Endocrine Flashcards
Pituitary Adenoma
Benign tumor anterior pituitary
functional if it secretes hormones, nonfunctional if it is silent
Nonfunctional tumors can present as mass effect (compress optic chiasm get bitemporal hemianopsia, compress ituitary = hypopituitarism, headache)
Prolactinoma
Pituitary Adenoma that secretes prolactin
galactorrhea and ammenorhea in females
decreased libido and headaches
Treat with dopamine agonists like bromocriptine or cabergoline
Growth Hormone Cell adenoma
Pituitary Adenoma that secretes GH
Children = gigantism
Adults = acromegally (large hands, feet, and jaw), growth of visceral organs leads to dysfunction (heart failure) and enlarged tongue
Also get secondary DM (GH decreases glucose uptake in cells)
Treat with ostreotide (somatostatin that supresses release of GH), GH Receptro antagonists, or surgery
ACTH Cell Adenomas
Pituitary Adenoma that secretes ACTH
Get Cushing Syndrome
Hypopituitarism
Insufficeint production of hormones by the anterior pituitary
Causes include
1) pituitary adenomas or craniopharyngioma with mass effects or pituitary apoplexy (bleeding into an adenoma)
2) Sheehan syndrome = pregnancy related infarction of the pituitary gland
3) Empty Sella Syndrome - herniation of the arachnoid and CSF into the sell compresses and destroys the pituitary gland
Sheehan Syndrome
Pituitary gland doubles in size during pregnancy but vasculature cannot keep up , blood loss during parturition precipitates infarction and leads to hypopituitarism
Hormones in Posterior Pituitary
ADH - acts on distal tubules and collecting ducts to promote free water retention
Oxytocin = mediates uterine contraction and release of breast milk
both are made in hypothalmaus and then transported to posterior by axonal transport
Central Diabetes Insipidus
ADH deficiency due to hypothalamic or posterior pituitary pathology
Get loss of free water leading to
1)polyuria and polydipsia with dangerous dehydration
2)hypernatremia and high serum osmolarity
Water deprivation test fails to increase urine osmolality
Treatment is desmopressin (ADH analog)
Nephrogenic Diabetes insipidus
Impaired renal response to ADH
Due to inherited mutations or drugs (lithium and demeclocycline)
Get loss of free water leading to
1)polyuria and polydipsia with dangerous dehydration
2)hypernatremia and high serum osmolarity
Does not respond to desmopressin treatment
Syndrome of Inappropriate ADH Secretion
Excessive ADH secretion
Usually due to ectopic production (small cell carcinoma of lung), CNS trauma, pulmonary infection, COPD, drugs like cyclophosphamide.
Retention of free water leads to
1) hyponatremia
2)Mental status change and seizures since hyponatremia leads to neuronal swelling and cerebral edema
treatment is free water restriction or democlocycline
Thyroglossal Duct Cyst
Cystic dilation of thyroglossal duct remnant which is supposed to normally involute.
Presents as an anterior neck mass
Lingual Thyroid
Persistence of thyroid tissue at the base of the tongue
Presents as a base of tongue mass
Mechanism and Symptoms of hyperthyroidism
Increased levels of circulating thyroid hormone 1) increases basal metabolic rate (by increasing synthesis of Na-K-ATPase) 2) Increases sympathetic nervous system activity (due to icnreased expression of Beta1 adrengergic receptors)
SYMPTOMS
weight loss, heat intolerance, tachycardia, arrythmia, tremor, anxiety, insomnia, diarrhea, oligomennorhea, bone resoprtion (hypercalcemia and osteoperosis), decreased muscle mass, HYPOCHOLESTEROLEMIA, HYPERGLYCEMIA
Grave Disease
- mechanism
- symptoms
- Path
- Labs
- Treatment
- Complications
M = Autoantibody (IgG) that stimulates the TSH receptor (type II hypersensitivity) leads to increased synthesis and release of thyroid hormone. Classically seen in women of childbearing age. S = Get hyperthyroidism, diffuse goiter, exophthalmos and pretibial myxedema (fibroblasts behind the orbit and overlying the shin express the TSH receptor, activation results in GLYCOSAMINOGLYCAN buildup, inflammation, fibrosis, and edema) P = irregular follicles with scalloped and chronic inflammation L = Increased total and free T4, decreased TSH, hypocholesterolemia, increased serum glucose T = Beta blockers, thioamide, and radioiodide ablation C= Thyroid storm (elevated catecholamines and massive hormone excess, arrythmia, hyperthermia, and vomitting with hypovolemic shock) treat with propylthiouracil (inhibits peroxidase and peripheral conversion of T4 to T3), beta blockers, and steroids
Multinodular Goiter
Enlarged thyroid gland with multiple nodules
Due to relative iodine deficiency
Usually nontoxic
Rarely regions become TSH-independent leading to T4 release and hyperthyroidism (toxic goiter)
Cretinism
Hypothyroidism in neonates and infants
Characterized by mental retardation, short stature, caorse facial features, enlarged tongue, and umbilical hernia
Can be casued by maternal hypothyroidism in early pregnancy, thyroid agenesis, dyshormonogenetic goiter, and iodine deficiency (peroxidase mutation)
Myxedema
hypothyroidism in older children and adults
Clinical features based on decreased metabolic rate and decreased sympathetic nervous system activity
Get myxedema (results in DEEP VOICE and ENLARGED TONGUE), weight gain, slowing of mental activity, ,muscle weakness, cold intolerance, bradycardia, oligomenorrhea, HYPERCHOLESTEROLEMIA, constipation
Usually due to iodine deficiency, hashimoto thyroiditis, lithium, or surgical removal
Hasimoto Thyroiditis
Autoimmune destruction of thyroid gland, associated with HLA-DR5
Clinical presents intially as hyperthyroidism as preformed follicles release their T3, T4, but eventually progresses to hypothyroidism (decreased T4 and Increased TSH)
See Chronic inflammation with germinal centers and hurthle cells
Increased risk for B-Cell (marginal zone) lymphoma
Subacute Granulomatous (De Quervain) Thyroiditis
Granulomatous thyroiditis that follows a viral infection
Presents as tender thyroid with transient hyperthyroidisim. Usually self limited but may progress to hypothyroidism
Reidel Fibrosing Thyroiditis
Chronic Inflammation with extensive fibrosis of the thyroid gland
Hypothyroidism with a “HARD AS WOOD” nontender thyrid gland
Fibrosis may extend to involve local structures such as airways
See in YOUNG patients (40s)
“Hot” vs “Cold Nodule
I radioactive uptake studies are useful to charcteriz thyroid nodules.
Take up lots of I = hot = seen in graves disease or nodular goiter
Take up little I = cold = seen in adenoma and carcinoma, often warrants biopsy
How to biopsy Thyroid
Fine Needle Aspiration since it is highly vascualr and would bleed to much if do actual biopsy
Follicular Adenoma
Benign proliferation of follicles surrounded by a fibrous capsule.
Typically nonfunctional but can secrete thyroid hormone