endocrinology board review presented by med/peds pgy iii class

ENDOCRINOLOGY BOARD ENDOCRINOLOGY BOARD REVIEWREVIEW

Presented by Med/Peds PGY III Class

ENDOCRINOLOGYENDOCRINOLOGY

Disorders of the Hypothalamic Disorders of the Hypothalamic – Pituitary Axis– Pituitary Axis

K. Dionne Posey, MD, MPH

ENDOCRINOLOGYENDOCRINOLOGY

• Pituitary Disorders

• Thyroid Disorders

• Adrenal Disorders

• Gonadal Disorders

• Calcium Disorders

• Lipid Disorders

H orm on e excess H orm on e d e fic ien cy H orm on e res is tan ce

E n d oc rin e d iseases

Hypothalamic–Pituitary AxisHypothalamic–Pituitary Axis

Pituitary GlandPituitary Gland

• Located within the sella tursica • Contiguous to vascular and neurologic structures

– Cavernous sinuses– Cranial nerves– Optic chiasm

• Hypothalamic neural cells synthesize specific releasing and inhibiting hormones – Secreted directly into the portal vessels of the pituitary

stalk

• Blood supply derived from the superior and inferior hypophyseal arteries


• Anterior pituitary gland– Secrete various trophic hormones– Disease in this region may result in syndromes of

hormone excess or deficiency

• Posterior pituitary gland– More of a terminus of axons of neurons in the

supraoptic and paraventricular nuclei of the hypothalamus

– Storehouse for the hormones – The main consequence of disease in this area is

disordered water homeostasis

Anterior Pituitary GlandAnterior Pituitary Gland• Anterior Pituitary “Master gland”

– Major blood source: hypothalamic-pituitary portal plexus

• Allows transmission of hypothalamic peptide pulses without significant systemic dilution

• Consequently, pituitary cells are exposed to sharp spikes of releasing factors and in turn release their hormones as discrete pulses

– Production of six major hormones: • Prolactin (PRL)• Growth hormone (GH)• Adrenocorticotropin hormone (ACTH)• Luteinizing hormone (LH)• Follicle-stimulating hormone (FSH)• Thyroid-stimulating hormone (TSH)

Anterior Pituitary GlandAnterior Pituitary Gland

• Anterior Pituitary “Master gland”

– Secreted in a pulsatile manner – Elicits specific responses in peripheral target

tissues – Feedback control at the level of the

hypothalamus and pituitary to modulate pituitary function exerted by the hormonal products of the peripheral target glands

– Tumors cause characteristic hormone excess syndromes

– Hormone deficiency • may be inherited or acquired

HypopituitarismHypopituitarism

Gonadotropin Deficiency

Women

• Oligomenorrhea or amenorrhea

• Loss of libido

• Vaginal dryness or dyspareunia

• Loss of secondary sex characteristics (estrogen deficiency)

Men• Loss of libido• Erectile dysfunction• Infertility• Loss of secondary sex

characteristics (testosterone deficiency)

• Atrophy of the testes• Gynecomastia

(testosterone deficiency)

ACTH Deficiency

• Results in hypocortisolism– Malaise– Anorexia– Weight-loss– Gastrointestinal disturbances– Hyponatremia

• Pale complexion– Unable to tan or maintain a tan

• No features of mineralocorticoid deficiency– Aldosterone secretion unaffected

TSH Deficiency

• Hypothyroidism

• Atrophic thyroid gland

Prolactin Deficiency

• Inability to lactate postpartum

• Often 1st manifestation of Sheehan syndrome

Growth Hormone Deficiency

• Adults– Often asymptomatic– May complain of – Fatigue– Degrees exercise tolerance– Abdominal obesity– Loss of muscle mass

• Children– GH Deficiency– Constitutional growth delay


EtiologyEtiology• Anterior pituitary diseases

– Deficiency one or more or all anterior pituitary hormones

• Common causes: – Primary pituitary disease– Hypothalamic disease– Interruption of the pituitary stalk– Extrasellar disorders


– Primary pituitary disease• Tumors

• Pituitary surgery

• Radiation treatment

– Hypothalamic disease• Functional suppression of

axis– Exogenous steroid use– Extreme weight loss– Exercise– Systemic Illness

– Interruption of the pituitary stalk

– Extrasellar disorders• Craniopharyngioma• Rathke pouch


• Developmental and genetic causes– Dysplasia

• Septo-Optic dysplasia

– Developmental hypothalamic dysfunction

• Kallman Syndrome• Laurence-Moon-

Bardet-Biedl Syndrome

• Frohlich Syndrome (Adipose Genital Dystrophy)

• Acquired causes:– Infiltrative disorders

– Cranial irradiation

– Lymphocytic hypophysitis

– Pituitary Apoplexy

– Empty Sella syndrome

Hypopituitarism: Developmental and Hypopituitarism: Developmental and Genetic causesGenetic causes

• Septo-Optic dysplasia

• Kallman Syndrome• Laurence-Moon-Bardet-Biedl Syndrome• Frohlich Syndrome (Adipose Genital

Dystrophy)

Hypopituitarism: GeneticHypopituitarism: Genetic

– Septo-Optic dysplasia– Hypothalamic dysfunction and hypopituitarism

» may result from dysgenesis of the septum pellucidum or corpus callosum

– Affected children have mutations in the HESX1 gene» involved in early development of the ventral

prosencephalon– These children exhibit variable combinations of:

» cleft palate » syndactyly » ear deformities » hypertelorism» optic atrophy» micropenis » anosmia

– Pituitary dysfunction» Diabetes insipidus» GH deficiency and short stature» Occasionally TSH deficiency

Hypopituitarism: DevelopmentalHypopituitarism: Developmental

• Kallman Syndrome• Defective hypothalamic gonadotropin-releasing hormone (GnRH)

synthesis

• Associated with anosmia or hyposmia due to olfactory bulb agenesis or hypoplasia

• May also be associated with: color blindness, optic atrophy, nerve deafness, cleft palate, renal abnormalities, cryptorchidism, and neurologic abnormalities such as mirror movements

• GnRH deficiency prevents progression through puberty

• characterized by – low LH and FSH levels – low concentrations of sex steroids


• Kallman Syndrome• Males patients

– Delayed puberty and hypogonadism, including micropenis» result of low testosterone levels during infancy

– Long-term treatment: » human chorionic gonadotropin (hCG) or testosterone

• Female patients – Primary amenorrhea and failure of secondary sexual

development – Long-term treatment:

» cyclic estrogen and progestin

• Diagnosis of exclusion • Repetitive GnRH administration restores normal pituitary • Fertility may also be restored by the administration of

gonadotropins or by using a portable infusion pump to deliver subcutaneous, pulsatile GnRH


• Laurence-Moon-Bardet-Biedl Syndrome• Rare autosomal recessive disorder • Characterized by mental retardation; obesity;

and hexadactyly, brachydactyly, or syndactyly• Central diabetes insipidus may or may not be

associated • GnRH deficiency occurs in 75% of males and

half of affected females• Retinal degeneration begins in early childhood

– most patients are blind by age 30


• Frohlich Syndrome (Adipose Genital Dystrophy)

• A broad spectrum of hypothalamic lesions – hyperphagia, obesity, and central hypogonadism

• Decreased GnRH production in these patients results in

– attenuated pituitary FSH and LH synthesis and release

• Deficiencies of leptin, or its receptor, cause these clinical features


• Acquired causes:– Infiltrative disorders– Cranial irradiation– Lymphocytic hypophysitis– Pituitary Apoplexy– Empty Sella syndrome

Hypopituitarism: AcquiredHypopituitarism: Acquired

• Lymphocytic Hypophysitis– Etiology

• Presumed to be autoimmune

– Clinical Presentation• Women, during postpartum period• Mass effect (sellar mass)• Deficiency of one or more anterior pituitary hormones

– ACTH deficiency is the most common

– Diagnosis• MRI - may be indistinguishable from pituitary adenoma

– Treatment• Corticosteroids – often not effective• Hormone replacement


• Pituitary Apoplexy– Hemorrhagic infarction of a pituitary

adenoma/tumor– Considered a neurosurgical emergency– Presentation:

• Variable onset of severe headache• Nausea and vomiting• Meningismus• Vertigo • +/ - Visual defects• +/ - Altered consciousness

– Symptoms may occur immediately or may develop over 1-2 days


• Pituitary Apoplexy– Risk factors:

• Diabetes• Radiation treatment• Warfarin use

– Usually resolve completely– Transient or permanent hypopituitarism is possible

• undiagnosed acute adrenal insufficiency

– Diagnose with CT/MRI– Differentiate from leaking aneurysm– Treatment:

• Surgical - Transsphenoid decompression– Visual defects and altered consciousness

– Medical therapy – if symptoms are mild• Corticosteroids

MedStudy 2005 - Endocrine

Quick Quiz!!! Quiz!!!

• When should you suspect pituitary apoplexy?

AnswerAnswer

• Suspect in patient presenting with• Variable onset of severe headache• Nausea and vomiting• Meningismus• Vertigo • +/ - Visual defects• +/ - Altered consciousness


• Empty Sella Syndrome– Often an incidental MRI finding – Usually have normal pituitary function

• Implying that the surrounding rim of pituitary tissue is fully functional

– Hypopituitarism may develop insidiously– Pituitary masses may undergo clinically silent

infarction with development of a partial or totally empty sella by cerebrospinal fluid (CSF) filling the dural herniation.

– Rarely, functional pituitary adenomas may arise within the rim of pituitary tissue, and these are not always visible on MRI


Clinical PresentationClinical Presentation• Can present with features of deficiency

of one or more anterior pituitary hormones

• Clinical presentation depends on:– Age at onset– Hormone effected, extent– Speed of onset– Duration of the deficiency


DiagnosisDiagnosis

• Biochemical diagnosis of pituitary insufficiency – Demonstrating low levels of trophic

hormones in the setting of low target hormone levels

• Provocative tests may be required to assess pituitary reserve


TreatmentTreatment

• Hormone replacement therapy – usually free of complications

• Treatment regimens that mimic physiologic hormone production – allow for maintenance of satisfactory

clinical homeostasis

Hormone ReplacementHormone ReplacementTrophic Hormone Deficit Hormone Replacement

ACTH Hydrocortisone (10-20 mg A.M.; 10 mg P.M.)Cortisone acetate (25 mg A.M.; 12.5 mg P.M.)Prednisone (5 mg A.M.; 2.5 mg P.M.)

TSH L-Thyroxine (0.075-0.15 mg daily)

FSH/LH MalesTestosterone enanthate (200 mg IM every 2 wks)Testosterone skin patch (5 mg/d)FemalesConjugated estrogen (0.65-1.25 mg qd for 25days)Progesterone (5-10 mg qd) on days 16-25Estradiol skin patch (0.5 mg, every other day)For fertility: Menopausal gonadotropins, human chorionic gonadotropins

GH Adults: Somatotropin (0.3-1.0 mg SC qd)Children: Somatotropin [0.02-0.05 (mg/kg per day)]

Vasopressin Intranasal desmopressin (5-20 ug twice daily)Oral 300-600 ug qd

Take home points:Take home points:

• Remember that the cause may be functional – Treatment should be aimed at the underlying cause

• Hypopituitarism may present– Acutely with cortisol deficiency– After withdrawal of prolonged glucocorticoid therapy that

has caused suppression of the HPA axis.– Post surgical procedure– Post trauma

• Hemorrhage

• Exacerbation of cortisol deficiency in a patient with unrecognized ACTH deficiency– Medical/surgical illness– Thyroid hormone replacement therapy

Pituitary TumorsPituitary Tumors

Pituitary TumorsPituitary Tumors• Microadenoma < 1 cm• Macroadenoma > 1 cm

• Is the tumor causing local mass effect?• Is hypopituitarism present?• Is there evidence of hormone excess?

• Clinical presentation:– Mass effect

• Superior extension– May compromise optic pathways – leading to impaired visual acuity and visual field

defects– May produce hypothalamic syndrome – disturbed thirst, satiety, sleep, and

temperature regulation

• Lateral extension– May compress cranial nerves III, IV, V, and VI – leaning to diplopia

• Inferior extension– May lead to cerebrospinal fluid rhinorrhea

Pituitary TumorsPituitary Tumors

• Diagnosis– Check levels of all hormones produced– Check levels of target organ products

• Treatment– Surgical excision, radiation, or medical therapy – Generally, first-line treatment surgical excision– Drug therapy available for some functional tumors– Simple observation

• Option if the tumor is small, does not have local mass effect, and is nonfunctional

• Not associated with clinical features that affect quality of life

CraniopharyngiomaCraniopharyngioma

– Derived from Rathke's pouch. – Arise near the pituitary stalk

• extension into the suprasellar cistern common

– These tumors are often large, cystic, and locally invasive

– Many are partially calcified • characteristic appearance on skull x-ray and CT images

– Majority of patients present before 20yr • usually with signs of increased intracranial pressure,

including headache, vomiting, papilledema, and hydrocephalus


• Associated symptoms include:– visual field abnormalities, personality changes and

cognitive deterioration, cranial nerve damage, sleep difficulties, and weight gain.

• Children– growth failure associated with either hypothyroidism

or growth hormone deficiency is the most common presentation

• Adults– sexual dysfunction is the most common problem – erectile dysfunction– amenorrhea


• Anterior pituitary dysfunction and diabetes insipidus are common

• Treatment – Transcranial or transsphenoidal surgical resection

• followed by postoperative radiation of residual tumor• This approach can result in long-term survival and ultimate

cure • most patients require lifelong pituitary hormone

replacement.

• If the pituitary stalk is uninvolved and can be preserved at the time of surgery– Incidence of subsequent anterior pituitary

dysfunction is significantly diminished.


• How does prolactin differ from LH/FSH in regard to hypothalamic control?

AnswerAnswer

• Tonic hypothalamic inhibition by Dopamine

ProlactinomaProlactinoma• Most common functional pituitary tumor• Usually a microadenoma• Can be a space occupying macroadenoma –

often with visual field defects• Although many women with hyperprolactinemia

will have galactorrhea and/ or amenorrhea– The absence these the two signs do not excluded

the diagnosis

• GnRH release is decreased in direct response to elevated prolactin, leading to decreased production of LH and FSH

ProlactinomaProlactinoma

• Women– Amenorrhea – this symptom causes

women to present earlier– Hirsutism

• Men– Impotence – often ignored– Tend to present later – Larger tumors– Signs of mass effect

ProlactinomaProlactinoma• Essential to rule out secondary causes!!

– Drugs which decrease dopamine stores• Phenothiazines• Amitriptyline• Metoclopramide

– Factors inhibiting dopamine outflow• Estrogen • Pregnancy• Exogenous sources

– Hypothyroidism• If prolactin level > 200, almost always a prolactinoma (even

in a nursing mom)• Prolactin levels correlate with tumor size in the

macroadenomas– Suspect another tumor if prolactin low with a large tumor

ProlactinomaProlactinoma• Diagnosis

– Assess hypersecretion• Basal, fasting morning PRL levels (normally <20 ug/L)

– Multiple measurements may be necessary • Pulsatile hormone secretion • levels vary widely in some individuals with hyperprolactinemia

– Both false-positive and false-negative results may be encountered

• May be falsely lowered with markedly elevated PRL levels (>1000 ug/L)

– assay artifacts; sample dilution is required to measure these high values accurately

• May be falsely elevated by aggregated forms of circulating PRL, which are biologically inactive (macroprolactinemia)

– Hypothyroidism should be excluded by measuring TSH and T4 levels

ProlactinomaProlactinoma

• Treatment– Medical

• Cabergoline – dopamine receptor agonist• Bromocriptine - dopamine agonist

– Safe in pregnancy– Will restore menses

• Decreases both prolactin and tumor size (80%)

– Surgical • Transsphenoidal surgery – irridation (if pt

cannot tolerate rx)



• What type of tumors are most prolactinomas?

• Prolactin levels >200 almost always indicate what?

• Do prolactin levels correlate with tumor size?

AnswerAnswer

• What type of tumors are most prolactinomas? Microadenomas

• Prolactin levels >200 almost always indicate what? Almost always indicates prolactinoma

• Do prolactin levels correlate with tumor size? Yes, in macroadenomas

Growth Hormone TumorsGrowth Hormone Tumors

• Gigantism– GH excess before closure of epipheseal

growth plates of long bones

• Acromegaly– GH excess after closure of epipheseal

growth plates of long bones– Insidious onset

• Usually diagnosed late

Growth Hormone TumorsGrowth Hormone Tumors

• May have DM or glucose intolerance• Hypogonadism• Large hands and feet• Large head with a lowering brow and

coarsening features• Hypertensive – 25%• Colon polyps

– 3-6 more likely than general population

• Multiple skin tags

Growth Hormone TumorsGrowth Hormone Tumors• Diagnosis

– Screen:• Check for high IGF-I levels (>3 U/ml)• Remember, levels very high during puberty

– Confirm: • 100gm glucose load• Positive: GH levels do not increase to <5ng/ml

• Treatment– Surgical – Radiation– Bromocriptine - temporizing measure

• May decrease GH by 50%

– Octreotide• For suboptimal response to other treatment



• How do you screen for acromegaly?

AnswerAnswer

• Check for high IGF-I levels (>3 U/ml)


• Anterior pituitary gland– Secrete various trophic hormones– Disease in this region may result in syndromes of

hormone excess or deficiency

• Posterior pituitary gland– More of a terminus of axons of neurons in the

supraoptic and paraventricular nuclei of the hypothalamus

– Storehouse for the hormones – The main consequence of disease in this area is

disordered water homeostasis

Posterior Pituitary GlandPosterior Pituitary Gland• The Neurohypophysis• Major blood source: the inferior

hypophyseal arteries• Directly innervated by hypothalamic

neurons – (supraopticohypophyseal and

tuberohypophyseal nerve tracts) via the pituitary stalk

• Sensitive to neuronal damage by lesions that affect the pituitary stalk or hypothalamus

Posterior Pituitary GlandPosterior Pituitary Gland• Production of

– Vasopressin (antidiuretic hormone; ADH; AVP)– Oxytocin

• Vasopressin (antidiuretic hormone; ADH; AVP) – Acts on the renal tubules to reduce water loss by

concentrating the urine – Deficiency causes diabetes insipidus (DI), characterized by

the production of large amounts of dilute urine – Excessive or inappropriate production predisposes to

hyponatremia if water intake is not reduced in parallel with urine output

• Oxytocin– Stimulates postpartum milk letdown in response to suckling

Posterior Pituitary GlandPosterior Pituitary Gland

• Vasopressin (Anti Diuretic Hormone)– Some control via anterior hypothalamus

• Contains separate osmoreceptors which aid in ADH release and thirst regulation

– Osmotic stimulus• Sodium• Mannitol

– Non osmotic factors• Blood pressure and volume at extremes• Nausea• Angiotensin II• Insulin induced hypoglycemia• Acute hypoxia• Acute hypercapnia

Posterior Pituitary GlandPosterior Pituitary Gland• Rapidly secreted in direct proportion to serum osmolality

– Increased with• Aging• Hypercalcemia• Hypoglycemia• Lithium treatment• Volume contraction

– Decreased with• Hypokalemia

• Threshold set point – Increased

• Hypervolemia, Acute hypertension, Corticosteroids

– Decreased • Pregnancy, Pre-menses, Volume contraction

Diabetes InsipdusDiabetes Insipdus• Etiology

– Deficient AVP can be primary or secondary• The primary form

– Deficiency in secretion » Agenesis or irreversible destruction of the neurohypophysis » Malformation or destruction of the neurohypophysis by a

variety of diseases or toxins » Neurohypophyseal DI, Pituitary DI, or Central DI

– Deficiency in action» Can be genetic, acquired, or caused by exposure to various

drugs » Nephrogenic DI

– It can be caused by a variety of congenital, acquired, or genetic disorders

» 50% idiopathic

Diabetes InsipdusDiabetes Insipdus

• Gestational DI– Primary deficiency of plasma AVP – Result from increased metabolism by an N-terminal

aminopeptidase produced by the placenta – Signs and symptoms manifest during pregnancy and

usually remit several weeks after delivery

Diabetes InsipdusDiabetes Insipdus• Secondary deficiencies of AVP

– Results from inhibition of secretion by excessive intake of fluids

• Primary polydipsia – Dipsogenic DI

» characterized by an inappropriate increase in thirst » caused by a reduction in the "set" of the osmoregulatory

mechanism. » association with multifocal diseases of the brain such as

neurosarcoid, tuberculous meningitis, or multiple sclerosis but is often idiopathic.

– Psychogenic polydipsia» is not associated with thirst» polydipsia seems to be a feature of psychosis

– Iatrogenic polydipsia» results from recommendations of health professionals or the

popular media to increase fluid intake for its presumed preventive or therapeutic benefits for other disorders


• Secondary deficiencies of AVP– Antidiuretic response to AVP

• Results from polyuria• Caused by washout of the medullary

concentration gradient and/or suppression of aquaporin function.

• Usually resolves 24 to 48 h after the polyuria is corrected

– Often complicate interpretation of tests commonly used for differential diagnosis

Diabetes InsipdusDiabetes Insipdus• Pathophysiology

– When secretion or action of AVP is reduced to 80 to 85% of normal

• urine concentration ceases and the rate of output increases to symptomatic levels

– Primary defect (pituitary, gestational, or nephrogenic DI)

• Polyuria results in a small (1 to 2%) decrease in body water and a commensurate increase in plasma osmolarity and sodium concentration that stimulate thirst and a compensatory increase in water intake

• Overt signs of dehydration do not develop unless the patient also has a defect in thirst or fails to drink for some other reason


• Pathophysiology– Primary polydipsia

• Pathogenesis of the polydipsia and polyuria is the reverse of that in pituitary, nephrogenic, and gestational DI

– Excessive intake of fluids slightly increases body water, thereby reducing plasma osmolarity, AVP secretion, and urinary concentration.

– Results in a compensatory increase in urinary free-water excretion that varies in direct proportion to intake

– Clinically appreciable overhydration uncommon » unless the compensatory water diuresis is impaired by

a drug or disease that stimulates or mimics endogenous AVP


• Clinical Presentation– Production of abnormally large volumes of dilute

urine• The 24-h urine volume is >50 mL/kg body weight and the

osmolarity is <300 mosmol/L.

– The polyuria produces symptoms of urinary frequency, enuresis, and/or nocturia, which may disturb sleep and cause mild daytime fatigue or somnolence.

– It is also associated with thirst and a commensurate increase in fluid intake (polydipsia).

– Clinical signs of dehydration are uncommon unless fluid intake is impaired.


• Diagnosis– Verify polyuria

• a 24-h urine output collection• > 50 mL/kg per day (>3500 mL in a 70-kg man).

– Check osmolarity • >300 mosmol/L

– due to a solute diuresis and the patient should be evaluated for uncontrolled diabetes mellitus or other less common causes of excessive solute excretion

• <300 mosmol/L– Due to water diuresis and should be evaluated further to

determine which type of DI is present


• Diagnosis– Water deprivation test

• If does not result in urine concentration before body weight decreases by 5% or plasma osmolarity/sodium exceed the upper limit of normal

– (osmolarity 300 mosmol/L, specific gravity 1.010)

– Primary polydipsia or a partial defect in AVP secretion or action are largely excluded

– Severe pituitary or nephrogenic DI are the only remaining possibilities


Diagnosis: Neurogenic vs Nephrogenic• Administer Desmopressin (DDAVP)

• 1 g • 0.03 ug/kg • subcutaneously or intravenously

• Measure urine osmolality – (30,60,120 min)– 1 to 2 h later

• An increase of >50% indicates severe pituitary DI• Smaller or absent response is strongly

suggestive of nephrogenic DI

Diabetes InsipdusDiabetes Insipdus• Treatment

– Neurogenic DI • DDAVP • Chlorpropamide (Diabinese)

– Antidiuretic effect can be enhanced by cotreatment with a thiazide diuretic

– SE: hypoglycemia, disulfiram like reaction to ethanol – Contraindicated in Gestional DI

– Nephrogenic DI• Not affected by treatment with DDAVP or chlorpropamide • May be reduced by treatment with a thiazide diuretic and/or amiloride

in conjunction with a low-sodium diet • Inhibitors of prostaglandin synthesis (e.g., indomethacin) are also

effective in some patients

– Psychogenic or dipsogenic DI • there is no effective treatment

Syndrome of Inappropriate ADH Syndrome of Inappropriate ADH secretionsecretion

• Etiology– CNS

• Lesions, Inflammatory disease• Trauma, psychosis

– Drugs• Stimulate AVP release

– Nicotine, phenothiazines, TCAs, SSRIs

• Chlorpropamide, clofibrate, carbamazepine, cyclophosphamide, vincristine

– Pulmonary• Infection• Mechanical/ventilatory issue


• Pathophysiology– Excessive AVP production resulting in

decreased volume of highly concentrated urine

– Water retention– Decreased plasma osmolarity – Decreased plasma Na


• Clinical Presentation– Acute

• Water intoxication• Headache, confusion• Nausea, vomiting • Anorexia • Coma, convulsions

– Chronic• May be asymptomatic


• Diagnosis– Diagnosis of exclusion– AVP level inappropriately elevated relative

to plasma osmolality


• Treatment– Acute

• Fluid restriction• Hypertonic saline

– Central myelinolysis

– Chronic• Demeclocyline 150-300mg PO TID-QID

– Reversible Nephrogenic DI

Treatment Guidelines

• See Handout

References

• Harrison's Principles of Internal Medicine - 16th Ed. (2005)

• Up to Date

• Med Study – Endocrine

• Mayo Clinic Board Review

QuestionsQuestions

True or FalseTrue or False

The pituitary:1. Pituitary tumors are usually macroadenomas.2. Lack of galactorrhea essentially rules out a

prolactinoma.3. Prolactin levels correlate with the size of a

prolactinoma4. Prolactin level of 230 in a nursing woman is

probably due to a prolactinoma5. An enlarged sella tursica can be seen in a

hypothyroid patient.


AnswersAnswers

The pituitary:1. Pituitary tumors are usually macroadenomas.

– – True2. Lack of galactorrhea essentially rules out a

prolactinoma. – False– False3. Prolactin levels correlate with the size of a

prolactinoma – – True4. Prolactin level of 230 in a nursing woman is

probably due to a prolactinoma – – True5. An enlarged sella tursica can be seen in a

hypothyroid patient. – – True

• A 24 year old woman complains of fatigue and malaise. She gave birth to a healthy infant 4 months before presentation. She did not breastfeed. Menses have subsequently been irregular and infrequent, representing a change from before pregnancy. The family history is notable for a sister who has Hashimoto thyroiditis. The pregnancy test is negative, and the serum level of prolactin is normal. Of interest, TSH is 0.9mIU/L (normal, 0.3-5.0) and free thyroxine is 0.8ng/dL (normal, 0.8-1.4). The results of MRI of the pituitary are reported as normal. The next step would be to:

•A) Start thyroxine replacement therapy

•B) Request a neurosurgeon to perform a biopsy of the pituitary

•Perform a water deprivation test

•Perform a 1 µg corticotropin (ACTH) stimulation test

•Measure IGF-1

•A) Start thyroxine replacement therapy

•B) Request a neurosurgeon to perform a biopsy of the pituitary

•C) Perform a water deprivation test

•D) Perform a 1 Perform a 1 µg corticotropin (ACTH) µg corticotropin (ACTH) stimulation teststimulation test

•E) Measure IGF-1

A 38-year-old woman is referred to you by her gynecologist. She first presented to her gynecologist 4.5 years ago with amenorrhea of 3 years’ duration and galactorrhea of 1 year’s duration. She had been taking no medications, and her initial physical examination was unremarkable except for expressible galactorrhea bilaterally. A routine chemistry screen was normal; her T4 level was 7.8 µg/dL, serum TSH was 1.4 µU/mL, and prolactin level was 48.2 ng/mL.

After taking bromocriptine for 2 months, her prolactin level was 19 ng/mL, at which point her galactorrhea ceased and she had her first menstrual period in 3 years. She continued to take bromocriptine over the next 4 years; her prolactin level remained less than 20 ng/mL, and she continued to have regular periods. However, she stopped taking her bromocriptine 6 months ago and is now having progressively worse headaches.

Her prolactin level is now 60.5 ng/mL, and a visual field examination shows a small superotemporal field cut in the right eye. A computed tomographic (CT) scan shows a 2.4-cm ´ 1.6-cm sellar mass with considerable suprasellar extension. She is now referred to you for further management.

What is the most likely diagnosis? (A) Prolactinoma(B) Clinically nonfunctioning pituitary adenoma(C) Metastatic cancer to the sella(D) Craniopharyngioma

What is the most likely diagnosis?

(A) Prolactinoma

(B) Clinically nonfunctioning pituitary adenoma

(C) Metastatic cancer to the sella

(D) Craniopharyngioma

endocrinology board review presented by med/peds pgy iii class

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