The seventh-most abundant metal on the earth, potassium is an essential electrolyte in the body. The movement of potassium ions through cell membranes determines the contraction-relaxation state of muscles, according to "Rapid Interpretation of EKG's." Normal levels are important to your baby's health and well-being. Abnormalities in potassium levels can result in dangerous heart dysfunction and death.
Significance
Maintenance of normal potassium levels is crucial to heart electrical conduction. Potassium is a positive ion that is responsible for the relaxation phase of heart muscle, according to "Harrison's Principles of Internal Medicine." When potassium ions leave cardiac cells, the positive charge inside the cells drops, causing an electrical repolarization. What does this mean for heart contraction? Once the heart cells repolarize, they can relax and prepare for the next wave of electrical conduction or contraction phase.
Normal Blood Levels
Infants normally have higher potassium levels in the blood than adults do. Whereas the serum potassium levels range from 3.5 to 5.0 millimoles per liter fluid, mmol/L, normal newborn levels fall between 3.7 and 5.9 mmol/L and an infant under the age of 1 normally has blood potassium levels of 4.1 to 5.3 mmol/L, according to "The Johns Hopkins Hospital: The Harriet Lane Handbook."
Hyperkalemia
Hyperkalemia occurs when your baby's serum potassium levels increase beyond the normal parameters. A dangerous state, hyperkalemia results in serious electrical conduction abnormalities in the heart, according to "The Johns Hopkins Hospital: The Harriet Lane Handbook." The sinoatrial node, which is the main pacemaker of your baby's heart, becomes depressed, affecting the contraction of the atria, the two upper chambers of the heart. Next, the contraction phase of the ventricles -- the lower two chambers of the heart -- lengthens, because the high concentration of potassium prevents it from being released out of the cells. Atrial-ventricular conduction abnormalities occur. Other signs and symptoms include muscle weakness, diarrhea and muscle paralysis.
Hypokalemia
According to "Current Consult Medicine 2007," hypokalemia is a dangerous condition where the blood potassium levels drop below the norm. In this condition, your baby's ventricles become irritable and spontaneously contract, unable to go into relaxation phase. Heart abnormalities resulting from hypokalemia include heart block, torsades de pointes and paroxysmal tachycardia. Other signs that your baby may have low potassium are muscle cramps, fatigue, decreased deep tendon reflexes and constipation.
Treatment
If your child has hyperkalemia, she is treated with intravenous calcium gluconate, glucose and insulin, according to "The Johns Hopkins Hospital: The Harriet Lane Handbook." The safest treatment for your child if he has hypokalemia is oral potassium chloride in the majority of situations. Severe hypokalemic states are treated with intravenous potassium.
References
- "The Johns Hopkins Hospital: The Harriet Lane Handbook"; Jason Roberston, M.D. and Nicole Shilkofski, M.D.; 2005
- "2007 Current Consult Medicine"; Maxine Papadakis, M.D. and Stephen McPhee, M.D.; 2007
- "Rapid Interpretation of EKG's"; Dale Dubin, M.D.; 2000
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., et al; 2008
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