Clinical: Hypothalamus and Anterior Pituitary Flashcards
What are some etiologies of pituitary-hypothalamis lesions?
- Non-Functioning Pituitary Adenomas
- Endocrine active pituitary adenomas: Prolactinoma, Somatotropinoma, Corticotropinoma, Thyrotropinoma, Other mixed endocrine active adenomas
- Malignant pituitary tumors: Functional and non-functional pituitary carcinoma
- Metastases in the pituitary (breast, lung, stomach, kidney)
- Pituitary cysts: Rathke’s cleft cyst, Mucocoeles, Others
- Empty sella syndrome
- Developmental abnormalities: Craniopharyngioma (occasionally intrasellar location), Germinoma, Others
- Primary Tumors of the central nervous system: Perisellar meningioma, Optic glioma, Others
- Vascular tumors: Hemangioblastoma, Others
- Malignant systemic diseases: Hodgkin’s disease, Non-Hodgkin lymphoma, Leukemic infiltration, Histiocystosis X, Eosinophilic granuloma, Giant cell granuloma (tumor)
- Granulomatous diseases: Neurosarcoidosis, Wegner’s granulomatosis, Tuberculosis, Syphilis
- Vascular aneurysms
What is a hormonal disorder that results when the pituitary gland produces excess growth hormone after puberty?
Acromegaly
Who does acromegaly most often affect?
Middle-aged adults
What causes acromegaly?
Prolonged overproduction of GH by the pituitary gland
What 2 categories of tumors can cause acromegaly?
- Pituitary tumors
2. Non-pituitary tumors
Is a random GH test useful for diagnosis of acromegaly?
NO
What is best for screening for acromegaly?
Insulin like growth factor 1 (IGF-1)
What is the gold standard to confirm diagnosis of acromegaly?
Oral glucose GH suppression testing
If acromegaly isn’t caused by a pituitary tumor, what other organs can have tumors leading to this?
Pancreas, lungs, and adrenal glands
How do pancreatic, lung, or adrenal gland tumors lead to an excess of GH?
Produce GH themselves, or more often, produce GHRH (stimulate pituitary to make GH)
In patients with non-pituitary tumors, what can be measured in the blood?
Excess GHRH
In over 90% of acromegaly patients, what causes the overproduction of GH?
A benign tumor of the pituitary gland- Adenoma
What do adenomas of the pituitary gland do?
Produce excess GH and can compress brain tissue like the optic nerves as they expand
Because pituitary tumors can compress the surrounding normal pituitary tissue, what can be seen in men and women due to altered production of other hormones?
Women: Changes in menstuation and breast discharge
Men: Impotence
How do adenomas grow?
Slow or fast
What 3 things are done to evaluate an incidental pituitary mass?
- Radiologic evaluation
- Clinical evaluation
- Hormonal evaluation (ALWAYS GET HORMONE LEVELS)
What is the preferred imaging study for the pituitary?
MRI
Which type of imaging gives better visualization of soft tissues and vascular structures, CT or MRI?
MRI
Does MRI result in exposure to ionizing radiation?
NO
What are images generated based upon with an MRI?
Magnetic properties of H atoms
What type of MRI produce high signal intensity images of fat?
T1
What type of MRI produces high intensity signals of structures with high water content?
T2
What is a T1 image good for to see?
Fatty marrow and orbital fat- Bright images
What is a T2 image good for to see?
CSF and cystic lesions
What is CT better at visualizing?
Bony structures and calcifications within soft tissues
What is CT better at determining the diagnosis of?
Tumors with calicfication, like germinomas, craniopharyngiomas, and meningiomas
When might CT be necessary over MRI?
When MRI is contraindicated
-Pacemakers or metallic implants in brain or eyes
What are 3 disadvantages to CT?
- Less optimal soft tissue imaging compared to MRI
- Use of IV contrast media
- Exposure to radiation
What should all patients with macroadenomas have?
Formal visual field testing
Besides radiographic and hormonal evaluation, what else should patients be asked and examined for (with a macroadenoma)?
Pituitary hyerfunction or hypofunction
What 2 types of hormonal evaluation should be done?
Basal hormone measurement and dynamic stimulation testing
All pituitary masses should have screening basal hormone measurements… what are they?
- Prolactin
- TSH, FT4
- ACTH, AM cortisol, midnight salivary cortisol
- LH, FSH, estradiol or testosterone
- Insulin-like growth factor-1 (IGF-1)
What might be useful in select cases to further evaluate pituitary reserve and/or for pituitary hyperfunction?
Dynamic stimulation/suppression testing
What are some examples of dynamic stimulation/suppression testing?
- Dexamethasone suppression testing
- Oral glucose GH suppression test
- GHRH, L-dopa, arginine
- CRH stimulation
- Metyrapone
- TRH stimulation
- GnRH stimulation
- Insulin-induced hypoglycemia
There are a lot of symptoms for acromegaly… list as many as you can…
- swelling of the hands and feet
- facial features become coarse as bones grow
- body hair becomes coarse as the skin thickens and/or darkens
- increased perspiration accompanied with body odor
- protruding jaw
- voice deepening
- enlarged lip, nose, and tongue
- degenerative arthritis
- thickened ribs (creating a barrel chest)
- joint pain
- enlarged heart
- enlargement of other organs
- impotence in men
- strange sensations and weakness in arms and 15. legs
- snoring*** SLEEP APNEA
- fatigue and weakness
- headaches
- loss of vision
- irregular menstrual cycles in women
- breast milk production in women
- Abnormal glucose tolerance test (glucosuria/polyuria)
What 3 things can be done to help diagnose acromegaly?
- Serial photos over years to observe physical changes in patient
- XR to detect bone thickening
- Blood tests to check GH level
Are the changes seen with acromegaly subtle or quick?
SUBTLE…over many years
What is the gold standard for treatment of GH-secreting tumors because of its aggressive nature?
Surgical therapy- Must be done as the primary choice in all patients who are otherwise acceptable surgical risks
What are the 2 surgical modalities?
- Transsphenoidal (better option)
2. Craniotomy
What size limit is there for operation of pituitary tumors?
No larger than 10mm in diametert
What are 3 drugs that can be given for pituitary tumors?
- Dopaminergic analogues: Bromocriptime
- Somatostatin analogues: Octreotide
- Pegvisomant: Directly blocks effects of GH
If untreated, acromegaly can lead to what 2 things?
- DM
2. HTN
What can acromegaly also increase a patient’s risk for?
- CV disease
2. Colon polyps- Lead to CA
What is due to excess cortisol from pituitary, adrenal, or other sources (exogenous glucocorticoids, ectopic ACTH, ect.)
Cushing’s Syndrome
What is hypercortisolism due to ecess pituitary secretion of ACTH
Cushing’s Disease
What accounts for about 70% of cases of endogenous Cushing’s syndrome?
Cushing’s Disease
What are 4 prominent feature of Cushing’s Syndrome?
Proximal muscle wasting, progressive/central obesity, striae (“stretch marks”), Buffalo Hump
Lots of symptoms for Cushing’s Syndrome… name as many as you can…
- Moon facies
- Facial plethora
- Supraclavicular fat pads
- Buffalo hump
- Truncal obesity
- Weight gain
- Purple striae
- Proximal muscle weakness
- Easy bruising
- Hirsutism
- Hypertension
- Osteopenia
- Diabetes mellitus/IGT
- Impaired immune function/poor wound healing
What 4 things can help diagnose Cushing’s Syndrome?
- ACTH, AM cortisol
- 24 hour urine cortisol
- Dexamathasone suppression testing
- Midnight salivary control
What do circadian studies of serum cortisol levels show?
High cortisol all the time in Cushing’s disease and Ectopic ACTH syndrome
-In normal people, the levels peak in the AM and slowly decrease thoughout the day
What can women present with with hyperprolactinemia/prolactinoma?
Oligomenorrhea, amenorrhea, galactorrhea, or infertility
What can men present with with hyperprolactinemia/prolactinoma?
Less symptoms than women and diagnosed later, but sexual dysfunction, visual problems, or headache
In both sexes, what can cause visual-field defects or headache due to hyperprolactinemia/prolactinoma?
Tumor mass effects
What are 4 causes of hyperprolactinemia?
- Hypothalamic dopamine deficiency
- Defective transport mechanisms
- Lactotroph insensitivity to dopamine
- Stimulation of lactotrophs
What 2 things can lead to hypothalamic dopamine deficiency?
- Disease of hypothalamus (tumors, AV malfornations, inflammation)
- Drugs (alpha-methyldopa and reserpine)
What can cause defective transport mechanisms?
Pituitary or stalk tumors- section of the pituitary stalk (ALL GOES BACK TO THIS)
What type of drugs can cause lactotroph insensitivity to dopamine?
Dopamine-receptor-blocking agents: phenothiazines (e.g. chlorpromazine), butyrophenones (haloperidol), and benzamides (metoclopramide, sulpiride, and domperidone)
What 3 things can cause stimulation of lactotrophs?
- HYPOthyroidism: Increased TRH production
- Estrogens
- Chest wall injury
How does chest wall injury lead to stimulation of lactotrophs?
abnormal stimulation of the reflex associated with the rise in prolactin that is seen normally in lactating women during suckling- Nerves not growing back as fast as they should post rib-fx or injury
True or False: Not all hyperprolactinemia is due to a prolactinoma?
TRUE
What are some other things that can cause hyperprolactinemia?
Pregnancy, stress, drugs, other pituitary and hypothalamic disease
What must be ruled out in females when working up a patients for hyperprolactinemia?
PREGNANCY
What blood test should be ordered to evaluate hyperprolactinemia?
TSH- Hypothyroidism can cause high prolactin
What part of the history is super important for evaluating hyperprolactinemia?
DRUGS- Medications can cause this
What are some other common causes of hyperprolactimeia that have to be ruled out?
- Nonfasting sample
- Nipple stimulation or sex
- Excessive exercise
- History of chest wall surgery or trauma
- Renal failure
- Cirrhosis
If no cause is determined or a tumor is expected and the prolactin is high (over 100ng/mL) what should be considered?
MRI
What are 3 options for treatment for a prolatin-secreting tumor?
- Pharmacotherapy
- Surgical resection
- Radiotherapy
What surgical approach is used for 95% of pituitary tumors?
Transsphenoidal
What are other surgical approaches for pituitary tumors?
- Endonasal submucosal transseptal approach
- Septal Pushover/Direct Sphenoidotomy
- Endoscopic approach
What class of drugs is the treatment of choice for most prolactinomas?
Dopamine agonists
What are some examples of dopamine agonists used for prolactinomas?
Bromocriptine, pergolide, cabergoline
What are some SE of dopamine agonists?
Postural hypotension, dizziness, nasal stuffiness, GI SE
