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{{Hypokalemia}}
{{CMG}}'''; Associate Editor-In-Chief:''' {{CZ}}; {{AIDA}} '''Assistant Editor(s)-In-Chief:''' [[User:Jack Khouri|Jack Khouri]]
==Overview==
==Overview==
'''Hypokalemia''' is a potentially fatal condition in which the body fails to retain sufficient [[potassium]] to maintain health. It is defined as a serum potassium level below 3.5 mEq/L. The condition is also known as '''potassium deficiency'''. The prefix ''hypo-'' means low (contrast with ''hyper-'', meaning high).  The middle ''kal'' refers to ''kalium'', which is Neo-Latin for potassium. The end portion of the word, ''-emia'', means "in the blood" (note, however, that hypokalemia is usually indicative of a ''systemic'' potassium deficit).
Low level of [[potassium]] (usually below 3.5 mEq/L) in body is called [[hypokalemia]]. The condition is also known as potassium deficiency.  
==Historical Perspective==
The prefix ''hypo-'' means low and ''kal'' refers to ''kalium'', which is Neo-Latin for potassium. The end portion of the word, ''-emia'', means "in the blood" (note, however, that hypokalemia is usually indicative of a ''systemic'' potassium deficit).


==Pathophysiology==
==Pathophysiology==
Potassium is the most abundant intracellular cation. Any derangement of potassium serum levels can disturb the transmembrane potential and renders excitable cells (nerve and muscle) hyperpolarized and less excitable. However, cardiac cells don't obey this rule and become hyperexcitable.
[[Potassium]] is one of the [[intracellular]] [[cation]]. Any derangement of potassium serum levels can disturb the transmembrane [[potential]] and renders excitable cells ([[nerve]] and [[muscle]]) [[Hyperpolarization (biology)|hyperpolariz]]<nowiki/>ed and less excitable. However, [[Cardiac|cardiac cells]] don't obey this rule and become hyperexcitable. [[Potassium]] regulation is essential to maintain a normal activity in cells. Any imparment in potassium serum levels will have severe consequences on several organs especially the [[heart]] and the [[nervous system]]. Normally, total potassium excretion in stool is low and most ingested potassium is absorbed. The [[Kidney|kidne]]<nowiki/>y is the main regulator of potassium balance through excretion (the kidney excretes 90-95% of dietary potassium); the gut excretes a minimal amount of dietary potassium (approximately 10%).


==Causes==
==Causes==
Hypokalemia can be the consequence of decreased ingestion, increased losses (renal, GI or excessive sweating) or transcellular shift from the extracellular to the intracellular compartment. The most common causes are diarrhea, vomiting and diuretic use (mostly loop and thiazide diuretics).
The etiology of hypokalemia can be quite difficult to diagnose. Diferent organ systems play role in the regulation of [[potassium]] level and any derangement to their normal function can cause hypokalemia. [[Drugs]], [[diarrhea]], [[kidney disease]], [[endocrine disease]]s and many others are potential culprits. Hypokalemia can be the consequence of decreased [[ingestion]], increased losses (renal, GI or [[excessive sweating]]) or transcellular shift from the extracellular to the intracellular compartment. The most common causes are [[diarrhea]], [[vomit]]ing and [[diuretic]] use (mostly loop and [[thiazide]] diuretics).


==Diagnosis==
==Diagnosis==
Diagnosis relies on a constellation of findings including:
Diagnosis relies on a constellation of findings including:
===History===
Past medical history and medication history are so important in finding the reason of hypokalemia (eg hyperthyroidism, hyperaldosteronism, Cushing's disease,etc).
===Symptoms===
===Symptoms===
Mostly constitutive with predominance of muscle weakness and cramping. The heart can be affected; ECG can reveal arrhythmias and other major changes. The kidney can be involved: nephrogenic diabetes insipidus and hyponatremia can occur.
* [[Muscle weakness]], [[cramping]], and [[paralysis]].  
===History===
* [[Palpitation]].
It should include the past medical history to point out some relevant diseases and conditions that can result in hypokalemia (eg hyperthyroidism, hyperaldosteronism, Cushing's disease,etc). The medication history should be detailed given the long list of medications that can be culprit.
* [[Polyuria]].
* [[Depression]], [[psychosis]], [[delirium]].
 
===Laboratory findings===
===Laboratory findings===
Many labs can be helpful. The transtubular potasium gradient (TTKG), urine potassium and urine chloride levels can help define the etiology of hypokalemia.
Many labs can be helpful. The transtubular potasium gradient (TTKG), urine [[potassium]], [[sodium]], [[osmolality]] and [[chloride]] levels can help define the etiology of hypokalemia.
 
===Electrocardiogram===
The most notable EKG findings in [[hypokalemia]] are due to the delayed [[Repolarization|ventricular repolarization]], manifesting as (QT-U) with prominent [[U waves]].  The [[ECG]] changes of hypokalemia are commonly seen at potassium levels < 3 meq/Li. 90% of the patients with potassium levels <2.7 meq/L have abnormal ECG findings.


==Treatment==
==Treatment==
The oral route is the safest. There are many oral potassium salts that can be prescribed including potassium chloride KCl (the most popular) and the organic alkalinizing salts that are metabolized to potassium bicarbonate KHCO3 in the body. Severe hypokalemia ca be treated via IV KCl infusion with doses that shouldn't exceed 60 mEq/L unless ECG monitoring is provided. A central line can be used for administration of greater concentrations of KCl.
The oral route is the safest. There are many oral potassium salts that can be prescribed including [[potassium chloride]] (the most popular) and the organic alkalinizing salts that are metabolized to [[potassium bicarbonate]] in the body. Severe hypokalemia ca be treated via IV [[potassium chloride]] infusion with doses that shouldn't exceed 60 mEq/L unless [[ECG]] monitoring is provided. A central line can be used for administration of greater concentrations of [[potassium chloride]].
 
==References==
{{Reflist|2}}
 
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Latest revision as of 22:50, 17 July 2018

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Aida Javanbakht, M.D. Assistant Editor(s)-In-Chief: Jack Khouri

Overview

Low level of potassium (usually below 3.5 mEq/L) in body is called hypokalemia. The condition is also known as potassium deficiency.

Historical Perspective

The prefix hypo- means low and kal refers to kalium, which is Neo-Latin for potassium. The end portion of the word, -emia, means "in the blood" (note, however, that hypokalemia is usually indicative of a systemic potassium deficit).

Pathophysiology

Potassium is one of the intracellular cation. Any derangement of potassium serum levels can disturb the transmembrane potential and renders excitable cells (nerve and muscle) hyperpolarized and less excitable. However, cardiac cells don't obey this rule and become hyperexcitable. Potassium regulation is essential to maintain a normal activity in cells. Any imparment in potassium serum levels will have severe consequences on several organs especially the heart and the nervous system. Normally, total potassium excretion in stool is low and most ingested potassium is absorbed. The kidney is the main regulator of potassium balance through excretion (the kidney excretes 90-95% of dietary potassium); the gut excretes a minimal amount of dietary potassium (approximately 10%).

Causes

The etiology of hypokalemia can be quite difficult to diagnose. Diferent organ systems play role in the regulation of potassium level and any derangement to their normal function can cause hypokalemia. Drugs, diarrhea, kidney disease, endocrine diseases and many others are potential culprits. Hypokalemia can be the consequence of decreased ingestion, increased losses (renal, GI or excessive sweating) or transcellular shift from the extracellular to the intracellular compartment. The most common causes are diarrhea, vomiting and diuretic use (mostly loop and thiazide diuretics).

Diagnosis

Diagnosis relies on a constellation of findings including:

History

Past medical history and medication history are so important in finding the reason of hypokalemia (eg hyperthyroidism, hyperaldosteronism, Cushing's disease,etc).

Symptoms

Laboratory findings

Many labs can be helpful. The transtubular potasium gradient (TTKG), urine potassium, sodium, osmolality and chloride levels can help define the etiology of hypokalemia.

Electrocardiogram

The most notable EKG findings in hypokalemia are due to the delayed ventricular repolarization, manifesting as (QT-U) with prominent U waves. The ECG changes of hypokalemia are commonly seen at potassium levels < 3 meq/Li. 90% of the patients with potassium levels <2.7 meq/L have abnormal ECG findings.

Treatment

The oral route is the safest. There are many oral potassium salts that can be prescribed including potassium chloride (the most popular) and the organic alkalinizing salts that are metabolized to potassium bicarbonate in the body. Severe hypokalemia ca be treated via IV potassium chloride infusion with doses that shouldn't exceed 60 mEq/L unless ECG monitoring is provided. A central line can be used for administration of greater concentrations of potassium chloride.

References


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