An abnormally low level of the mineral potassium is called hypokalemia. Because potassium is needed for normal function of both muscle cells --- including those within the heart --- and nerve cells, low levels can be problematic. As explained by MedlinePlus, children may develop hypokalemia for several reasons. Diarrhea or ongoing vomiting --- both of which may occur in cases of viral illnesses or food poisoning --- may result in hypokalemia. Certain antibiotics may also cause low potassium. Severe low potassium levels in children is potential fatal, so it is important to be aware of possible symptoms.
Muscle Weakness or Paralysis
The normal range of potassium, as defined by MayoClinic.com, is between 3.6 and 4.8 mEq/L. As potassium levels begin drifting downward, children may not notice any symptoms. When potassium reaches dangerously low levels --- defined as a potassium level in the blood of less than 2.5 mEq/L --- symptoms may begin to be felt. One such symptom is that of muscle weakness. This is an especially ominous situation if the respiratory muscles are affected. As described by the medical reference website UpToDate, in such cases, the muscle weakness may lead to difficulty breathing, respiratory failure, or even death. If the muscles within the digestive tract are affected, children may suffer from symptoms such as nausea and vomiting or a lack of appetite. Muscle weakness in the arms or legs may be experienced as cramps, tenderness, or even, in the most severe cases, paralysis of the muscles.
Abnormal Rhythms of the Heart
An arrhythmia is a heart rhythm that is abnormal. While not all arrhythmias are dangerous, some are life-threatening. UpToDate lists several arryhthmias that may occur as a result of hypokalemia. One especially dangerous rhythm is called ventricular fibrillation. In ventricular fibrillation, the muscle fibers in the lower two chambers of the heart--called the ventricles--begin to contract, or twitch, in an uncontrolled fashion. Rather than the blood being pumped out of the ventricles into the body, it remains within the ventricles. This may result in sudden cardiac death and requires immediate medical attention to maximize the chance for survival.
Rhabdomyolysis
Children who have had a significant and sudden decrease in their potassium levels may experience the unpleasant condition known as rhabdomyolysis. This is a condition in which the muscle cells undergo cell death or necrosis. As the cells die, they release their contents, resulting in several characteristic symptoms. Severe muscle pain is a common indicator of rhabdomyolysis. Children may also notice that their urine has become brown or red in color. This occurs when proteins released by the dying muscle cells, called myoglobins, are excreted in the urine and result in this characteristic color. The collection of symptoms indicating rhabdomyolysis is generally not seen until the levels of potassium have gone below 2.5 mEq/L, indicating a severe depletion in the body's store of potassium.
References
- UpToDate; Clinical Manifestations and Treatment of Hypokalemia; B. Rose; January 2009
- MedlinePlus: Hypokalemia
- MayoClinic.com: Low Potassium
- UpToDate; Clinical Manifestations, Diagnosis, and Causes of Rhabdomyolysis; M. Miller; May 2010
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