Pit Tumors 2009 Part Ii
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This document discusses various hypothalamic and pituitary disorders including craniopharyngioma, hypothalamic dysfunction, hypopituitarism, growth hormone deficiency, thyroid stimulating hormone deficiency, gonadotropin deficiency, adrenocorticotropic hormone deficiency, antidiuretic hormone deficiency, diabetes insipidus, and syndrome of inappropriate antidiuretic hormone secretion. It provides details on signs and symptoms, evaluations, and treatments for each condition.
Pit Tumors 2009 Part Ii
- 1. Jimmy Santana, MBA, P.A.-C
- 2. Pituitary and Hypothalamic Disorders Hypothalamic Dysfunction Craniopharyngioma: most frequent cause of hypothalamic dysfunction in children and young adults Primary central nervous system tumors, pinealomas, dermoid and epidermoid tumors seen in adulthood
- 3. ENDOCRINOLOGY Hypothalamic dysfunction S&S: visual loss, headache and vomiting ( due to raised intracranial pressure), hypopituitarism including growth failure and diabetes insipidus (DI). Hypothalamic disturbances can cause disorders of thirst, appetite, temperature regulation, behavior and consciousness
- 4. ENDOCRINOLOGY Craniopharyngioma is tx’ed primarily w/surgical resection and then radiotherapy Biopsy of other tumors required as germinoma is very radiosensitive Hypopituitarism results from decreased secretion of pituitary hormone(s)
- 5. ENDOCRINOLOGY Hypopituitarism can occur from: pituitary gland dysfunction due to deficiency of hypothalamic stimulatory/inhibitory factors anterior pituitary gland destruction congenital or acquired lesions lesions may cause single or multiple hormonal losses
- 6. ENDOCRINOLOGY GH Deficiency manifests in infancy and childhood as growth retardation, short stature and fasting hypoglycemia in adults, may present as increased abdominal adiposity, reduced strength and exercise capacity, cold intolerance, and impaired psychosocial well-being usually presents w/ other symptoms of panhypopituitarism
- 7. ENDOCRINOLOGY GH reserve eval provocative test are used to indirectly stimulate somatotroph required in assessing children w/short stature GH basal levels are frequently low in nl individuals may also help in work-up of adults w/suspected hypopituitarism
- 8. ENDOCRINOLOGY GH reserve Clonidine and propranolol given orally Arginine infusion, L-dopa (precursor of dopamine), norepinephrine and insulin are used to stimulate secretion from pituitary somatotroph Insulin-induced hypoglycemia is the most reliable stimulus of GH hyper-secretion
- 9. ENDOCRINOLOGY In elderly or pts w/CNS disorders avoid insulin-induced hypoglycemia Multiple tests used to dx GH deficiency approx 90% respond to one test Insulin-like growth factors and Binding proteins(IGF-BP) produced by liver low levels of IGF-BP3 can be used to to screen for GH deficiency, which is regulated by GH
- 10. ENDOCRINOLOGY Hypothalamic dysfunction a single dose of GHRH can be used to stimulate GH secretion GH deficiency from hypopituitarism does not respond to GHRH dose stimulation TSH deficiency caused by thyroid gland hypo-function and involution
- 11. ENDOCRINOLOGY TSH deficiency S&S: Hypothyroidism : lethargy, constipation, cold intolerance, cold-stimulate, bradycardia, weight gain, poor appetite, dry skin, delayed reflexes secondary hypothyroidism can be differentiated from primary hypothyroidism by presence of low circulating TSH in presence of low thyroid hormone levels
- 12. ENDOCRINOLOGY TSH eval Thyroid function tests (free thyroxine {FT4}, free tri-iodothyronine {FT3}, or free thyroxine index {FT1}) TSH measurement needed in presence of low thyroid function test to differentiate primary gland failure ( elevated TSH) from hypothyroidism from hypothalamic/pituitary gland failure (low or inappropriately normal TSH)
- 13. ENDOCRINOLOGY Gonatropin deficiency failure to enter puberty is due to central hypogonadism during childhood females have delayed breast development, scant pubic and axillary hair, and primary amenorrhea boys have sparse body hair and phalus and testes remain small
- 14. ENDOCRINOLOGY In gonadotropin deficiency, growth continues (GH is intact), epiphyses on long bones fail to fuse due to absence of sex steroids which is needed for fusing of epiphyseal growth plates adolescents become tall with eunuchoid proportions ( upper-to-lower segment ration <1)
- 15. ENDOCRINOLOGY Gonadotropin deficiency in adult women; hypogonadism presents as loss of axillary and pubic hair, breast atrophy and secondary amenorrhea in adult males; they have testicular atrophy, decreased libido, impotence and loss of body hair
- 16. ENDOCRINOLOGY Hypothalamic-Pituitary-Gonadal Axis best dx’ed w/concurrent measurement of serum gonadotropins and gonadal steroid concentrations in amenorrheic women serum LH, FSH, estradiol, prolactin and Human chorionic gonadatropin (Hcg) must be measured
- 17. ENDOCRINOLOGY Primary ovarian failure elevated FSH and LH, nl prolactin levels Hyperprolactinemia elevated prolactin lvls, normal follicular phase LH, FSH, and estradiol lvls lvs >200ng/dl of PRL secreting adenomas Pregnancy (+) Hcg, nl to high prolactin lvl, nl to high LH, high estradio
- 18. ENDOCRINOLOGY Low to nl FSH/LH lvls w/low testosterone (males) and estradiol (females) confirms Gonadotropin deficiency Low gonadal steroids w/elevated gonadotropins suggest primary gonadal failure
- 19. ENDOCRINOLOGY ACTH deficiency results in adrenocorticol insufficiency w/decreased cortisol and androgen secretion results in adrenal failure S&S: lethargy, weakness, nausea, vomiting, dehydration, orthostatic hypotension and if not tx’ed coma if not recognized and tx’ed may lead to DEATH
- 20. ENDOCRINOLOGY ACTH eval Basal lvls: unreliable due to short plasma half-life and pulsatile secretion ACTH regulates cortisol secretion plasma cortisol lvls reflect hypothalamic-pituitary-adrenal function an 8am lvl > 10micro/dl will r/o adrenal insufficiency, but does not assess adrenal reserve
- 21. ENDOCRINOLOGY ACTH eval adrenal insufficiency from a primary adrenal disorder nl to high ACTH plasma lvls adrenal insufficiency due to hypothalamic-pituitary hypo-function will show low to absent ACTH lvls
- 22. ENDOCRINOLOGY ACTH reserve eval adrenal atrophy results from prolonged ACTH deficiency : adrenal cortisol reserve can be measured indirectly by testing pituitary ACTH inadequate response implies primary adrenal failure or impaired pituitary ACTH secretion provocative testing is performed under stress potentially hazardous if adrenal function is compromised
- 23. ENDOCRINOLOGY ADH (Vasopressin) deficiency ADH deficiency results in a lg vol of urine which is very dilute occurs w/posterior pituitary dysfunction leads to Diabetes Insipidus (DI), polyuria, polydypsia and nocturia
- 24. ENDOCRINOLOGY DI Central (neurogenic) origin: failure of posterior pituitary to secrete adequate amts of ADH Nephrogenic origin: failure of kidney to respond to circulating ADH regardless of cause, pts secret lg volumes of dilute urine causing cellular and extra-cellular dehydration resulting in excess thirst
- 25. ENDOCRINOLOGY DI needs to be differentiated from: Primary polydypsia a compulsive psychoneurotic disorder appearing as a thirst disorder. Pt drinks > 5L of water a day results in decreased ADH secretion and water causes subsequent diuresis plasma and urine are dilute as opposed to DI where urine osmolarity is less than plasma osmolarity due to inappropriate water diuresis
- 26. ENDOCRINOLOGY Primary test for cause of polyuria water deprivation for 12- 18hrs body wght, BP,urine vol, urine specific gravity, plasma and osmolarity measured q 2hrs nl response is decreased urine output, increased urine concentration greater than plasma pts w/DI maintain high dilute urine output pts w/primary polydypsia have urine omsolarity greater than plasma
- 27. ENDOCRINOLOGY DI water deprivation cont until plasma lvl plateaus, then AVP is given and urine osmolarity is checked in 1hr pts w/ complete central DI; urine osmolarity increases to about plasma osmolarity pts w/ nephrogenic DI; osmolarity of urine increases less than 50% pts w/primary poldypsia; osmolarity increases <10%
- 28. ENDOCRINOLOGY Central DI tx Desmopressin acetate (DDAVP) intranasal or orally serum osmolarity and sodium is monitored Nephrogenic DI tx seek underlying cause maintain a state of mild sodium depletion w/reduction in solute load on kidney by giving diuretics and salt restriction
- 29. ENDOCRINOLOGY Syndrome of Inappropriate secretion of Antidiuretic Hormone (SIADH) plasma ADH concentrations inappropriately high for plasma osmolarity leads to water retention and hyponatremia w/ decrease plasma osmolarity dx can only be made in absence of hyper-volumemia (nephrotic syndrome, cardiac failure, cirrhosis) and w/ nl thyroid, adrenal and renal function
- 30. ENDOCRINOLOGY SIADH S&S: depends on degree of hyponatremia and rate of fall of plasma osmolarity HA, anorexia, vomiting and confusion w/ sodium lvls between 115 and 120mEq/l w/ lvs <110mEq/l; disorientation, stupor, coma, seizures, paralysis, and focal neurologic findings several malignant and benign conditions are associated w/SIADH
- 31. ENDOCRINOLOGY Disorders associated w/SIADH Pulmonary: malignant- Oat cell carcinoma benign- TB, pneumonia, abscess CNS: meningitis, brain abscess, hd trauma Adverse drug effects: Clofibrate, Chlorpropamide, Cyclophosmamide, Phenothiazine, Carbamazapine Tumors (ectopic production of ADH): lymphoma, Sarcoma, Carcinoma of pancreas or duodenum
- 32. NEXT TOPIC : THYROID DYSFUNCTIONS