Pituitary pars intermedia dysfunction (equine Cushing’s disease) in a Thoroughbred stallion: a single report

Hatazoe, Takashi; Kawaguchi, Hiroaki; Hobo, Seiji; Misumi, Kazuhiro

doi:10.1294/jes.26.125

Cited by 6 publications

(10 citation statements)

References 12 publications

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“…While changes in the oestrus cycle have been documented in aged mares with PPID (McCue 2007), changes in fertility of stallions with PPID are unknown, due to low numbers of reports of PPID in stallions. In a previous case report, a 20-year-old Thoroughbred stallion showed no changes in fertility prior to diagnosis of PPID using ODST, CT and histopathology (Hatazoe et al 2015). The stallion reported here recently bred several mares, therefore libido and fertility were likely not affected, although a breeding soundness examination was not performed.…”

Section: Discussionmentioning

confidence: 74%

“…In a previous case report, a 20‐year‐old Thoroughbred stallion showed no changes in fertility prior to diagnosis of PPID using ODST, CT and histopathology (Hatazoe et al . ). The stallion reported here recently bred several mares, therefore libido and fertility were likely not affected, although a breeding soundness examination was not performed.…”

Section: Discussionmentioning

confidence: 97%

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Large pituitary adenoma in an 8‐year‐old Arabian stallion

Madrigal

Andrews

Rademacher

et al. 2016

Equine Veterinary Education

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Summary An 8‐year‐old Arabian stallion weighing 361 kg presented to Louisiana State University Veterinary Teaching Hospital with a 3‐month history of weight loss, exercise intolerance, long hair coat and recent history of seizures and aimless wandering in the pasture. An initial presumptive diagnosis of pituitary pars intermedia dysfunction (PPID) was made based on clinical signs. The initial examination revealed weight loss and loss of body condition (BCS 3/9), hypertrichosis, muscle wasting and reluctance to move when prompted. A neurological examination revealed dull mentation with no evidence of proprioceptive deficits in the limbs. Mild hyperglycaemia and a stress leucogram were noted on initial biochemical panel and haematology, respectively. Plasma adrenocorticotrophic hormone (ACTH) concentrations before and after thyrotropin releasing hormone (TRH) stimulation were markedly increased. Rapid slice computed tomography (CT) scan of the head before and after contrast revealed a large mass in the region of the pituitary gland suggestive of macroadenoma causing PPID. Prior to imaging, treatment consisted of supportive nursing care. Due to size of the pituitary gland (measuring 4.6 × 4.6 × 3.8 cm) and the presence of seizure‐like activity and dull mentation, the stallion was subjected to euthanasia. A necropsy was not performed. Pituitary macroadenomas in horses affected with PPID, who show neurological signs such as seizure‐like activity, dull mentation and aimless wandering, might have a poor prognosis and treatment with pergolide mesylate might not reduce pituitary gland size or relieve clinical signs. A CT scan is indicated in horses with neurological signs suspected of PPID to further evaluate pituitary gland size and surrounding structures and rule out other causes to better assess prognosis.

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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 97%

Large pituitary adenoma in an 8‐year‐old Arabian stallion

Madrigal

Andrews

Rademacher

et al. 2016

Equine Veterinary Education

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“…Em equinos hígidos, a inibição da liberação de ACTH devido a administração exógena de dexametasona resulta na consequente supressão de cortisol. Entretanto na presença da enfermidade, não há supressão da liberação de ACTH na porção intermédia da hipófise, considerando que não há resposta de feedback por aumento de gli-cocorticoides [7]. Este teste foi originalmente relatado como tendo aproximadamente 100% de sensibilidade e especificidade, considerando equinos com sinais clínicos evidentes de síndrome de Cushing [11].…”

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Diagnostic Process in a Crioulo Horse with Cushing’s Syndrome

Franco

Santos

Costa

et al. 2021

Acta Scientiae. Vet.

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Background: Equine pituitary pars intermedia dysfunction, also known as equine Cushing’s syndrome, is a neurodegenerative disease. An important risk factor for Cushing’s is advanced aging and it is the most common endocrine disorder in older horses. The prevalence in horses aged over 10 and 15 years is reported as 9.3% and 21%, respectively. Due to the slow progressive nature of the disease, seasonal variation in hormone output and overlapping endocrine response to other events, accurate diagnosis is challenging. The diagnosis requires the combination of anamnesis, clinical signs, in addition to laboratory tests results. This study aimed to report Cushing’s syndrome in a Crioulo breed horse focusing on diagnostic methods.Case: A 13-year-old male Crioulo breed, orchiectomized, was attended at the Universidade de Passo Fundo (UPF), in Passo Fundo, RS, Brazil. The owner reported that the animal had progressive weight loss and coat abnormal growth, with curly appearance. From visual inspection, body condition score was 4 (1-9) bulging abdomen was noticed, hirsutism, depression and lethargy. Also, there was a large neoplastic mass on the left side of gluteal region. Later, this mass was classified in histopathological examination as a fibroblastic sarcoid and was treated. The animal presented physical parameters within the physiological limits of the specie. Normochromic normocytic anemia and neutrophilic leukocytosis were reported in the hematologic evaluation. In coproparasitological examination, there were 300 eggs per gram of feaces. Hyperadrenocorticism was suspected in the clinical examination and dexamethasone suppression test was performed to confirm the fact. Basal serum was collected at 17 h (M0) and subsequently 40 µg/kg of dexamethasone was administered intramuscularly. Serum samples were taken after 15 (M15) and 19 (M19) h, resulting in cortisol levels of 1.7 and 1.8 μg/dL, respectively. The M15 and M19 results were above reference values for horses (below 1 μg/dL). Combination of information gathered from anamnesis, clinical examination and dexamethasone suppression test resulted in the definitive diagnosis of hyperadrenocorticism, also known as Cushing’s syndrome. Paliative treatment included shearing all over the body and vitamin supplementation.Discussion: In animals without obvious clinical signs, Cushing's syndrome diagnosis is challenging. The most unique and specific clinical signs are the development of abnormal hair coat, mainly hirsutism, delayed or incomplete shedding, and in aged horse, lightening of coat color. The mechanistic cause of these signs is still barely understood. Cushing's is a collection of syndromes each with a unique set of clinical signs and hormone profiles, which varies according to each individual. Complementary examinations are extremely important and endocrine tests are highly recommended in addition to suggestive findings. However, despite the variety of existing tests, false negatives or false positives can frequently happen. Dexamethasone suppression test is considered the gold standard, well validated, practical and low cost for the diagnosis of this disease. In the present report, the combination of anamnesis (13 years old, weight loss, and abnormal coat), clinical exam (hirsutism) and dexamethasone suppression test (over 1 μg/dL of cortisol 15 h and 19 h after dexamethasone administration) resulted in the definitive diagnosis of Cushing’s syndrome. Measurements of plasma concentrations of cortisol and adrenocorticotropic hormone (ACTH), thyrotropin releasing hormone (TRH) stimulation test, serum insulin concentration and necropsy are other available tests. History, clinical signs and test results are important to achieve the definitive diagnoses, and when possible, it is advisable to perform post-mortem evaluation of the pituitary gland.

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“… 20 , 23 , 24 In Japan, no studies have focused on PPID in Thoroughbred broodmares, and no literature on diagnosis and treatment is available. 25 , 26 Without such guidance, negative economic impact is likely for owners whose aging broodmares have decreased fertility and a shortened reproductive period.…”

Section: Introductionmentioning

confidence: 99%

Relationship between endogenous plasma adrenocorticotropic hormone concentration and reproductive performance in Thoroughbred broodmares

Tsuchiya

Noda

Ikeda

et al. 2021

Veterinary Internal Medicne

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Background: Pituitary pars intermedia dysfunction (PPID) is an endocrine disorder the clinical signs of which include infertility, but few reports have examined the relationship between PPID and reproductive performance in broodmares.Hypothesis/Objective: Broodmares with infertility of unknown etiology were screened for PPID using baseline endogenous plasma ACTH concentrations, and its relationship with subsequent reproductive performance was analyzed.Animals: Sixty-seven Thoroughbred broodmares.Methods: Adrenocorticotropic hormone concentrations were measured in autumn.The broodmares were divided into 3 groups based on endogenous plasma ACTH concentration (low, <50 pg/mL; intermediate 50-100 pg/mL; and high >100 pg/mL) as recommended by the Equine Endocrinology Group. We compared these results with those of other blood tests, clinical examinations, subsequent conception, and frequency of normal delivery.Results: The numbers of horses per group (percentage) were 22 (32.8%), 20 (29.9%), and 25 (37.3%). The mean ± SD ages (years) were 11.1 ± 3.4, 12.1 ± 4.5, and 13.0 ± 4.3, with no significant difference among groups. Mean ± SD plasma cortisol concentrations (μg/dL) were 4.0 ± 1.6, 7.1 ± 1.4, and 7.6 ± 1.9, with the intermediate and high ACTH groups having significantly higher results than the low ACTH group (P < .001). Conception rates were 77.3%, 89.5%, and 56.5% and normal delivery rates were 77.2%, 84.2%, and 43.5% with the percentage of each significantly lower in the high ACTH group (P = .02, P = .008, respectively). Conclusions and Clinical Importance:The study group of infertile broodmares may include horses with PPID. The reproductive performance of the high ACTH group was significantly lower than the other groups. Early diagnosis and treatment of infertile broodmares by screening plasma ACTH concentrations could help improve reproductive performance.

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Pituitary pars intermedia dysfunction (equine Cushing’s disease) in a Thoroughbred stallion: a single report

Cited by 6 publications

References 12 publications

Large pituitary adenoma in an 8‐year‐old Arabian stallion

Large pituitary adenoma in an 8‐year‐old Arabian stallion

Diagnostic Process in a Crioulo Horse with Cushing’s Syndrome

Relationship between endogenous plasma adrenocorticotropic hormone concentration and reproductive performance in Thoroughbred broodmares

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