Brainscape's Knowledge GenomeTM

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


See full index

ENDOCRINE > DIABETES INSIPIDUS > Flashcards

DIABETES INSIPIDUS Flashcards

1
Q

what is diabetes insipidus?

A

condition where the body is unable to control the balance of water -> excretion of large volumes of dilute urine

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

what is the age epidemiology for diabetes insipidus?

A

can be seen in any age but mostly seen in adults

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

what are the types of diabetes insipidus?

A
  1. central diabetes insipidus
  2. nephrogenic diabetes insipidus
  3. gestational diabetes insipidus
  4. dispogenic diabetes insipidus (primary polydipsia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the 2 potential complications of diabetes insipidus?

A
  1. severe dehydration
  2. electrolyte imbalance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

in normal functioning of ADH, what do osmoreceptors in the hypothalmaus do?

A

they sense changes in osmolality of the blood (normal: 275-295)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is osmolality?

A

concentration of dissolved particles
major particles include: glucose, sodium, and BUN

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

what happens when there is increased plasma osmolality (due to dehydration)?

A
  1. this stimulates the sense of thirst
  2. stimulates release of ADH from posterior pituitary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does ADH act on?

and what happens to plasma osmolality?

A

the distal tubule to reabsorb water leading to decreased plasma osmolality (concentrate urine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is central diabetes insipidus also known as?

A

neurogenic diabetes insipidus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is central diabetes insipidus characterized by?

A

a decreased production by the hypothalamus or decreased release of ADH from the posterior pituitary resulting in a variable degree of polyuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the most common cause of central diabetes insipidus?

A

idiopathic (30-50%)
- assumes to be caused by autoimmune damage to ADH-producing cells

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

what are the types of acquired central diabetes insipidus?

A
  1. cancerous or noncancerous tumors in the brain or pituitary gland
  2. head injury (pance)
  3. prior surgery (trans-sphenoidal) or radiation at or around the hypothalamus or pituitary gland
  4. infections: encephalitis or meningitis
  5. rare familial (auto dom gene mutation) and congenital diseases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is nephrogenic diabetes insipidus characterized by?

A

decrease in urinary concentrating ability as a result of resistance to action of ADH

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

what are the hereditary causes of nephrogenic diabetes insipidus?

A
  1. x-linked inheritance for a mutation in the vasopressin
    V2 receptor gene
  2. mutation in the aquaporin-2 gene
    - dysfunction of the aquaporin-2 water channel
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the drug-induced causes of nephrogenic diabetes insipidus?

A

CHRONIC INGESTION OF LITHIUM
-leads to dysfxn of the aquaporin-2 water channel

often reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the acute or chronic kidney disease causes of nephrogenic diabetes insipidus?

also, why is there a reduction in renal concetrating ability?

A
  1. reduction in maximum renal concentrating ability d/t fewer nephrons or damage to tubules
    • examples: pyelonephritis, polycystic kidney disease,
      amyloidosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the 2 other types of diabetes other than nephrogenic DI and central?

A
  1. gestational DI
  2. dipsogenic DI
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is gestational diabetes insipidus?

A

transient ADH resistance in the second half of pregnancy d/t the release of Vasopressinase by the placenta (breaks down vasopressin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is dipsogenic diabetes insipidus also known as?

A

psychogenic polydipsia

20
Q

what is the cause of dipsogenic diabetes insipidus?

A

drinking excessive amounts of water

21
Q

what is dipsogenic diabetes insipidus related to?

A

psychologic problems (schizophrenia)

22
Q

what is the pathophsy of dipsogenic diabetes insipidus?

A

dipsogenic diabetes insipidus causes a decreased blood osmolality and the hypothalamus decreases the release of ADH as a normal physiological response and the kidneys produce excessive amount of urine (polyuria)

23
Q

what is the clinical presentation of diabetes insipidus?

A

polyuria
polydipsia
nocturia-> daytime sleepiness
hypotension
dehydration
neuro sx relating to hypernatremia

24
Q

what is polyuria characterized by?

A
  • > 3L urine output/day in adults (age-specific in children); severe: 10-15 L/day
  • degree of polyuria correlates with the degree of ADH deficiency or resistance
25
Q

what sx can you see in someone who is dehydrated?

A

HA, dry mucus membranes, light-headed, muscle cramps, confusion, weakness

26
Q

what neuro sx related to hypernatermia can be seen clinically in patients with DI?

A
  1. irritability
  2. seizures
  3. AMS-> coma
27
Q

what are the dx tests that can be done for DI?

A
  1. 24-hr urine volume
  2. serum sodium level
  3. serum ADH level
  4. plasma osmolality
  5. urine osmolality
28
Q

in the 24-hr urine volume test, what levels are considered polyuria?

A

> 3L/day in adults
2L/day in children
R/O DI if <2L/day in 24 hrs in absence of hypernatermia

29
Q

what level will be decreased in central DI?

A

decreased ADH levels

30
Q

what does hypernatremia indicate?

A

either CDI or NDI

31
Q

what does hyponatremia indicate?

A

dipsogenic diabetes insipidus (primary polydipsia)

32
Q

what plasma osmolality implies CDI or NDI?

A

> 300

33
Q

what plasma osmolality implies primary polydipsia?

A

< or equal to 280

34
Q

what urine osmolality suggests complete CDI or NDI?

A

<300

35
Q

what is the diagnostic water deprivation test/ADH stimulation test?

A

-plasma and urine osmolality are measured before water restriction
- no water intake for 2-3 hours
- hourly measurements of plasma and urine osmolality
after this interval

36
Q

what if there is no increase in urine osmolality during the water deprivation test/ADH stimulation test?

what do you give

A

an ADH analog (desmopressin) is administered

37
Q

what if urine osmolality increases during the water deprivation test/ADH stimulation test?

A

CDI (lack of central ADH secretion)

38
Q

what if urine osmolality stays low during the water deprivation test/ADH stimulation test?

A

NDI (defect in kidneys)

39
Q

what is the important first step before treating DI?

A

stop any possible meds that could cause or aggravate DI

40
Q

what is the first line for central DI?

A

desmopressin (DDAVP)
-synthetic ADH/vasopressin
-preferred med in most patients
-given at minimum dose to reduce nocturia; admin at
bedtime

41
Q

what does desmopressin have a risk for?

A

HYPONATREMIA- causes N/V, HA, lethargy, seizures, and coma

42
Q

what is the first line treatment for nephrogenic DI?

A

thiazide diuretics -> hydrochlorothiazide (HCTZ)

43
Q

what does HCTZ do?

A

decrease polyuria (increase proximal tubule sodium and water reabsorption and less water delivered to the ADH-sensitive collecting tubules)

44
Q

what is the 2nd line tx for nephrogenic DI that can also be used in combo with HCTZ?

A

NSAID (Indomethacin)

45
Q

what does indomethacin do?

A

increase renal concentration of urine by inhibiting renal synthesis of prostaglandins (ADH antagonists)

46
Q

what is another treatment option other than central DI or nephrogenic DI treatments?

A

fluid replacement
- thirst intact- replace water losses orally
- electrolyte abnormalities do not normalize through
oral water intake:
>IV dextrose and water <500 mL/hr with serum
glucose monitoring
>risk for hyperglycemia

ENDOCRINE (18 decks)

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