374 Neurohypophysis Flashcards

1
Q

What are the two hormones produced by the posterior pituitary

A

ADH

oxytocin

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2
Q

syndrome associated with production of large amounts of dilute urine

A

diabetes insipidus

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3
Q

average threshold for AVP release

A

osmolality of 280 mOsm/L or 135 meq/L

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4
Q

what can lower the osmoregulatory system in AVP release

A

pregnancy, menstrual cycle, estrogen, relatively large, acute reductions in blood pressure or volume

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5
Q

what is the physiologic action of AVP

A

reduce water excretion by promoting concentration of urine

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6
Q

reduce water excretion by promoting concentration of urine

A

water diuresis

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7
Q

where is the thirst center

A

anteromedial hypothalamus

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8
Q

how is oxytocin different from AVP in chemical structure

A

differ only at positions 3 and 8

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9
Q

decrease in AVP that results in diabetes insipidus

A

decrease of 75%

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10
Q

urine volume and osmolality in diabetes insipidus

A

urine more than 40 cc/kg in 24 hr and osmolality of less than 300 mOsm/L

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11
Q

also known as primary deficiency of AVP

A

neurohypophyseal DI, neurogenic DI, pituitary DI, central DI

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12
Q

mutation in the WFS1 gene leading to diabetes insipidus, diabetes mellitus, optic atropahy, neural deafness

A

Wolfram syndrome

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13
Q

causes nephrogenic DI

A

mutations in the AQP2 gene

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14
Q

Urinary frequency, nocturia, enuresis. Volume less than 40 ml/kg. Osmolality more than 300 mOsm/L. Consideration?

A

GU evaluation

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15
Q

Urinary frequency, nocturia, enuresis. Volume more than 40 ml/kg. Osmolality less than 300 mOsm/L.What next?

A

Basal AVP

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16
Q

Urinary frequency, nocturia, enuresis. Volume more than 40 ml/kg. Osmolality less than 300 mOsm/L. Basal AVP less than 1 pg/ml

A

Brain MRI. Check for pituitary bright spot.

17
Q

Urinary frequency, nocturia, enuresis. Volume more than 40 ml/kg. Osmolality less than 300 mOsm/L. Basal AVP more than 1 pg/ml

A

Nephrogenic DI

18
Q

Urinary frequency, nocturia, enuresis. Volume more than 40 ml/kg. Osmolality less than 300 mOsm/L. Basal AVP less than 1 pg/ml. Brain MRI absent bright spot. Diagnosis?

A

Pituitary DI

19
Q

Urinary frequency, nocturia, enuresis. Volume more than 40 ml/kg. Osmolality less than 300 mOsm/L. Basal AVP less than 1 pg/ml. Brain MRI present bright spot. Diagnosis?

A

Primary polydipsia

20
Q

difference between AVP and synthetic DDAVP

A

DDAVP has 3-4x longer duration of action

21
Q

in what ways can DDAVP be given

A

IV or SC injection, orally and nasal inhalation

22
Q

dose of DDAVP

A

1-2 ug qd or BID by injection; 10-20 ug BID by nasal spray; 100-400 ug bid or tid orally

23
Q

when does hyponatremia in DI occur

A

when urine is reduced to less than 10 ml/kg/day

24
Q

syndrome characterized by chronic or recurrent hypertonic dehydration

A

hypodipsic hypernatremia

25
laboratory findings in SIADH
low normal BUN and creatinine, low plasma renin activity, normal serum potassium, high urinary sodium
26
treatment of SIADH
restriction of total fluid intake; ADH receptor antagonist
27
how is convivaptan given
20 mg IV over 30 mins followed by continuous infusion of 20 mg over 24 hr
28
how is tolvaptan given
15 mg po and increasing to 30 mg to 60 mg at 24 hr interval depending on effect