Bikman: Endocrine Path Flashcards
Anterior Pituitary hormones
ACTH
LH
FSH
GH
PRL
TSH
Which glands are affected with primary, secondary, tertiary deficiencies?
Primary - Target gland
Secondary - Pituitary
Tertiary - Hypothalamus
Where do most problems occur in the hypothalamus-pituitary axis?
Hypothalamus and Pituitary
(Tertiary and Secondary)
Posterior pituitary
- Consists of neurons with a cell body in the hypothalamus and the axon ending in the posterior pituitary
- Neurons release the small peptides oxytocin and ADH directly into the blood
Posterior Pituitary Disorders
Hypersecretion of ADH - SIADH
Hyposecretion of ADH - Diabetes Insipidus
Hypersecretion of oxytocin - Galactorrhea
Hyposecretion of oxytocin - lack of milk ejection, prolonged labor, lack of compassion/bonding
What are the causes of SIADH?
- Ectopic production of ADH (by cancer cells)
- Surgery (surgery related stress)
- Some drugs
- Cranial abnormalities (trauma, tumor, etc)
What are the clinical manifestations of SIADH?
- ↑water retention
- ↑Na+ loss due to ↑BV
- Hyponatremia - blood is becoming more dilute while urine is becoming more concentrated
- Hypoosmolarity - ↓serum osmolarity
The body is slowlyl becoming hypOtonic; the urine, hypERtonic
What are actions of SIADH?
-
↑permeability of renal collecting duct to water
- ADH inserts aquaporins into the wall of the collecting duct
- Constriction of arterial SM @ high concentrations
What are treatments for SIADH?
- Restrict H2O
- Remove tumor (if present)
- ADH receptor blocker
What are the clinical manifestations of diabetes insipidus?
- Manifests with polyuria (high urine flow)
- Polydipsia - drinking lots of H2O
- Dilute urine - cannot concentrate it
- Dehydration
What are the different types of diabetes insipidus?
- Neurogenic
- Nephrogenic
- Psychogenic
Neurogenic Diabetes Insipidus
Insufficient ADH
Damage to the brain or posterior pituitary from head trauma, cranial surgery or tumor; idiopathic
Nephrogenic Diabetes Insipidus
Insufficient ADH response
- Lack of ADH receptors in kidney or failure of receptors to modify permeability of the collecting duct
- Genetic
- Temporary nephro DI can be caused by some drugs, pregnancy, electrolyte imbalance, kidney trauma
- Permanent nephro DI from kidney failure
Psychogenic Diabetes Insipidus
Drinking too much H2O
From trying to get rid of toxins, demons?!, etc
Tx for Neurogenic DI?
ADH replacement
Tx for nephrogenic DI?
Drink lots of H2O and eat a lot of NaCl
Tx for psychogenic DI?
Restrict H2O intake
What is oxytocin release stimulated by?
- Cervix stretching during birth
- Breast stimulation (nursing)
- Psychological: Hearing the baby cry, thinking about the baby, stress
What are the effects of oxytocin?
- Role in intimacy (bonding, orgasm)
- May cause a degree of amnesia
- Endorphins might also play a role
What are the hormones that are released by the anterior pituitary?
- FSH - Follicle Stimulating hormone
- LH - Lutenizing hormone
- ACTH - Adrenocorticotrophic hormone
- TSH - Thyroid Stimulating hormone
- PRL - Prolactin
- GH - Growth hormone
Hormone pairs in the hypothalamic-pituitary axis
- GnRH –> FSH, LH
- TRH –> TSH
- CRH –> ACTH
- PIF –> PRL
- GHRH –> GH
Hypothalamic Factor Stimulation Tests
Determining if problem originates in hypothalamus or anterior pituitary
- Take blood from patient under resting conditions
- Inject one or more hypothalamic releasing factors
- Wait a few minutes and then take another sample
- Compare the amount of various anterior pituitary hormones before and after injection of hypothalamic factors
If pituitary hormone increases - Hypothalamus
If pituitary hormone does NOT increase - Pituitary
Hypothalamic hormone is high, pituitary hormone is low - Target gland
Anterior pituitary disorders
Hypopituitarism - Pituitary infarction, Empty sella syndrome
Hyperpituitarism - Pituitary adenoma, end organ destruction, hypothalamic disorder, carcinoma (not as common as adenoma)
Tx of pituitary adenoma
- Hormone therapies (depending on the problem)
- Surgery (may return)
- Radiation
Symptoms of pituitary adenoma
- Visual defect (if tumor is large)
- Headache (if tumor is large)
- Oculomotor palsies may result
- Manifestation: can’t properly dilate or constrict the pupil in one or both eyes
- No eye tracking
- Can’t open eyelids properly
Regulation of PRL Release
Actions of PRL
- Proliferation of glandular tissue of mammary glands
- Synthesis of milk proteins by mammary glands
- ↑calcium mobilization from bone and secretion of calcium into milk
- Stimulates immune system
Sex Effects of Hypersecretion of PRL
- Females
- Amenorrhea
- Galactorrhea
- Hirsutism
- Osteopenia - weakening of the bones due to ↑Ca2+ mobilization
- Males
- Hypogonadism
- Impaired libido
- Infertility
- Gynecomastia
- Galactorrhea
Tx for Hypersecretion of PRL
- DA agonists i.e. bromocryptin
- Somatostatin analogs i.e. octreotide
Manifestation of Hyposecretion of PRL
- Poor milk production
- Poor immune system function
Tx for Hyposecretion of PRL
- ↓plasma concentrations of PRL
- TRH-stimulation test utilized to determine if the problem is at pituitary or hypothalamus
- ↓PRL after TRH injection: problem at pituitary
- ↑PRL release after TRH injection: problem at hypothalamus
Hypersecretion of GH disorders
- Gigantism (pre-pubertal adenoma)
- Tall & long limbs
- Acromegaly (post-pubertal adenoma)
- May be tall
- Enlarged bones of face, hands
- Enlarged soft tissues (tongue, heart)
Why can GH hypersecretion be lethal?
Increased risk of hypertrophic cardiomyopathy
What are clinical manifestations of GH hypersecretion?
- Large tongue, lips, fingers, toes, jaw bone, ears, skull bones
- ↑blood glucose
- Headaches if tumor is large
- Vision problems if tumor is large
- Joint pain
- Barrel chest
- CV diseases - HTN, cardiac hypertrophy, etc. = early death
- Malignancies may become more aggressive (GH and IGF are growth factors)
Tx for hypersecretion of GH
Somatostatin analog - inhibits GH, glucagon, insulin
Hyposecretion of GH
- Growth failure
- ↑% of fat and reduced lean mass
- Poor strength and development of bones (bones are thin and fragile)
- Poor immune function
Hyposecretion of GH: young adult onset
- Poor lactation
- Poor immune function
- ↓blood glucose
- Depression
- ↓mass of bone
Hyposecretion of GH: GH and aging
- GH falls at about age 60-65
- May cause ↓function of immune system, ↑fat mass, ↓protein mass, ↓bone density associated with aging
- IGF ↑tumor aggressiveness
What is the normal regulatory pathway for thyroid hormone?
Hypothalamic TRH > Pituitary TSH > T3/T4
What are the actions of T3?
- Regulates basal activity of most cells - “Metabolic choke valve”
- Affects cellular activity by binding to an IC receptor and interacting with DNA to ↑mRNA synthesis
- Functions of most cells require thyroid hormones (muscles, nerves, glands, etc)
- ↓thyroid hormones = ↓cell growth, poor protein synthesis, poor conduction of nerve impluses
Clinical manifestations of hyerthyroidism AKA thryotoxicosis
- General: weight loss, heat intolerance
- Cardiac: rapid pulse, arrhythmias, clots
- Neuromuscular: tremor
- Skin: warm, moist
- GI: diarrhea
- Eye: exophthalmos, lid lag
- Thyroid storm: extreme, dangerous symptoms
What are common causes of hyperthyroidism AKA thyrotoxicosis?
- Graves disease
- Multinodular goiter
- Thyroid adenoma
What are uncommon causes of hyperthyroidism AKA thyrotoxicsis?
- Thyroiditis
- Thyroid carcinoma
- Pituitary adenoma
- Struma ovarii
- Factitious
Clinical manifestations of hypothyroidsm AKA myxedema?
- General: fatigue, weight gain, cold intolerance, edema
- Cardiac: slow pulse
- Nervous: delayed reflexes, lethargy
- Skin: rough, dry; hair loss
- Oral: macroglossia
- Myxedema: deepened voice
- Myxedema coma: deteriorating mental status
What are common causes of hypothyroidism?
- Hashimoto
- Iatrogenic
What are uncommon causes of hypothyroidism?
- Too little iodine
- 2° hypothyroidism
- 3° hypothyroidism
- Other thyroiditis
What are some non-neoplastic thyroid disease?
- Thyroiditis
- Graves Disease
- Goiter
What diseases fall under thyroiditis?
- Hashimoto
- DeQuervain
- Silent
- Reidel
What is Hashimoto?
Hashimoto - Autoimmune destruction of thyroid
- Most common cause of hypothyroidism in US
- Females (more susceptible to autoimmune disorders in general)
- Histological markers: Hurthle cells
What is DeQuervain?
DeQuervain - Immune cross-reaction with thyroid follicles
- Enlarged, sore thyroid
- Follows URI
- Self-limiting
- Histological markers: Multinucleated giant cell
What is Silent Thyroiditis?
Silent - Cycles of hyper- and hypo-
- Post-partum or middle age
- Painless, slightly enlarged thyroid
- Histological markers: Lymphoid infiltrate
What is Reidel?
Reidel - Hard, inflamed mass
- Hypothyroidism
- Rare
- If large enough, may compress the trachea
- Histological markers: Extensive fibrosis
Graves Disease
Graves Disease
- Most common cause of hyperthyroidism in the US
- Type II hypersensitivity - Ab-Ag complex mediated
- Autoimmune: Anti-TSH receptor antibodies stimulate TSH receptors
- TSI activates hormone production and thyroid gland growth so TSH and TRH would be low because they’re trying to make them stop producing the thyroid hormone
- Triad of symptoms
- Histological markers: Hyperplasia of epithelium; scalloped colloid
What is the Triad of Symptoms for Graves Disease?
Triad of symptoms:
- General Hyperthyroidism Symptoms
- Exophthalmos
- Dermopathy - abnormal edema (like a unique form of edema); skin texture looks like an orange peel
Tx for Graves Disease?
Treatment - controlling symptoms
- Beta blockers (to control symptoms)
- Iodine blockers (thiouracil)
- Hot iodine (radioactive)
- Surgery
Goiter
The presence of a goiter only provides evidence that there is some problem with the thyroid axis
Two origins
- Inflammatory
- Non-inflammatory (hyperstimulation)
Can be present with:
- ↓thyroid hormones
- ↑thyroid hormones
- Normal thyroid hormones
As TSH levels are high to make more thyroid hormone, but also stimulates growth
–> Goiter
What is T3 and T4?
T3 = Thyroxine
T4 = Triiodothyronine
What are neoplastic thyroid diseases?
Adenoma
Carcinoma
Thyroid Adenoma & Carcinoma - Which is common? Uncommon?
Adenoma - Common
Carcinoma - Uncommon
What are the different types of thyroid carcinomas? Rank in order from most common to rarest..
Most Common
- Papillary thyroid carcinoma
- Follicular thyroid carcinoma
- Medullary thyroid carcinoma
- Anaplastic thyroid carcinoma
Rarest
Papillary Thyroid Carcinoma
Papillary thyroid carcinoma - MOST COMMON
- >95% 10yr survival
- Orphan Annie tumor
- Younger women
- Mild
- Nuclei
- Histological features: Psamomma body (Ca2+ rich deposits)
Follicular Thyroid Carcinoma
Follicular thyroid carcinoma - SECOND MOST COMMON
- 95% 10yr survival in young patients with small, minimally invasive tumor
- Prognosis gets worse with ↑age, size, invasiveness
- Histological features: Vascular invasion
Medullary Thyroid Carcinoma
Medullary thyroid carcinoma - RARE
- Endocrine tumor (or parafollicular cells)
- Parafollicular cells release calcitonin (regulates Ca2+ cells)
- 90% 10yr survival if confined to thyroid
- 20% 10 yr survival if metastasized
Anaplastic Thyroid Carcinoma
Anaplastic thyroid carcinoma - RAREST TYPE
- Bulky, fast-growing, invasive neck mass
- Pure chaos in the thyroid gland
- Usually metastatic at dx
- BAD PROGNOSIS - <10% 5yr survival
Parathyroid Glands
- Small glands located behind the upper and lower poles of the thyroid gland
- Produce parathyroid hormone
- Regulate serum Ca2+
- Calcitonin antagonist
Alterations of parathyroid function
Hyperparathyroidism
Hypoparathyroidism
Types of hyperparathyroidism
-
Primary hyperparathyroidism
- Excess secretion of PTH from one or more parathyroid glands
-
Secondary hyperparathyroidism
- ↑PTH secondary to a chronic disease causing hypocalcemia (i.e. renal failure)
What usually causes hypoparathyroidism?
Parathyroid damage during thyroid sugery
What are the different layers of the adrenal glands? What hormones are produced by each layer?
- Cortex
- Glomerulosa
- Mineralocorticoids - Aldosterone
- Retain SALT
- Mineralocorticoids - Aldosterone
- Fasciculata
- Glucocorticoids - Cortisol
- Release SUGAR
- Glucocorticoids - Cortisol
- Reticularis
- Sex hormones - Androgens, Estrogens
- SEX
- Sex hormones - Androgens, Estrogens
- Glomerulosa
- Medulla
- Epi
- NE
Cushing Syndrome vs. Cushing Disease
- Cortisol Hypersecretion
- Cushing Syndrome - Elevated plasma cortisol
- Iatrogenic (taking too much cortisol) - most common
- Adrenal tumor
- Cushing Disease - Elevated ACTH production b/c of pituitary tumor
- W/ subsequent elevated cortisol
Tx for cortisol hypersecretion
Tx: Remove or destroy the tumor; ↓cortisol injections
Clinical manifestations of cortisol hypersecretion
Clinical manifestations
- Insulin resistance
- Weight gain (trunk and moon face)
- ↑blood glucose
- Muscle wasting, weakness b/c of muscle breakdown
- AA supporting gluconeogenesis
- Osteoporosis
- ↓inflammatory activity
- Poor wound healing and immune system function
- Thin skin
-
↑sensitivity to catecholamines b/c of ↑adrenergic receptors
- ↑BP, HR
- Altered mental status (depression, psychosis, irritability)
Sex steroid hypersecretion
- Feminization - estrogens
- Virilzation - androgens
Problem @ reticularis layer?
Catecholamine Hypersecretion
Adrenal Medulla Hyperfunction
Caused by tumors derived from chromaffin cells of the ADRENAL MEDULLA
Pheochromocytoma
Symptoms of catecholamine hypersecretion
- ↑HR, BP
- Diaphoresis (sweating)
- Weight loss
- Hyperglycemia/hyperlipidemia
What are some adrenal hypotension syndromes?
Addison Disease (primary adrenal insufficiency)
Waterhouse-Friderichsen Syndrome
What is Addision Disease
Primary adrenal insufficiency
- ↓↓cortisol and mineralocorticoids
- Usually autoimmune at origin
What are symptoms of Addison Disease?
- Slow onset
- Weakness
- Hypotension
- Skin hyperpigmentation: oral manifestation - making too much ACTH because there’s no feedback that cortisol levels are low due to adrenal gland deficiency and when you have a lot of ACTH, you also have a lot of MSH
What is Waterhouse-Friderichsen Syndrome?
Hemorrhaging at the adrenal gland caused by
- Bacterial infection (N. meningitidis)
- Massive, bilateral adrenal hemorrhage
- Hypotension, shock
- DIC - disseminated intravascular coagulation
What is MEN syndrom and what are the two classifications?
Multiple Endocrine Neoplasia
- Genetic disorder
- Endocrine disorder
- Two classifications:
- MEN-1
- MEN-2
What are the features of MEN syndrome?
- Younger people
- Multifocal
- Aggressive
What are the features of MEN-1?
- Parathyroid hyperplasia
- Pancreatic hormone tumors
- Pituitary adenoma
- Duodenal gastrinoma
- Carcinoid (neuroendocrine tumor AKA gut tumor producing 5HT)
- Thyroid/adrenal adenomas
- Lipomas
What are the genetics of MEN-1?
MEN1 gene mutation
- Encodes menin
- Tumor suppressor gene
- Mutation turns gene off
What are the features of MEN-2A & -2B?
- *Medullary thyroid carcinoma
- Pheochromocytoma - produces catecholamines
- Parathyroid hyperplasia
What are the genetics of MEN-2A & -2B?
RET gene mutation
- Proto-oncogene
- Encodes tyrosine kinase receptor
- Mutation turns gene on
What is the only difference between MEN-2A and -2B?
MEN-2B has a collagen mutation!!!!!
- Marfanoid habitus