4. Pathophysiology
Total body potassium deficit
Shifting of serum potassium into the
intracellular compartment
Causes
Drugs (loop and thiazide diuretics)
Diarrhea
Vomiting
Hypomagnesemia
10. Clinical Presentation
Nonspecific signs and symptoms
Cardiovascular
Hypertension
Cardiac arrhythmias: heart block, atrial flutter,
paroxysmal atrial tachycardia, ventricular fibrillation,
and digitalis-induced arrhythmias
ECG effects (serum K <2.5 mEq/L): ST-segment
depression or flattening, T-wave inversion and U-
wave elevation
Neuromuscular symptoms
Muscle weakness, cramping, malaise and myalgias
11. Treatment
Every 1 mEq/L fall of K below 3.5 mEq/L Total
body deficit of 100-400 mEq
Chronic used of loop or thiazide diuretics
generally need 40-100 mEq of K
K supplementation
Oral: KCl
IV:
severe hypokalemia
signs and symptoms of hypokalemia
Inability to tolerate oral therapy
12. Treatment
K administration
Dilute in saline because dextrose can
stimulate insulin secretion and worsen
intracellular shifting of K
10-20 mEq of K in 100 ml of NSS through a
peripheral vein over 1 hr
ECG monitoring (If infusion rates > 10 mEq/hr)
14. Pathophysiology
Kintake > Kexcretion
Transcellular distribution of K is disturbed
Causes
Increased K intake
Decreased K excretion
Tubular unresponsiveness to aldosterone
Redistribution of K to the extracellular space
Drugs: ACEI, ARB, K-sparing diuretics
15. Clinical Presentation
Frequently asymptomatic
Heart palpitations or skipped heartbeats
ECG change (serum K 5.5-6 mEq/L)
Peaked T waves
Widening of the PR interval
Loss of the P wave
Widening of the QRS complex
Merging of the QRS complex with the T wave
resulting in a sine-wave pattern
18. Treatment
Dialysis
Most rapid lowering serum K
Calcium
Rapidly reverses ECG & arrhythmias
Not lower serum K
Short acting
Must be repeated if signs or symptoms recur
Insulin & dextrose/sodium bicarbonate/albuterol
Rapid shift potassium intracellularly
19. Treatment
Sodium polystyrene sulfonate (kayexalate)
Mild to moderate hyperkalemia (K 5-7 mEq/L)
Each gram of resin exchanges 1 mEq of Na for
1 mEq of K
Sorbitol promotes excretion of K (by diarrhea)
Tolerated & effective: oral > rectal
Calcium polystyrene sulfonate
Same kayexalate used
For patient who restriction of Na
20. Therapeutic Alternatives for the Management of
Hyperkalemia
Medication Dose Route of
Administration
Onset/Duration of
Action
Calcium 1 g (1 ampule) IV over 5–10 min 1–2 min/10–30 min
Furosemide 20–40 mg IV 5–15 min/4–6 hr
Regular insulin 5–10 units IV or SC 30 min/2–6 hr
Dextrose 10% 1,000 mL (100 g) IV over 1–2 hr 30 min/2–6 hr
Dextrose 50% 50 mL (25 g) IV over 5 min 30 min/2–6 hr
Sodium bicarbonate 50–100 mEq IV over 2–5 min 30 min/2–6 hr
Albuterol 10–20 mg Nebulized over 10 min 30 min/1–2 hr
Hemodialysis 4 hours N/A Immediate/variable
Sodium polystyrene
sulfonate
15–60 g Oral or rectal 1 hour/variable
36. References
Charles F Lacy, et al. Drug Information Handbook
2008-2009. 17th edition: 2008.
Barbara G Wells, et al. Pharmacotherapy
Handbook. 7th edition: 2009.
สมาคมโรคเบาหวานแห่งประเทศไทยในพระราชูปถัมภ์
สมเด็จพระเทพรัตนราชสุดาฯ สยามบรมราชกุมารี,
สมาคมโรคต่อมไร ้ท่อแห่งประเทศไทย สานักงาน
หลักประกันสุขภาพแห่งชาติ. แนวทางเวชปฏิบัติสาหรับ
โรคเบาหวาน พ.ศ. ๒๕๕๑: 2552.
Mancia G, et al. 2007 ESH-ESC Practice
Guidelines for the Management of Arterial
Hypertension. Journal of Hypertension: 25 (9),
2007.
http://www.thomsonhc.com