Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endocrine 2 > Pituitary Gland - Posterior pituitary > Flashcards

Pituitary Gland - Posterior pituitary Flashcards

1
Q

Posterior pituitary

  • aka
  • function
  • blood supply
  • main consequence of disease
A
  • neurohypophysis
  • nervous tissue: storehouse for hormones made in hypothalamus (ADH and oxytocin)
  • inferior hypophyseal arteries
  • disordered water homeostasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Posterior pituitary

- innervation

A

Directly innervated by hypothalamic neurons

  • Supraoptic nucleus: ADH
  • Paraventricular nucleus: oxytocin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Posterior pituitary

- what might cause neuronal damage?

A

lesions that affect pituitary stalk or hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Oxytocin

A

stimulates postpartum milk letdown in response to suckling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ADH

  • released when
  • action
A
  • low bp/volume, high plasma osmolality, pain, emotional stress
  • action: concentrates urine by increasing water reabsorption in the kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe osmoreceptors that are related to ADH

A
  • located in supraoptic nucleus

- aid in ADH release and thirst regulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What inhibits ADH

A
  • high bp
  • low plasma osmolality
  • alcohol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Diabetes insipidus

- etiology

A
  • no association with DM
  • damaged pituitary gland or hypothalamus
  • disrupts nl production, storage, release of ADH
  • pass abnl large volume urine that is “insipid”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diabetes insipidus

- ADH changes

A
  • loss of ADH secretion OR action
  • decreased ADH = less water reabsorption
  • increased dilute urine output
  • increased serum concentration
  • Euvolemic hypernatremia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4 types of Diabetes insipidus

A
  • central
  • nephrogenic
  • disogenic
  • gestational
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Diabetes insipidus

- central

A
  • primary: genetic abnormality of ADH gene or idiopathic

- secondary (MC): Sx, skull base fx/cranial injury, suprasellar/intrasellar tumor, infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Diabetes insipidus

- nephrogenic

A

kidneys do not have normal response to ADH, usually dt tubule defect (inherited or CKD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Diabetes insipidus

- disogenic

A

problem with thirst mechanism, often associated with mental illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Diabetes insipidus

- gestational

A
  • placenta breaks ADH down and produces prostaglandins, reducing kidney’s sensitivity to ADH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Diabetes insipidus

- signs and sx

A
  • abnl large volume dilute urine
  • polyuria, enuresis, nocturia
  • thirst, polydipsia
  • dry skin, dizzy, nausea, confusion
  • low bp, hypernatremia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Diabetes insipidus

- dx

A
  • History and PE
  • verify polyuria with 24h urine output collection (>50 ml/kg/day)
  • check osmolarity
  • check sodium
  • water deprivation test
  • MRI: not diagnostic but can help visualize tumor
17
Q

Osmolarity in Diabetes

A

> 300 due to solute diuresis, pt should be eval for DM or other causes of excessive solute excretion
< 300: due to water diuresis, should be evaluated for type of DI

18
Q

Diabetes insipidus

- how to distinguish between central and nephrogenic

A
  • administer desmopressin (synthetic ADH)
  • measure urine osmolality at timed intervals, an increase of >50% indicates central DI
  • smaller/absent response suggests nephrogenic
19
Q

Diabetes insipidus

- tx of central

A
  • mild: increase fluid

- otherwise: desmopressin (DDAVP)

20
Q

Diabetes insipidus

- tx of nephrogenic

A
  • NO desmopressin
  • low salt diet to reduce urine production
  • increase fluids
  • HCTZ
21
Q

Diabetes insipidus

- tx of gestational

A
  • DDAVP

- deliver baby

22
Q

Diabetes insipidus

- tx of disogenic

A
  • no tx…

- decrease fluid intake

23
Q

SIADH

- describe

A
  • MC cause euvolemic hyponatremia in hospitalized pts
24
Q

SIADH

- define

A

hyponatremia and hyposmolality resulting from inappropriate and continued secretion/action of ADH despite normal/increased plasma volume
(retain too much water)

25
Q

SIADH

- urine

A

concentrated, impaired water secretion

26
Q

SIADH

- pathophysiology

A
  • excessive ADH production = decreased volume of highly concentrated urine
  • water retention
  • elevated urine osmolality
  • decreased serum osmolality
  • hyponatremia dt excess water, not deficient sodium
27
Q

SIADH

- etiology

A 
CNS
- lesions, inflammatory dz
- trauma, psychosis
Drugs
- nicotine, phenothiazines, TCAs, SSRIs and others
Pulmonary
- infection
- mechanical/ventilatory issue
28
Q

SIADH

- signs and sx

A 
Acute:
- water intoxication
- HA, confusion
- Ataxia
- Nausea, vomiting
- anorexia
- Coma, convulsions
Chronic
- may be asymptomatic
29
Q

SIADH

- Dx

A
  • PMH: trauma, drug use, etc.
  • PE: euvolemic, normotensive
  • hyponatremia and hypoosmolality
  • renal excretion of na
  • concentrated urine
  • no volume depletion
  • no other causes of hyponatremia
  • fluid restriction corrects hyponatremia
30
Q

SIADH

- Tx goal

A
  • correct hyponatremia at a rate that does not cause neurologic complications
  • increase serum na 0.5-1.0 mEq/h
  • no more than 10-12 mE in first 24 hours
  • rule of sixes (6 in 6 hours for severe sx and then stop)
31
Q

SIADH

- Acute tx

A
  • fluid restriction
  • hypertonic saline (3%)
  • vasopressin receptor antagonists
  • furosemide (diuretic)
32
Q

SIADH

- chronic tx

A
  • fluid restriction
  • vasopressin receptor antagonists
  • loop diuretics

Endocrine 2 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions