Electrolytes 2 Flashcards
1
Q
Evaluation of Hyponatremia
- After initial steps of a thorough H&P, evaluate fluid status and then get which 4 labs first?
- Which 2 labs second?
A
- 1st: UA sodium, UA osmolality, serum osmolality, CMP
- 2nd: TSH, serum cortisol
2
Q
Tx of Hyponatremia
- If Na is <125 or symptomatic, what is the tx?
- ___ hyponatremia must be managed w/ extreme care
- Rapid increase in serum sodium can lead to _______
- Use of _____ is reserved for severe symptomatic cases
- What is the “traditional” treatment of chronic hyponatremia? to induce what?
- _____ are a newer class of tx agents which are vasopressin receptor antagonists
A
- Hospitalize!
- Chronic
- Cerebral pontine myelinolysis (CPM)
- Hypertonic solutions (3% NaCl)
- Demeclocycline / to induce nephrogenic diabetes insipidus
- “Vaptans”
3
Q
Tx of Hyponatremia
- In pts w/ severe symptomatic hyponatremia, the rate of sodium correction should be ____ in the first 24 hrs and ___ or less in 48 hours.
- ****If CHRONIC hyponatremia, should try to keep it ___ or less in the first 24 hours*****
A
- 6-12 mEq/L
- 18 mEq/L
- 8 mEq/L
4
Q
When correcting Hyponatremia, how often should you be checking serum sodium as you are replacing it (to make sure not overcorrecting)?
A
q2h
5
Q
- Poorly understood entity characterized by focal demyelination in the pons and extra-pontine areas
- Is it reversible?
- Dysarthria, dysphagia, seizures, AMS, quadriparesis, hypotension begin ___ after over-correction of hyponatremia
A
Central Pontine Myelinolysis (CPM)
- Irreversible
- 1-3 days after
6
Q
Which condition?
- A hypertonic disorder due to serum sodium >145 mEqL
- “Too little water relative to salt”
- Clinical features due to brain shrinkage secondary to increased ECF osmolality
A
Hypernatremia
7
Q
3 causes of Hypernatremia
A
- Too little dietary water
- Too much dietary salt
- Excessive water loss from the body
8
Q
4 causes of Hypernatremia
A
- GI losses: elderly / infants w/ diarrhea
- Skin loss: sweating, fever
- Renal loss
- Drug related: diuretics, lithium (can induce nephrogenic diabetes insipidus)
9
Q
Clinical features of what condition?
- Often asymptomatic
- Thirst
- AMS / weakness
- Neuromuscular irritability
- Focal neurologic deficits
- Seizures or coma
A
Hypernatremia
10
Q
Symptoms of Hypernatremia are related to rate of onset. If hypernatremia develops slowly, sxs will be ____.
A
Less dramatic
11
Q
Normal Response to Hypernatremia
- In response to hypernatremia, the body’s homeostatic mechanisms will normally do what 2 things?
- The vast majority of cases of hypernatremia are due to _____.
A
- Create thirst / increase fluid intake
- Maximally concentrate urine to prevent further water loss
- Water loss (GI tract, skin, renal)
12
Q
Which condition?
- Non-osmotic urinary water loss in setting of elevated serum sodium: urine is dilute when it should be concentrated (the collecting ducts are impermeable to water - water is not reabsorbed)
A
Diabetes Insipidus
13
Q
Which type of diabetes insipidus?
- Due to impaired secretion of antidiuretic hormone (ADH)
- Also called _____.
- Typically treated w/ _____
A
- Central DI
- Neurogenic DI
- Desmopressin (often an inhaled dDAVP nasal spray or IV DDAVP)
14
Q
Which type of diabetes insipidus?
- Lack of kidney response to ADH, causing continued water loss even though patient is low on water.
- Adequate ADH is present
A
Nephrogenic DI
15
Q
Nephrogenic Diabetes Insipidus can be genetic or acquired.
- Acquired is typically from which 4 things?
- What is the treatment?
A
- Chronic renal insufficiency
- Tubulointerstitial renal disease
- Amyloidosis
- Lithium toxicity
Tx:
- Thiazide diuretic
- Amiloride (K sparing diuretic)
- Chlorpropamide (antidiabetic oral agent)
- NSAIDs have been tried (including Indomethacin)
16
Q
Tx of Hypernatremia
- ____ if severe
- Stop water loss
- Replace water deficit in what 3 ways? w/ what fluid?
- Do not replace too rapidly, especially is the hypernatremia is _____. Why?
- It is okay to correct rapidy if what?
A
- Hospitalize
- Oral, NG tube, IV w/ hypotonic fluids
- present for several days (can cause seizures, brain damage, CPM)
- Tx Rapid: If hypernatremia developed acutely
17
Q
In order to replace free water in hypernatremia, you need to calculate what?
A
Water deficit
18
Q
- Major intracellular cation
- Renal excretion is the major route of elimination
- Regulation of renal ___ excretion and total body ___ balance occurs in the distal nephron
- Aldosterone causes increased renal excretion
A
Serum Potassium
19
Q
Which condition?
- Nearly 98% of body’s K is intracellular
- Total body K stores of approximately 50 mEq/kg
- 20% of hospitalized pts are _____
- 80% of pts who are receiving diuretics become ____.
A
Hypokalemia
20
Q
Clinical presentation of which condition?
- Weakness, fatigue
- Muscle cramps
- Hyporeflexia
- Flaccid paralysis (ascending)
- Hypercapnia
- Which one is most important (not listed here)****
A
Hypokalemia
- Cardiac arrhythmias
21
Q
T/F
- K can be replaced more rapidly than Na
A
True
22
Q
4 ECG findings of Hypokalemia
A
- Flattened T waves
- Prominent U waves
- Premature Ventricular Contractions (PVC’s)
- Depressed ST segments
23
Q
Hypokalemia mnemonic
hYpOkalemia U CRAMP
A
- U waves
- Cramping
- Resp failure / rhabdomyolysis
- Anorexia, N/V
- Muscle weakness
- Paralysis
