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Tertiary hypothyroidism in a dog.

Shiel RE, Acke E, Puggioni A, Cassidy JP, Mooney CT - Ir Vet J (2007)

Bottom Line: Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved.A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination.Tertiary hypothyroidism has not been previously reported in dogs.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. robert.shiel@ucd.ie.

ABSTRACT
: A nine-year-old male entire Labrador was diagnosed with pituitary dependent hyperadrenocorticism. Following seven months of successful mitotane therapy, the dog presented with marked weight gain, seborrhoea and alopecia. Routine clinicopathological analyses revealed marked hypercholesterolaemia. Serum total and free thyroxine (T4) concentrations were below their respective reference ranges. Serum thyroid stimulating hormone (cTSH) concentration was within reference range. TSH and thyrotropin releasing hormone (TRH) response tests revealed adequate stimulation of total T4 in both, and cTSH in the latter test. Magnetic resonance imaging revealed a mass arising from the pituitary fossa, with suprasellar extension. A diagnosis of tertiary hypothyroidism was made. Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved. Euthanasia was performed four months later due to the development of neurological signs. A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination. Tertiary hypothyroidism has not been previously reported in dogs.

No MeSH data available.


Related in: MedlinePlus

Transverse T1 weighted post contrast image of the brain. The hyperintense mass in the 'sella turcica' appears bilobed and mildly asymmetric, protruding slightly towards the left cerebral hemisphere (indicated with arrow).
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Figure 2: Transverse T1 weighted post contrast image of the brain. The hyperintense mass in the 'sella turcica' appears bilobed and mildly asymmetric, protruding slightly towards the left cerebral hemisphere (indicated with arrow).

Mentions: Routine clinicopathological tests were repeated and amarked hypercholesterolaemia was detected (Table 1). An ACTH stimulation test showed adequate control of hyperadrenocorticism (Table 2). Basal serum total and free thyroxine (T4) values were below their respective reference ranges (Table 3). Serum cTSH concentration was within the lower end of the reference range (Table 3). A TSH stimulation test was performed using 75 μg of intravenous recombinant human TSH (Thyrogen, Genzyme corporation) [29,28] and revealed an adequate rise in concentration of total T4 after six hours (Table 3). A TRH response test was subsequently performed using 200 μg of TRH (Protirelin, Cambridge Labs, Cambridge, UK) [30] and revealed a substantial elevation in cTSH concentration after 30 minutes and an adequate increase in total T4 after four hours (Table 3). Magnetic resonance imaging (MRI) revealed a roughly bilobed, 2 × 2 × 3 cm mass arising from the pituitary fossa, showing suprasellar extension dorsally and rostrally, with a marked mass effect on neighbouring structures (Figures 1 and 2).


Tertiary hypothyroidism in a dog.

Shiel RE, Acke E, Puggioni A, Cassidy JP, Mooney CT - Ir Vet J (2007)

Transverse T1 weighted post contrast image of the brain. The hyperintense mass in the 'sella turcica' appears bilobed and mildly asymmetric, protruding slightly towards the left cerebral hemisphere (indicated with arrow).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113834&req=5

Figure 2: Transverse T1 weighted post contrast image of the brain. The hyperintense mass in the 'sella turcica' appears bilobed and mildly asymmetric, protruding slightly towards the left cerebral hemisphere (indicated with arrow).
Mentions: Routine clinicopathological tests were repeated and amarked hypercholesterolaemia was detected (Table 1). An ACTH stimulation test showed adequate control of hyperadrenocorticism (Table 2). Basal serum total and free thyroxine (T4) values were below their respective reference ranges (Table 3). Serum cTSH concentration was within the lower end of the reference range (Table 3). A TSH stimulation test was performed using 75 μg of intravenous recombinant human TSH (Thyrogen, Genzyme corporation) [29,28] and revealed an adequate rise in concentration of total T4 after six hours (Table 3). A TRH response test was subsequently performed using 200 μg of TRH (Protirelin, Cambridge Labs, Cambridge, UK) [30] and revealed a substantial elevation in cTSH concentration after 30 minutes and an adequate increase in total T4 after four hours (Table 3). Magnetic resonance imaging (MRI) revealed a roughly bilobed, 2 × 2 × 3 cm mass arising from the pituitary fossa, showing suprasellar extension dorsally and rostrally, with a marked mass effect on neighbouring structures (Figures 1 and 2).

Bottom Line: Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved.A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination.Tertiary hypothyroidism has not been previously reported in dogs.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. robert.shiel@ucd.ie.

ABSTRACT
: A nine-year-old male entire Labrador was diagnosed with pituitary dependent hyperadrenocorticism. Following seven months of successful mitotane therapy, the dog presented with marked weight gain, seborrhoea and alopecia. Routine clinicopathological analyses revealed marked hypercholesterolaemia. Serum total and free thyroxine (T4) concentrations were below their respective reference ranges. Serum thyroid stimulating hormone (cTSH) concentration was within reference range. TSH and thyrotropin releasing hormone (TRH) response tests revealed adequate stimulation of total T4 in both, and cTSH in the latter test. Magnetic resonance imaging revealed a mass arising from the pituitary fossa, with suprasellar extension. A diagnosis of tertiary hypothyroidism was made. Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved. Euthanasia was performed four months later due to the development of neurological signs. A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination. Tertiary hypothyroidism has not been previously reported in dogs.

No MeSH data available.


Related in: MedlinePlus