|
Overview |
|
|
Definition |
|
Hyperkalemia is an excess of serum potassium. Most potassium in the body
(98%) is found within cells. Small changes in extracellular potassium levels can
disturb the cellular membrane potential, with profound effects on the
cardiovascular and neuromuscular systems. Excess potassium is ordinarily
excreted in the urine, and hyperkalemia is most often a result of renal
insufficiency. It may also be precipitated by conditions that cause the release
of potassium from the cells into the bloodstream, such as tissue trauma.
Untreated, hyperkalemia may be associated with up to 67% mortality, mainly due
to the effect of the potassium imbalance on cardiac
function. |
|
|
Etiology |
|
- Renal insufficiency
- Acidosis (e.g., diabetic ketoacidosis)
- Increased potassium intake
- Hypoaldosteronism (Addison's disease)
- Rhabdomyolysis
- Hemolysis (sickle-cell disease, venipuncture, blood transfusions,
burns, tumor lysis)
- Side effect of some
medications
|
|
|
Risk Factors |
|
- Renal failure (acute or chronic)
- Trauma, especially crush injuries or burns
- Diet high in potassium (bananas, oranges, tomatoes, high protein
diets, salt substitutes)
- Use of medications such as potassium supplements, potassium-sparing
diuretics, digoxin, nonsteroidal anti-inflammatory drugs, cyclosporine,
succinylcholine, heparin, ACE inhibitors, and
beta-blockers
|
|
|
Signs and Symptoms |
|
- Fatigue
- Weakness
- Paresthesia
- Paralysis
- Palpitations
- Difficulty
breathing
|
|
|
Differential
Diagnosis |
|
- Pseudohyperkalemia—e.g., from hemolysis
during phlebotomy, erythrocyte fragility disorders
- Laboratory error—False high potassium
reading may occur in patients with high platelet or white cell count.
- Other neurologic syndromes
- Heart disease/congestive heart
failure
|
|
|
Diagnosis |
|
|
Physical Examination |
|
Assess for weakness and paresthesia. Check for evidence of dialysis sites and
signs of trauma. Deep tendon reflexes or motor strength may be decreased. Pulse
may be slow or irregular. |
|
|
Laboratory Tests |
|
- Potassium level—upper limit of normal is 5
to 5.5 mEq/liter
- Digoxin level
- Calcium level—hypocalcemia exacerbates
cardiac effects
- Glucose level—if patient has
diabetes
- BUN and creatinine—to evaluate renal
status
- Arterial blood gas—if acidosis
suspected
|
|
|
Other Diagnostic
Procedures |
|
Assess patient's overall condition and stability. Perform blood workup and
monitor cardiac and renal function.
Electrocardiography should always be performed and may reveal the following
anomalies, usually in order of progression. Note that life-threatening cardiac
arrhythmias can occur without warning at almost any level of
hyperkalemia.
- Peaked T-waves, shortened QT interval, ST-segment
depression
- Widening of QRS complex, increases in PR interval, P-wave
flattening
- P-wave disappearance, QRS widening to sine wave
- Ventricular fibrillation,
asystole
|
|
|
Treatment Options |
|
|
Treatment Strategy |
|
Hyperkalemia is a life-threatening condition, and treatment must be prompt
and aggressive. Patients presenting in the emergency room should be evaluated as
to cardiac status and held under continuous electrocardiographic monitoring with
frequent checks of vital signs. If renal failure is detected, admit patients to
the ICU and consult a nephrologist. Treatment is aimed at stabilizing cardiac
function, promoting movement of potassium from the extracellular environment to
the cells, and encouraging excretion of excess potassium. Once the acute
condition is stabilized, the root cause of the hyperkalemia should be determined
and treated. Dialysis may be indicated if more conservative treatments
fail. |
|
|
Drug Therapies |
|
- Calcium—Works quickly to stabilize membrane
resting potential, ameliorating cardiac and neuromuscular effects. However,
calcium does not lower potassium level and its effects last only about one hour,
so other treatment must be started as well. Give 10 ml of 10% calcium gluconate
solution IV over two minutes, or 5 ml of 10% calcium chloride solution IV over
two minutes. Contraindicated in hypercalcemic patients.
- Insulin—Promotes potassium shift
intracellularly. In normoglycemic patients, 10 units IV with 1 ampule D 50 to
prevent hypoglycemia
- Sodium bicarbonate—Promotes potassium shift
intracellularly; 1 mEq/kg, up to 50 to 100 mEq, slow IV or continuous drip.
Caution required in patients with renal failure due to high sodium and fluid
load.
- Beta agonists—Promote potassium shift
intracellularly; 2.5 mg albuterol mixed with saline via high flow nebulizer
every 20 minutes as tolerated. Safety in pregnancy is not established. Monitor
for tachycardia and nervousness.
- Diuretics—Cause potassium excretion from
kidneys but effects may be slow and inconsistent; furosemide (Lasix) 40 mg IV
push. Dose may need to be doubled for patients with renal failure. Safety in
pregnancy is not established. Contraindicated in hypovolemic
patients.
- Binding resins—Promote potassium/sodium
exchange in gastrointestinal system; sodium polystyrene sulfonate (Kayexalate)
15 to 30 g (4 to 8 tsp) in 50 to 100 ml of 20% sorbitol orally every 3 to 4
hours, or retention enema 50 g in 200 ml of 20% sorbitol for 30 to 60 minutes
every four hours. Sorbitol contraindicated in post-op patients; may cause
colonic necrosis. Caution required in patients with renal failure due to sodium
load. Safety in pregnancy is not
established.
|
|
|
Complementary and Alternative
Therapies |
|
Hyperkalemia is an acute, life-threatening condition requiring immediate and
aggressive medical intervention. Alternative therapies may be appropriate for
concurrent support and in treatment of the underlying cause once the patient has
been stabilized. |
|
|
Nutrition |
|
- Avoid alcohol, caffeine, refined foods, sugar, and saturated fats
(meat proteins and dairy products). In addition, eliminate high potassium foods,
such as bananas, from the diet.
- Increase water intake, as dehydration can exacerbate
hyperkalemia
- Eat small amounts of protein and favor vegetable proteins and fish
over chicken and red meats.
- Small, frequent meals can help prevent hypoglycemia. Insulin release
potentiates intracellular potassium shift.
- Magnesium (200 mg bid to tid) is essential for the sodium-potassium
pump. It also has vasodilatory effects and may help stabilize cardiac
arrhythmias.
|
|
|
Herbs |
|
Herbs are generally a safe way to strengthen and tone the body's systems. As
with any therapy, it is important to ascertain a diagnosis before pursuing
treatment. Herbs may be used as dried extracts (capsules, powders, teas),
glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless
otherwise indicated, teas should be made with 1 tsp. herb per cup of hot water.
Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for
roots. Drink 2 to 4 cups/day. Tinctures may be used singly or in combination as
noted.
Of primary concern is the effect of hyperkalemia on the heart. While most
kidney tonics are rich in potassium and should be avoided, some cardiac
glycosides and flavonoids have a neutral effect on potassium levels and are
protective of cardiac function.
- Hawthorn (Crataegus monogyna) increases cardiac output without
increasing cardiac load. It has a mild vasodilatory effect, helps to stabilize
cardiac arrhythmias, and also supports liver function. Compromised liver
function and poor fat digestion can exacerbate hyperkalemia. Drink 3 to 4 cups
of tea/day. Hawthorn is a relatively safe herb and may be used
long-term.
- Lily of the valley (Convalleria majalis) increases cardiac
output and has a regulating effect on heart rhythm. It is a secondary diuretic
which relieves edema and has a neutral to slightly lowering effect on sodium and
potassium. This herb has toxic side effects and should not be used without
physician supervision.
|
|
|
Homeopathy |
|
An experienced homeopath should assess individual constitutional types and
severity of disease to select the correct remedy and
potency. |
|
|
Physical Medicine |
|
Contrast hydrotherapy. Alternating hot and cold applications brings nutrients
to the site and diffuses metabolic waste from inflammation. The overall effect
is decreased inflammation, pain relief, and enhanced healing. Use the
applications over the kidneys. Alternate 3 minutes hot with 1 minute cold.
Repeat three times to complete one set. Do two to three
sets/day. |
|
|
Acupuncture |
|
Acupuncture may be helpful in supporting normal kidney function and
minimizing the effects of hyperkalemia. |
|
|
Massage |
|
Swedish massage may help to stimulate the kidneys; whether this is
appropriate for a particular patient depends on his or her condition and the
underlying cause of the hyperkalemia. |
|
|
Patient Monitoring |
|
Continue cardiac monitoring; track serum potassium levels while patient
remains in hospital. Measure urine output and potassium excretion levels. Repeat
potassium tests 2 to 3 days after discharge. Monitor for renal
insufficiency. |
|
|
Other
Considerations |
|
|
Prevention |
|
Patients should be advised to avoid foods high in potassium. Medications
should be reviewed to avoid those which predispose to hyperkalemia. If the
problem was precipitated by noncompliance with a dialysis schedule, encourage
the patient to make this a priority. |
|
|
Complications/Sequelae |
|
Severe hyperkalemia is itself a life-threatening emergency that can lead to
cardiac and/or respiratory arrest. Over-correction of the potassium level must
also be guarded against. |
|
|
Prognosis |
|
Many of the therapies for hyperkalemia discussed above begin to work in about
half an hour. However, they address only the immediate ion balance and not the
root cause of the hyperkalemia. The prognosis depends on treating for such
conditions as renal failure or diabetic ketoacidosis. |
|
|
Pregnancy |
|
Hyperkalemia in pregnancy is a medical
emergency. |
|
|
References |
|
Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic
Guide to Herbal Medicines. Boston, Mass: Integrative Medicine
Communications; 1998:162.
Lee HS, Yu YC, Kim ST, Kim KS. Effects of moxibustion on blood pressure and
renal function in spontaneously hypertensive rats. Am J Chin Med.
1997;25: 21-26.
Wheeless CR. Management of Hyperkalemia. Wheeless' Textbook of
Orthopaedics. 1996. Accessed at
http://wheeless.belgianorthoweb.be/oo3/24.htm on February 17, 1999.
Zwanger M. Hyperkalemia. Emergency Medicine Online Text. 1998.
Accessed at http://www.emedicine.com/emerg/topic261.htm on February 13,
1999. |
|
Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. |