Medications homeostatic mechanisms

Electrolytes are involved in many metabolic and homeostatic functions, including enzymatic and biochemical reactions, maintenance of cell membrane structure and function, neurotransmission, hormone function, muscle contraction, cardiovascular function, bone composition, and fluid homeostasis. The causes of electrolyte abnormalities in patients receiving PN may be multifactorial, including altered absorption and distribution excessive or inadequate intake altered hormonal, neurologic, and homeostatic mechanisms altered excretion via gastrointestinal and renal losses changes in fluid status and fluid shifts and medications. 

The most extreme manifestation of untreated hypothyroidism is myxedema coma, which even if detected early and appropriately treated, carries a mortality rate of 30 to 60%. Myxedema coma is a misnomer. Most patients exhibit neither the myxedema nor coma. Patients with myxedema coma usually have longstanding hypothyroidism with the classic symptoms of hypothyroidism. Decompensation into myxedema coma may occur when the homeostatic mechanisms of the severely hypothyroid patient are subject to a stressful precipitating event (e.g., infection, trauma, some medications, stroke, surgery). The principal manifestation of myxedema coma is a deterioration of mental status (apathy, confusion, psychosis, but rarely coma). Other common clinical features include hypothermia, diastolic hypertension (early), hypotension (late), hypoventilation, hypoglycemia, and hyponatremia. If myxedema coma is suspected, the patient is usually admitted to an intensive care unit for pulmonary and cardiovascular support... 

Homeostatic mechanisms are very important for the prevention of accumulation of excess Fe that is believed to generate oxidative stress by catalysis of variety of chemical reactions involving free radicals, which could result in cell damage (Pietrangelo, 2002 Puntarulo, 2005). Excess Fe accumulation may promote cancer and increase the cardiovascular risk (Martmez-Navarrete et ah, 2002). Iron overload can be observed in some cases including an excessive dietary iron intake, inherited diseases, for example, idiopathic hemochromatosis, congenital atransferrinemia, or the medical treatment of thalassemia (Fontecave and Pierre, 1993). 

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