Electrolyte Disturbances Flashcards Preview

USMLE > Electrolyte Disturbances > Flashcards

Flashcards in Electrolyte Disturbances Deck (33):
1

Low serum Na+

Nausea, malaise, stupor, coma

2

High serum Na+

Irritability, stupor, coma

3

Low serum K+

U waves on ECG, flattened T waves, arrhythmias, muscle weakness

4

High serum K+

Wide QRS and peaked T waves on ECG, arrhythmias, muscle weakness

5

Low serum Ca2+

Tetany, seizures, QT prolongation
Chvostek's
Trousseau's

6

High serum Ca2+

Stones = renal
Bones = pain
Groans = abdominal pain
Moans/psychiatric overtones = anxiety, altered mental status
Not necessarily calciuria

7

Low serum Mg2+

Tetany, torsades de pointes

8

High serum Mg2+

Decreased DTRs, lethary, bradycardia, hypotension, cardiac arrest, hypocalcemia

9

Low PO4 3-

Bone loss, osteomalacia

10

High PO4 3-

Renal stones, metastatic calcifications, hypocalcemia

11

Shifts K+ out of cell --> Hyperkalemia

Digitalis
Hyperosmolarity
Insulin deficiency (insulin shifts K+ into cells)
Lysis of cells
Acidosis
B-adrenergic antagonist

12

Shifts K+ into cell --> Hypokalemia

Hypo-osmolarity
Insulin (increases N+/K+ ATPase)
Alkalosis
B-adrenergic agonist (increases N+/K+ ATPase)

13

Total body weight breakdown

40% nonwater mass
60% total body water

14

60% total body water breakdown

1/3 ECF = 20% total body weight
2/3 ICF = 40% total body weight

15

Extracellular fluid breakdown

1/4 plasma volume = 5% total body weight
3/4 interstitial volume = 15% total body weight

16

Calculation GFR

Inulin
Freely filtered and neither reabsorbed nor secreted

17

Normal GFR

100 mL/min

18

Estimation GFR

Creatinine clearance
Slightly overestimates because is moderately secreted

19

Estimation ERPF

Para-aminohippuric acid (PAH)
Both filtered and actively secreted in proximal tubule, nearly all is excreted
Underestimates true renal plasma flow by 10%

20

Prostaglandins _____ the _____ arteriole

Prostaglandins DILATE the AFFERENT arteriole

21

Angiotensin II _____ the _____ arteriole

Angiotensin II CONSTRICTS the EFFERENT arteriole

22

Respiratory acidosis

pH 40 mmHg

23

Respiratory acidosis causes

*Hypoventilation*
Airway obstruction
Acute lung disease
Chronic lung disease
Opioids, sedatives
Weakening of respiratory muscles

24

Metabolic acidosis with compensation (hyperventilation)

pH

25

Anion gap

Na+ - (Cl- + HCO3-)
Normal = 8-12 mEq/L

26

Causes of metabolic acidosis with increased anion gap

MUDPILES:
Methanol (formic acid)
Uremia
Diabetic ketoacidosis
Propylene glycol
Iron tablets or INH (isoniazid)
Lactic acidosis
Ethylene glycol (oxalic acid)
Salicylates (late)

27

Causes of metabolic acidosis with normal anion gap

HARD-ASS:
Hyperalimentation
Addison disease
Renal tubular acidosis
Diarrhea
Acetazolamide
Spironolactone
Saline infusion

28

Respiratory alkalosis

pH > 7.4
Pco2

29

Respiratory alkalosis causes

*Hyperventilation*
Hysteria
Hypoxemia = high altitude)
Salicylates (early)
Tumor
Pulmonary embolism

30

Metabolic alkalosis with compensation (hypoventilation)

pH > 7.4
Pco2 > 40 mmHg

31

Metabolic alkalosis causes

Loop diuretics
Vomiting
Antacid use
Hyperaldosteronism

32

Henderson Hasselbalch Equation

pH = 6.1 + log([HCO3-]/0.03xPco2)

33

Winters Formula

Predicted respiratory compensation for simple metabolic acidosis
Pco2 = 1.5[HCO3-] + 8 +/- 2