Hyperkalemia
Hyperkalemia is defined as a serum potassium concentration ([K+]) >5.5 mmol/L. The normal response to a potassium “load” and increased plasma [K+] includes an immediate response (K+moves into cells, H+out), without an effect on net total body potassium, and a delayed response (increased renal excretion via increased aldosterone). Potassium is removed from the body by secretion primarily in the collecting tubule, under the influence of aldosterone. This process requires sufficient delivery of sodium and water to the distal tubule.
Differential Diagnosis
- Laboratory artifact
–Due to hemolyzed specimen; very common seen with heel-stick blood collection or difficult phlebotomy
–Thrombocytosis
–Leukocytosis
- Impaired renal excretion
–Renal failure
–Volume depletion or decreased effective circulating volume (e.g., congestive heart failure), leading to decreased sodium delivery to the distal tubule and impaired potassium excretion
–Hypoaldosteronism (Addison disease,
congenital adrenal hyperplasia)
–Type IV RTA/aldosterone resistance
–Potassium-sparing diuretics
–Medications (trimethoprim, pentamidine)
-
Increased potassium load
–Overly rapid administration of IV potassium
–Use of aged banked blood
–Increased cell breakdown (rhabdomyolysis,
tumor lysis syndrome, burns, starvation)
–Geophagia
-
Transcellular shifts
–Hypoaldosteronism
–Adrenal insufficiency
–Medications (NSAIDs, ACE inhibitors,
cyclosporine, FK506, β-blockers, digitalis)
–Metabolic acidosis from any cause
–Hyperglycemia/insulin deficiency
Workup and Diagnosis
- History
–Symptoms including oliguria, edema, dizziness,
arrhythmias, flaccid paralysis, paresthesias
–Renal disease, heart disease, diabetes, cancer
–Medications, IV potassium administration
–Heavy exercise
–Family history including recurrent rhabdomyolysis
(rare metabolic condition)
-
Physical exam
–Blood pressure (hypertension suggests renal disease,
hypotension could suggest adrenal insufficiency)
–Cardiac findings (gallop, JVD)
–Muscle tenderness (rhabdomyolysis)
–Lymphadenopathy (potential malignancy)
-
Labs
–Serum chemistries obtained by venipuncture
–Urinalysis
–CBC and differential
-
Studies
–CXR: If cardiac disease or volume overload suspected
–ECG: Early findings include peaked T-waves; late
findings include widened QRS and ventricular fibrillation
Treatment
-
Immediately remove all sources of potassium administration (including IVF and dietary)
-
If significant ECG changes are present, immediate lowering of potassium and cardiac stabilization are achieved temporarily by agents that induce rapid transcellular movement of potassium into cells without net removal from the blood
–Calcium (stabilizes cardiac rhythm)
–Insulin (with glucose to prevent hypoglycemia)
–Bicarbonate (promotes metabolic alkalosis)
-
More definitive measures to remove total body potassium
-
(delayed effect 6–8 hours)
–Cation exchange resins
–Diuretics (especially loop diuretics)
-
In cases of severe, life-threatening hyperkalemia, acute dialysis may be required
Book Source Details
- Book Title: In A Page: Pediatric Signs and Symptoms
- Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
- Year of Publication: 2007
- Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hyperkalemia
Read excerpts from these other book chapters related to Hyperkalemia:
Medical Books Excerpts
- Hyperkalemia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2008 Williams & Wilkins.
More About Causes of Hyperkalemia
|
|
More About This Book:
Title: In A Page: Pediatric Signs and Symptoms
Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
Publisher: Lippincott Williams & Wilkins
Copyright: 2007
ISBN: 1-4051-0427-9
|
|
» Next page: HYPERKALEMIA (Differential Diagnosis in Primary Care)
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
