Transsphenoidal hypophysectomy for treatment of pituitary-dependent hyperadrenocorticism in 7 cats

OBJECTIVE: Evaluation of microsurgical transsphenoidal hypophysectomy for the treatment of pituitary-dependent hyperadrenocorticism (PDH) in cats. STUDY DESIGN: Prospective clinical study. ANIMALS OR SAMPLE POPULATION: Seven cats with PDH. METHODS: Urinary cortisol/creatinine ratios, pituitary-adrenocortical function tests, and computed tomography (CT) were performed on 7 cats that presented with a provisional diagnosis of hyperadrenocorticism. All cats underwent microsurgical transsphenoidal hypophysectomy with histologic examination of the excised specimen. Follow-up consisted of clinical evaluation, repeat adrenocortical function testing, and CT. RESULTS: Four cats had concurrent diabetes mellitus. In all cats, the urinary cortisol/creatinine (C/C) ratios were elevated. The dexamethasone screening test showed that 2 cats did not meet the criterion for hyperadrenocorticism. The response of the cats' plasma concentrations of cortisol and adrenocorticotrophic hormone to a high dose of dexamethasone varied from very sensitive to completely dexamethasone resistant. Basal plasma alpha-melanocyte-stimulating hormone concentrations were elevated in 2 cats with a pars intermedia adenoma and in 3 cats with an adenoma that originated from the anterior lobe. Preoperative CT enabled accurate assessment of pituitary size (5 nonenlarged pituitaries with a height <4 mm and 2 enlarged pituitaries with a height >5 mm) and localization relative to intraoperative anatomic landmarks. Two cats died within 4 weeks after surgery of a nonrelated disease. In the remaining 5 cats, the hyperadrenocorticism went into both clinical and biochemical remission. Hyperadrenocorticism recurred in 1 cat after 19 months, but no other therapy was given and the cat died at home 28 months after surgery. CT evaluation of this cat had identified pituitary remnants 6 weeks after surgery. The main postoperative complications were oronasal fistula (1 cat), complete dehiscence of the soft palate (1 cat), and transient reduction of tear production (1 cat). One cat died at 6 months (undefined anemia), and another cat at 8 months (recurrent nose and middle ear infection secondary to soft palate dehiscence) after surgery. In the surviving 2 cats, the remission periods at the time of writing were 46 and 15 months. In the 2 cats with sufficient follow-up time, the concurrent diabetes mellitus disappeared, ie, insulin treatment could be discontinued at 4 weeks and 5 months after hypophysectomy. In all 7 cats, the histologic diagnosis was pituitary adenoma. CONCLUSIONS: Microsurgical transsphenoidal hypophysectomy is an effective method of treatment for feline PDH in specialized veterinary institutions having access to advanced pituitary imaging techniques. Concurrent diabetes mellitus is usually reversible after hypophysectomy. Thorough presurgical screening for coexisting diseases is imperative. CLINICAL RELEVANCE: PDH in cats can be effectively treated by hypophysectomy. The neurosurgeon performing hypophysectomy must master a learning curve and must be familiar with the most frequent complications of the operation to treat them immediately and effectively. Urinary C/C ratios are sensitive indicators for the assessment of remission and recurrence of hyperadrenocorticism.     

Plasma pro-opiomelanocortin, pro-adrenocorticotropin hormone, and pituitary adenoma size in dogs with Cushing's disease

It is difficult to predict the size of pituitary corticotroph tumors in dogs with Cushing's disease (pituitary-dependent hyperadrenocorticism [PDH]) without pituitary imaging techniques. The purpose of this study was to examine the relationship between plasma adrenocorticotropin hormone (ACTH) precursor concentration and pituitary size in dogs with Cushing's disease. Plasma concentrations of ACTH precursors (pro-opiomelanocortin [POMC]/pro-ACTH) and pituitary tumor height/brain area were measured in 36 dogs with pituitary corticotroph adenomas of various sizes. There was a correlation between tumor size (measured as the pituitary tumor height/brain area ratio [P/B]) and POMC/pro-ACTH concentration (r = .70; P < .0001). Dogs with P/B > or = 0.40 x 10(-2) mm(-1) had higher concentrations of ACTH precursors than dogs with P/B < 0.40 x 10(-2) mm(-1) (median concentration 85 pmol/L, range 15-1,350 pmol/L, n = 14 versus 15 pmol/L, range 15-108 pmol/L, n = 22; P < .0001). With a threshold of 35 pmol/L of POMC/pro-ACTH concentration, the estimated sensitivity and specificity of the kit were 93% (95% confidence interval [CI], 79-100%) and 86% (95% CI, 73-100%), respectively. We interpret these data as indicating that measurement of POMC and pro-ACTH might be of value in the characterization of tumor size in dogs with Cushing's disease. Low POMC/pro-ACTH concentrations make it unlikely that a large pituitary tumor exists in dogs with PDH.     

Efficacy of transsphenoidal hypophysectomy in treatment of dogs with pituitary-dependent hyperadrenocorticism

The long-term survival, disease-free fractions, and the complications of hypophysectomy in 150 dogs with pituitary-dependent hyperadrenocorticism (PDH) were examined in a prospective study. Long-term survival and disease-free fractions in relation to pituitary size were analyzed by the Kaplan-Meijer estimate procedure. The 1-, 2-, 3-, and 4-year estimated survival rates were 84% (95% confidence interval [CI], 76-89%), 76% (67-83%), 72% (62-79%), and 68% (55-77%), respectively. Treatment failures included procedure-related mortalities (12 dogs) and incomplete hypophysectomies (9 dogs). The 1-, 2-, 3-, and 4-year estimated relapse-free fractions were 88% (CI: 80-93%), 75% (64-83%), 66% (54-76%), and 58% (45-70%), respectively. Postoperative reduction of tear production (58 eyes in 47 dogs) was often reversible but remained low until death in 11 eyes of 10 dogs. Central diabetes insipidus (CDI) occurred more frequently (62%) in dogs with enlarged pituitaries than in dogs with nonenlarged pituitaries (44%). Survival and disease-free fractions after hypophysectomy were markedly higher in dogs with nonenlarged pituitaries than in dogs with enlarged pituitaries. Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs. The survival and disease-free fractions after hypophysectomy decrease and the incidence of CDI increases with increasing pituitary size. Therefore, early diagnosis of PDH is important and transsphenoidal hypophysectomy is expected to have the best outcome when used as primary treatment for dogs with nonenlarged or moderately enlarged pituitaries.     

Hypertrophic osteopathy in a pony with a pituitary adenoma

Hypertrophic osteopathy was diagnosed in a pony that had no antemortem or postmortem evidence of an intrathoracic lesion. With a history of hirsutism in an aged pony, a pituitary adenoma was suspected, and evaluation of plasma cortisol and insulin values and their response to thyrotropin-releasing hormone supported the diagnosis.     

Melanotroph pituitary adenoma in a cat with diabetes mellitus

A 13-year-old male, castrated, crossbred cat was referred for insulin-resistant diabetes mellitus. The cat had a ravenous appetite and a dull coat. Basal urinary corticoid/creatinine ratios were normal. In the low-dose dexamethasone suppression test there was no suppression of the (nonelevated) plasma cortisol concentration, whereas the (nonelevated) plasma adrenocorticotropic hormone (ACTH) concentration declined to low values. Basal plasma alpha-melanocyte-stimulating hormone (alpha-MSH) concentrations were highly elevated (> 1,500 ng/liter). Computed tomography revealed a pituitary tumor originating from the pars intermedia (PI). After microsurgical transsphenoidal hypophysectomy, the clinical signs resolved and the cat no longer required insulin administration. Microscopic examination of the surgical specimen revealed a pituitary adenoma originating from the PI with infiltration into the neural lobe. The adenoma immunostained intensely positive for alpha-MSH and only weakly for ACTH. It is concluded that the ACTH-independent cortisol production was probably due to the (weak) glucocorticorticotropic effects of the extremely high plasma concentration of alpha-MSH and related peptides.     

四种犬的美容

犬的美容是在犬的原貌的基础上进行的整容,给犬美容不能因犬主人的喜好随意地改变,应根据犬的品种、毛色分布、体形、生理因素结合进行.给犬美容的主要手法就是给自己的爱犬进行剪毛以达到掩饰爱犬缺点,展示犬的优美,夸大并突出爱犬的长处.现就不同品种犬分别浅谈一下.     

Vitamin D status before and after hypophysectomy in dogs with pituitary-dependent hypercortisolism

Both spontaneous hypercortisolism and chronic glucocorticoid treatment are associated with osteoporosis and low circulating concentrations of 1,25-dihydroxy-vitamin D in humans. Pituitary-dependent hypercortisolism (PDH) is a common disorder in dogs, but little is known about the vitamin D status of affected dogs. Pituitary-dependent hypercortisolism in dogs can be treated effectively by hypophysectomy and subsequent hormone supplementation. Because hormone supplementation does not include GH, dogs that have undergone hypophysectomy have low circulating concentrations of GH and IGF-1, which may result in low plasma 1,25-dihydroxy-vitamin D concentrations and consequently increased parathyroid hormone secretion. The aim of this study was to determine whether dogs with PDH need vitamin D supplementation before and/or after hypophysectomy. To this end, we measured plasma concentrations of GH, IGF-1, parathyroid hormone, calcium, phosphate, and vitamin D metabolites in 12 dogs with PDH before and 8 wk after hypophysectomy and in 12 control dogs. Although plasma GH concentrations were lower in dogs with PDH than in control dogs both before and after hypophysectomy, the vitamin D status was similar. In conclusion, there is no need for vitamin D supplementation in dogs with PDH, either before or after hypophysectomy.     

Facial dermatosis in four dogs with hyperadrenocorticism

In hyperadrenocorticism in the dog, cutaneous lesions may include alopecia, thin, hypotonic skin, hyperpigmentation, comedones, calcinosis cutis, secondary bacterial and fungal infections, and demodicosis. Skin lesions affecting only the face have not been reported in reviews of hyperadrenocorticism, nor has the disease been included in the differential diagnoses of facial dermatoses. This report involves 4 dogs with hyperadrenocorticism in which cutaneous signs were limited to the face.     

Neurologic manifestations associated with hypothyroidism in four dogs

Hypothyroidism was believed responsible for peripheral and central neurologic abnormalities in 4 dogs. Clinical signs consisted of abnormalities of gait and postural reactions and dysfunction of multiple cranial nerves in all 4 dogs. Circling, hypermetria, and spontaneous verticle nystagmus were observed in some of the dogs. Hypothyroidism was diagnosed in all 4 dogs on the basis of low resting serum thyroxine concentration and inadequate response to thyroid stimulating hormone. After thyroid hormone supplementation, resolution of neurologic abnormalities was complete in 2 dogs and partial in the other 2 dogs.     

Malignant histiocytosis in four dogs

The clinical and pathologic features of 4 dogs with malignant histiocytosis were evaluated. The most common clinical signs were weight loss, lethargy, lymphadenopathy, hepatosplenomegaly, and anemia. Neoplastic histiocytic infiltrates most commonly were found in the spleen, bone marrow, liver, or lymph nodes. Malignant histiocytosis was considered as a differential diagnosis for anemic dogs with lymphadenopathy and/or hepatosplenomegaly.     

Study of long-term survival after transsphenoidal hypophysectomy in clinically normal dogs

Experimental hypophysectomies were performed in 7 clinically normal dogs, using a new modification of the transsphenoidal approach. This approach facilitated centering of the sphenoid bone trephination and allowed safe exposure of the hypophysis regardless of the size or shape of a dog's skull. Complications did not occur during surgery and all dogs recovered well from surgery. Growth hormone secretory capacity was measured over a 3-month period to assess completeness of hypophysectomies. One dog was euthanatized 2 months after surgery, 4 dogs were euthanatized at 3 months after surgery, and 2 dogs were allowed to survive and their progress was followed for 2.5 years. Soft palate dehiscence and keratoconjunctivitis sicca developed in 2 of the dogs. The technical deficiencies responsible for these complications were corrected shortly after the beginning of the study. In 4 of the 5 necropsied dogs, minute remnants of adenohypophyseal tissue were found in the sellae turcica. Measurement of in vivo growth hormone secretory capacity revealed that these remnants had an altered stage of functional activity. Although complete hypophysectomy was not achieved consistently, the main technical obstacle of hypophysectomy, the reliable identification and the avoidance of the vascular structures surrounding the hypophysis, has seemingly been overcome. The surgical technique proved to enhance the safety of hypophysectomy, and the procedure can be recommended to treat clinical cases of canine pituitary-dependent hyperadrenocorticism. The clinical significance of potential subtotal hypophysectomy remains yet to be evaluated.     

Vascular encephalopathy associated with bacterial endocarditis in four dogs

Vascular encephalopathy is a commonly encountered clinical complication of infectious endocarditis in humans, but it has been infrequently reported in dogs. A series of four dogs with bacterial endocarditis that subsequently developed acute onset of neurological deficits is described. Clinical signs, diagnostic test results, and outcomes for each case are presented and compared with the human clinical syndrome.     

Percutaneous balloon valvuloplasty in four dogs with pulmonic stenosis

Four young dogs with severe pulmonic stenosis were treated by percutaneous balloon valvuloplasty. Pressure gradients between the right ventricle and pulmonary artery were markedly reduced by the procedure resulting in dramatic improvements in growth rate and clinical condition. No postoperative problems were encountered.     

Transcatheter arterial embolisation in four dogs with hepatocellular carcinoma

Four dogs with hepatocellular carcinoma were treated by transcatheter arterial embolisation. In all dogs, the tumour‐supplying arteries were selectively embolised with gelatine sponge particles. Post‐embolisation tumour volumes decreased relative to pre‐embolisation volumes in all dogs. No adverse reactions were observed in three dogs after treatment but one dog showed pancreatitis. These results suggest that transcatheter arterial embolisation is a feasible treatment for dogs with hepatocellular carcinoma.