Brainscape's Knowledge GenomeTM

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


See full index

S2B5 MEDI > Hyponatremia > Flashcards

Hyponatremia Flashcards

1
Q

hypovolemia

  • define
  • what causes it?
A
  • contraction of the EVF (extracellular fluid volume)
  • due to combined salt and water loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is hyponatremia and what causes it

A
  • a decrease in Na+ serum concentration
    • defined as serum [Na+] below 135 mEq/L
    • due to either loss of Na+ or or dilution of Na+ due to excessive body water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what serum [Na+] constites mild, moderate and severe hyponatremia

A
  • Mild :130-134 mEq/L - often asymptomatic
  • Moderate: 120-129 mEq/L
  • Severe: <120 mEq/L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

at what serum [Na] might neurological symptoms present?

A

115 mEq/L

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

various symptomatology seen in hyponatremia

A
  1. Mild or absent symptoms
  2. Moderately severe symptoms:
  • Nausea without vomiting
  • Confusion
  • Headache
  1. Severe symptoms:
  • Vomiting
  • Cardiorespiratory arrest
  • Seizures
  • Reduced consciousness/ coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

major causes of hyponatremia

A
  • vomitting, diarrhea: fluid and Na+ loss
  • diuretics: fluid and Na+ loss
  • inadequate salt intake
  • gastrointestinal suckling
  • mannitol:
    • dilution hyponatremia
    • a shift of fluid from teh ICF to the ECF due to hypertonicity in the ECF dilutes serum Na+ and lowers serum Na+ concentration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is normal serum osmolality?

A

280-295 mosm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how to calculate serum osmolality

A

2 [Na+] + [glucose]/18 + BUN/2.8

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

ADH

  • where is it synthesized
  • when it is released
  • what does it do
A
  • a hormone synthesized by the hypothalamus
  • stored in the pituitary and released in states of high serum osmolality
    • _​_acts on distal collecting tubule and collecting ducts to increase their permeability to water
    • is a vasoconstrictor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what compartments make hole the total body water?

how much volume does each contain?

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

what is hypoosmolality

A
  • serum osmolality less than 280 mOsm/Kg
  • indicates excess total body water relative to body solutes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

IV infusions are administered into what fluid compartment?

A

into the insterstitium (component of ECV)

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

what is hypertonic hyponatremia?

what are examples?

A
  • hyponatremia due to overall hypertonicity ( > 290 mOsm) caused by a different solute in the extracellular space that draws water from the ICV into the ECV, thus diluting soeium
    • hyperglycemia - high serum glucose
    • hypertonic infusions (these are administered into the interstitial space, cause a hypertonic ECV)
      • glucose infusion
      • mannitol infusion - given for cerebral edema
      • maltose - given alongside IgG administration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

isotonic hyponatremia

  • define
  • what causes it?
A
  • hyponatremia seen when ECV osmolarity overall normal (270-290)
  • caused by:
  • psueodhyponatremia: fake lab error resulting from
    • ​hyperlipidemia
    • hyperproteinemia
  • gycine in TURP: isotonic glycine given in trans urethral prostate resection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

hypotonic hyponatremia

A
  • hyponatremia in the context of low overall osmolarity (<270 Mosm) in the extracellular space
    • three types of hopotonic hyponatremia
      • hypovolemic
      • euvolemic
      • hypervolemic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

hypovolemic hyponatremia

  • describe the fluid/solute status of the extracellular space
  • what are causes of this state?
A
  • this is a type of hypotonic hyponatremia ( <270 mosm)
  • due to a loss of both total body water and total body sodium but a proportionally LARGER loss of sodium
  • causes:
    • GI losses:
      • vomitting
      • diarrhea
      • blood loss
    • Renal loss:
      • diruetics
      • adrenal insufficiency: Na+ wasting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define euvolemic hyponatremia

A

a type of hypotonic hyponatremia where

  • TBW has increased
  • total salt is normal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what pathological states can cause euvolemic hyponatremia?

A
  • SIADH: syndrome of innapropriate ADH secretion
  • psychogenic polydispia

both lead to elevated total body water in the context of normal total body salt

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

define hypervolemic hyponatremia

A

a type of hypotonic hypontremia where

  • BOTH TBW and total body Na+ increase
    • relatively LARGER increase in TBW with respect to total body Na+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what pathological states can lead to hypervolemic hyponatremia?

A
  • states that decrease extracellular circulating blood volume (ECBV)
    • ​these states all lead to edema (either due to impaired fluid return to heart or low plasma oncotic pressure) ​
      • CHF: weak heart function
      • ​cirrhoris: low sythesis of plasma proteins
      • nephrotic syndrome: innapropriate filtration of plasma proteins, leading to low serum plasma proteins
    • renal railure (acute or chornic)
  • low ECVB leads to –> increased Na+ and water retentention –> hypervolemia
    • more water retention relative to sodium retention
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what clinical presentations to look for in possible hypovlemia?

A

 Examination of skin and mucous membranes

 Low BP

 Postural hypotension

 Increased capillary refill

22
Q

what clinical presentations to look for in possible hypervolemia?

A

 JVD

 Edema

23
Q

what is the use of urine sodium concentration in the assesment of hyponatremia?

A

urine sodium concentration can be used to distinguish between hypovolemia (decreased by TBW and TBNa+, bigger drop in TBNa+) and euvolemia (increased TBW, normal TBNa+)

24
Q

what specific history should you estbalish with a hyponatremic patients?

A

determine if they had recent surgery and involving administration of:

  • large volumes hypotonic fluid
    • ex: prostate or intrauterine procedures)
  • large volume of hypertonic IV fluid
    • mannitol, glycerol, IVIg
  • they were treated with lipemic serum
25
Q

what are the three main labs you should order for the diagnosis of hyponatremia?

A
  • serum osmolality (normal: 270-290 mOsm)
  • urine osmolality
  • urine sodium concentration
26
Q

what does urine osmolarity > 100 mOsm/kg indicate?

A

indicates in impaired ability of the kidney to dilute the urine.

  • urine is therefore too concentrated
  • usually secondary to increased ADH
27
Q

other than the main labs, what labs to get for diagnosis of hyponatremia?

A

 TSH/ FT4- to rule out hypothyroidsm

 Uric acid: Low in SIADH

 Cortisol- to rule out Adrenal insufficiency

 Lipids/albumin

28
Q

uric acid levels can be used to rule in what type of hyponatremia?

A

uric acid levels will be low in SIADH (type of euvolemic hyponatremia)

29
Q

what type of imaging to get in patients with suspected SIADH or suspected cerebral salt wasting ?

A

had CT scan and chest radiography

30
Q

based on plasma osmolality, volume status, and urine sodium, outline the diagnosis of the different subsets of hyponatremia

A
31
Q

SIADH

  • define
  • list its causes
  • what type of hyponatremia does ADH cause
  • how to diagnose
A
  • inappropriate ADH secretion
    • excess water reaborption limits the ability of the kidney to dilute urine
    • leads to a euvolemic hypotonic hyponatremia
  • causes:
    • neoplasms
    • pneumonia
    • menigitis
    • drugs:
      • SSRIs
      • NSAIDS
      • carbamazepine
      • chemotherapy (cilastin)
  • diagnosis:
    • main labs
      • low serum osmarility:
        • < 270 mOsm (confirms hyponatremia)
      • check urine osmolalitity!
        • high serum osmolarity:
          • ​> 100 mOsm/kg
        • high urine [na+]
          • ​> ​20 mEq/L
    • other labs:
      • REDUCED URIC ACID*
32
Q

discuss cardio, renal and hepatic function in SIADH

A

Normal renal, hepatic and cardiac function

33
Q

psychogenic polydypsia

  • define
  • what type of hyponatremia does it lead
  • how to diagnose
A
  • caused by excessive intake of water
    • this increases total body water and leads to severly diluted urine
    • euvolemic hypotonic hyponatremia
  • diagnosis:
    • serum osmolarity low (< 270 mOsm)
    • check urine osmolality:
      • low urine osmolaritity
        • < 100 mOsm/kg
        • < 20 mEq/L
34
Q

exercise associated hyponatremia - what is the serum/urine osmolarity

who is at risk?

what is the treatment?

A
  • excessive water intake seen in the context of marathons & other endurance events
    • anyone who has prolonged exercise who is drinking lots of fluids is at risk
  • urine osmolarity
    • low ( < 100 mOSm)
    • urine is dilute
  • treatment:
    • if pt is asymptomatic: water restriction
    • if pt is symptomatic: give hypertonic saline
35
Q

beer potomia

A
  • excessive beer consumption
    • beer has low solute/water ratio
      • causes a hypotonic hyponatremia
      • low urine osmolarity (< 100 mOsm/kg) like in EAH
    • can also lead to malnutrition
36
Q

define acute, subuacte and chronic hypotranemia

A

 Acute (< 24 hours)

 Subacute (>24-48)

 Chronic (>48hrs)

37
Q

define mild, moderate and severe hyponatremia

A

 Mild: 130-134 mEq/L
 Mod: 120-129 mEq/L
 Severe<120 mEq/L

38
Q

hyponatremia treatment goals

A
  • to oprevent further decline in the Na+ concentration
  • to relieve symptoms of hyponatremia
39
Q

excessive correction of hyponatremia can lead to what disease?

A

osmotic demylination syndrome

40
Q

describe the presentation of ODS (osmotic demylination syndrome)

A

 Paresis
 Dysphagia
 Dysarthria
 Diplopia
 Loss of consciousness  Ataxia
 Parkinsonism

41
Q

what are the fluid replacement options for hyponatremia?

A
  • normal saline
  • lactated ringers
  • hypertonic saline
    • reserved for patients with moderate-severe hyponatremia (< 129 mEq/L)
42
Q

acute hyponatremia

  • what defines “acute”
  • what is the goal of treatment
  • what are the limitations of treatment
A
  • acute: presented < 48 hrs ago
  • goal is to raise [Na+] by 4-6 mmol
    • ​takes about 6-8 hrs to correct, then maintain for 24 hrs
    • blood [Na+] not to increase by more than 12 mEq in 24 hrs
43
Q

chronic hyponatremia

  • treatment goals
  • what adjustments should be made regading risk of ODS?
A
  • chronic hyponatremia: > 48 hours
    • goal: raise [Na+] by 4-8 mmol/L in 24 hours
    • accounting for ODS:
      • low risk for ODS:
        • max correction of hyponatremia by an increase of 10-12 mmol/L in 24 hr period (or 18 mmol/L in 48 hr period)
      • high risk for ODS:
        • max correction of of hyponatremia by an increase of 8 mmol/L in 24 hrs
        • possible high ODS risk pts:
          • pt with [Na+] < 105 mEq/L
          • hypokalemic pts
          • malnourished pts
          • alcoholic/liver diseases pts
44
Q

treatment of hypovolemic hyponatremic patients?:

A
  • administer isotonic/hypertonic saline
    • hypovolemia secondary to diuretic use may also need K+ repletion
45
Q

how to treat euvolemic hyponatremia patients that are

A

asymptomatic

  • f_ree water restriction_ (<1/day)
  • treat SIADH, psychogenic polydispia, EAH this way
46
Q

treatment for hypervolemic hyponatremic patients:

A
  • give Na+ while restricting fluid
  • vasopressin (receptor) antagonists
  • if CHD:
    • add loop diuretics and an ACE/ARB
47
Q

how to treat hyponatremic patients that are overtly symptomatic - i.e., have seizures/severe neurological deficits

A

administer 3% hypertonic saline

48
Q

furosemide

  • what kind of drug?
  • indications for use?
  • how it is given?
  • MOA and effects?
  • when it is possibly contradindicated/when should it be used with caution?
A
  • indications: hypervolemic hypontramia
    • ​given with saline
  • loop diuretic
    • MOA: acts on the thin ascending loop of henle, on the NKCC (Na+/K+/2Cl-) transporter
    • decreases Na+ reabsorption (as well as Cl, Mg++, Ca++, mildly K+), i_ncreasing free water excretion_
  • use with caution in hypokalemic patients, since it can lead to K+ secretion in the collecting ducts
49
Q

demeclocycline

  • what kind of drug is it
  • indications
  • MOA
A
  • a tetracycline antiobiotic
    • MOA: binds 30s subunit inhibiting protein synthesis
    • causes diuresis
  • indication: in conjunction with fluid restriction, be used to treat SIADH
50
Q

tolvaptan

  • what kind of drug/MOA/effects
  • what are is uses
  • contraindications/cautions
A
  • uses: hypervolemic or euvolemic hyponatremia
  • is a vasopressin (ADH) antagonist
    • MOA: binds vasopressin receptor V2, inhibiting ADH binding
    • effects:
      • increases urine output
      • decrease urine osmlality (dilutes urine)
      • normalizes serium sodiu mlevels
  • cautions:
    • do NOT use over 30 days or you risk liver injury
    • if given to patients in a hospital: the hospital MUST have serum Na+ monitoring
  • contraindicaitons: liver disease
51
Q

covinaptan

what kind of drug/MOA/effects

uses

A
  • a ADH(vasopressin) antagonists
    • blocks V2 and V1a receptors
      • MOA/effects are same as tolvaptan
        • increased urine ouput
        • decreased urine osmolality (dilute urine)
  • indication: euvolemic and hypervolemic hyponatremia in patients that are hospitalized
    • ​given IV

S2B5 MEDI (7 decks)

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