Biomedical subjects

M Alegre

Publications and source records attributed to M Alegre.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Etiology and outcome of non-estrogen associated hyperthyroxinemia in euthyroid patients at the San Juan City Hospital.

INTRODUCTION: Hyperthyroxinemia does not always equate to hyperthyroidism. Laboratory tests should always be correlated with the clinical picture. A mismatch should make one doubt true hyperthyroidism. The purpose of our study was to assess the etiology of euthyroid hyperthyroxinemia not associated with estrogen use or pregnancy and to review the outcome of those erroneously treated. METHODS: The medical records of thirteen euthyroid patients with non estrogen associated hyperthyroxinemia were reviewed. They had a complete set of thyroid function tests including free T3 and free T4 by membrane dialysis, TRH stimulation test and thyroid hormone binding panel. RESULTS: Two diagnostic groups were identified: Hyperthyroxinemia secondary to binding abnormalities (7/13), better known as familial dysalbuminemic hyperthyroxinemia (FDH) and hyperthyroxinemia secondary to Thyroid Hormone Resistance (THR) (6/13). The FDH group had an elevated T4 and FTI, with normal T3RU, TSH, TRH stimulation test but an abnormal thyroid hormone binding panel which was used to confirm the diagnosis. The THR group had two laboratory presentations: Four patients presented with all the thyroid hormone tests elevated (T4, T3, T3RU, FTI) including a free T3 and free T4 by membrane dialysis with a normal TSH and TRH stimulation test and a normal T4 binding panel. This presentation is typical for a TRH patient with a nuclear receptor defect where all the precursos to the defect accumulate. Two patients with THR presented elevated T4 and free T4 but normal T3 and free T3, localizing the defect at the level of the active T4 transport mechanism across the cellular membrane. These two patients had a normal TSH, TRH stimulation test and T4 binding panel. Two patients were treated erroneously with radioactive iodine and became extremely hypothyroid in spite of normal TFTs. Very high dose of thyroid hormone replacement were required to restore euthyroidism. CONCLUSION: One must suspect these two entities in patients clinically euthyroid who have elevated T4 but non-suppressed TSH. A normal TSH and TRH test confirm euthyroidism. A thyroid hormone binding panel differentiates FDH from THR. Neither group require treatment. If treated erroneously and T4 drops to normal values, one must again induce hyperthyroxinemia to restore euthyroidism in these patients.

Adolescent↗

PubMedDate not supplied

[Pathogenesis of Alzheimer's disease].

Alzheimer's disease (AD) is a multifactorial entity with a complex pathogeny. Recent findings on this subject are discussed in this article, centering mainly on genetic factors, cerebral ischemia and their association with the most typical histologic lesions in AD. Finally, a hypothetical model is proposed, in which beta-amyloid represents the key element.

Alzheimer Disease↗

PubMedDate not supplied

[Male pseudohermaphroditism caused by enzymatic deficiency of 17-alpha-hydroxylase. 1st case reported in Puerto Rico].

A 36 year old white female came to our service after having been evaluated on repetitive occasions in the past for a workup of gigantism and acromegalic features. Since childhood she had developed tall stature, frontal bossing, prominence of zygomatic bones, separated teeth, large hands and size 14 shoes. Human growth hormone and somatomedin serum levels had been normal on all occasions tested. Her past history was significant for primary amenorrhea and a 12 year history of hypertension. On physical examination BP was 140/100, height 6' 2", weight 2571 bs. Her phenotype was truly acromegalic. There was absence of axillary and pubic hair with no breast development. External genitalia was of female appearance. Laboratory evaluation showed increased FSH of 88 mlU/ml, increase LH of 65.6 mlU/ml and decreased E2 of 12.6 pg/ml. Other findings were low serum cortisol of 0.2 mg/dl, high ACTH of 344 pg/ml, low 17-Ketosteroids, high pregnenolone levels of 595 mg/dl, low 17-hydroxypregnenolone less than 10 ng/dl, very high aldosterone of 31 ng/dl and suppressed PRA of less than 0.1 ng/ml. A pelvic sonogram showed a right ovoid structure which could represent a gonad and failed to identify the uterus and left gonad. A bone densitometry showed a decrease bone mineral density compatible with osteoporosis. Chromosome study showed a karyotype of 46-XY. A diagnosis was made of congenital adrenal hyperplasia secondary to 17-alpha-hydroxylase deficiency in a genotypic male. Our patient was referred to the department of gynecology for surgical removal of the gonads. It is amazing how a patient with severe adrenal insufficiency can withstand 36 years of her life undiagnosed without going into an adrenal crisis. Her tall stature and acromegalic features were the striking signs confusing all physicians and delaying the correct diagnosis and appropriate treatment. There has been reported worldwide, nearly 120 cases with documented severe 17-alpha-hydroxylase deficiency. To our knowledge this is the first case identified in Puerto Rico of male pseudohermaphroditism secondary to 17-alpha-hydroxylase enzyme deficiency.

Acromegaly↗