HPT Axis And Disorder Flash Cards
What is the hypothalamic-pituitary axis?
A complex neuroendocrine system that regulates hormone secretion from the hypothalamus and pituitary gland.
What are the two main components of the pituitary gland?
Anterior pituitary (adenohypophysis) and posterior pituitary (neurohypophysis).
What hormones are released by the anterior pituitary?
ACTH, TSH, GH, PRL, LH, and FSH.
What hormones are stored and released by the posterior pituitary?
Oxytocin and vasopressin (ADH).
What hormone regulates the release of ACTH?
Corticotropin-releasing hormone (CRH).
What is the function of growth hormone (GH)?
Stimulates growth, protein synthesis, and metabolism.
What is the primary inhibitory factor for prolactin secretion?
Dopamine.
What is the function of TSH?
Stimulates the thyroid gland to produce T3 and T4.
What is the role of oxytocin?
Stimulates uterine contractions during labor and milk ejection during breastfeeding.
What are common causes of pituitary dysfunction?
Tumors, trauma, inflammation, infarction, and genetic disorders.
What is the most common type of pituitary adenoma?
Prolactinoma.
What are the symptoms of a prolactinoma?
Galactorrhea, amenorrhea, infertility, and decreased libido.
What is the first-line treatment for prolactinoma?
Dopamine agonists like cabergoline or bromocriptine.
What is Sheehan’s syndrome?
Postpartum pituitary infarction leading to hypopituitarism.
What is the most common cause of growth hormone deficiency?
Pituitary tumors or congenital defects.
What is acromegaly?
Excess growth hormone secretion in adults, leading to enlarged hands, feet, and facial features.
What is the most common cause of acromegaly?
Pituitary adenoma secreting GH.
What test is used to diagnose acromegaly?
Oral glucose tolerance test with GH measurement.
What is the main treatment for acromegaly?
Transsphenoidal surgery to remove the tumor.
What is diabetes insipidus?
A disorder of ADH deficiency leading to polyuria and polydipsia.
What are the two types of diabetes insipidus?
Central DI (due to ADH deficiency) and nephrogenic DI (due to renal resistance to ADH).
What is the water deprivation test used for?
To differentiate between central and nephrogenic diabetes insipidus.
What is the treatment for central diabetes insipidus?
Desmopressin (DDAVP).
What is SIADH?
Syndrome of inappropriate ADH secretion, leading to hyponatremia and water retention.
What are the common causes of SIADH?
Lung cancer, CNS disorders, medications, and infections.
What is the treatment for SIADH?
Fluid restriction, salt tablets, and vasopressin receptor antagonists.
What is panhypopituitarism?
Deficiency of all anterior pituitary hormones.
What is the gold standard test for assessing adrenal insufficiency?
ACTH stimulation test.
What is Cushing’s disease?
Excess ACTH secretion from a pituitary adenoma causing hypercortisolism.
What is the most common cause of secondary hypothyroidism?
Pituitary dysfunction leading to decreased TSH production.
What is the effect of excess GH in children?
Gigantism.
What is the most common cause of hyperprolactinemia?
Prolactinoma.
What medication is commonly associated with drug-induced hyperprolactinemia?
Antipsychotics (e.g., risperidone, haloperidol).
What is Nelson’s syndrome?
Pituitary tumor enlargement following bilateral adrenalectomy for Cushing’s disease.
What is Kallmann syndrome?
Congenital GnRH deficiency leading to hypogonadotropic hypogonadism and anosmia.
What is the function of FSH and LH?
FSH stimulates follicular development and spermatogenesis; LH triggers ovulation and testosterone production.
What is the effect of hypopituitarism on cortisol levels?
Low cortisol due to decreased ACTH production.
What is the first-line treatment for GH deficiency?
Recombinant human growth hormone therapy.
What is pituitary apoplexy?
Sudden hemorrhage or infarction of the pituitary gland, often in a pre-existing adenoma.
What are the symptoms of pituitary apoplexy?
Severe headache, visual disturbances, and hormonal deficiencies.
What is Laron syndrome?
GH receptor insensitivity leading to short stature despite high GH levels.
What is the first-line treatment for Cushing’s disease?
Transsphenoidal surgery to remove the pituitary adenoma.
What are the primary effects of ADH on the kidneys?
Increases water reabsorption in the collecting ducts to concentrate urine.
What is the common cause of pituitary dwarfism?
GH deficiency in childhood.
What test confirms ACTH-dependent Cushing’s syndrome?
High-dose dexamethasone suppression test.
What imaging is used for pituitary tumors?
MRI with contrast.
What is the most common symptom of a non-functioning pituitary adenoma?
Bitemporal hemianopia due to optic chiasm compression.
What is a craniopharyngioma?
A benign tumor affecting the hypothalamic-pituitary region, often seen in children.
What condition is associated with optic nerve compression and hormonal dysfunction?
Pituitary macroadenoma.
What is the role of TRH in the hypothalamic-pituitary axis?
Stimulates the release of TSH and prolactin from the anterior pituitary.
What is the effect of pituitary stalk compression on prolactin levels?
Increased prolactin due to loss of dopamine inhibition.
What is the function of the median eminence of the hypothalamus?
Site where hypothalamic hormones are released into the portal circulation.
What is the major cause of secondary adrenal insufficiency?
Prolonged corticosteroid use leading to HPA axis suppression.
What is the major regulator of aldosterone secretion?
Renin-angiotensin system.
What is the primary treatment for pituitary tumors?
Transsphenoidal surgery, medical therapy, or radiation.
