Prevalence of pituitary tumors among diabetic cats with insulin resistance

OBJECTIVE: To determine prevalence of pituitary tumors, detectable by means of computed tomography or magnetic resonance imaging, in cats with insulin resistance suspected to have acromegaly or hyperadrenocorticism versus cats with well-controlled diabetes mellitus. DESIGN: Case series. ANIMALS: 16 cats with insulin resistance that were also suspected to have acromegaly (n = 12) or pituitary-dependent hyperadrenocorticism (4) and 8 cats with well-controlled diabetes mellitus. PROCEDURE: Computed tomography was performed on all 16 cats with insulin resistance and 2 cats in which diabetes mellitus was well-controlled. The remaining 6 cats in which diabetes mellitus was well-controlled underwent magnetic resonance imaging. Images were obtained before and immediately after i.v. administration of contrast medium. RESULTS: Computed tomography revealed a mass in the region of the pituitary gland in all 16 cats with insulin resistance. Maximum width of the masses ranged from 4.4 to 12.7 mm; maximum height ranged from 3.1 to 12.6 mm. Results of computed tomography performed on 2 cats with well-controlled diabetes and magnetic resonance imaging performed on the remaining 6 cats were considered normal. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cats with insulin resistance suspected to have acromegaly or pituitary-dependent hyperadrenocorticism are likely to have a pituitary mass detectable by means of computed tomography or magnetic resonance imaging.     

Radiotherapy of pituitary tumours in five cats

Five cats tentatively diagnosed with pituitary adenoma (four cases) or pituitary carcinoma (one case), based on computed tomography (CT) or magnetic resonance imaging, were treated with radiotherapy. Electrons were applied in four cats and electrons and photons in the fifth. Ten to 12 fractions of 3.5 to 4.0 Gy each were delivered on a Monday/Wednesday/Friday schedule. The mean total dose applied was 39 Gy. No severe acute side effects to treatment were seen. Follow-up CT examination was performed in four cats; the mass had disappeared in one cat and remained stable or slightly decreased in size in the other three. The survival times were 5.5, 8.0, 15.0, 18.0 and 20.5 months, with two cats dying of causes unrelated to the tumour. Based on these cases, radiotherapy appears to be a valuable treatment option for feline pituitary tumours.     

Outcomes of pituitary tumor irradiation in cats

BACKGROUND: Information on tumor control and normal tissue effects of radiotherapy to treat pituitary tumors in cats is limited. HYPOTHESIS: Radiation therapy is effective in controlling the clinical signs associated with pituitary tumors in cats, with a low incidence of adverse effects. ANIMALS: Eight cats were irradiated at Colorado State University between 1991 and 2002 for spontaneous pituitary tumors. METHODS: A retrospective review of records was made to assess tumor control and incidence of radiation-induced adverse effects. RESULTS: Pituitary carcinoma was diagnosed in 2 cats and pituitary adenoma in 6 cats. Total radiation dosage ranged from 4,500 to 5,400 cGy administered Monday through Friday in 270 or 300 cGy fractions. Acute effects were limited to epilation and mild otitis externa. Focal brain necrosis adjacent to regrowth of a pituitary carcinoma and a second tumor in the radiation field were reported as possible late effects. Median survival, regardless of cause of death of the 8 cats, was 17.4 months (range, 8.4 to 63.1 months). Median survival could not be determined if cats were censored for non-tumor-related causes of death. Six cats were alive at 1 year, and 3 cats were alive at 2 years after treatment. Tumor recurrence was seen in 1 cat with a pituitary carcinoma. Neurologic signs improved within 2 months in all 5 cats that presented with abnormal neurologic signs. Clinical signs caused by a concurrent endocrine disorder began to improve within 1-5 months in the 7 cats with hyperadrenocorticism or acromegaly. CONCLUSIONS AND CLINICAL RELEVANCE: Radiation therapy is an effective primary treatment modality for cats presenting with neurologic signs associated with a pituitary mass and can improve clinical signs associated with concurrent hyperadrenocorticism or acromegaly in cats with no neurologic abnormalities.     

Radiation therapy for long-term control of odontogenic tumours and epulis in three cats.

Orthovoltage radiation was used to treat odontogenic tumours in three cats following incomplete surgical resection. Cats received a total radiation dose of 48-52 Gy over a period of 26-29 days. Acute toxicities were mild, consisting of hair loss within the radiation field in all cats, and mild mucositis in one cat. All cats had long-term (>35 months) control of their tumour, and two cats are still alive without recurrence of tumour 60 and 39 months, respectively, after completing treatment. Radiation therapy should be considered to be an adjuvant to incomplete surgery in cats with odontogenic neoplasms or epulides.     

Insulin therapy in cats with diabetes mellitus

Thirteen cats with diabetes mellitus were evaluated. Clinical signs included polydipsia, polyuria, polyphagia, lethargy, and weight loss. Results of physical examination included obesity, hepatomegaly, mild seborrhea sicca, muscle wasting, and dehydration. One cat walked plantigrade and was suspected of having a diabetic neuropathy. Persistent hyperglycemia, glucosuria, high liver enzyme activities, hypercholesterolemia, hyperproteinemia, and low electrolyte concentrations were the common laboratory findings. In 3 cats diabetes mellitus developed after megestrol acetate therapy; 2 of these cats required only temporary insulin treatment. In a 3rd cat, which had no history of receiving diabetogenic drug therapy, remission of diabetes mellitus also was observed. Serum insulin and plasma glucose concentrations were determined in 6 cats after administration of an intermediate-acting insulin (isophane insulin) and in 3 cats after administration of a long-acting insulin (protamine zinc insulin). The insulin concentration peaked 2 to 6 hours after the injection of intermediate-acting insulin and 6 to 12 hours after the injection of long-acting insulin. The lowest glucose concentration was recorded 4 to 8 hours after injection of intermediate-acting insulin, and 6 to 12 hours after injection of long-acting insulin. It was concluded that, although insulin therapy must be adjusted to the individual, the diabetic cat usually requires twice-daily administration of isophane insulin; however, the protamine zinc insulin can be given once daily for satisfactory control.     

Protothecosis in two cats

Protothecosis was diagnosed in 2 cats from Florida with nodular skin lesions. Microscopically, lesions were composed of macrophages and multinucleated giant cells arranged in solid sheets in the dermis and subcutis. In both cats, characteristic algal endospores identified as Prototheca wickerhamii were observed within the cytoplasm of infiltrating cells.     

Hydrometra in two cats

Chronic abdominal distension in two female cats 2½ and 13 years old respectively was due to bilateral hydrometra. In both cases the condition resulted from absence of an internal cervical os with consequent accumulation of normal uterine secretions. The most likely cause was a segmental failure in the development of the Müllerian duct system.     

Megaesophagus in two cats

Megaesophagus was diagnosed in 2 cats. Both had a history of regurgitation, and one was dyspneic. Radiography of the thorax and abdomen revealed generalized megaesophagus and gastric distention with gas. There was no esophageal motility during fluoroscopic observation. The prognosis for cats with megaesophagus is guarded. Although they may be satisfactory pets, cats with this condition should not be used for breeding because the condition is believed to be inherited through recessive genes.     

Lymphangiosarcoma in two cats

Lymphangiosarcoma is a malignant neoplasm of the lymphatic endothelium that is rare in cats. This report describes two cases of feline lymphangiosarcoma that originated in the distal limb, causing intractable lymphoedema and serosanguineous discharge with ecchymoses in local and distant sites. In association with the neoplasia, one cat had cortical bone lysis of multiple metacarpal bones of the affected limb and the other had severe immune-mediated haemolytic anaemia (IMHA). The disease in both cases affected young cats and progressed rapidly. Persistent distal limb lymphoedema with serosanguineous discharge is suggestive of lymphangiosarcoma especially when local or distal ecchymoses are evident.     

Trichosporonosis in two cats

Infection with Trichosporon spp was diagnosed in 2 cats. In one cat, infection consisted of a granulomatous dermatitis and was concurrent with disseminated lymphoblastic lymphosarcoma. In another cat, urinary cystitis caused by T beigelii was diagnosed.     

Antemortem diagnosis and treatment of toxoplasmosis in two cats on cyclosporin therapy

Clinical toxoplasmosis was diagnosed antemortem in two cats being treated with therapeutic doses of cyclosporin. The diagnosis was made by detecting tachyzoites on cytological examination of bronchoalveolar lavage fluid from one case and pleural effusion from the other. Despite early diagnosis and aggressive treatment in both cases, only one cat survived. Reactivation of latent Toxoplasma gondii infection secondary to cyclosporin-induced immunosuppression was considered likely in both cases. The presence of respiratory signs in cats treated with cyclosporin should alert clinicians to the possibility of clinical toxoplasmosis. Consideration should be given to determining the serostatus of cats to T gondii prior to use of drugs which are potent inhibitors of cell mediated immunity, such as cyclosporin. Two cases of feline toxoplasmosis are presented.