Pituitary Deficiencies

Nestle Purina Petcare, New York, NY, USA.
Topics in Companion Animal Medicine (Impact Factor: 1.41). 02/2012; 27(1):2-7. DOI: 10.1053/j.tcam.2012.04.002
Source: PubMed


Diabetes insipidus, arising from damage to or congenital abnormalities of the neurohypophysis, is the most common pituitary deficiency in animals. Hypopituitarism and isolated growth hormone or thyrotropin deficiency may result in growth abnormalities in puppies and kittens. In addition, treatment of associated hormone deficiencies, such as hypothyroidism and hypoadrenocorticism, in patients with panhypopituitarism is vital to restore adequate growth in dwarfed animals. Secondary hypoadrenocorticism is an uncommon clinical entity; however differentiation of primary versus secondary adrenal insufficiency is of utmost importance in determining optimal therapy. This article will focus on the pathogenesis, diagnosis and treatment of hormone deficiencies of the pituitary gland and neurohypophysis.

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    ABSTRACT: Hypothalamic hypopituitarism is relatively rare cause of secondary adrenal deficiency which is often accompanied by severe hypoglycemia. Hydrocortisone replacement therapy is essential for this condition, but gastrointestinal symptom such as nausea and vomiting is not well-recognized adverse effect of hydrocortisone. A 64-year-old-woman was referred to our hospital because of frequent severe hypoglycemia. She was diagnosed as type 2 diabetes when she was 58 years old but had not been treated since she was 60. We ruled out the possibility of exogenous administration of insulin or other anti-diabetic drugs, insulinoma and insulin autoimmune syndrome. After glucose injection, she once became conscious, but severe hypoglycemia was often observed even after that. In addition, counter-regulatory hormone levels were not increased even at the time of hypoglycemia. We conducted several hormone load tests. In corticotropin-releasing hormone (CRH) load test, excess and delayed reaction of ACTH was observed. In thyrotropin-releasing hormone (TRH) load test, TSH and prolactin were normally secreted in response to TRH. In luteinizing hormone-releasing hormone (LHRH) load test, delayed reaction of LH and FSH was observed. Based on such hormone loading tests, we diagnosed this patient as idiopathic hypothalamic hypopituitarism and consequent adrenal deficiency. We immediately intravenously injected hydrocortisone and started oral hydrocortisone therapy. However, just after taking hydrocortisone, vomiting was often observed which disturbed sufficient steroid hormone replacement, leading to recurrent hypoglycemia. Therefore, we stopped hydrocortisone and instead started an alternative treatment with prednisolone. After that, vomiting and hypoglycemia were not observed at all. We diagnosed this subject as hypothalamic hypopituitarism mainly by the following two findings: (1) excess and delayed reaction of ACTH in CRH load test, (2) delayed reaction of LH and FSH in LHRH load test. We should be aware of the possibility of hypothalamic hypopituitarism as a cause of recurrent severe hypoglycemia. Also, we should be aware that hydrocortisone could induce gastrointestinal symptom and that in such a case we should stop hydrocortisone and start prednisolone to sufficiently replace steroid hormone and avoid recurrent hypoglycemia.
    SpringerPlus 12/2015; 4(1):173. DOI:10.1186/s40064-015-0934-6