Tear-film osmolarity in normal cats and cats with conjunctivitis

Objective To compare the tear‐film osmolarity of normal cats and cats with conjunctivitis. Animal studied The population consisted of shelter, research, and privately owned cats. Procedures Cats were classified as normal or having conjunctivitis. An ophthalmic examination including Schirmer tear test (STT), fluorescein staining, tear‐film break‐up time (TFBUT), intraocular pressure (IOP), and slit‐lamp biomicroscopy of the anterior segment was performed. The severity of conjunctivitis was graded and assigned a numerical score. The Tear Lab^TM Osmolarity System was utilized to determine the tear‐film osmolarity. Unpaired t‐tests were used to compare tear‐film osmolarity, TFBUT, IOP, and STT of the two groups. Results A total of 93 cats (186 eyes) were examined. There were 37 normal cats (74 eyes) and 39 conjunctivitis cats (78 eyes). The mean age was 2.34 years. There was no statistical difference (P = 0.2065) between the median tear‐film osmolarity of normal cats (328.5 ± 17.94 mOsms/L) and conjunctivitis cats (325.0 ± 24.84 mOsms/L). Cats with conjunctivitis had an accelerated TFBUT (P < 0.0001) and lower IOPs (P < 0.0001) as compared to normal cats. No statistical difference was found between STT values (P = 0.1304). Conclusions The median tear‐film osmolarity of normal cats was 328.5 mOsms/L. Despite the accelerated TFBUT, conjunctivitis did not cause a statistically significant change in tear‐film osmolarity. The Tear Lab^TM Osmolarity System was easily used and well tolerated by the cats in the study.     

Angiosarcoma in cats

In a survey of 3145 feline necropsies at The Animal Medical Centre, eighteen cases of haemangiosarcoma and one case of lymphangiosarcoma were diagnosed. The haemangiosarcomas were primarily located in the spleen (four), liver (six), mesentery (four), mediastinum (three) and the lungs (one). The lymphangiosarcoma was seen in the skin and subcutaneous tissue of the abdominal wall and thighs. The clinical, macroscopic, and microscopic features of these tumours have been described. The most common clinical signs in the case of haemangiosarcoma were due to the rupture of the primary or metastatic neoplasms (70%). Metastases wese observed in 67% of the cases. Three main histological types (1, cavernous; 2, solid; and 3, capillaries separated by stroma) were observed, although mixtures of more than one histological type were seen in any one particular tumour. Rare cases of pulmonary haemangiosarcoma and lymphangiosarcoma in the cat have also been described.     

Osteopetrosis in cats

Osteopetrosis was found in two adult cats, radiographically characterised by a ‘marble bone’ appearance of the axial skeleton and of the subchondral bone of all joints, and endosteal thickening of the cortex of long bones. Computer tomography and histological assessment revealed massive endosteal lamellar bone formation. Bone resorption was still apparent, though only atypical mononuclear osteoclasts were seen. Histological findings support the assumption that the disorder was acquired. Severe anaemia was found in one cat. In the other, no clinical abnormalities were present. The condition appears to be different from feline leukaemia virus-induced medullary osteosclerosis described by Hoover and Kociba (1974).     

Osteoarthritis in cats

Osteoarthritis is a common radiographic finding in older cats, with a prevalence of up to 90% in appendicular joints. Many cats experience impaired mobility from osteoarthritis; however, there are more and more treatment options available, including diet modification, environmental modification, medical therapy, and physical rehabilitation. Continuing challenges involve accurate diagnosis and outcome assessment of treatment, but considerable progress has been made in the last decade.     

Pharmacokinetics of methimazole in normal cats and cats with hyperthyroidism

The intravenous and oral disposition of the antithyroid drug methimazole was determined in 10 clinically normal cats and nine cats with naturally occurring hyperthyroidism. After intravenous administration of 5 mg methimazole, the mean residence time was significantly (P less than 0.05) shorter in the cats with hyperthyroidism than in the normal cats, but there was no significant difference between the mean values for total body clearance (CL), steady state volume of distribution (Vdss), terminal elimination rate constant (ke), or serum terminal half-life (t1/2) in the two groups of cats. After oral administration, the mean bioavailability of methimazole was high in both the normal cats (77.6 per cent) and cats with hyperthyroidism (79.5 per cent). The values for mean residence time, ke and serum terminal t1/2 after oral dosing were significantly shorter in the cats with hyperthyroidism than in the normal cats. However, after oral administration of methimazole there were no significant differences between the mean values for CL, Vdss, bioavailability and maximum serum concentrations or the time for maximal concentrations to be reached in the two groups of cats. Overall, most pharmacokinetic parameters for methimazole were not altered by the hyperthyroid state. However, the cats with hyperthyroidism did show a trend toward faster elimination of the drug compared with the normal cats, similar to what has been previously described for the antithyroid drug propylthiouracil in cats. These results also indicate that methimazole is well absorbed when administered orally and has a higher bioavailability than that of propylthiouracil in cats with hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Demodicosis in cats

Feline demodicosis, caused by Demodex cati, may be associated with immunosuppression, as from FeLV infection or diabetes mellitus. Clinical signs include nonpruritic alopecia, scaling, erythema and hyperpigmentation in the facial region. Local topical application of 2.5% lime sulfur solution every 10 days is usually curative in a few weeks or months.