Journal of Feline Medicine and Surgery

To elucidate the impact of dietary influence on carbohydrate and lipid metabolism and on the development of diabetes mellitus in the carnivorous cat, a 3 weeks feeding trial was carried out on six sexually intact and six neutered adult male cats. The effects of two isonitrogenic diets, differing in carbohydrate and fat content, were investigated on plasma metabolite levels in a 24-h blood sampling trial. Plasma leptin concentrations were also determined at the beginning and at the end of the 24-h trial. Glucose and insulin response was measured in an iv glucose tolerance test. A 5 days long digestion trial was also performed, which revealed a high digestion capacity of both fat and carbohydrates in cats. The high fat diet induced a significant rise in the plasma triglyceride, FFA, β-hydroxybutyrate and cholesterol concentration, while the elevation in the glucose level did not reach significance. In the glucose tolerance test no significant difference was found between the neutered and intact cats. However, independently of the sexual state, the cats on the high fat diet showed a slightly elongated glucose clearance and reduced acute insulin response to glucose administration. This is indicative of diminished pancreatic insulin secretion and/or β-cell responsiveness to glucose. The results of this preliminary study may be the impetus for a long-term study to find out whether it is rather the fat rich ration than carbohydrate rich diet that is expected to impair glucose tolerance and thus might contribute to the development of diabetes mellitus in cats. Whether the alteration in glucose metabolism is due to altered leptin levels remains to be determined.

Oral glucosamine was compared to a placebo for the management of cats with feline idiopathic cystitis (FIC) in a randomised, double-blinded, placebo-controlled, study. Forty cats with a history of recurrent cystitis due to FIC were divided into two groups and treated daily per os with either 125 mg N-acetyl glucosamine or a placebo for six months. Owners graded their cats' clinical signs at the beginning and end of the study, and kept daily diaries documenting signs of cystitis using visual analogue scales. Further episodes of cystitis were seen in 26 (65%) of the cats during the study. Affected cats experienced a mean of five recurrences (range 1–19) with each recurrence lasting a mean of four days (range 1–64 days).

There were no significant differences between the two groups when considering the owners assessments of the mean health score (P > 0.5), the average monthly clinical score (P = 0.22) or the average number of days with clinical signs (P = 0.28). Two cats suffered from such severe recurrent urethral obstruction that they were euthanased; they were both in the placebo group. Compared to the start of the study the majority of cats in both groups improved significantly (P < 0.001) (mean health score of each group at the start was 0.5 ± SD 0.5, compared to glucosamine 4.4 ± 0.7 and placebo 3.9 ± 1.6 at the end). This is believed to have occurred because the owners of 36 of the 40 cats (90%) started feeding more canned cat food. The urine specific gravity at the start of the trial was significantly higher (mean 1.050 ± SD 1.007) than when reassessed one month later (1.036 ± 1.010, P < 0.01).

In this retrospective study of 22 cats with lower airway disease of either intermittent (23%) or persistent nature (77%), the Siamese breed (55%) was significantly over-represented. Females (68%) were slightly but not significantly over-represented. No significant association was found between the clinical stage of disease and the physical findings, thoracic radiographic changes or the response to treatment. Cough, the most common presenting complaint, was the only symptom detected in the cats with intermittent disease, yet the two most severely affected animals did not show it. Thoracic auscultation did not reveal any abnormality in 41% of the cats. Haematology revealed eosinophilia in 46% of the cats. A bronchial pattern was the most common radiographic abnormality (73%), followed by alveolar (32%) and interstitial patterns (23%). Interestingly, thoracic radiographs were normal in 23% of the cats. The combination of short-term corticosteroids and bronchodilators resulted in complete and long-term remission of symptoms in nine cats, while the other 11 required ongoing medication because of relatively frequent relapses. One of the remaining two cats died during an asthmatic crisis, while the other was lost to follow up.

16S rRNA gene sequence analysis provided evidence for two different mycobacterial species, Mycobacterium lepraemurium and a potentially novel species, as causative agents of ‘feline leprosy’. Comparison of 16S rRNA gene sequence data obtained for M. lepraemurium and the potentially novel species indicated 12 nucleotide differences over a 446 bp region encompassing the V2 and V3 hypervariable regions. From available 16S rRNA gene sequence data, M. lepraemurium shared greatest nucleotide identity with M. avium subsp paratuberculosis and M. avium. The novel species had a long helix 18 in the V3 region and shared greatest nucleotide identity with M. leprae, M. haemophilum and M. malmoense. The novel species had an additional ‘A’ nucleotide at position 105 of the aligned 16S rRNA gene sequence, the only other mycobacterial database sequence having this same extra nucleotide being M. leprae. This nucleotide variation was exploited to develop specific PCR assays for the two species. These were found to be effective and specific when tested against a panel of mycobacteria including species found in feline leprosy lesions and closely related mycobacteria and also when applied directly to formalin-fixed, paraffin-embedded tissues from feline leprosy cases.

A retrospective study was undertaken to determine the prevalence of different diseases in cats referred for investigation of chronic nasal disease, to identify historical, clinical and diagnostic features which may assist in making a diagnosis, and to provide information pertaining to outcome in these cats. Diagnoses included neoplasia (30 cases), chronic rhinitis (27), foreign body (8), nasopharyngeal stenosis (5), Actinomyces infection (2), nasal polyps (2), stenotic nares (2), and rhinitis subsequent to trauma (1). The most common neoplasia was lymphosarcoma (21 cases), with a median survival of 98 days for cats treated with multiagent chemotherapy. Cats with neoplasia were older on average than the other cats, and were more likely to be dyspnoeic and have a haemorrhagic and/or unilateral nasal discharge than cats with chronic rhinitis. Cats with neoplasia were more likely to have radiographic evidence of nasal turbinate destruction, septal changes, or severe increases in soft tissue density than cats with chronic rhinitis. It was unusual for cats with diseases other than neoplasia to be euthanased as a result of their nasal disease.

The three calcitropic hormones, parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol and calcitonin are together responsible for calcium homeostasis in the mammal. Feline PTH is an 84 amino acid, single chain polypeptide with a molecular weight of 9449, which is secreted by the parathyroid glands. The principle secretagogue for PTH is a low plasma ionised calcium concentration, although both 1,25-dihydroxycholecalciferol and phosphate have significant roles in regulating PTH secretion. The ability to accurately measure circulating PTH in the cat has simplified the evaluation of disorders of calcium metabolism in this species. In primary parathyroid disorders the lesion is located within the parathyroid gland, with parathyroid secretion being inappropriate to the prevailing mineral balance. By contrast, in secondary conditions a pathological state out with the parathyroid gland alters mineral homeostasis and the parathyroid gland responds in an appropriate manner. The measurement of circulating PTH may then be used to determine if PTH secretion is appropriate to the prevailing calcium concentrations to differentiate primary from secondary disorders. Although primary hyper and hypoparathyroidism are generally considered rare endocrine conditions of the cat, the ability to measure PTH has led to their increasing recognition.

A 7-year-old cat was presented initially with multiple draining sinuses on the metatarsal region of its right hindlimb. Another lesion had appeared at the same time on the fifth proximal interphalangeal joint of the left forelimb. Histopathological examination of a biopsy from the right hindlimb lesion revealed chronic pyogranulomatous inflammation associated with yeast-like bodies and septate mycelia; a fungus was cultured on conventional media but not identified further. Culture of a swab collected from the left forelimb lesion demonstrated a pigmented fungus, also not characterised further.

Although there was initially a favourable response to ketoconazole (Nizoral, Janssen-Cilag Pty. Ltd) and β-lactam therapy, the infection in the hind limb relapsed subsequently, and Fusarium chlamydosporum was cultured from deep biopsy specimens. Clinical improvement followed debridement and itraconazole (Sporanox, Janssen-Cilag Pty. Ltd; 100 mg orally once daily), however amputation of the limb represented the best chance for a cure. The cat made an uncomplicated recovery following surgery and remained well for five months until the lesion on the left forelimb recurred. Amputation of the distal fourth digit was then performed, and the resected tissue submitted for culture. The dematiaceous fungus Microsphaeropsis arundinis was subsequently cultured. The cat remained well for several months, until a further F. chlamydosporum infection developed on the body wall. This was excised 7 months ago, and no lesions have recurred in this area.

Importantly, this is the first reported case of M. arundinis infection in a mammalian host.

Unilateral swelling of submandibular salivary gland in two cats was diagnosed as necrotising sialometaplasia. Histological features that differentiate the disease from other salivary gland lesions, particularly neoplasia are: lobular necrosis of salivary tissue; squamous metaplasia conforming to duct and/or acinar outlines; preservation of salivary lobular morphology; and variable inflammation and granulation tissue.

A 5-year-old cat presented with haemorrhagic left aural discharge, 2 days following a road traffic accident. Otoscopic examination identified disruption of the external ear canal at the auricular/annular cartilage junction. This was managed by total ear canal ablation and lateral bulla osteotomy. Left sided facial nerve deficits were present following surgery. Eighteen months postoperatively there were no auricular problems, however facial nerve deficits persisted.

There are no previous reports describing management of acute separation at the auricular/annular cartilage junction of the external ear in the cat or dog. This case report describes the presentation, diagnosis and surgical management of an acute ear canal separation at the auricular/annular junction of the external ear canal in a cat.