CAUSES OF HYPOKALEMIA

Hypokalemia due to decreased potassium uptake:

-marked reduction in K+ intake is required to develop hypokalemia
-kidneys ability to conserve plasma [K+]
-kidneys ability to decrease urinary [K+] as low as 5 – 15 mEq/L
Hypokalemia due to increased potassium losses:

 Increased K+ losses be generally be from:
-renal loss: urinary [K+] > 20 mEq/L
ex. diuresis, chronic metabolic alkalosis, inc mineralcorticoid, antibiotics, RTA
-GI loss: urinary [K+] < 20 mEq/L
ex. vomiting, diarrhea, fistulas

Hypokalemia due to increased intracellular movements:

-acute alkalosis
-insulin therapy
-(2 agonist
-hypothermia
-vitamin B12 treatment

CLINICAL MANIFESTATIONS FOR HYPOKALEMIA:

-usually asymptomatic until [K+] < 3 mEq/L
Central nervous system:
possible encephalopathy due to:
-metabolic alkalosis
-advanced liver disease
-resultant decreased [K+] and increased ammonia levels
Cardiovascular system:
electrocardiogram changes include:
-flattening/inversion of T wave
-prominent U wave
-ST segment depression
-increased P wave
-prolonged PR interval
dysrhythmias may involve:
-increase in myocardial automaticity
-delayed ventricular repolarization
decreased cardiac contractility
labile mean arterial pressure
-secondary autonomic dysfunction
Respiratory system:
-possible compensatory acidosis (hypoventilation) secondary to metabolic alkalosis
Hepatic system:
-increased ammonia production
-intracellular acidosis
-H+ moves intracellular to compensate for intracellular K+ loss
Renal system:
-renal dysfunction includes:
-impaired concentrating ability
-ex. resistance to ADH (nephrogenic diabetes insipidus)

TREATMENT FOR HYPOKALEMIA:
 
Oral replacement:
-60 – 80 mEq/L ; generally the safest
Intravenous replacement:
reserved for:
-serious cardiac manifestation
-muscle weakness
Goal for intravenous treatment of hypokalemia:
-remove patient from immediate danger
-then replace the K+ PO
KCL is preferred in metabolic alkalosis especially in hypochloremic metabolic alkalosis
K+acetate or K+citrate: preferred for metabolic acidosis
K+phosph: preferred when both K+ and Phosphorus are decreased
peripheral intravenous line: replace K+ 8 mEq/hr due to venoirritation
central intravenous line: replace K+ 10 –20 mEq/hr
maximum K+ replacement/day: 240 mEq/day
 
ANESTHETIC CONSIDERATIONS FOR HYPOKALEMIA:

-lower limits of K+: 3 – 3.5 mEq/L without ECG changes
-generally does not appear to be significant anesthetic risk
-exception may occur in patients taking digoxin
-patients taking digoxin should have K+ maintained at 4 mEq/L
Anesthetic consideration decisions in hypokalemic patients may be based on:
-rate of K+ loss
-presence or absence of organ dysfunction
Intraoperative management in hypokalemic patients:
Provide intravenous K+ supplementation if:
-atrial dysrhytmias occur due to decreased K+ levels
-ventrilcular dysrhythmias occurs due to decreased K+ levels
avoid glucose containing solutions in hypokalemic patients
avoid hyperventilation in hypokalemic patients

The Dangers of Low Potassium Levels

The mineral potassium is an essential part of a healthy diet, as the body needs it to function and stay healthy. The body uses potassium to help build muscles, aid in the process of metabolism and maintain the proper balance of acids and bases, say the experts at the U.S. National Library of Medicine (NLM). People get most of their potassium from foods--like meat, fish, some fruits and many vegetables. Though potassium is essential for proper cell function, it is important to get exactly the right amount of potassium--either too much or too little can be harmful to your health. Potassium deficiency is a health condition called hypokalemia.

Paralysis

Hypokalemia can be very serious--even fatal. One of the most serious risks associated with potassium deficiency is paralysis, say the experts at the NLM. If that paralysis strikes major organs like the lungs or the heart, it can be a fatal complication. Cardiac arrest can result from paralysis caused by insufficient potassium.

Abnormal Heart Rhythm

Since cells can't function well without enough potassium, major organs--including the heart--can be affected. The experts at the NLM note that an abnormal heart rhythm can result from potassium deficiency. This can lead to significant heart problems, including heart attack, that could be fatal.

Damage to Kidneys

Every organ needs potassium in the cells to work properly, particularly the kidneys. According to the NLM, potassium deficiency can lead to serious damage to the kidneys. Potassium deficiency can cause a kidney condition called hypokalemic nephropathy.

Milder Symptoms

Low potassium levels can cause a number of more minor symptoms, including constipation and fatigue, say the experts at the NLM. It can also lead to the destruction of fibers in the muscles, causing significant weakness, cramping or even spasms in the muscles. A general feeling of weakness may also occur, in addition to excessive thirst and urination. Children and babies can suffer from excessive diarrhea and vomiting, which can be fatal.

Function of Potassium in the Body

Potassium is a soft silvery white metal substance that is essential for living things. Potassium is a mineral that is important for the kidney to function normally. It is also essential for muscle contraction and for the proper regulation of the heart contractility. Enough supply of Magnesium

is needed to maintain the normal level of potassium in the body.

• Hyperkalemia is a condition wherein there is too much potassium in the blood.
• Hypokalemia a condition wherein there is too little potassium in the blood.

Proper balance of potassium in the body depends on sodium. Too much use of sodium may deplete the body's store of potassium. Other cases that can cause deficiency of potassium in the body are ; vomiting, excessive sweating, diarrhea and use of diuretics.

High potassium diet prevent high blood pressure.Coffee and alcohol can increase the amount of potassium excreted in the urine.

Symptoms of Deficiency :

• Muscle fatigue
• Constipation
• Irregular pulse
• Rapid heart beat
• Paralytic ileus
• Muscle cramps while jogging
• Lack of appetite
• Mental apathy
• Muscle weakness
• Actual paralysis of the muscles

Daily Requirements - 3-5 gm.
Supplemental Dosage - Usually unnecessary.
Food Sources : Fish, fruits especially bananas, fruit juices, instant coffee, dried fruits especially prunes, vegetables, soybeans, other dried beans, sweet potato, molasses, nuts, cocoa, wheat germ.

La importancia del potasio

El consumo equilibrado de vegetales proporciona la cantidad necesaria de potasio para cubrir los requerimientos diarios

El potasio es un mineral con interesantes funciones orgánicas. Participa en la transmisión del impulso nervioso y, junto con el sodio, regula el nivel de agua dentro y fuera de las células. El contenido de potasio del músculo está relacionado con la masa muscular y el almacenamiento de glucógeno (reserva energética de glucosa). El correcto aporte de este mineral a través de la dieta es esencial, sobre todo, mientras el músculo se forma. Verduras, frutas, legumbres, cereales integrales, patatas, frutas desecadas y frutos secos son sus principales fuentes alimentarias.

En su justa medida

- Imagen: Emi Yañez -

El requerimiento diario de potasio para las personas adultas y niños a partir de 10 años es de 2.000 miligramos. Para niños de edades entre 1 y 9 años, las necesidades oscilan entre 1.000 y 1.600 miligramos. Los vegetales son los alimentos que brindan a la dieta este mineral. Verduras y hortalizas, frutas, legumbres y cereales integrales, patatas, frutas desecadas y frutos secos contienen, en mayor o menor medida, cantidades sobresalientes de potasio. Dentro de cada grupo hay alimentos destacados como acelga (378 mg/100 g), cardo (400 mg), espinaca (529 mg) y calabaza (450 mg), entre las hortalizas. La soja (1.730 mg), las alubias blancas (1.718 mg) y los garbanzos (1.000 mg) son las legumbres más ricas en potasio, también abundante en la patata (525 mg).
De las frutas destacan el plátano (385 mg), la uva negra (320 mg) y el melón tipo cantalupo (297 mg). Entre las frutas desecadas resaltan los orejones de albaricoque (1.520 mg), el melocotón seco (1.000 mg) y la ciruela pasa (950 mg). Los frutos secos tienen de media unos 600 mg/100 g, entre ellos, destaca el pistacho (1.050 mg), las almendras fritas o tostadas (800 mg) y los piñones (780 mg).
Para cubrir los requerimientos de potasio de una persona adulta es suficiente con seguir las indicaciones de dieta sana en consumo de frutas y hortalizas; cinco al día: tres frutas frescas y dos raciones de verduras. Una podría ser una ensalada.

Consecuencias de su carencia

La deficiencia de potasio originada por una ingesta inadecuada no es frecuente en personas sanas, debido a que este mineral es frecuente en una amplia variedad de alimentos. La deficiencia de potasio en el organismo puede originarse si se siguen dietas estrictas y sin control, por vómitos y diarreas persistentes y por bajadas excesivas de peso asociadas a la toma de diuréticos. Si bien estos fármacos eliminan líquidos, también fuerzan la pérdida de potasio a través de la orina en cantidades superiores a lo normal. Si éstas no se compensan con una ingesta adecuada, se corre el riesgo de que aparezcan síntomas como debilidad muscular, taquicardia, hipotensión, sed y falta de apetito.