[Discrepancy between IGF-1 and GH during 75 g oral glucose tolerance test measures to acromegaly screening in a patient with macroprolactinoma--case report and literature review]. / Discordância entre IGF-1 e GH pós-sobrecarga de glicose no rastreamento de acromegalia em paciente com macroprolactinoma--relato de caso e revisão sobre o tema.

We describe a patient with macroprolactinoma and discrepant insulin-like growth factor (IGF-1) concentration (elevated) and growth hormone (GH) values during a 75 g oral glucose tolerance test (normal), that were measured to evaluate the co-secretion of GH by tumor. With the bromocriptin use, the patient achieved normalization of prolactin, but persisted with high levels of IGF1, suggesting to be subclinical acromegaly. After the development of new more sensitive GH assays, cases of discrepant GH and IGF-1 results have been observed and taken to some authors to suggest that GH nadir concentration during 75 g OGTT used to acromegaly diagnosis and treatment could be lower than values considered currently normal. Thus, if this is confirmed, subclinical and oligosymptomatic acromegaly cases could have earlier diagnoses.

Discordância entre IGF-1 e GH pós-sobrecarga de glicose no rastreamento de acromegalia em paciente com macroprolactinoma: relato de caso e revisão sobre o tema / Discrepancy between IGF-1 and GH during 75 g oral glucose tolerance test measures to acromegaly screening in a patient with macroprolactinoma: case report and literature review

Neste artigo, descrevemos o caso de um paciente com diagnóstico de macroprolactinoma, que apresentava valores discordantes entre IGF-1 (elevado) e GH (hormônio de crescimento) pós-teste de tolerância oral à glicose (normal) realizados para pesquisa de co-secreção de GH pelo tumor. Houve normalização dos níveis de prolactina após uso de bromocriptina, porém, durante o acompanhamento, o paciente persistiu com níveis elevados de IGF-1 sem clínica aparente, sugerindo tratar-se de possível forma subclínica de acromegalia. Após o desenvolvimento de novos métodos laboratoriais, mais sensíveis, para a dosagem de GH, casos de discordância entre esses testes vêm sendo observados, levando alguns autores a sugerir que o nadir de GH pós-teste de tolerância à glicose oral (TTGO) para diagnóstico e tratamento da acromegalia pode ser bem menor do que o limite considerado atualmente (1,2). Assim, se isto for confirmado, casos subclínicos ou oligossintomáticos de acromegalia serão diagnosticados mais precocemente.

We describe a patient with macroprolactinoma and discrepant insulin-like growth factor (IGF-1) concentration (elevated) and growth hormone (GH) values during a 75 g oral glucose tolerance test (normal), that were measured to evaluate the co-secretion of GH by tumor. With the bromocriptin use, the patient achieved normalization of prolactin, but persisted with high levels of IGF1, suggesting to be subclinical acromegaly. After the development of new more sensitive GH assays, cases of discrepant GH and IGF-1 results have been observed and taken to some authors to suggest that GH nadir concentration during 75 g OGTT used to acromegaly diagnosis and treatment could be lower than values considered currently normal. Thus, if this is confirmed, subclinical and oligosymptomatic acromegaly cases could have earlier diagnoses.