MT Notes Endocrine Flashcards
Pituitary disease clinical manifestations
-Hyperpituitarism
•Excess secretion of trophic hormones
•Caused by tumors, hypothalamic disorders
-Hypopituitarism
•Deficiency of trophic hormones
•Caused by ischemia, surgery, radiation, inflammation, tumor
-Local mass effects
•Sella turcica deformation
•Optic chiasm compression- bitemporal hemianopsia
•Increased intracranial pressure
Pituitary adenomas
-Functional adenomas •Associated with hormone excess •Classified based on hormone produced, ie lactotroph adenoma -Nonfunctional adenomas •Without hormone excess -Peak incidence 35-65 years -Nonfunctional tend to be larger when diagnosed •Microadenomas < 1 cm •Macroadenomas > 1cm
Lactotroph adenoma
-Prolactin-secreting adenoma •Increased serum prolactin- hyperprolactinemia -MC functional pituitary adenoma •30% of cases -Manifestations: •Amenorrhea (responsible for ¼ of cases) •Galactorrhea (milky nipple discharge) •Loss of libido •Infertility
Somatotroph adenoma
-Growth hormone-secreting adenoma
•2nd MC functioning pituitary adenoma
-Primary manifestations:
•Gigantism in children
•Acromegaly in adults (after epiphyseal closure- soft tissue affected)
•Effects may be subtle
•Leads to late diagnosis and relatively large tumor
-Also associated with:
•Gonadal dysfunction, diabetes mellitus, hypertension, arthritis, muscle weakness, congestive heart failure, GI cancers
Corticotroph adenomas
-Adrenocorticotrophic hormone (ACTH) secreting adenomas
•Leads to adrenal hypersecretion of cortisol
•Development of hypercortisolism (Cushing’s)
-Treated with removal of adrenal glands
•Can lead to large destructive pituitary adenomas
•Known as Nelson syndrome
Other anterior pituitary adenomas
-Gonadotroph adenomas •Produce LH and FSH •Inefficient production; effectively nonfunctioning •Diagnosed by mass effect symptoms -Thyrotroph adenomas •Very rare •Lead to hyperthyroidism -Nonfunctioning adenomas •25-30% of pituitary tumors -Pituitary carcinoma •Very rare •Craniospinal or systemic metastases
Hypopituitarism
-Decreased secretion of pituitary hormones
-Results from hypothalamic or pituitary disease:
•Tumors and other mass lesions
•Traumatic brain injury / subarachnoid hematoma
•Pituitary surgery or radiation
•Pituitary apoplexy
•Sudden hemorrhage into pituitary causing rapid expansion
•Ischemic necrosis of pituitary
•Sheehan’s syndrome
•AKA postpartum necrosis of anterior pituitary
•Obstetric hemorrhage causes vasoconstriction to enlarged pituitary
Hypopituitarism Causes (continued):
-Rathke cleft cyst
-Empty sella syndrome
•Any destruction of part or all of pituitary
•Primary: diaphragma sella defect allows CSF herniation into sella
•Secondary: Mass enlarges sella then is removed or undergoes infarction
•Hypothalamic lesions
•Interfere with hormone-releasing hormones
•Generally tumors, benign or malignant
•Inflammation / infection
•Genetic defects
Hypopituitarism
Manifestations:
- Growth failure in children (pituitary dwarfism)
- Gonadotropin deficiency -> amenorrhea, infertility, decreased libido
- Hypothyroidism, hypoadrenalism
- Failure of postpartum lactation
Posterior pituitary syndromes Manifestations involve ADH:
- Central diabetes insipidus
- Inadequate ADH production
- Syndrome of inappropriate ADH (SIADH)
- Excess secretion of ADH
- Increased blood volume
- Hyponatremia
Thyroid gland
- -Hyperthyroidism- hypermetabolic state caused by elevated circulating levels of free T3 and/ or T4
- Primary: Intrinsic thyroid abnormality
- Secondary: Due to external process such as TSH-secreting pituitary tumor
- MC causes:
- Diffuse hyperplasia of thyroid associated with Graves (85% of cases)
- Hyperfunctional multinodal goiter
- Hyperfunctional thyroid adenoma
Hyperthyroidism Clinical manifestations:
- Increase in BMR
- Warm and flushed skin
- Heat intolerance
- Sweating
- Weight loss despite increased appetite
- tachycardia
Hyperthyroidism Cardiac manifestations:
- Tachycardia, palpitations, cardiomegaly
- Congestive heart failure
- Fibrous changes
- Thyrotoxic / hyperthyroid cardiomyopathy- left ventricular dysfunction and “low output” heart failure
hyperthyroid sympathetic overactivity presentations
- Sympathetic overactivity
- Tremor, hyperactivity, emotional lability, anxiety, insomnia
- GI- hypermotility, diarrhea, decreased absorption
- Thyroid myopathy- proximal muscle weakness and atrophy
hyperthyroid ocular changes
- Wide, staring gaze and lid lag
- Due to sympathetic overstimulation of superior tarsal m.
- Thyroid ophthalmopathy occurs only in Graves
skeletal changes
osteoporosis and increased fracture risk
thyroid storm
- Abrupt onset of severe hyperthyroidism
- Medical emergency
- Untreated patients may die of cardiac arrhythmia
- MC in Graves
- Due to elevated catecholamine due to surgery, infection, other stress
- Fever, tachycardia common
apathetic hyperthyroidism
- Thyrotoxicosis symptoms may be blunted in older patients due to reduced response to thyroid hormones
- Often diagnosed incidentally during lab work-up for weight loss
hyperthyroidism diagnosis
- Serum TSH concentration is most diagnostic
- Free T4 usually elevated
- Radioactive iodine uptake determines etiology (graves, toxic adenoma, thyroiditis)
Hyperthyroidism: Graves Disease
Clinical triad:
-Hyperthyroidism associated with diffuse enlargement of thyroid gland
-Infiltrative ophthalmopathy with resultant exophthalmos
Protrusion of eyeball
-Localized dermopathy (pretibial myxedema)
-MC in women 20-40 years old
Hyperthyroidism:
Graves disease pathogenesis
Production of antibodies against thyroid proteins, especially TSH receptor
- MC thyroid-stimulating immunoglobulin (TSI)
- Mimics TSH and causes release of thyroid hormone
- Minority of patients may also have blocking antibodies leading to hypothyroidism