrenal Disease in Small Mammals

Adrenal gland disease has been described as a rare disease in pet rabbits and rodents. Hyperadrenocorticism with excessive secretion of corticosteroids is most commonly observed in guinea pigs and hamsters, with dermatologic signs similar to those seen in dogs. Diagnosis is based on clinical signs, diagnostic imaging such as abdominal ultrasound, and determination of the blood hormone concentrations. In guinea pigs, an adrenocorticotrophic hormone stimulation test with the measurement of salivary cortisol or corticosterone concentrations is recommended. The recommended treatment of adrenal disease in guinea pigs and hamsters is oral administration of trilostane or ketoconazole; surgical treatment is also possible.

Sonography of the pituitary gland in pet rats

Pituitary gland (PG) tumors are common in rats over the age of 2. CT and MRI can be difficult to apply in this species, whereas ultrasound is more feasible and useful. To our knowledge, there are no studies on PG ultrasound in rats. The aim of this prospective, analytical study was to evaluate the reliability of ultrasound in identifying PG, to define the ultrasound dimension of the gland in a group of rats with no evidence of pituitary diseases, and to examine its correlations with age, sex, and weight. After localizing the PG with an MRI study on one rat, the gland was identified in 21 rats by ultrasound by two sonographers using a ventral neck approach and a transversal scan with a linear probe. The gland appears as a hypoechoic oval structure with a thin hyperechoic margin. The rats (15 male and 6 female) ranged from 4 to 18 months in age (median 6 months) and from 270 to 640 g in weight (median 370 g). The median pituitary width was 3.96 mm (interquartile range 25-75%: 6-4.5 mm), and the median height was 1.48 mm (interquartile range 25-75%: 1.3-1.67 mm). There was no statistically significant correlation between PG size and rat weight, gender, or age. We believe that these ultrasound measurements could be useful for the diagnosis of pituitary disease, irrespective of whether neurological symptoms are present. We report a clinical case of a rat with a pituitary mass detected by ultrasound and CT.

Lower Urinary Tract Diseases in Guinea Pigs: A 14-Year Retrospective Study (2004-2018)

The clinical records of all guinea pigs diagnosed with a lower urinary tract disease in a single veterinary hospital, over a period of 14 years (2004−2018), were retrospectively searched in order to characterize this population and investigate the potential association between the epidemiological and clinical variables. A total of 117 clinical cases were identified, corresponding to 57 animals. Urolithiasis was the most common diagnosis (n = 52; 44.4%), followed by cystitis and/or a urinary tract infection (UTI). Several statistically significant associations (p < 0.05) were found between different variables, showing that female guinea pigs were more likely than the male ones to have a previous family history of urinary disease, to present dysuria and stranguria at admission, and to suffer recurrence. Moreover, males were more prone to urolithiasis and females to cystitis/UTI, and animals diagnosed with cystitis/UTI frequently had more clinical urinary signs and abdominal pain on palpation compared to those diagnosed with urolithiasis. Finally, the use of potassium citrate and the urethrotomy approach were associated with a better therapeutic response. Further studies are needed in larger populations of guinea pigs to confirm the present findings, especially as some of them were described for the first time.

Endocrine Diagnostics for Exotic Animals

Endocrine disease in exotic species is less common than in small animals. Nevertheless, the diagnostic principles used in small animals can be adapted to evaluate endocrine disease in many of the exotic species although species-specific aspects need to be considered. This article covers important diseases such as thyroid dysfunction in reptiles and birds, hyperthyroidism in guinea pigs, and hyperadrenocorticism in ferrets. Glucose metabolism in neoplasms affecting normal physiology, such as insulinoma in ferrets and gastric neuroendocrine carcinoma in bearded dragons, is discussed. Calcium abnormalities, including metabolic bone disease in reptiles and hypocalcemia in birds, are also covered.

Deslorelin acetate implant induces transient sterility and behavior changes in male olive baboon (Papio anubis): A case study

This case study evaluates the effects of a 4.7 mg deslorelin acetate implant on one male olive baboon (Papio anubis). Implantation induces transient azoospermia after which the subject was able to conceive again. Behavior was also impacted with a decrease in our proxies of aggressiveness and sexual arousal.