Resumo

PIZARRO-TORRES, Daniel. Diarrhea and vomiting cause dehydration and electrolyte imbalance. Bol. Med. Hosp. Infant. Mex. [online]. 2005, vol.62, n.1, pp.57-68. ISSN 1665-1146.

Normonatremic dehydration is by far the most common electrolyte imbalance. Hyponatremic and hypernatremic dehydration are less frequent and are caused by offering the patient hypotonic fluid in cases presenting hyponatremic dehydration or hypertonic and/or fluid containing high sodium concentration in cases presenting hypernatremic dehydration. Dehydration promotes vasoconstriction. Intravascular space contraction causes tissue hypoxia. The aerobic ATP production in mitochondria diminishes, the glycolytic ATP production is enhanced and its consumption yields high hydrogen and lactate concentration, causing acidemia. The production of activated oxygen species (AOS) increases in systemic arteries and diminishes in pulmonary arterioles. Acidemia and AOS open K_ATP in systemic arteries. Potassium extrusion causes hyperpotassemia, hyperpolarization of miocytes and vasodilatation. In pulmonary arterioles acidemia and diminishing in AOS release cause closure of Kv, membrane depolarization and pulmonary vasoconstriction. Acidemia causes opening of Cl-C2 chloride channels and outward rectification. Imbalance in calcium, phosphate and magnesium is minimum. Oral or intravenous rehydration with balanced polyelectrolytic rehydration solution rehydrates successfully the diarrheic dehydrated patients presenting electrolyte and acid-base imbalance.

Palavras-chave : Dehydration; diarrhea disease; hydro-electrolyte imbalance; acidosis; acidemia; ionic channels; rehydration.

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