Path 3 Pituitary

Front 1

DISORDERS OF THE PITUITARY - WILSON - MONDAY JAN 29

Front 3

what is the most common abnormality of the anterior lobe?

Back 3

pituitary adenoma

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PITUITARY ADENOMAS

Front 7

what % are secretory?

Back 7

75%

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how are they characterized, based on size (2)?

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1) microadenomas (<1cm); 2) macroadenoma (>1cm)

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what may symptoms be due to (2)?

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1) hormonal secretion; 2) mass effects; or both

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what are the most significant forms of secretory pituitary adenomas (3) in order of frequency?

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1) prolactinomas; 2) GH-secreting adenomas; 3) ACTH-secreting adenomas

Front 11

what are two less frequent forms of secretory pituitary adenomas?

Back 11

1) LH/FSH secreting adenomas; 2) TSH-secreting adenomas

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MASS EFFECTS OF PITUITARY ADENOMAS

Front 15

what sense is impaired, why, and what example effect is seen?

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impaired vision including field defects, such as bitemporal hemianopsia, due to compression of the optic chiasm or optic nerves, or both

Front 16

movement of what muscles can be impaired, and why?

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extraocular muscles - ocular palsies - due to compression of cranial nerves 3, 4, and 6, which control eye movement

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what happens to the pituitary fossa (sella turcica)?

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expansion and gradual destruction

Front 18

what happens to intracranial pressure, and what is the result?

Back 18

it increases, resulting in nausea and vomiting

Front 19

what happens to the size of the pituitary gland, and why?

Back 19

hypopituitarism, due to pressure-related destruction of surrounding normal cells of anterior lobe

Front 20

what is the stalk effect, and what can cause it?

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stalk effect is elevation of serum prolactin due to interference with normal inhibition of prolactin seccretion - this can be the result of any suprasellar mass

Front 21

what is normal inhibition of prolactin secretion the result of?

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transport of dopamine from the hypothalamus to the anterior lobe

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what is pituitary apoplexy, and what can cause it (2)?

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sudden enlargement of a pituitary macroadenoma due to hemorrhage or infarction

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how seriuos is this condition?

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surgical emergency

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what are some of the severest effects of pituitary apoplexy (6)?

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1) sudden severe headache; 2) diplopia; 3) hypopituitarism; 4) cardiovascular collapse; 5) loss of consciousness; 6) sudden death

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PROLACTINOMAS

Front 28

what adjectives were used to describe the way prolactin is secreted by these tumors (2) and what does each mean?

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they secrete prolactin efficiently (microadenomas are symptomatic) and proportionally (serum levels correllate with size of tumor)

Front 29

what group experiences the most signs and symptoms from prolactinomas?

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premenopausal women

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what are the signs and symptoms seen in premenopausal women (3)?

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1) galactorrhea; 2) amenorrhea; 3) infertility

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what are the effects like in postmenopausal women and and men?

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hormonal effects are more subtle, and mass effects are more likely

Front 32

what other type of tumor may result in elevated prolactin, and why?

Back 32

elevated serum prolactin may accompany a non-proalctin-secreting macroadenoma due to stalk effect (a mass effect)

Front 33

what are the treatments for prolactinomas (2)?

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1) bromocriptine (dopamine agonist); 2) transsphenoidal resection

Front 34

what does bromocriptine do to a prolactinoma?

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shrinks tumor (controls, but not curative)

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GH-SECRETING ADENOMAS (SOMATOTROPH ADENOMAS)

Front 38

what do GH-secreting adenomas occasionally secrete, in addition to GH?

Back 38

prolactin

Front 39

what does GH hypersecretion stimulate to be secreted, and from where?

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stimulates IGF-1 to be secreted hepatically (which causes many of the clinical effects)

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what are the signs and symptoms called in postpubertal individuals?

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acromegaly

Front 41

what parts of the body does excessive growth most conspicuously involve (3)?

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1) skin/soft tissues; 2) certain bones; 3) certain organs

Front 42

what bones were mentioned (3)?

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hands, feet, face - non-longitudinal bone growth

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what organs were mentioned (4)?

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liver, adrenals, heart, thyroid

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what type of cancer is there an increased risk for in acromegaly?

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GI carcinomas

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what are other metabolic and physiologic abnormalities caused by acromegaly (6)?

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1) diabetes mellitus; 2) HT; 3) CHF; 4) muscle weakness; 5) arthritis; 6) gonadal dysfunction

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what are the signs/symptoms called in prepubertal individuals?

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gigantism

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what is gigantism characterized by, and what is disproportionately long?

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excessive growth with disproportionately long extremities

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how do the metabolic and physiologic abnormalities compare to acromegaly?

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similar

Front 49

what is a sensitive test for GH-secreting adenoma?

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nonsuppression of GH production by oral load of glucose

Front 50

what is the treatment for GH-secreting adenomas (3)?

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1) transsphenoidal resection; 2) radiation; 3) drug therapy

Front 51

what are the results of effective control of GH oversecretion (2)?

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1) gradual recession of tissue overgrowth; 2) improvement of metabolic and physiologic abnormalities

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ACTH-SECRETING ADENOMAS (CORTICOTROPH ADENOMAS)

Front 55

what size are the majority of microadenomas?

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microadenomas - can be as small as 2mm

Front 56

what are the signs/symptoms of ACTH-secreting tumors called?

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Cushing's disease

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what do they directly result from?

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hypercortisolism secondary to ACTH-secreting pituitary adenoma

Front 58

what are the two groups of features of Cushing's disease?

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1) somatic features; 2) metabolic and physiologic abnormalities

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what are the somatic features (5)?

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1) Moon facies; 2) central obesity (truncal obesity); 3) skin fragility (striae, easy bruisability); 4) poor wound healing; 5) osteoporosis

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what are the metabolic and physiologic abnormalities (2)?

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1) diabetes mellitus; 2) hypertension

Front 61

what factors make it difficult to diagnose ACTH-secreting pituitary adenomas (3)?

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1) possible alternative sources of ACTH hypersecretion (bronchial carcinoid, other tumors); 2) small pituitary microadenomas may be below threshold of detectability by imaging; 3) invasive diagnostic technique

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what is the invasive diagnostic technique, and what does it involve?

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bilateral catheterization of inferior petrosal sinuses - venous drainage of pituitary gland is lateralized to right and left petrosal sinuses, respectively

Front 63

what type of assessment is done (what three things are measured to be assessed)?

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1) right pituitary venous effluent; 2) left pituitary venous effluent; 3) peripheral blood

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what is the treatment for ACTH-secreting adenomas?

Back 64

transsphenoidal resection

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LESS FREQUENT ESCRETORY ADENOMAS

Front 68

what is secretion like in LH/FSH secreting adenomas?

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secrete hormones inefficiently and variably

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what is the clinical syndrome?

Back 69

usually no recognizable clinical syndrome

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what are the rares of all adenomas?

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TSH-secreting adenomas

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NONSECRETORY ADENOMAS

Front 74

what are the hormonal effects of nonsecretory adenomas?

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hypopituitarism

Front 75

what is this due to, and what % does it occur in?

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pressure-related destruction of surrounding normal cells of anterior lobe (75%)

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INFARCTION

Front 79

what lobe of the pituitary is particularly vulnerable to infarction?

Back 79

the anterior lobe

Front 80

why is it vulnerable?

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because its main arterial blood supply, the portal vessels from the hypothalamus, is a low-pressure venous system

Front 81

what type of infarction occurs in the anterior lobe?

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ischemic necrosis

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what may this result in?

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hypopituitarism - depending on the extent of destruction of anterior lobe cells

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what type of patient is pituitary infarction most associated with?

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postpartum

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what is this referred to as?

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Sheehan's syndrome

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what happens to the anterior lobe in pregnancy, and why?

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it doubles in size, due to the physiologic hyperplasia of lactotrophs

Front 86

how does the blood supply change, and what is the result?

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it stays the same, and pituitary hypoxia results

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what complications of childbirth result in infarction?

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hemorrhage, shock

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is hypopituitarism immediate or delayed?

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can be either

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why might it be delayed?

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progressive destruction of cells secondary to entrapment in postinfarction scarring

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what are other predisposing conditions to necrosis of anterior pituitary lobe (5)?

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1) DIC; 2) sickle cell anemia; 3) elevated intracranial pressure; 4) trauma; 5) shock

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EMPTY SELLA SYNDROME

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what does empty sella syndrome reefer to?

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enlarged sella not filled with pituitary tissue

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what classifications of empty sella syndrome are there (2)?

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1) primary; 2) secondary

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what is the predisposing developmental abnormality for primary empty sella syndrome?

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incomplete diaphragma sellae

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what does this abnormality allow to happen, and what is the result?

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permits subarachnoid space to expand or balloon into sella (secondary to CSF pressure) which compresses the pituitary gland

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who is primary empty sella syndrome most often diagnosed in?

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obese multiparous women

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what may have a role that is associated with obesity and pregnancy?

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increased CSF pressure

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how may empty sella syndrome cause symptoms (2)?

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may cause hormonal distrurbances or mass effects, or may be asymptomatic

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what is secondary empty sella syndrome caused by?

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secondary to sellar enlargement by a tumor (pituitary macroadenoma) which leaves a sellar vacancy when it is destroyed or spontaneously necroses

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DISORDERS OF THE POSTERIOR LOBE-HORMONE

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what hormone comes from the posterior pituitary?

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ADH

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what disorder is caused by ADH deficiency?

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diabetes insipidus

Front 107

what problem results, and why?

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dehydration from excessive excretion of free water

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what are the main causes of DI (5)?

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1) tumors of hypothalamus/pituitary; 2) inflammation of hypothalamus/pituitary; 3) head trauma; 4) surgical injury to hypothalamus/pituitary; 5) idiopathic

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what is the treatment for DI?

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administration of ADH

Front 110

what is SIADH, and what is it caused by?

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syndrome of inappropriate ADH - due to ADH excess

Front 111

what problem results from the excessive resorption of free water?

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dilutional hyponatremia

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what symptoms may be caused by this dilutional hyponatremia (2)?

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1) nausea/vomiting; 2) cerebral edema (and resultant neurologic dysfunction - confusion, coma, seizures)

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what are the main causes of SIADH (3)?

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1) ectopic secretion of ADH by malignant neoplasms (small cell lung carcinoma); 2) non-malignant lung diseases (TB); 3) intracranial lesions (trauma, infection, stroke)

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what is the treatment for SIADH (2)?

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1) water restriction; 2) identification and correction of underlying cause

Front 115

what is the rationale for water restriction?

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to accomplish slow normalization of serum sodium

Front 116

why must it be slow (what may fast normalization (increase) in sodium cause?

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rapid elevation may lead to CMP (central pontine myelinosis) which may be fatal

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HYPOTHALAMIC ORIGIN OF ENCEPHALOPATHIES

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what can hormonal disturbances from hypothalamic origin include (3)?

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1) hypopituitarism; 2) hyperpituitarism; 3) diabetes insipidus - these can occur in combination

Front 121

what are conditions causing hypothalamic origin endocrinopathies (2)?

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1) infection; 2) inflammation