Electrolytes

In 1966, Desertenne, the first to describe the condition, suspected that it was caused by electrolyte disturbances in the form of hypokalemia or hypomagnesemia and that it had a bifocal etiology (Lüderitz 1993).

Electrolytes are salts that are present in ionic form - depending on their electrical charge - as anions or cations and are always dissolved in an aqueous environment (Heintze 2016). Electrolytes are carriers of osmotic pressure (Gründer 2019).

Electrolytes are always dissolved in body water. The water content is 60% of the bw in men, 50% of the bw in women and 75% of the bw in infants.

Body water is divided into:

• 1. extracellular fluid (ECF):

This accounts for approximately 20% bw. It includes the

- intravascular fluid (IVF), which represents about 5 % of the bw, and the

- interstitial fluid (ISF), which comprises approximately 15 % bw (Herold 2022).

IVF and ISF are separated by the capillary wall of the blood vessels (Külpmann 1997).

In the ECF, Na +, CL - and bicarbonate (HCO 3 -) are predominantly found. In IVF and ISF, the difference in protein content results in minor ion shifts, whereby, according to the Gibbs- Donnan mechanism, the protein-rich blood plasma contains slightly more Cl - than the

low-protein interstitial fluid (Herold 2022).

• 2. intracellular fluid (ICF):

The ICF comprises approximately 40% bw. It primarily contains potassium (K +) and phosphate esters (HPO 4 - ). (Herold 2022)

Tasks of electrolytes in general:

• Triggering of action potentials
• Buffer function of the plasma
• Maintenance of balance in the acid-base budget (Founder 2019).

The determination of electrolytes is one of the standard diagnostic procedures in human medicine, since deviations of the normal values on the one hand reflect pathophysiological changes in the organs and on the other hand can also trigger themselves (Gründer 2019).

For some electrolytes, the physiological concentration has only a small range of variation (Gründer 2019).

Classic emergency situations can be triggered by shifts in electrolytes due to, for example:

• Hyperkalemia
• Hypercalcemia
• Hyponatremia (Menche 2020).

Throughout the body, dissolved in extracellular and intracellular fluid, electrolytes are found. They include, for example:

1. Na +:

The most important ion of the extracellular space is sodium (Scholz 2013). It regulates the water balance. From there, disturbances of sodium are closely linked to disturbances of water balance (Ziegenfuß 2014). Alterations affect, for example, the renin- angiotensin- aldosterone system (RAAS) (Gründer 2019).

1. 1 Sodium deficiency:

• Symptoms may be:
  • In slowly developing hyponatremia: asymptomatic.
  • In rapidly developing:
    • Nausea
    • Malaise
    • neurological disorders such as headaches, seizures, drowsiness and even coma (Schoenenberger 2009)
• Caused by e.g: Cause of hyponatremia is a disturbance in renal water excretion and / or increased intake of water such as found in:
  • severe vomiting
  • diarrhea
  • Kidney disease
  • diuretics (Menche 2020)
  • outpatient colonoscopy (Kluge 2010)

1. 2.Excess sodium:

• Symptoms can be:
  • Apathy
  • Weakness
  • Seizures
  • Clouding of consciousness up to coma (Schoenenberger 2009)
• Caused by e.g.:
  • Diabetes insipidus
  • fever
  • heavy sweating (Menche 2020)

2. K +:

Potassium is the quantitatively most important cation. Only 2 % is found in the extracellular space, the remaining 98 % is found in the intracellular space. Elimination occurs to about 90 % via the kidney, to about 10 % via the gastrointestinal tract and to a small extent via sweating (Scholz 2013). Disturbances in potassium balance are always closely associated with disturbances in pH regulation (Ziegenfuß 2014).

K + is primarily important for the heart muscle, as it ensures correct repolarization in the cardiomyocytes and also serves to maintain the resting membrane potential. A change in potassium concentration can lead to severe cardiac arrhythmias (Founders 2019).

Alterations affect the renin- angiotensin- aldosterone system (RAAS), for example (Gründer 2019).

2. 1 Potassium deficiency:

• Symptoms may be:
  • Fatigue
  • Apathy
  • Constipation
  • Rhabdomyolysis
  • Tetany
  • Muscle cramps
  • Muscle weakness up to paralysis with respiratory paralysis (Schoenenberger 2009)
• Caused by e. g.:
  • Vomiting
  • Diarrhea
  • Diuretics
  • Laxatives
  • primary and secondary hyperaldosteronism
  • primary polydipsia with polyuria (Schoenenberger 2009)

2. 2 Potassium excess:

Excess potassium, which is life-threatening, can practically only occur in the case of massive exogenous potassium intake or due to a lack of elimination of potassium (Schoenenberger 2009).

• Symptoms can be:
  • Muscle weakness
  • in polyradiculitis ascending paralysis
  • furry feeling in the area of the tongue
  • paresthesias perioral
  • cardiac arrhythmia up to ventricular fibrillation and asystole (Schoenenberger 2009)
• Caused by e. g.:
  • renal dysfunction (Menche 2020)
  • severe cell decay
  • drug-induced by e.g. potassium-sparing diuretics, beta-blockers, succinylcholine (Ziegenfuß 2014).
  • Insulin deficiency
  • Hyperglycemia
  • Digitalisintoxication
  • Hypoaldosteronism (Schoenenberger 2009)

3. Ca 2 +:

Calcium is the most abundant mineral in the body. (Scholz 2013)

It plays an important role in neuromuscular excitation transmission (Kirschbaum 2008) such as muscle contractions and cardiac contractility (Scholz 2013). It also provides bone strength (Menche 2020).

Calcium (and phosphates), when above the normal range, cause poorly soluble salts that can damage joints (Founder 2019).

3.1 Calcium Deficiency:

• Symptoms can be:
  • Paresthesias in the area of the acras and perioral
  • striated muscles may develop painful tonic contractions
  • smooth musculature may react equivalently
  • extrapyramidal symptoms with hypo- and hyperkinesias
  • seizures
  • panic attacks (Schoenenberger 2009)
• Causes can be e. g.:
  • Parathyroid hormone deficiency
  • Vit. D hormone deficiency
  • Hyperventilation
  • Diuretics (Menche 2020)
  • Tissue sequestration in rhabdomyolysis, tumor lysis, pancreatitis (Schoenenberger 2009)

3. 2 Calcium excess

• Symptoms can be:
  • Apathy, somnolence up to coma
  • Vomiting
  • Fatigue
  • Muscle weakness
  • Polyuria
  • Hypertension
  • tachycardia (Schoenenberger 2009)
• Causes by e. g.:
  • primary hyperparathyroidism
  • in some malignancies such as breast, prostate, bronchial carcinoma, multiple myeloma
  • vitamin D intoxication (Schoenenberger 2009)

4. Mg 2 +:

Magnesium is the most abundant intracellular mineral next to potassium. It has a membrane stabilizing effect and is also required for the influx and efflux of potassium, sodium and calcium into and out of the cell (Scholz 2013).

4. 1 Magnesium deficiency

Due to a deficiency, the parathormone is inhibited. Therefore, a magnesium deficiency is often accompanied by hypocalcemia, fatigue, weakness.

• Symptoms can be:
  • Fatigue, weakness
  • Anorexia
  • cardiac arrhythmias
  • neuromuscular disorders (Gerok 2007)
• Possible causes e. g.:
  • malnutrition
  • during pregnancy (Menche 2020)
  • cardiac arrhythmias (Lüderitz 1993).

4. 2 Magnesium excess

• Symptoms can be:
  • Nausea, vomiting
  • Constipation
  • Muscle weakness
  • Vasodilation with drop in blood pressure
  • Respiratory paralysis
  • cardiac arrest (Gerok 2007)
• Possible causes can be:
  • acute and chronic renal insufficiency (Menche 2020)
  • increased intake by e.g. antacids, laxatives
  • endocrine diseases such as.
    • hypothyroidism
    • Addison's disease (Gerok 2007)

5. HPO 4 -

Phosphates (and Ca 2+) when above the normal range cause poorly soluble salts that can damage joints (Founder 2019).

5. 1 Phosphate Deficiency:

• Symptoms can be:
  • Signs of acute heart failure
  • Arrhythmias
  • Confusion
  • epileptiform seizures
  • Paresthesias
  • paralysis of the cranial nerves (Hartig 2004)
• Caused by e.g.:
  • in certain kidney diseases
  • malnutrition in alcoholics (Menche 2020)
  • anorexia nervosa
  • primary hyperparathyroidism
  • paraneoplastic syndrome
  • post kidney transplantation (Hartig 2004)

5. 2 Phosphate excess

• Symptoms can be:
  • hypocalcemia and extraosseous soft tissue calcification due to formation of poorly soluble calcium-phosphate bonds
  • Pain in the joints (Külpmann 2013).
• Caused by e. g.:
  • Renal insufficiency (major contributor [Hartig 2004]).
  • Hormone disorders (Menche 2020)
  • Hypoparathyroidism (PTH deficiency)
  • Acromegaly
  • Vit. D intoxication (Hartig 2004)

Electrolytes also include:

• CL -
• HCO 3 -
• SO 4 - (Halwachs- Baumann 2011)
• Fe 2 +
• Fe 3 + (Founder 2019)

The most frequent cause of emergency problems is a derailment of the potassium balance. Problems with calcium and magnesium balance can also cause life-threatening emergencies, but occur much less frequently (Ziegenfuß 2014).

The uneven distribution of electrolytes in the intracellular or extracellular space creates an electrical voltage, also called electrical potential. The function of muscle and nerve cells is based on the generation of electrical potentials, as are the stimuli from sensory organs, which transmit electrical signals to the brain (Lauber 2017).

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