Electrolytes play a vital role in maintaining
homeostasis within the body. They help to regulate myocardial and neurological function, fluid balance, oxygen delivery, acid-base balance and much more. Electrolyte imbalances can develop by the following mechanisms: excessive ingestion or diminished elimination of an electrolyte or diminished ingestion or excessive elimination of an electrolyte. The most common cause of electrolyte disturbances is
renal failure.
The most serious electrolyte disturbances involve abnormalities in the levels of
sodium,
potassium, and/or
calcium. Other electrolyte imbalances are less common, and often occur in conjunction with major electrolyte changes. Chronic
laxative abuse or severe
diarrhea or
vomiting can lead to electrolyte disturbances along with
dehydration. People suffering from bulimia or anorexia are at especially high risk for an electrolyte imbalance.
Nomenclature
There is a standard
nomenclature for electrolyte disorders:
# The name starts with a
prefix denoting whether the electrolyte is abnormally elevated ("hyper-") or depleted ("hypo-").
# The word stem then gives the name of the electrolyte in
Latin. If no Latin equivalent exists, then the corresponding term in
English is used.
# The name ends with the
suffix "-emia," meaning "in the
blood." (Note, this doesn't mean that the disturbance is ''only'' in the blood; usually, electrolyte disturbance is systemic. However, since the disturbance is usually detected from
blood testing, the convention has developed.)
For instance, elevated potassium in the blood is called "hyperkalemia" from the Latin term for potassium, "kalium".
Table of common electrolyte disturbances
Electrolyte Abnormalities and ECG Changes
The most notable feature of hyperkalemia is the "tent shaped" or "peaked" T wave. Delayed ventricular depolarization leads to a widened QRS complex and the P wave becomes wider and flatter. When hyperkalemia becomes severe, the ECG resembles a sine wave as the P wave disappears from view. In contrast, hypokalemia is associated with flattenting of the T wave and the appearance of a U wave. When untreated, hypokalemia may lead severe arrhythmias.
The fast ventricular depolarization and repolarization associated with hypercalcemia lead to a characteristic shortening of the QT interval. Hypocalcemia has the opposite effect, lengthening the QT interval.
See also
★
Acidosis
★
Alkalosis
★
Dehydration
★
Malnutrition
★
Starvation