When a person develops hypokalemia there are changes in how fast the nerves and muscle fibers are able to conduct electrical impulses. The normal concentration of potassium in the plasma oscillates between 3.5 mEq/L and 5.0 mEq/L. When the plasma potassium level decreases below 3.5 mEq/L, the nerves and muscles start to be less effective in the way they conduct electrical impulses. The consequence of this, in the heart, is that its conduction system becomes more prone to produce certain cardiac arrhythmias. Some of these arrhythmias can be life threatening.
Muscle contraction relies on how the electrical impulses are conducted within the muscle. Low potassium concentration in the serum creates an environment in which the transmission of impulses becomes more difficult. The clinical correlation of this is muscle weakness. A patient may complain of generalized weakness, not related to excess activity, which could be considered fatigue.
The lower the potassium levels in the serum (or plasma) the more severe the problems above mentioned can become. The body will react trying to preserve the most potassium possible. The kidney is the organ that will try to preserve the potassium by activating a mechanism that facilitate reabsorption of potassium when the forming urine travels through the renal tubules. This occurs by the reduction in the secretion of a hormone called aldosterone1, which (when present) stimulates potassium loss through the urine.
References
- William Henrich, Fred Katz, Perry Molinoff and Robert Schrier, “Competitive Effects of Hypokalemia and Volume Depletion on Plasma Renin activity, Aldosterone and Catecholamine Concentrations in Hemodialysis Patients,” Kidney International 12, no. 4 (1977): 280, https://doi.org/10.1038/ki.1977.112.
Disclaimer
Any information or statement present in this post does not replace your health care provider’s advice or treatment. This blog does not provide medical advice, prescribe medications or therapies, or diagnose conditions, it only expresses an opinion. If you have a health-related question or condition, confer with your healthcare provider.
Quotations
- In order to quote from this article please use the following (Chicago style):
Marco A. Ramos, “Hypokalemia for Everyone. #4. What Happens when Someone has Hypokalemia?,” SMO Blog (blog), May 27, 2019, https://steemit.com/health/@secondmedicalop/hypokalemia-for-everyone-4-what-happens-when-someone-has-hypokalemia
Read the other sections of this series:
Introduction
What Causes Hypokalemia? A
What Causes Hypokalemia? B
What Causes Hypokalemia? C
How Common is Hypokalemia?