|Acromegaly/gigantism||Etiology: Gigantism and acromegaly are usually caused by a pituitary adenoma that secretes excessive amounts of Growth Hormone; rarely, they are caused by non-pituitary tumors that secrete GHRH
Treatment: Pituitary tumor removal
|Diabetes insipidus (ReelDx)||Diabetes insipidus (DI) is caused by a deficiency of or resistance to vasopressin (ADH), which decreases the kidneys' ability to reabsorb water, resulting in massive polyuria
Serum osmolality (concentration) is high (unable to stop secretion of water into the kidneys so blood becomes more concentrated) and urine osmolality is low because it is so dilute
The water deprivation test is the simplest and most reliable method for diagnosing central diabetes insipidus but should be done only while the patient is under constant supervision. Serious dehydration may result
|Pituitary dwarfism||Etiology: Achondroplasia (FGFR3 mutation)
Presentation: Short stature/limbs, prominent brow, midfacial hypoplasia
Labs: ↓ GH, ↓ IGF1
BONE AGE: The primary symptom of pituitary dwarfism is lack of height. Therefore, a change in the individual's growth habits will help lead to a diagnosis.
If dwarfism is due to decreased human growth hormone, and not due to a primary skeletal disorder, the child can be treated with human growth hormone treatments to try and stimulate normal growth.
Surgery may be necessary to remove a pituitary adenoma if that is the cause of the dwarfism.
|Pituitary adenoma and Pituitary neoplastic disease||A 39-year-old woman with bilateral milky breast discharge decreased lateral vision fields, and pituitary mass (prolactinoma)
Most common tumors are microadenomas that are functional (hypersecretion of pituitary hormones), nonfunctional or compressive
|The posterior pituitary is an endocrine gland primarily composed of the nerve terminals of axons extending from the hypothalamus. It is important in the neuroendocrine reflex, which occurs when sensory neurons are stimulated resulting in action potential in hypothalamic cells and exocytosis of hormones from the posterior pituitary. Vasopressin is one of the hormones released from the posterior pituitary. Vasopressin is synthesized in the hypothalamus but stored in the posterior pituitary and released in response to synaptic input from osmoreceptors that detect increased osmolality of blood plasma. This hormone affects the kidney into retaining more water and also can constrict blood vessels. The second hormone released from the posterior pituitary is Oxytocin. It is released via a neuroendocrine reflex in response to stimulation of the nipples during breastfeeding that causes the mammary glands to contract and release milk. Stimulation of the nipples causes action potential generation in the oxytocin cells of the hypothalamus, which travels down to the nerve endings in the posterior pituitary and results in the exocytosis of Oxytocin. It also causes uterine smooth muscle contraction during the second and third stages of labor.|
|The anterior pituitary is an endocrine gland that releases a variety of hormones in response to stimulus from the hypothalamus and other sources. ACTH, adrenocorticotropic hormone, stimulates the adrenal glands into releasing cortisol. FSH and LH both stimulate the gonads (ovaries and testes). FSH (follicle-stimulating hormone) regulates reproductive processes, sexual maturation, development, and growth. LH stimulates the ovaries and testes into producing estrogen and progesterone, and testosterone respectively. Thyroid-stimulating hormone (TSH) stimulates the thyroid gland into producing thyroxine (T4) and triiodothyronine (T3), both of which stimulate metabolism in most tissues. Prolactin is a peptide hormone that stimulates milk production from the mammary glands and can affect levels of sex hormones. The other hormones released, but not shown here, are endorphins, which are released in response to exercise, pain, and excitement and cause a feeling of analgesia (well-being). Finally, growth-hormone stimulates cell reproduction, development, and growth.|