Q6 Endocrine Flashcards
Canvas Case studies - review
Post pituitary Hypo?
Hyper?
Hypo: DI
Hyper: SIADH
Adrenal cortex hypo?
Hyper?
Hypo = Addison’s
Hyper: Cushings
Posterior pituitary is ________ tissue connected to _______ tract. Produces ________ hormones.
Anterior pituitary is ______ tissue connected to ______. Produces _________ hormones.
PP: neural, *, Oxytocin, ADH
AP: vascular, *, TSH, LH/FSH, GH, ACTH, Prolactin
Hypothalamus secretes ?
TRH, GnRH, GHRH/GHIH, CRH, PIH
More important/common type of regulation?
Negative feedback loop.
T/F: Positive feedback loop is common in men
False. Rare in men. Some in women.
Catecholamines release is an example of ______ regulation.
Neural. Needed emergently fast!
Hypothalamic dysfunction usually shows up as
disruption in ADH and regulatory hormones (usually PLactin first - leaking breast milk.
If a patient has a head trauma and starts leaking breast milk, what would you suspect?
Hypothalamic damage.
Vasopressin is secreted in response to _______ and acts on _______ to _______
High serum osmolality (dehydration, concentration).
Distal tubule and collecting ducts
Increase H2O reabsorption.
causes of Neurogenic or central DI
Pituitary failure - lesion in hypothalamus, or pituitary gland, brain tumor, aneurysm, thrombus, infx, genetics, CHI. No ADH secreted.
Nephrogenic DI is _______
Non-responsiveness to ADH by collecting tubules.
Pseudo/psychogenic DI
Excess Water intake overwhelms any signal to retain - kidneys trying to get rid of it!
DI is kidney unable to _______ urine. They pee _____/day. Polydipsia. Rapid dehydration and _____ natremic. _____ urine osmolarity
Concentrate.
8-12L
Hypernatremia (concentration effect),
LOW
Nephrogenic DI is usually _____ onset
Idiopathic DI is usually ______ onset.
gradual
Abrupt.
DI has a _______ serum Na level and a ______ UOP - usually the opposite.
High serum
High
Chlorpropamide, clofibrate, carbamazepine used in the case of ______
ADH Desmopressin(DDAVP) in the case of ______
ADH insufficiency.
No ADH production at all.
Causes of SIADH
Cancer (bladder, prostate, SCLCA, GU, sarcoma)
CNS
Pulmonary (TB, asthma, CF, respiratory failure)
Meds (hypoglycemics, antidepressants, antipsychotics, narcotics, anesthesia, chemotherapy, NSAIDS)
What does SIADH do to the body?
Excess ADH —> increase CD permeability —> increased H2O reabsorption —> increase in ECF —> dilutional Hyponatremia (<135), low fluid osmolarity (<280), increased urine osmolarity compared to serum.
The ______ SIADH onset, the ______ symptoms.
More rapid
Severe
Hyponatremia s/s by severity:
140-130
120-130
<115
140-130 = thirst, impaired taste, anorexia, fatigue.
130-120 = GI symp, vomiting, abd cramps
<115 = CNS confusion, sz, lethargy, muscle twitching and irreversible neuro changes possibl
What other conditions could mimic SIADH?
Diuretics, HF, renal insufficiency.
Tx for SIADH
Hypertonic saline (SLOW)
Fluid restriction (600-800ml/day)
Usually resolves in 3 days.
Demeclocycline = increased renal tubule resistance to ADH
Conivaptan = hospitalized patients with excess ADH
What is central pontine myelinolysis?
Too rapid of infusion of hypertonic saline.
Genetic pituitary failure is _______onset
Non-genetic pit failure is ______ onset. The 9 I’s?
Pediatric
Adult
Invasion (tumor), Infarct, Infiltrated, Immunology, Iatrogenesis (radiation therapy), Infection, Idiopathy, Isolation.
Anterior pituitary VERY sensitive to _______ and ______
Blood flow and oxygen.
What is Sheehan’s syndrome?
Hypopituiatrism resulting from PP Hemorrhage (+/- DIC) due to circulatory collapse and pituitary artery vasospasm.
Will have S/s of loss of all hormones produced by pituitary (including Addison’s -from adrenal, **)
Cortisol deficiency (life threatening)
Thyroid deficiency (TSH)
Gonadal failure/loss of 2nd sex characteristics
Delayed growth (dwarfism), low lean body mass, low bone density
All these things ^^ indicate?
Panhypopituitarism
What is the most difficult thing to manage in hypopituitarism?
Cortisol levels - circulatory collapse.
GH is secreted in a _______ fashion with the largest amount w/in 1hr of sleep
GH ______ effects of skeletal muscle, liver and fat
GH ______ effects of IGF in liver (most important is IGF1) similar to insulin
Direct
Indirect
What is acromegaly?
GH excess - epiphyseal plates don’t close in children = excess vertical height. Face and hands are extra large
Cardiac hypertrophy - 33-50% with Left HF.
What causes excess IGF-1 production
Ie Excess GH
Pituitary adenoma - tumor.
Pituitary tumors most often result in excess prolactin not excess ______
GH - but it is possible.
What is pseudo acromegaly?
Acromegaly features with insulin resistance, NL GH and IGF1. Results from high dose Minoxidil (Rogaine)
Effects of chronically elevated GH levels?
Renal tubules —> increase Ph reabsorption so hyperphosphatemia.
Impaired carbohydrate tolerance —-> increased metabolic rate, inhibited peripheral glucose uptake, increased hepatic glucose production, insulin resistance and hyperinsulinemia —> T2DM
What lab is the most sensitive to excess growth hormone?
IGF 1
Somatostatin analogs are used to treat ______. Some examples are _______. Another tx is Pegvisomant which reduces tissue sensitivity to _______
GH excess
Octreotide, Ianreotide.
GH
Why is GH serum level not a good thing to measure?
Since it is secreted in Pulsitile fashion, the levels vary too much
Main cause of prolactin excess?
Pituitary adenoma.
Other than lactation and pregnancy, Prolactin is inhibited by _______
Dopamine (Catecholamines)
From: hypothalamic neurons
Pituitary neurons
Nonlactotroph-produced dopamine that flows over to lactotrophs.
Causes of prolactin (PRH) excess other than tumor
Primary Hypothyroidism
Renal failure
Drugs (antipsychotics, metoclopramide, TCAs, methyldopa, estrogens)
Why does high PRH impair fertility?
Suppresses GnRH pulses, impaired. FSH/LH release, blunts ovarian response to gonadotropins.
Everything is confused so they get amenorrhea.
In presence of PRH excess, women may get amenorrhea. Men get:
Hypogonadism, ED, impaired libido,galactorhea, Hirsutism, osteopenia, CNS symptoms.
In the case of PRH excess symptoms - what should you do first?
After that?
Careful eval of medication use!
Serum prolactin (NOT after a breast exam or after sexual intercourse)
What does a Prolactin level of 45 mean?
18? 248?
NL <20
>50 -> r/o non-pituitary cause
>200 = brain MRI
How do you treat PRH excess?
Dopaminergic agonists (Paroldel, cabergoline, pergolide
Glands that do NOT listen to the HPA axis?
Parathyroid glands.
Most common case of HyPOparathyroid?
Thyroidectomy with all 4 glands removed
What is DiGeorge syndrome?
Cardiac arrhythmias that result in sudden death from not regulating calcium
What other electrolyte imbalances can be tied to hypoparathyroid?
Hypomgnesemia (caused by ETOH abuse, malnutrition, malabsorption, Aminoglycoside abx and TPN) OR
Hyperphosphatemia (decreased PTH means decreased serum Ca = increased serum Ph - seesaw)